Large salt accumulations as a consequence of hydrothermal processes associated with ‘Wilson cycles’: A review, Part 2: Application of a new salt-forming model on selected cases

Abstract

The new hydrothermal salt model predicts that salt may accumulate in the sub-surface by hydrothermal circulation of seawater and brines in locations of high heat-flow. Such conditions are primarily found along tectonic plate boundaries, with processes of subduction and rifting, associated with the Wilson cycles.
Modern knowledge of the physicochemical and thermodynamic properties of salt solutions at elevated pressures and temperatures, allows numerical modeling of fluid behavior at relevant conditions in the deep crust. This modeling shows how seawater that migrates down towards hot magma bodies in a rift situation (e.g. in the Red Sea) is subject to phase transitions, where low-saline (distilled) water vapor migrates out of the system, while still saltier brine continues to migrate further down towards the heat source, until solid salt precipitates. Similarly, in a subduction situation, the seawater confined in the subducting oceanic plate is subjected to an ever increasing pressure and temperature during the descent towards the mantle, which leads to similar phase behavior of the brine as in the rifting situation. The salts forming in the deep of a subduction zone are not readily transported up to the surface due to thick overburden of mantle- and crustal rocks. Hence, much of the salt formed during subduction remains hidden from human observation in the roots of the mountains.
The formation of solid salt is therefore an inevitable process associated with the Wilson cycles, even without solar evaporation. Recent observations of thick carpets of mobile salt slurries on the Red Sea floor (Salt Flows) and huge accumulations of salts in the subsea/subsurface (Salt Walls and Salt Ridges), associated with topographic lows (Deeps), suggest that the Red Sea currently produces new volumes of brines and solid salts underground. The different solubilities of sea salts lead to a refining of the salt types. When reaching the seafloor, the warm brines are cooled down in brine pools, eventually becoming oversaturated with salts, which results in precipitation onto the seafloor. The dense brine layers protect seafloor salts from re-dissolution by normal seawater.
Magmatic and volcanic processes associated with hydrothermal activity, e.g. connected to the subduction under the Andes Mountains are associated with enormous deposits of salts. The brines are transported hydrothermally up from the subduction zone and are venting out at 3500–4000 m above sea level. At the surface, the brines evaporate in the dry climate, which is also protecting the salt from re-dissolution. The brine feeding the hydrothermal systems above the subduction zone originates from dewatering of the subducting slabs. This water is causing fractional melting of the mantle wedge above, initiating volcanism. The hydrothermal water is also transporting salts to the surface, thus, explaining the close relationship between some types of volcanism and salt accumulations.
It is assumed that this new understanding of hydrothermal salt formation will have a profound impact on interpretation of geological phenomena involving salt and salt formation, including the early development and behavior of salt basins.

Full text

UNCORRECTED PROOF
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UNCORRECTED PROOF
M. Hovland et al. Marine and Petroleum Geology xxx (2018) xxx-xxx
1. Introduction
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KI8EJGFIK LJL8CCP ?P;IFK?<ID8C GIF:<JJ<J KF 9I@E> K?< J8CKJ KF JFD< F9
J<IM89C< GFJ@K@FE 8J N<CC 8J ;<<G =8LCKJ K?8K 8I< FG<E <EFL>? KF =8:@C@
K8K< K?@J KI8EJGFIK
2.1. Oceanic - continental subduction and salts, the Andean subduction
zone
.?< <EKI8C E;<8E 'FLEK8@EJ 8I< BEFNE =FI <EFIDFLJ J8CK ;<
GFJ@KJ .?< J8CKJ 8I< D8@ECP :?CFI@;<J 8E; JLC=8K<J 9LK K?< ?@>? :FEK<EKJ
F= 9FIFE 8E; C@K?@LD D8B< K?<J< J8CK ;<GFJ@KJ <M<E DFI< @EK<I<JK@E>
"FN N<I< K?< J8CKJ 9IFL>?K LG K?<I< 8E; N?8K GIF:<JJ<J :8LJ< K?< <E
I@:?D<EK F= 9FIFE 8E; C@K?@LD
.?< ?@>? E;<J @E K?< 1<JK<IE FI;@CC<I8 F= EFIK?<IE ?@C< 8E; F
C@M@8 8I< :?8I8:K<I@Q<; 9P 8E 8II8P F= JKI8KFMFC:8EF<J N@K? K?<@I JLD
D@KJ JKI<K:?@E> LG KF 8IFLE; D 89FM< J<8 C<M<C ::FI;@E> KF &8D9
 “.?< E;<J 'FLEK8@EJ 8I< 9L@CK 9P KNF ;@JK@E:K GIF:<JJ<J @E
K?< <8JK 9<E<8K? K?< 8JK<IE FI;@CC<I8 K?< :ILJK ?8J 9<<E ;FD@E8EKCP
K?@:B<E<; 9P JHL<<Q@E> D8B@E> K?< DFLEK8@EJ 8E; K?<@I IFFKJ #E K?<
N<JK 9<E<8K? K?< 1<JK<IE FI;@CC<I8 9FK? K?< JHL<<Q@E> F= FC; :ILJK
8E; K?< 8;;@K@FE F= DFCK<E IF:B =IFD K?< D8EKC< ?8J 9<<E 8 J@>E@=@:8EK
:8LJ< KF K?@J K?@:B<E@E>”K K?< JL9;L:K@FE KI<E:? K?< J<;@D<EKJ 8I<
><E<I8CCP J:I8G<; FV 8E; G@C<; LG KF =FID 8E 8::I<K@FE8IP N<;><
0FC:8E@JD @J 8 :FDDFE =<8KLI< 89FM< JL9;L:K@FE QFE<J 8K GC8K< K<:
KFE@: 9FLE;8I@<J N?<I< F:<8E@: :ILJK @J ;<J:<E;@E> LE;<I :FEK@E<EK8C
:ILJK -KI8KFMFC:8EF<J 8I< :?8I8:K<I@Q<; 9P JK<<G GIFTC<J 8E; G<I@F;@:
<OGCFJ@M< <ILGK@FEJ ;L< KF ?@>? M@J:FJ@KP C8M8J F= 8E;<J@K@: :FDGFJ@
K@FE .?< ?@>? M@J:FJ@KP @J :8LJ<; 9P I<C8K@M<CP ?@>? J@C@:8 :FEK<EKJ ∼
N<@>?KG<I:<EK -@)X @E K?< C8M8 .?< MFC:8E@JD @J @E@K@8K<; 9P K?< I<
C<8J< F= N8K<I =IFD K?< JL9;L:K@E> GC8K< N?@:? CFN<IJ K?< D<CK@E> GF@EK
F= K?< FM<ICP@E> D8EKC< IF:B  G8IK@8C D<CK@E> F::LIJ N?@:? GIF;L:<J
D8>D8 K?8K I@J<J ;L< KF CFN<I ;<EJ@KP K?8E K?< JLIIFLE;@E> IF:BJ  @>
 @E "FMC8E; <K 8C 
.?LJ K?< N8K<I @E K?< JL9;L:K@E> JC89 @J M<IP @DGFIK8EK =FI K?< =LI
K?<I GIF:<JJ<J .?@J N8K<I @J @E K?< =FID F= =I<< N8K<I 9I@E< :IPJK8C
N8K<I 8E; ?P;IFOPC >IFLGJ 8JJF:@8K<; N@K? D@E<I8CJ C@B< :C8PJ 8E; J<I
G<EK@E@K<J 1?<E K?@J D8>D8 I@J<J K?IFL>? K?< :ILJK DFI< J@C@:8 I@:?
IF:BJ 8I< D@O@E> @EKF K?< D8>D8 GIF;L:@E> K?< 8E;<J@K@: :FDGFJ@K@FE
K?8K :?8I8:K<I@Q<J K?@J MFC:8E@: I<>@FE 1?<E K?< D8>D8 I<8:?<J K?<
JLI=8:< K?< CFN<I<; GI<JJLI< 8CCFNJ K?< MFC8K@C<J :FETE<; @E K?< C8M8 KF
<J:8G< @E 8 I8G@; JFD<K@D<J <OGCFJ@M< D8EE<I .?< D8@E MFC8K@C<J 8I<
N8K<I M8GFI 8E; )X 9LK FK?<I >8J<J 8I< 8CJF :FDDFE C@B< -)X "X-
CX (X "< I 8E; ,E .?< <OGCFJ@M< <ILGK@FEJ :I<8K< 8 C8E;J:8G< ;FD
@E8K<; 9P ?8I;<E<; C8M8 8E; MFC:8E@: 8J? KLV &8D9 
@>  @CCLJKI8K<J K?< <==<:KJ F= JL9;L:K@E> JC89 ;@G>I8;@<EK N@K?
F::LII<E:< F= 8:K@M< MFC:8EF<J 1?<I< K?< ;FNE>F@E> JC89 @J ;@GG@E>
JK<<GCP <> ∼° K?<I< 8I< 8:K@M< MFC:8EF<J 8E; 9CF:B =8LCK LGC@=K
8::FI;@E> KF !LKJ:?<I <K 8C   #E 8;;@K@FE N< TE; K?8K
K?< @E:I<8J<; ?<8KUFN 8E; F::LII<E:< F= M<IK@:8C =I8:KLI@E> 8E; =8LCK
@E> C<8;J KF JLI=8:< J8CK ;<GFJ@K@FE DFJK ;I8D8K@:8CCP @CCLJKI8K<; 9P K?<
GI<J<E:< F= -8C8I ;< /PLE@ K?< C8I><JK J8CK C8B< FE 8IK? J<<E 8J K?<
N?@K< G8K:? -;/ FE K?< C<=K D8G F= @> 
8J<; FE :FE;L:K@M@KP D<8JLI<D<EKJ &8LDFE@<I <K 8C  <JK@
D8K<; K?< MFCLD< F= 9I@E<J @E K?< IF:BJ 9<E<8K? FE< F= K?< E;<8E
JKI8KFMFC:8EF<J K?< /KLILE:L MFC:8EF FE K?< FC@M@8E CK@GC8EF .?<
GFIFJ@KP N8J <JK@D8K<; KF 8GGIFO@D8K<CP – F= K?< KFK8C IF:B MFC
LD< 8DFLEK@E> KF 8 9I@E< MFCLD< F=  D@CC@FE :L9@: BD 9<E<8K? K?@J
MFC:8EF 8CFE< .?< MFC:8EF @J CF:8K<; JFLK? F= &8B< /PLE@  @> 


UNCORRECTED PROOF
M. Hovland et al. Marine and Petroleum Geology xxx (2018) xxx-xxx
Fig. 1. Left )VJ?FI< 8E; FEJ?FI< JLI=8:< KFGF>I8G?P F= G8IKJ F= K?< E;<J JL9;L:K@FE QFE< .?< KNF 9IFB<E C@E<J ;<C@D@K8K< K?< I<>@FE F= K?< CK@GC8EF N?<I< K?< JL9;L:K@FE JC89 J@EBJ
8K 8E 8E>C< F= °FI DFI< .F K?< JFLK? 8E; EFIK? F= K?<J< C@E<J K?< JL9;L:K@FE JC89 @J D<I<CP ‘U8K’ N@K? 8E 8E>C< F= C<JJ K?8E ° -;/  -8C8I ;< /PLE@ &.  &8B< .@K@:8:8 $ , $L8E
<IE8E;<Q ,@;>< (,  (8Q:8 ,@;>< '8G GIF;L:<; N@K? !<F'8G8GG 8E; !FF>C< 8IK? Right -@DGC@T<; D8G F= -FLK? D<I@:8 @CCLJKI8K@E> K?< F::LII<E:< F= ?@JKFI@:8CCP 8:K@M< MFC
:8EF<J TCC<; 8E; FG<E I<; KI@8E>C<J (FK< K?< KNF 8I<8J F= ‘U8K JL9;L:K@FE’ - N@K?FLK ?@JKFI@:8CCP 8:K@M< MFC:8E@JD ‘' 4’8E; ‘( 4’8I< K?< '<E;8ñ8 8E; K?< (8Q:8 8LCK 4FE<J
I<JG<:K@M<CP D<EK@FE<; @E K?< K<OK 8E; @E FK?<I T>LI<J .?< >I<<E I<:K8E>C< J?FNJ K?< FLKC@E< F= K?< C<=K @D8>< '8G 98J<; FE -@DB@E 8E; -@<9<C  -<< K<OK =FI =LIK?<I ;@J:LJJ@FE
 FI @EK<IGI<K8K@FE F= K?< I<=<I<E:<J KF :FCFI @E K?@J T>LI< C<><E; K?< I<8;<I @J I<=<II<; KF K?< 1<9 M<IJ@FE F= K?@J 8IK@:C<
::FI;@E> KF %8N8DFKF <K 8C  K?< N8K<I @E K?< C8M8 @J :?8I
8:K<I@Q<; 9P ?8M@E> ?@>? J8C@E@KP @E K?< FI;<I F=  N<@>?KG<I:<EK .?<P
8CJF GF@EK FLK K?8K J8C@E< UL@;J ?8M< K?< :8G8:@KP F= C<8:?@E> DFI< D<K
8CJ =IFD K?< ?FJK IF:B K?8E GLI< N8K<I N?@:? ?8J 8E @DG8:K FE K?<
:?<D@JKIP F= 9FK? 9I@E<J 8E; IF:BJ %8N8DFKF <K 8C 
J K?< JL9;L:K@E> 9I@E<J8KLI8K<; F:<8E@: JC89 DFM<J ;FNEN8I;J
K?< GI<JJLI< 8E; K<DG<I8KLI< @E:I<8J<J :FEK@ELFLJCP 8E; K?< K<:KFE@:
8E; UL@; GI<JJLI<J @E;L:< =8LCK@E> 8E; =I8:KLI@E> F= K?< FM<I9LI;<E
K?LJ 8CCFN@E> KI8EJ=<I F= UL@;J 9I@E<J =IFD K?< F:<8E@: JC89 KF K?<
C@K?FJG?<I< LGG<I D8EKC< 4<CCD<I <K 8C  @>  @E "FMC8E; <K
8C  K 89FLK BD ;<GK? K?< K<DG<I8KLI< F= K?< LGG<I G8IK F=
K?< JC89 ?8J @E:I<8J<; KF DFI< K?8E ° K?< K<DG<I8KLI< N?<I< J<8
N8K<I 9<:FD<J JLG<I:I@K@:8C 8E; G?8J< :?8E><J K8B< GC8:< N@K? K?< =FI
D8K@FE F= JLG<I:I@K@:8C N8K<I M8GFI ;<EJ@KP ∼ >:DXW GI<:@G@K8K@FE
F= JFC@; J8CK 8E; ?@>?<I ;<EJ@KP 9I@E<J .?< CFN ;<EJ@KP N8K<I M8GFI 8E;
C@HL@; N8K<I N@CC D@>I8K< LGN8I;J KF><K?<I N@K? DFCK<E IF:BJ 8E; @E@K@
8K< ?P;IFK?<ID8C GIF:<JJ<J 8E; MFC:8E@JD -L:? M<IK@:8C KI8EJGFIK JPJ
K<DJ =FI ?P;IFK?<ID8C UL@;J ?8M< 9<<E ;F:LD<EK<; 9P D<J?<J F= :<
D<EK<; M<@EJ @E <IF;<; QFE<J F= K?< E;<J ,FHL<K <K 8C  LI
K?<I ;FNE 8K <M<E ?@>?<I K<DG<I8KLI<J 8E; GI<JJLI<J K?< J8CK @E K?<
9I@E< :FETE<; @E K?< JC89 N@CC GI<:@G@K8K< 8J JFC@; J8CK 8E; =FCCFN K?<
JL9;L:K@E> JC89 ;<<G<I ;FNE @EKF K?< D8EKC< *8IK@:LC8K< JFC@; J8CK D8P
8CJF D@O @EKF K?< D8>D8 89FM< K?< F:<8E@: JC89 KF 9<:FD< G8IK F= K?<
MFC:8E@: IF:BJ
2.1.1. Flat subduction beneath parts of the Andes
 :CL< KF LE;<IJK8E;@E> K?< F::LII<E:<J F= ?P;IFK?<ID8C J8CKJ @E
K?< E;<8E 'FLEK8@EJ @J K?< :FE:<GK F= U8K 8E; JK<<G JL9;L:K@FE #E
K?< I<>@FEJ F= JK<<G JL9;L:K@FE K?< F:<8E@: JC89 ;<J:<E;J KFN8I;J K?<
D8EKC< 8K 8E 8E>C< F= ∼° N?@C< K?< F:<8E@: JC89J K?8K LE;<I>F U8K
JL9;L:K@FE ;<J:<E; KF 8 ;<GK? F= 8IFLE;  BD 9<=FI< K?<P =FCCFN 8
JL9?FI@QFEK8C G8K? !LKJ:?<I <K 8C  #E K?@J C8KK<I J@KL8K@FE K?<
JPJK<D @J :FFC<; 8E; EF IF:B D<CK@E> K8B<J GC8:< @E K?< LGG<I :FEK8:K
QFE< 9<KN<<E K?< JC89 8E; K?< :FEK@E<EK8C C@K?FJG?<I< ?<E:< EF @E@K@8
K@FE F= MFC:8E@JD .?@J <==<:K KF><K?<I N@K? K?< JKI<E>K?<E@E> F= K?< LG
G<I C@K?FJG?<I< @J 8CJF @DG<;@E> K?< ;<M<CFGD<EK F= ?P;IFK?<ID8C :@I:L
C8K@FE F= 9I@E<J FEJ<HL<EKCP EF J@>E@=@:8EK MFCLD<J F= J8CK =FID8K@FE
8I< F9J<IM<; @E K?< 8I<8J F= U8K JL9;L:K@FE
#E @>  K?< =I<J?N8K<I &8B< .@K@:8:8 @J J<<E EFIK? F= -8C8I ;<
/PLE@ @E K?< 8I<8 :?8I8:K<I@Q<; 9P U8K JL9;L:K@FE <IIF:8C 8E;
<IE8E;<Q  (F MFC:8E@JD 8E; DL:? C<JJ ?P;IFK?<ID8C 8:K@M@KP
@J J<<E N@K?@E K?< GI<:@G@K8K@FE:8K:?D<EK 8I<8 F= &8B< .@K@:8:8 :
:FI;@E> KF <IIF:8C 8E; <IE8E;<Q  U8K JL9;L:K@FE F= K?< *8:@T:
(8Q:8 GC8K< F::LIJ 9<KN<<E °- 8E; °- 8CFE> K?< EFIK?<IE 8E; :<E
KI8C I<>@FEJ F= *<IL FM<I 8 I<>@FE D<8JLI@E>  × BDX .?@J 8I<8
@J 8JJF:@8K<; N@K? CFN C<M<CJ F= J<@JD@: 8:K@M@KP 8K ;<GK?J 9<KN<<E 
8E; BD
@>  #CCLJKI8K<J ?FN K?< JL9;L:K@E> JC89 8CK<IJ @KJ ;@G 8::FI;@E>
KF 9LFP8E:P 8E; FK?<I G8I8D<K<IJ 8::FI;@E> KF !LKJ:?<I <K 8C 
.?< G<IJG<:K@M< JB<K:? @CCLJKI8K<J K?< ><FD<KIP F= K?< (8Q:8 *C8K<
8E; K?< KNF 9LFP8EK I@;><J <8:? ?FC;@E> LG 8  BD CFE> J<:K@FE F= K?<
JL9;L:K@E> (8Q:8 *C8K< N@K? 8 J8> @E 9<KN<<E <:8LJ< K?<I< @J 8 JK<<GCP
;@GG@E> JC89 E<OK KF K?< (8Q:8 8LCK 4FE< K?<I< @J 8CJF <OKI8 ?<8K 8E;
UL@;J UFN@E> KF K?< JLI=8:< :8LJ@E> J8CK ;<GFJ@KJ FE K?< :LII<EK <8IK?
JLI=8:< 89FM< K?@J CF:8K@FE
.?< U8K JL9;L:K@FE KI8EJ@K@FEJ @EKF JK<<G JL9;L:K@FE FE K?< <8JK<IE
J@;< F= K?< E;<J !LKJ:?<I <K 8C  .?8K @J N?P N< TE; MFC:8EF<J
?FK JGI@E>J 8E; J8C8IJ @E (FIK?<IE I><EK@E8 <JG<:@8CCP @E K?< I<>@FE
9<KN<<E -8EK@8>F ;<C JK<IF 8E; 8K8D8I:8 @E K?< EFIK? 8E; FI;F98
@E K?< JFLK?
-@D@C8ICP U8K JL9;L:K@FE F= K?< (8Q:8 GC8K< 8CJF F::LIJ =LIK?<I
JFLK? 9<E<8K? :<EKI8CEFIK?<IE ?@C< 9<KN<<E °- 8E; °- FM<I
8 I<>@FE D<8JLI@E> ∼BD× BDX N?@:? @J 8CJF 8JJF:@8K<; N@K?
CFN J<@JD@: 8:K@M@KP #E K?@J 8I<8 K?<I< @J FECP D@EFI MFC:8E@: 8:K@M@KP


UNCORRECTED PROOF
M. Hovland et al. Marine and Petroleum Geology xxx (2018) xxx-xxx
Fig. 2. #CCLJKI8K@FE F= JK<<G 8E; U8K JL9;L:K@FE @E K?< E;<J DF;@T<; =IFD !LKJ:?<I <K 8C  .?< G<IJG<:K@M< JB<K:? @CCLJKI8K<J K?< GIFGFJ<; DF;<C M@<N CFFB@E> N<JK N@K? K?<
(8Q:8 *C8K< 8E; K?< KNF 9LFP8EK I@;><J <8:? ?FC;@E> LG 8  BD CFE> J<:K@FE F= K?< JL9;L:K@E> (8Q:8 *C8K< N@K? 8 J8> @E 9<KN<<E
<IIF:8C 8E; <IE8E;<Q  .?< I<>@FE 9<KN<<E K?<J< KNF QFE<J
F= U8K JL9;L:K@FE @J N?<I< K?< CK@GC8EF * I<>@FE @J CF:8K<; N?@:?
8CJF @E:CL;<J -8C8I ;< /PLE@ ::FI;@E> KF @I;  K?<I< 8I< J<M<I8C
‘:FDG<CC@E> I<8JFEJ’KF ;<J@>E8K< K?< I<>@FEJ EFIK? 8E; JFLK? F= K?< C
K@GC8EF 8J FIF><EJ N@K? U8K JL9;L:K@FE )E< F= K?<J< I<8JFEJ @J K?8K
“#= K?<J< U8EB@E> I<>@FEJ N<I< I@>@; G8IKJ F= - -FLK? D<I@:8 K?<E
K?<I< NFLC; E<:<JJ8I@CP 9< KI8EJ=FID FI KI8EJK<EJ@FE8C 9FLE;8I@<J 9<
KN<<E * 8E; - KF 9FK? K?< EFIK?N<JK 8E; JFLK? F= * 9LK EF J@>E F=
JL:? 9FLE;8I@<J @J J<<E @E K?< J<@JD@:@KP FI ><FCF>P”@I; 
@>  @CCLJKI8K<J ?FN U8K JL9;L:K@FE JFLK? F= °- KI8EJC8K<J @EKF
JK<<G JL9;L:K@FE 8IFLE; BD @EC8E; 8::FI;@E> KF !LKJ:?<I <K 8C
 .?< KI8EJ=FID8K@FE KF 8 JK<<GCP ;@GG@E> JC89 ?8J :FEJ<HL<E:<J
=FI  K?< ?<8KUFN 8E; 9<:8LJ< F= 8JJF:@8K<; CF:8C 9CF:B=8LCK LGC@=K
 8M8@C89C< M<IK@:8C :FE;L@KJ 8CFE> =8LCKJ =FI UL@;J KF D@>I8K< LG KF
JLI=8:< ::FI;@E> KF !LKJ:?<I <K 8C  “.?< K?<ID8C <==<:K @J 9<JK
@CCLJKI8K<; 9P ?<8K UFN F9J<IM8K@FEJ =IFD *<IL 8E; FC@M@8 "@>? ?<8K
UFN F= –D1DX @J GI<J<EK 89FM< K?< JK<<G JC89 @E FC@M@8 FN
@E> KF K?< LE;<ICP@E> 8JK?<EFJG?<I< N?<I<8J 89FM< K?< *<IL U8K JC89
N?<I< K?< 8JK?<EFJG?<I< @J 89J<EK CFN ‘=FI<8I:’M8CL<J F= – D1
DX 8I< F9J<IM<; LG KF BD =IFD K?< KI<E:?”
#E @>  @K :8E 9< J<<E K?8K K?< J8CK G8EJ 8I< CF:8K<; N?<I< K?< U8K
JL9;L:K@FE KI8EJC8K<J @EKF JK<<G JL9;L:K@FE 8::FI;@E> KF K?< DF;<C F=
!LKJ:?<I <K 8C  .F K?< N<JK F= K?@J CF:8K@FE K?<I< 8I< EF 8:K@M<
MFC:8EF<J 8E; EF J8C8IJ FI J8C@E8J F= J@>E@=@:8E:< )E< GFJJ@9@C@KP @J
K?< I8@E J?8;FN <==<:K I<C8K<; KF K?< ?@>? 8CK@KL;< F= K?< E;<8E 'FLE
K8@EJ N?@:? :FEJK@KLK<J 8 98II@<I =FI ?LD@;@KP C8E;N8I;J F= K?< DFLE
K8@E :?8@E :FE:<EKI8K@E> K?< ?LD@;@KP F:<8EN8I;J F= K?< ?@>? 8CK@KL;<J
CK<IE8K@M<CP K?<I< @J 8 GFJJ@9@C@KP K?8K MFC:8E@:I<C8K<; 9I@E<J @E K?<
JL9JLI=8:< F::LI FECP N?<I< =8LCKJ :FDDLE@:8K< :FE:<EKI8K<; 9I@E<J KF
K?< JLI=8:< N?<I< K?< N8K<I @J <M8GFI8K<; 8E; J8CKJ 8I< GI<:@G@K8K<;
LIK?<IDFI< @E 8>I<<D<EK N@K? !LKJ:?<IJ ;@8>I8D  @>  K?<I<
@J <M@;<E:< F= JLI=8:< ;@JILGK@FE N?<I< K?< J8C@E8J F::LI .?<P JL>><JK
K?8K K?< F9J<IM<; JLI=8:< ;@JILGK@FE N?<I< K?< JC89 @J ;@GG@E> JK<<GCP @J
:8LJ<; 9P ‘KI8EJ:LII<EK =8LCK@E> 8E; 9CF:B =8LCK LGC@=K@E>’!LKJ:?<I <K
8C 
.F K?< <8JK F= K?< J8C@E8J @J 8 C8I>< =I<J? N8K<I C8B< EFK 8==<:K<; 9P
K?< ?P;IFK?<ID8C GIF:<JJ<J .?@J @E;@:8K<J K?8K UL@;J :8LJ@E> K?< J8C@E8J
8I< <D@KK@E> 8K K?< JLI=8:< FECP N?<I< K?< JC89 @J JK<<GCP ;@GG@E> J<<
8CJF GI<M@FLJ T>LI< -@D@C8ICP =LIK?<I EFIK? .F K?< <8JK F= &8B< .@K@
:8:8  @>  N?<I< K?< JC89 @J JK<<GCP ;@GG@E> J<M<I8C G<:LC@8ICP CFFB
@E> 8CB8C@E< C8B<J F::LI .?<P 8I< CF:8K<; 8K K?< I@>?K ;@JK8E:< =IFD
K?< KI<E:? .?@J I<>@FE ?FN<M<I ;F<J EFK ?8M< K?< 8I@; :FE;@K@FEJ F=
K?< 8I<8 J?FNE @E @>  8E; K?<I<=FI< 8EP ?P;IFK?<ID8C J8CKJ 8;;<;
KF K?< JLI=8:< NFLC; C@B<CP 9< ;@CLK<; 9P D<K<FI@: N8K<I @E K?< C8B<J
2.1.1.1. Mantle processes evidenced by helium anomalies .?< ?<C@LD
C<8B8>< =IFD K?< JL9JLI=8:< :8E 9< LJ<; 8J 8 KFFC KF =FCCFN D8EKC<8J
JF:@8K<; GIF:<JJ<J @E K?< ;<<G .?< I8K@F F= X"< KF X"< @J 8IFLE; 
D@CC@FE @E K?< 8IK?J :ILJK  D@CC@FE @E K?< 8KDFJG?<I< 8E;  D@C
C@FE @E K?< D8EKC< &8D9  ;<J:I@9<J 8E <8JKN<JK GIFTC< 8:IFJJ
K?< E;<J JK8IK@E> FLK N@K? M<IP CFN GIFGFIK@FEJ F= X"< 8K K?< *8:@T:
:F8JK @E;@:8K@E> K?8K K?< :ILJK @J K?< JFLI:< F= K?< ?<C@LD 1?<E 8G
Fig. 3. #CCLJKI8K@FE F= K?< KI8EJ@K@FE =IFD U8K JL9;L:K@FE KF JK<<G JL9;L:K@FE CF:8K<; 89FLK –BD =IFD K?< JL9;L:K@FE KI<E:? DF;@T<; =IFD @>  @E !LKJ:?<I <K 8C  .?@J
JC89 :FET>LI8K@FE F::LIJ KF K?< EFIK? <8JK F= -@<II8J *8DG<8E8J 8IFLE; °–°- @E K?< E;<J (FK< K?< JLI=8:< ;@JILGK@FE 8E; ;<<GJ<8K<; =8LCKJ 89FM< K?< JK<<G<E@E> JC89


UNCORRECTED PROOF
M. Hovland et al. Marine and Petroleum Geology xxx (2018) xxx-xxx
Fig. 4. -8K<CC@K< @D8>< =IFD K?< 8I<8 F= -FLK? D<I@:8 @CCLJKI8K<; @E @>  89FM< <KN<<E  BD 8E;  BD =IFD K?< JL9;L:K@FE KI<E:? 8E; 9<KN<<E °8E; °- J<M<I8C J8CKG8EJ
8I< M@J@9C< -&-8C@E8 &8 EK@>L8 -!-8C@E8J !I8E;<J óI;F98 -;' -8C@E8J ;< '8:8J@E 8E; *;C- *8DG8 ;< C8J -8C@E8J <:8LJ< K?<I< 8I< EF J@>E@=@:8EK J8C@E8J KF K?< N<JK F=
-& @E K?< EFIK? 8E; -;' @E K?< JFLK? @K @J C@B<CP K?8K K?< JK<<GCP ;@GG@E> GFIK@FE F= K?< JC89 @J JK@DLC8K@E> K?< =FID8K@FE F= K?<J< J8C@E8J 8J ;@J:LJJ<; @E K?< K<OK #D8>< GIF;L:<; N@K?
!FF>C<8IK?
GIF8:?@E> K?< MFC:8EF<J F= K?< 1<JK<IE FI;@CC<I8 K?< ?<C@LD >8J 9<
:FD<J I@:?<I @E X"< @E;@:8K@E> D8EKC< JFLI:<; >8J FM<I  F= K?< ?<
C@LD GIF;L:<; 9P K?< MFC:8EF<J 8E; ?FK JGI@E>J 8JJF:@8K<; N@K? K?< MFC
:8EF<J @J K?LJ :FD@E> =IFD K?< D8EKC< &8D9 
LIK?<IDFI< 8 J@>E@=@:8EK 8DFLEK F= K?< ?<C@LD >8J <D@KK@E> =IFD
?FK JGI@E>J @E K?< CK@GC8EF 8E; N<JK<IE D8I>@E F= K?< 8JK<IE
FI;@CC<I8 LG KF BD <8JK F= K?< >I<8K :?8@E F= MFC:8EF<J N8J 8CJF
JFLI:<; =IFD D8EKC< IF:BJ &8D9  .?@J @E;@:8K<J D8EKC<N8K<I
@EK<I8:K@FEJ @E 8 M8JK I<>@FE LE;<I K?< E;<J 'FLEK8@EJ 8J 8 I<JLCK
F= ;<N8K<I@E> F= K?< JL9;L:K@FE JC89J 8J @CCLJKI8K<; 9P 4<CCD<I <K 8C
  @>  @E "FMC8E; <K 8C  .?< N8K<ID8EKC< @EK<I8:K@FE
;I@M<J K?< ?P;IFK?<ID8C GIF:<JJ<J K?8K D8E@=<JK K?<DJ<CM<J FE K?< JLI
=8:< N@K? MFC:8E@JD 8E; K?< M<EK@E> F= JK<8D 8E; ?FK JGI@E>J @JJL@E>
9I@E<J @EKF K?< J8CK C8B<J
2.1.2. Accumulation and re>ning of salts
IFD K?< 89FM< <M@;<E:< 8E; I<8JFE@E> @K @J :FE:CL;<; K?8K K?< ?P
;IFK?<ID8C <G@K?<ID8C 9I@E<J @JJL@E> =IFD K?< 8IK<J@8E JGI@E>J 8I< K?<
JFLI:<J F= K?< ?L>< D8JJ<J F= J8CKJ ;<GFJ@K<; @E K?< E;<J 'FLEK8@EJ
*@I8AEF  4<CCD<I <K 8C  .?< ;I@M@E> =FI:<J 8I< ;<<GCP ><E
<I8K<; FM<IGI<JJLI<; UL@;J 8JJF:@8K<; N@K? ;<N8K<I@E> F= K?< JL9;L:K
@E> F:<8E@: :ILJK 8E; K?< I<JLCK@E> MFC:8E@: 8:K@M@KP @E K?< 8I<8
.?< <O:<JJ F= JF;@LD 8E; :?CFI@;< J<<E @E .89C<  =FI J@O F= K?< D8
AFI J8CK 8::LDLC8K@FEJ @E K?< <EKI8C E;<J :C<8ICP GF@EKJ 8K 8 D8I@E<
FI@>@E F= K?< J8CK ;<GFJ@KJ .?< DFJK I<8JFE89C< <OGC8E8K@FE =FI K?< ;<
GFJ@K@FE F= K?<J< J8CKJ 8K DFI< K?8E  D 8CK@KL;< @J ?P;IFK?<ID8C
KI8EJGFIK8K@FE =IFD K?< JL9;L:K@FE QFE< 8JJF:@8K<; N@K? MFC:8E@JD
.?< TE8C G?8J< F= :FE:<EKI8K@E> K?< 9I@E<J @EKF JFC@; J8CKJ @J ;L< KF ;IP
@E> FLK @E 8 GI<M8@C@E> ;IP :C@D8K< .?@J ;IP :C@D8K< @J 8CJF GIFK<:K@E>
K?< J8CK =IFD 9<@E> N8J?<; FLK .89C<  J?FNJ K?8K GFK8JJ@LD 8E; D8>
E<J@LD M8CL<J 8I< 8CJF DL:? KFF ?@>? :FDG8I<; KF J<8N8K<I 8E; JF @J
JLCG?8K< .?<J< ?@>? M8CL<J KF><K?<I N@K? ?@>? :FEK<EKJ F= 9FIFE 8E;
C@K?@LD 8I< K<CC@E> 8 JKFIP 89FLK J8CK I<TE@E> 8E; N8K<IIF:B @EK<I8:
K@FEJ JK8IK@E> N@K? J<8N8K<I 9IFL>?K ;FNE @E K?< JL9;L:K@FE QFE<
8I<=LC <O8D@E8K@FE F= K?< JLI=8:< F= -8C8I ;< /PLE@ 8:KL8CCP J?FNJ
K?8K K?<I< 8I< K?FLJ8E;J F= J<<G8>< =<8KLI<J FE K?< J8CK G8E JLI=8:<
J<<E 8J :FE:<EKI@: JKIL:KLI<J <8:? I<GI<J<EK@E> GF@EKJFLI:<J F= 8IK<
J@8E 9I@E< UFN  @>  $L;; 8E; "FMC8E;  .?<J< =<8KLI<J @E;@
:8K< K?8K K?< J8CK C8B< @J 9<@E> =<; 9P 8IK<J@8E 9I@E<J =IFD 9<CFN N?@:?
<M<EKL8CCP ;IP FLK 9P <M8GFI8K@FE @E K?< 8I@; :C@D8K< C<8M@E> K?<@I J8CK
:FEK<EKJ FE K?< 9FKKFD F= K?< C8B<
1?<E K?< 8IK<J@8E 9I@E<J :FEK8@E DFI< K?8E FE< KPG< F= J8CK N@K? ;@=
=<I<EK JFCL9@C@K@<J 8K K?< GI<M8@C@E> K<DG<I8KLI<J F= K?< C8B< K?< C<JJ
JFCL9C< J8CK N@CC GI<:@G@K8K< TIJK N?@C< K?< DFJK JFCL9C< J8CK N@CC GI<:@G
@K8K< C8JK K?LJ :8LJ@E> 8 I<TE@E> 8E; C8P<I@E> F= K?< ;<GFJ@K<; J8CKJ
<:8LJ< K?< 8J:<E;@E> UL@;J 8I< G8JJ@E> K?IFL>? @EK<IM8CJ N@K? ;<
:I<8J@E> K<DG<I8KLI<J 8E; GI<JJLI<J N?@:? ;<K<ID@E< K?< JFCL9@C@KP F=
K?< J8CKJ I<TE@E> F= J8CKJ @J <OG<:K<; KF 9< 8 :FEK@ELFLJ GIF:<JJ =IFD
Table 1
?<D@:8C 8E8CPJ<J @E GGD F= J<C<:K<; 9I@E<J =IFD -8C8IJ @E K?< :<EKI8C E;<J -F;@LD :?CFI@;< @J K?< ;FD@E8EK J8CK GF@EK@E> KF 8 D8I@E< FI@>@E F= K?< <M8GFI@K<J .?< <M8GFI@K<J 8I<
JKIFE>CP <EI@:?<; @E &@K?@LD 8E; FIFE I@:BJ<E  18II<E 
K8:8D8 /PLE@ "'L<IKF <C,@E:FE DG<O8 J:FK8E
C      
-)X      
")X   E; E;  
X)X      
&@      
(8      
%      
'>      
8      
.-      


UNCORRECTED PROOF
M. Hovland et al. Marine and Petroleum Geology xxx (2018) xxx-xxx
Fig. 5. Left (LD<IFLJ J<<G8>< =<8KLI<J 8I< =FLE; @E K?< :<EKI8C GFIK@FE F= &8B< /PLE@ I<; I<:K8E>C< .?< MFC:8EF J<<E KF K?< EFIK? @J K?< ;FID8EK .LELG MFC:8EF 8CJF @D8><; @E @> 
Right .?<I< 8I< 8K C<8JK KNF KPG<J F= =<8KLI<J JD8CC ‘GF:BD8IBJ’ FI :@I:LC8I ;<GI<JJ@FEJ 8E; C8I><I <CC@GK@:8C :FE:<EKI@: @DGI@EKJ .?<P GIF989CP I<JLCK =IFD GLCJ8K@E> J<<G8>< F= 9I@E<J
N?@:? GI<:@G@K8K< J@DLCK8E<FLJCP C<8M@E> 8 :FE:<EKI@: G8KK<IE FK? @D8><J GIF;L:<; N@K? !FF>C<8IK?  FI @EK<IGI<K8K@FE F= K?< I<=<I<E:<J KF :FCFI @E K?@J T>LI< C<><E; K?< I<8;<I @J
I<=<II<; KF K?< 1<9 M<IJ@FE F= K?@J 8IK@:C<
Fig. 6. Left *<IJG<:K@M< @D8>< F= .LELG MFC:8EF CF:8K<; FE K?< EFIK?<IE <;>< F= -8C8I ;< /PLE@  @>  C<=K @D8>< .?< C8B< 8E; MFC:8EF @J M@<N<; =IFD 8E <C<M8K@FE F= ∼BD Right
EC8I><; ;<K8@C =IFD K?< =FFK F= .LELG MFC:8EF .?< @D8>< :C<8ICP J?FNJ K?8K N8K<I @J ;I8@E@E> =IFD JGI@E>J 8IK<J@8E <G@K?<ID8C N8K<I 9CL< 8E; P<CCFN 8IIFNJ 8K K?< =FFK F= K?< MFC:8EF
#D8>< GIF;L:<; N@K? !FF>C<8IK?  FI @EK<IGI<K8K@FE F= K?< I<=<I<E:<J KF :FCFI @E K?@J T>LI< C<><E; K?< I<8;<I @J I<=<II<; KF K?< 1<9 M<IJ@FE F= K?@J 8IK@:C<
K?< JL9;L:K@FE QFE< 8E; LG KF K?< JLI=8:< #K @J K?<I<=FI< <OG<:K<; K?8K
C8I>< 8::LDLC8K@FEJ F= 9I@E<J 8E; J8CKJ 8I< ?@;;<E @E K?< IF:B :FCLDE
9<CFN K?< M@J@9C< J8CK 8::LDLC8K@FEJ FE K?< JLI=8:<
#E @>  K?< EFIK?<IE G8IK F= -8C8I ;< /PLE@ @J J<<E KF><K?<I N@K?
K?< ;FID8EK .LELG MFC:8EF .?< JLDD@K F= K?@J MFC:8EF @J 8K  D
N?<I<8J K?< J8CK C8B< @J 8K 8E <C<M8K@FE F= D .?<P 8CC ;I8@E @EKF
-8C8I ;< /PLE@ 8E; :FEKI@9LK< KF K?< 8::LDLC8K@FE F= 9I@E<J 8E; J8CKJ
CJF GF:BD8IBJ @< J?8CCFN :@I:LC8I ;<GI<JJ@FEJ 8I< J<<E .?<P @E;@
:8K< GLCJ8K@E> 8IK<J@8E :FE;@K@FEJ @E K?< >IFLE;N8K<I F= K?< 8I<8 $L;;
8E; "FMC8E;  .?< @D8>< :C<8ICP @E;@:8K<J 8E 8IK<J@8E >IFLE;N8
K<I JPJK<D 8CFE> K?< 98J< F= .LELG MFC:8EF 8E; GIF989CP 8CJF 8CFE> K?<
98J< F= K?< FK?<I MFC:8E@: JKIL:KLI<J JLIIFLE;@E> -8C8I ;< /PLE@
2.1.3. Lithium and boron salts
CFEJF  GIFM@;<; 8 K?FIFL>? I<M@<N F= K?< FI@>@E F= K?< C8I><
9FI8K< ;<GFJ@KJ @E I><EK@E8 8E; ?< <JG<:@8CCP 8;;I<JJ<; K?< <E;FI?<@:
CK@GC8EF*LE8 GC8K<8L 8K <C<M8K@FEJ 8M<I8>@E> D  @>  .?<
*LE8 GC8K<8L 8I<8 N?<I< K?< 9FI;<IJ F= I><EK@E8 FC@M@8 8E; ?@C<
D<<K 8E; 8I< 9FLE;<; 9P K?< -8C8I ;< K8:8D8 K?< -8C8I ;< /PLE@ 8E;
K?< -8C8I ;< "FD9I< 'L<IKF @J F=K<E I<=<II<; KF 8J K?< ‘&@K?@LD .I@8E
>C<’8E; K?< K?I<< :FLEKI@<J D<EK@FE<; 8I< K?< ‘&@K?@LD J’
FIFE  8E; C@K?@LD &@ 8I< MFC8K@C< 8E; DF9@C< <C<D<EKJ F:
:LII@E> D8@ECP @E CFN :FE:<EKI8K@FEJ 8E; ?@>?CP ;@JG<IJ<; @E E8KLI<
18II<E  -<8N8K<I :FEK8@EJ GGD  8E;  GGD &@ N?@C< K?<
8IK?J :ILJK :FEK8@EJ –GGD 8E; – GGD &@ 9P N<@>?K FIFE
@J DFJKCP =FLE; @E E8KLI< 8J =LCCP FO@;@Q<; 9FI8K<J N?@C< C@K?@LD @J
8CJF =FLE; @E JFD< J@C@:8K< D@E<I8CJ <> JGF;LD<E< G<K8C@K< C<G@;F
C@K< 8E; ?<:KFI@K< #E K?< E;<J 'FLEK8@EJ K?< C8I><JK 8::LDLC8K@FEJ F=
C@K?@LD J8CKJ 8I< =FLE; @E -8C8I ;< /PLE@ I><EK@E8 8E; <J@<IKF ;<
K8:8D8 ?@C<  @>  .?< C@K?@LD :FEK<EKJ 8M<I8><J GGD @E K?<
:<EKI8C QFE< F= K?< K8:8D8 ;<GFJ@KJ 18II<E  I@:BJ<E <K 8C

::FI;@E> KF 18II<E  K?< D8@E @EUFNJ KF K?<J< J8C8IJ 8I<
;I8@E8>< N8K<I =IFD K?< MFC:8E@: =FID8K@FEJ F= K?< E;<8E "@>?C8E;J
<8JK F= K?< 98J@E 8E; K?8K K?< J8CKJ @E K?@J 9I@E< FI@>@E8K< 9FK? =IFD
N<8K?<I@E> F= MFC:8E@: IF:BJ D8@ECP % &@ '>  8E; C<8:?@E> F= 8E
:@<EK .<IK@8IP <M8GFI@K<J N@K? 8 ‘DFK?<I J8CK’C8P<I 9<E<8K? K?< MFC
:8E@: =FID8K@FEJ GIFM@;@E> (8 8 C -)X KF K?< DFJK J8C@E< @EUFN
N8K<IJ 18II<E 
"FN<M<I K?<I< @J <M<IP I<8JFE KF 9<C@<M< K?8K K?< .<IK@8IP <M8GFI
@K<J ‘DFK?<I J8CK’ K?8K 8::LDLC8K<; @E K?@J 8I<8 N<I< ;<GFJ@K<; 9P K?<
J8D< GIF:<JJ<J 8J 8K K?< GI<J<EK @< 9P ?P;IFK?<ID8C GIF:<JJ<J ;I@M<E
9P K?< JL9;L:K@FE F= F:<8E@: :ILJK 8E; K?< 8JJF:@8K<; MFC:8E@JD .?@J @J
8CJF :FETID<; 9P 8 JKL;P F= -K<@ED<KQ  N?F @EM<JK@>8K<; 8 GC8P8
C8B< 8K <8JK<IE *LE8 °–°′- N@K? I<JG<:K KF 9FIFE 8E; C@K?@LD
@E I<J@;L8C 9I@E<J =<<; N8K<IJ 8E; JFCLK@FEJ =IFD N<8K?<I<; IF:BJ .?<
I<JLCKJ F= ?@J 8E8CPQ<J 8I< K?8K I<J@;L8C 9I@E<J =IFD K?< GC8P8 C8B< :FE
K8@E LG KF D>C F= 9FIFE 8E;  D>C F= C@K?@LD .?< DFJK @D
GFIK8EK JLGGC@<I F= K?<J< <C<D<EKJ KF K?< C8B< &8J LII8J ,@M<I :FE
K8@EJ D>C 9FIFE 8E; D>C C@K?@LD "@J :FE:CLJ@FEJ 8I<”'FJK F=
K?< C@K?@LD @EGLK KF K?< 98J@E @J C@B<CP ><E<I8K<; 9P GI<J<EK ><FK?<ID8C
JFLI:<J I8K?<I K?8E 9P N<8K?<I@E> 8E; C<8:?@E> F= @>E@D9I@K<J 8E; GCL
KFE@: IF:BJ”-K<@ED<KQ 
.?< <EI@:?D<EK GIF:<JJ<J K?8K 8I< I<JGFEJ@9C< =FI K?< C8I>< <EI@:?
D<EKJ F= C@K?@LD 8E; 9FIFE @E K?<J< J8CK 8::LDLC8K@FEJ ?8J 9<<E 8
CFE>;@J:LJJ<; :FELE;ILD "FN<M<I <OG<I@D<EK8C NFIB 9P FJK8C <K
8C  J?<; JFD< C@>?K FE GFJJ@9C< D<:?8E@JDJ 9P J?FN@E> K?8K
9FK?  8E; &@ 9<?8M< 8J @E:FDG8K@9C< <C<D<EKJ @E 98J8CK@: D8>D8J
.?< K<ID ‘@E:FDG8K@9C< <C<D<EK’I<=<IJ KF <C<D<EKJ N@K? C8I>< @FE@: ;@
8D<K<I 8E;FI ?@>? :?8I><J K?8K TK GFFICP @EKF K?< :8K@FE J@K<J F= K?<
D@E<I8CJ N?<I< K?<P DFJK :FDDFECP F::LI .?@J @J :8LJ@E> K?<D KF


UNCORRECTED PROOF
M. Hovland et al. Marine and Petroleum Geology xxx (2018) xxx-xxx
Fig. 7. -8C8I ;< *8JKFJ !I8E;<J *LE8 8I<8 ?@C< J?FN@E> @E;LJKI@8C GIF;L:K@FE F= J8CKJ FE K?< J8C8I *IF;L:<; N@K? !FF>C<8IK?
DFI< <8J@CP G8IK@K@FE @EKF K?< DFCK<E G?8J< F= 8 IF:B FI @EKF 8 N8
K<IG?8J< @= K?8K @J 8M8@C89C< FI K?@J I<8JFE 9FK?  8E; &@ 8I< DFI<
<8J@CP C<8M@E> K?< JL9;L:K@FE JC89 <@K?<I N@K?@E K?< N8K<IG?8J< 8E;
FI K?< DFCK<E IF:B F= K?< ?8E>@E> N8CC 89FM< K?< F:<8E@: JC89 FJK8C
<K 8C  :FE:CL;< K?8K “FK?  8E; &@ 8I< GIF989CP JKI@GG<; FV
=IFD 8 C@K?FJG?<I@: JC89 ;LI@E> JL9;L:K@FEI<C8K<; D<K8DFIG?@JD 8E;
8I< K?LJ EFK @EMFCM<; @E ;<<G D8EKC< I<:P:C@E>”
.?@J :FE:CLJ@FE @J 98J<; FE <OG<I@D<EK8C NFIB K?8K J?FN<; K?8K
C@K?@LD N8J JKI@GG<; FV =IFD K?< 98J8CK 9P D8>D8K@: UL@;J 8K K<DG<I8
KLI<J 89FM< X° FJK8C <K 8C  FEJ<HL<EKCP  8E; &@ =IFD K?<
JL9;L:K@E> JC89 N@CC K<E; KF D@>I8K< LGN8I;J N@K? K?< N8K<I 8E; >8J<J
=IFD K?< JL9;L:K@FE QFE< 8E; K?@J ?FK N8K<I N@CC 8CJF @EK<I8:K N@K? K?<
IF:BJ 8CFE> K?< D@>I8K@FE IFLK< 8E; C<8:? FLK DFI<  8E; &@ @E :FE;L@KJ
F= K?< 8J:<EK KF K?< JLI=8:<
LIK?<IDFI< K?< MFC:8E@: <ILGK@FEJ F= 8E;<J@K@: C8M8 ;<J:I@9<;
89FM< :I<8K< 89LE;8EK MFC:8E@: 8J? N?@:? ?8J 8 M<IP ?@>? JG<:@T: JLI
=8:< 8I<8 =FI <OK<EJ@M< @EK<I8:K@FE N@K? K?< ?P;IFK?<ID8C >IFLE; N8
K<I .?@J >IFLE; N8K<I J<<DJ KF 9< 8IK<J@8E GLCJ8K@E> @E K?< 8I<8J F=
J8CK ;<GFJ@K@FE <8I@E> @E D@E; 8CJF K?8K K?< ?FK ?P;IFK?<ID8C8IK<J@8E
>IFLE;N8K<I <> X° ?8J 8 C8I>< :8G8:@KP KF JKI@G FV 9FK?  8E;
&@ =IFD K?< MFC:8E@: 8J? 8E; C8M8J @K I<GI<J<EKJ 8E <=T:@<EK :FEM<PFI
=FI K?<J< KNF JG<:@<J KF K?< J8CK C8B<J FJK8C <K 8C 
,?PFC@K?@: D8>D8 @J BEFNE KF :FEK8@E DFI<  8E; &@ K?8E 8E;<J@K@:
98J8CK 8J<; FE K?@J =8:K ,<KK@> <K 8C  JL>><JK<; K?8K I<C8K@M<CP
?@>?<I :FE:<EKI8K@FEJ F= &@ 8E;  @E 9I@E<J =IFD K?< JFLK? <E; F= -8C8I
;< /PLE@ E<8I K?< DFLK? F= K?< ,@F !I8E;< ;< &@G<Q N<I< JFLI:<;
=IFD I<:<EK I?PFC@K?@: MFC:8E@: IF:BJ -?8N <K 8C  8E; -?8N 8E;
-KLI:?@F  ?8M< 8CJF ;<DFEJKI8K<; K?8K 9FK?  8E; &@ 8I< C@B<CP KF
9< ;<GC<K<; =IFD I?PFC@K?@: IF:BJ 9P ?FK N8K<I UFN @E K?< ;<<G<I :ILJK
8E; KF 9< <EI@:?<; @E K?< LGG<I :ILJK
.?LJ K?< D8@E JFLI:<J F= K?< 9FIFE 8E; C@K?@LD J8CKJ @E K?< E;<J
'FLEK8@EJ 8I< JL>><JK<; KF 9< 9I@E<J =IFD K?< F:<8E@: JL9;L:K@FE JC89
.?<J< ?FK 9I@E<J 8I< C<8:?@E> 9FIFE 8E; C@K?@LD =IFD D8EKC< IF:BJ 8E;
MFC:8E@: IF:BJ @E K?< FM<I9LI;<E .?< :?CFI@;<J JLC=8K<J 8E; :8I9FE8
:<FLJ J8CKJ @E K?< ?FK JGI@E>J K?8K =<<; K?< J8CK C8B<J 8I< JL>><JK<; KF
?8M< K?< J8D< FI@>@E .?< ?P;IFK?<ID8C GIF:<JJ<J ?8M< 9<<E FE>F@E>
=IFD K?< FEJ<K F= K?< F:<8E@: JL9;L:K@FE @< ;LI@E> K?< <EK@I< 9L@C;LG
F= K?< E;<8E 'FLEK8@EJ JK8IK@E> @E K?< $LI8JJ@: CFEJF  CFEJF
8E; ,@J8:?<I  <EJFE <K 8C 
.?LJ @K :8E 9< :FE:CL;<; K?8K ;<<GJ<8K<; ?P;IFK?<ID8C GIF:<JJ<J
8JJF:@8K<; N@K? 8:K@M< FI;@CC<I8E 8I: MFC:8E@JD 8E; 8JJF:@8K<; ?P
;IFK?<ID8C 8:K@M@KP ?8M< GIF;L:<; DFJK F= K?< M@J@9C< J8CK 8::LDLC8
K@FEJ @E K?< E;<8E 'FLEK8@EJ @E:CL;@E> K?< C@K?@LD 8E; 9FIFE J8CKJ
2.1.4. Hidden salts of the Andes and other subduction zones
.?< E;<8E 'FLEK8@EJ I<GI<J<EK K?< CFE><JK :FEK@E<EK8C DFLEK8@E
I8E>< @E K?< NFIC; ∼BD CFE> 8E; 8I< ∼– BD N@;< @E K?<
:<EKI8C G8IK .?< FIF><EP @E@K@8K<; @E K?< $LI8JJ@: G<I@F; 9LK :ILJK8C
K?@:B<E@E> F= K?< FM<II@;@E> GC8K< JK8IK<; @E K?< /GG<I I<K8:<FLJ
N@K? D8IB<; GLCJ<J @E F:<E< 8E; (<F><E< N@K? I<8II8E><D<EKJ F=
K?< FIF><EP .?< :FEM<I><E:< M<CF:@KP @J M<IP LE:<IK8@E 9LK M8CL<J F=
–DDPIXW 8I< <JK@D8K<; :I<8K@E> 8 KI<E:?G<IG<E;@:LC8I J?FIK<E@E>
F= –BD '8IK@EF; <K 8C  .?< FEJ<K F= U8K JL9;L:K@FEJ
:FII<C8K<J N@K? JCFN<I :FEM<I><E:< 8K K?< KI<E:? 8::<EE8 <K 8C 
?8M< :8C:LC8K<; K?< C<E>K? F= JL9;L:K<; C@K?FJG?<I< @E K?< E;<8E JL9
;L:K@FE QFE< KF 9< @E K?< I8E>< F= BD– BD FM<I 8 G<I@F; F=
– '8 "<E:< K?< MFCLD<J F= JL9;L:K<; F:<8E@: :ILJK 8I< 8CDFJK
LE@D8>@E89C<
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J<8N8K<I ?8M< 9IFL>?K @DD<EJ< MFCLD<J F= 9I@E<J 8E; J8CK ;FNE @EKF
K?< JL9;L:K@FE QFE< .?< @E@K@8K@FE F= ?P;IFK?<ID8C UFN 8E; MFC:8E
@JD 89FM< K?< JL9;L:K@FE JC89 ?8M< KI8EJGFIK<; J@>E@=@:8EK MFCLD<J F=
K?<J< 9I@E<J 8E; J8CKJ LGN8I;J @EKF K?< DFLEK8@EJ 9LK GIF989CP ALJK 8
JD8CC =I8:K@FE F= K?< KFK8C J8CK MFCLD< ?@;@E> @E K?< JL9;L:K@FE QFE< (FK
8CC F= K?< DF9@C@Q<; J8CK ?8J I<8:?<; KF K?< JLI=8:< 8E; @K @J K?<I<=FI<
C@B<CP K?8K M<IP C8I>< MFCLD<J F= J8CKJ 8E; 9I@E<J 8I< JK@CC ?@;@E> @E K?<
IF:B MFCLD<J 89FM< K?< JL9;L:K@FE QFE< N?@:? ?8M< LG KF  GFIFJ@KP
&8LDFE@<I <K 8C 
.?< J8CKJ FECP 9<:FD< M@J@9C< N?<E ;<GFJ@K<; FEKF K?< JLI=8:< 9P ><
FCF>@:8C 8E; ?P;IF><FCF>@:8C GIF:<JJ<J 8E; N?<E K?<P 8I< GI<J<IM<; 9P
8 GI<M8@C@E> ;IP :C@D8K< )ECP ><FG?PJ@:8C D<8JLI<D<EKJ C@B< K?< :FE
;L:K@M@KP D<8JLI<D<EKJ F= &8LDFE@<I <K 8C  :8E GIFM@;< ?@EKJ
89FLK JL:? ?@;;<E ;<GFJ@KJ F= J8CKJ 8E; 9I@E<
2.2. Other types of subduction
LI@E> JL9;L:K@FE GIF:<JJ<J K?< ;<EJ@KP F= K?< JC89 ;<K<ID@E<J
N?<K?<I @K N@CC JL9;L:K FI EFK #DGFIK8EK @JJL<J @E K?@J GIF:<JJ 8I< K?<
;<EJ@KP F= K?< F:<8E@: :ILJK N@K? @KJ CF8; F= J<;@D<EKJ K?< ;<EJ@KP
F= 8EP D@:IF:FEK@E<EKJ 8E; K?< ;<EJ@KP 8E; :FDG<K<E:< F= K?< :FCC@;
@E> :FEK@E<EK <> !LKJ:?<I <K 8C  LI@E> :FCC@J@FE8C JL9;L:
K@FE C@B< @E K?< CGJ FI "@D8C8P8J J<;@D<EKJ 8E; C<JJ ;<EJ< IF:BJ 8I<
:FDDFECP GLJ?<; FE KFG ;LI@E> K?< FIF><E<J@J =FID@E> 8::I<K@FE8IP


UNCORRECTED PROOF
M. Hovland et al. Marine and Petroleum Geology xxx (2018) xxx-xxx
N<;><J :?8I8:K<I@JK@: E8GG<J 8E; DFLEK8@EJ 89FM< K?< JL9;L:K@E> JC89
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KF K?< @E:FD@E> JC89 .?< K?@:BE<JJ 8E; :FDGFJ@K@FE F= K?@J IF:B G8:B
8>< FE KFG F= K?< JL9;L:K@E> JC89 ?8J :FEJ<HL<E:<J =FI K?< C8K<I 9<?8M
@FI F= 9I@E<J 8E; J8CKJ =FID<; ;LI@E> JL9;L:K@FE -8CKJ K?8K 8I< =FID@E>
@EJ@;< 8E; 8IFLE; K?< JL9;L:K@E> JC89 D8P 9< ;<<GCP 9LI@<; 8E; 8EP
J8CK N@CC K?<I<=FI< ?8M< KF D@>I8K< K?IFL>? C8I>< 9F;@<J F= IF:BJ KF <D
8E8K< FEKF K?< JLI=8:< #E K?< "@D8C8P8J 8E; K?< CGJ J8CKJ 8I< <E:FLE
K<I<; K?8K N<I< G8IK F= K?< J<;@D<EKJ N@K?@E K?< GI<<O@JK@E> 98J@EJ GI@FI
KF K?< :FCC@J@FE .?@J J8CK J?FNJ 8CC K?< :FDDFE J@>EJ F= ;<=FID8K@FE 8J
8 I<JLCK F= K?< FIF><E<J@J
"FN<M<I ;<<G ;FNE @E <M<IP B@E; F= JL9;L:K@FE QFE< N@K? F:<8E@:
:ILJK K?<IDF;PE8D@:J K<CCJ LJ K?8K K?<I< 8I< C@B<CP ?@;;<E J8CKJ =FID<;
@EJ@;< 8E; 8IFLE; K?< JL9;L:K@E> JC89 LI@E> C8K<I I@=K@E> FC; JLKLI<
QFE<J 8I< F=K<E GI<=<II<; I@=K@E> QFE<J ;<G<E;@E> FE K?< ;@I<:K@FE F=
:ILJK8C JKI<JJ JL:? J8CKJ D8P 9< I<DF9@C@Q<; 8E; 9<:FD< M@J@9C< 8E;
D8P 8CJF D@O N@K? E<NCP =FID<; J8CK 1@K?@E JL:? 8E 8I<8 K?< :?IFEFC
F>P F= J8CK =FID8K@FE @J K?<I<=FI< M@IKL8CCP @DGFJJ@9C< KF ;<K<ID@E<
N@K?FLK BEFN@E> K?< K<:KFE@: ?@JKFIP F= K?8K 8I<8
.?@J @J @CCLJKI8K<; 9P K?< "@D8C8P8E FIF><E<J@J @E @>  .?< DFLE
K8@E 9L@C;@E> N8J ;FD@E8K<; 9P K?ILJK@E> F= E8GG<J :FDGFJ<; F= D8I@E<
J<;@D<EK8IP IF:BJ =IFD K?< .<K?PJ ):<8E LG @EKF K?< DFLEK8@E :?8@E
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LJKI8C@8E :FCC@;@E> K<:KFE@: GC8K<J N<I< :FDGFJ<; F= CFN ;<EJ@KP :FE
K@E<EK8C IF:BJ .?< J<;@D<EK8IP IF:BJ @E K?< E8GG<J 8CJF @E:CL;<; J8CKJ
‘"@D8C8P8E J8CKJ’ =IFD K?< 8E:@<EK F:<8E N?@:? @J =FLE; K<:KFE@Q<;
N@K? K?< FK?<I J<;@D<EK8IP IF:BJ
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8IFLE; K?< FC; JL9;L:K<; JC89 8I< :LII<EKCP 9<@E> KI8EJGFIK<; KF K?<
JLI=8:< ;L< KF K?< FG<E =8LCKJ @E K?< GLCC8G8IK 98J@E FE KFG F= K?< JC89
N@K?@E K?< <8; -<8 8I<8 -<< 8CJF *8IK  F= K?@J GL9C@:8K@FE "FMC8E; <K
8C 
3. Oceanic-oceanic subduction and salts
3.1. Some characteristics of the Mediterranean Ridge subduction zone
#E :FEKI8JK KF :FEK@E<EK8C JL9;L:K@FE F:<8E@: JL9;L:K@FE @DGC@<J
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@E> F:<8E@:  F:<8E@: JL9;L:K@FE 8 C@D@K<; 8DFLEK F= J<;@D<EKJ 8I<
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K@FE GIFM@;<J K?< 9<JK :?8E:< =FI <J:8G< KF K?< J<89<; 9P J8CKJ =FID<;
8IFLE; K?< JL9;L:K@E> JC89 CK?FL>? FE< D@>?K K?@EB K?8K J8CKJ FE K?<
J<89<; 8I< DFI< <OGFJ<; KF ;@JJFCLK@FE K?8E J8CKJ FE K?< JLI=8:< K?@J
@J EFK E<:<JJ8I@CP K?< :8J< -8CKJ FE K?< J<89<; D@>?K 9< GIFK<:K<; 9FK?
9P ?@>?;<EJ@KP 9I@E<J 8E; J<;@D<EKJ 8>8@EJK <IFJ@FE 8E; ;@JJFCLK@FE
9P F:<8E :LII<EKJ ):<8E@:  F:<8E@: JL9;L:K@FE K?<I<=FI< GIFM@;<J 8
>FF; FGGFIKLE@KP KF F9J<IM< K?< DFJK JFCL9C< J8CKJ E <O8DGC< :8J< F=
F:<8E@:  F:<8E@: JL9;L:K@FE @E K?< '<;@K<II8E<8E -<8 @J I<M@<N<; N@K?
I<=<I<E:< KF K?< conceptual element F= J8CK I<TE@E>
3.2. Submarine brine lakes at the Mediterranean Ridge
.?< '<;@K<II8E<8E ,@;>< =FIDJ K?< 8::I<K@FE8IP :FDGC<O F= K?<
"<CC<E@: JL9;L:K@FE QFE< CF:8K<; N?<I< K?< =I@:8E GC8K< JL9;L:KJ
EFIK?<8JKN8I;J 9<E<8K? K?< <><8E GC8K< .?< =I@:8E JL9;L:K@E> JC89
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N?@:? ;@JK@E>L@J?<J @K =IFD FK?<I 8::I<K@FE8IP :FDGC<O<J @J K?< GI<J
<E:< F= 8 J<HL<E:< F= <M8GFI@K<J F= '<JJ@E@8E 8>< N?@:? C@< N@K?@E K?<
J<;@D<EKJ 8K 8 ;<GK? F= 8 =<N ?LE;I<; D<K<IJ 9<E<8K? K?< J<8 9<;”
1<JK9IFFB 8E; ,<JKFE  J<< @>  @E *8IK  <> "FMC8E; <K 8C

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GFE;J 8CFE> K?< J<8UFFI =<; 9P 9I@E<J M<EK@E> LG K?IFL>? K?< J<8UFFI
.?@J M<EK@E> F= ?P;IFK?<ID8C 9I@E<J JKIFE>CP @E;@:8K<J K?8K K?< GIF:<JJ
@J 8JJF:@8K<; N@K? K?< D8I@E< JL9;L:K@FE K?8K =FIDJ K?< '<;@K<II8E<8E
,@;>< :FDGC<O 8J ;@J:LJJ<; 9P "FMC8E; <K 8C  J<< K?<@I @>J 
8E;  .?< ?P;IFK?<ID8C E8KLI< F= K?<J< 9I@E<J @J JLGGFIK<; 9P K?<
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LG KF X° 8K D N8K<I ;<GK? @E K?@J 8I<8  @>  8J<; FE I8
;@F><E@: ;8K8 F= ?<C@LD 8E; 8I>FE J<<G8>< 1@E:BC<I <K 8C  :FE
:CL;<; “)LI J:<E8I@F GI<;@:KJ K?8K K?< I8;@F><E@: J@>E8C @J –8K C<8JK
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K?< J<8 UFFI @= 8 G8K?N8P K?IFL>? K?< <M8GFI@K<J @J FG<E<;” .?LJ @K
@J @E=<II<; K?8K K?< 9I@E<J 8I<  KI8EJGFIK<; @E 8 ?P;IFK?<ID8C JPJK<D
:FEJ@JK@E> F= =8LCKJ 8E; =I8:KLI<J K?8K G<E<KI8K< ;<<G @EKF K?< :ILJK 8E;
 :FEK@EL<J LG K?IFL>? C8P<IJ F= <M8GFI@K<J .?@J @J 8CJF @E;@:8K<; 9P
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8C  -<< ?  @E *8IK  "FMC8E; <K 8C 
3.2.1. Discovery basin
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TCC<; N@K? 8 9I@E< F= :FE:<EKI8K<; '>CX <EI@:?<; @E JLCG?8K< *FI<N8
K<I GIFTC<J ;<DFEJKI8K< K?8K K?@J 9I@E< ;@JJFCM<J J<;@D<EK8IP :8C:@K< KF
Fig. 8. #CCLJKI8K@FE F= K?< :FCC@J@FE QFE< 9<KN<<E #E;@8 8E; .@9<K Left #CCLJKI8K@FE F= K?< ;I@=K@E> G8K? F= #E;@8 .?< =8JK EFIK?N8I;J DFM@E> #E;@8E 8E; LJKI8C@8E K<:KFE@: GC8K<J :CFJ<;
K?< .<K?PJ ):<8E 89FLK  D@CC@FE P<8IJ 8>F FK? GC8K<J N<I< :FDGFJ<; F= CFN ;<EJ@KP :FEK@E<EK8C :ILJK I<JLCK@E> @E 8 DFLEK8@E 9L@C;@E> ;FD@E8K<; 9P K?ILJK@E> F= E8GG<J :FEJ@JK@E>
F= D8I@E< J<;@D<EK8IP IF:BJ @E:CL;@E> J8CK =IFD K?< 8E:@<EK F:<8E Right .?< :FCC@J@FE F= #E;@8 8E; .@9<K 8E; K?< FIF><E<J@J F= "@D8C8P8 .?< JLKLI< QFE< N?<I< E<N I@=K@E> D@>?K K8B<
GC8:< @J @E;@:8K<; 'F;@T<; =IFD @CCLJKI8K@FE 9P -FEA8 &<PM8 *8J8;<E8 @KP FCC<>< J<< ?KKG><FG?@C<E<K&<JJFEJ*C8K<.<:KFE@:J*C8K<.<:KFE@:J7?KDC


UNCORRECTED PROOF
M. Hovland et al. Marine and Petroleum Geology xxx (2018) xxx-xxx
Fig. 9. Left  J@;< J:8E JFE8I @D8>< F= K?< J<8UFFI FM<I K?< &K8C8EK< I@E< GFFC 98J@E 8;A8:<EK KF K?< '<;@K<II8E<8E ,@;>< 1FF;J@;< <K 8C  * I@E< GFE; Right :?FJFLE;<I
@D8>< F= K?< KFGF>I8G?P F= K?< /I8E@8 I@E< GFE; .?< I<; 8IIFN GF@EKJ 8K K?< 9I@E< GFE;J 8:FLJK@: I<U<:KFI K?8K KPG@T<J JL:? GFE;J  FI @EK<IGI<K8K@FE F= K?< I<=<I<E:<J KF :FCFI @E K?@J
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D8C JPJK<D K?@J @J F= :FLIJ< 8 GFJJ@9C< JFLI:< =FI K?< 9I@E<
"FN<M<I K?< :FDGFJ@K@FE F= K?< 9I@E< @E K?<  ;<M@8K<J JKIFE>CP
=IFD K?8K F= EFID8C J<8N8K<I .?@J @J ;<DFEJKI8K<; @E .89C<  N@K? ;8K8
=IFD 18CCD8EE <K 8C  .?< TIJK JKI@B@E> F9J<IM8K@FE @J K?8K (8
@E  @J I<;L:<; KF FECP  G<I :<EK KF K?8K F= J<8N8K<I N?@C< C @J @E
:I<8J<; E<8ICP  K@D<J FK? % 8E; '> @E  8I< 8IFLE;  K@D<J ?@>?<I
K?8E @E K?< J<8N8K<I E <OGC8E8K@FE KF K?@J :8E 9< C@EB<; KF K?< M8I@FLJ
JFCL9@C@K@<J F= K?< J<8 J8CKJ 8K ?@>?<I K<DG<I8KLI< @< K?< JFCL9@C@KP F=
GFK8JJ@LD 8E; D8>E<J@LD :?CFI@;<J @J D8EP K@D<J ?@>?<I K?8E K?8K F=
JF;@LD :?CFI@;< 8K ?@>?<I K<DG<I8KLI<J P 8JJLD@E> K?8K EFID8C J<8
N8K<I N8J @E@K@8CCP =<<;@E> K?< ?P;IFK?<ID8C JPJK<D K?<J< ;8K8 @E;@
:8K< K?8K JF;@LD :?CFI@;< ?8C@K< @J GI<:@G@K8K<; N@K?@E K?< ?P;IFK?<I
D8C JPJK<D N?@C< K?< DFI< JFCL9C< :?CFI@;<J 8E; JLC=8K<J 8I< M<EK@E>
LG @EKF K?<  9I@E< GFE;
.?@J @J 8E 8CK<IE8K@M< <OGC8E8K@FE KF K?8K F= 18CCD8EE <K 8C 
N?F JL>><JK<; ?P;IFK?<ID8C C<8:?@E> F= '<JJ@E@8E 9@J:?F=@K< 8J K?<
JFLI:< =FI K?< D8>E<J@LD :?CFI@;< GIFM@;<; K?8K 9@J:?F=@K< @J GI<J<EK @E
K?< ?P;IFK?<ID8C JPJK<D LK K?<E N< ?8M< K?< E<OK HL<JK@FE ?FN N8J
K?< '<JJ@E@8E 9@J:?F=@K< =FID<; @E K?< TIJK GC8:< 18J K?8K 8CJF =FID<;
9P ?P;IFK?<ID8C GIF:<JJ<J
EFK?<I JKI@B@E> F9J<IM8K@FE @J K?< CFN G" F= K?<  9I@E<  G" F=
 @J =8I 9<CFN K?< JK89@C@KP C@D@K F= :8I9FE8K<J 8K G"  8K 8D9@<EK
:FE;@K@FEJ 8E; <OGC8@EJ N?P :8I9FE8K<J 8I< ;@JJFCM<; @E K?< J<;@D<EKJ
18CCD8EE <K 8C  .?< ;@JJFCLK@FE F= :8I9FE8K<J @J 9LV<I@E> K?<
GFI< N8K<I KF ?@>?<I G" N?<I< E<N :8I9FE8K<J :8E :IPJK8CC@Q< &<8:?
@E> F= 9@J:?F=@K< ;F<J EFK <OGC8@E K?< CFN G" F= K?< 9I@E<
-<;@D<EKJ @E K?< 98J@E 8I< ;8IB:FCFI<; ?<D@G<C8>@: DL;J N@K?
9@F><E@: FG8C@E< FFQ< 8E; 89LE;8EK FI>8E@: :8I9FE 18CCD8EE <K 8C
Table 2
FDGFJ@K@FE F= @J:FM<IP 8J@E 9I@E< :FDG8I<; KF EFID8C J<8N8K<I DFCB> N8K<I .?<
G" M8CL< F= K?< 9I@E< @J M<IP CFN :FDG8I<; KF J<8N8K<I
-G<:@<J 9I@E< J<8N8K<I
(8  
%  
8  
'>  
C  
-)X  
G"  
 -L:? FI>8E@: DL;J 8I< GI<J<IM<; @E K?< ?PG<IJ8C@E< 8E; 8EFO@:
9I@E< GFE; N?@:? 8CJF TKJ N@K? 8 ?P;IFK?<ID8C FI@>@E F= K?< 9I@E<
4. Early stage continental rifting and salts
.?<I< @J FECP FE< KIL< :FEK@E<EK8C I@=K@E> :LII<EKCP 8:K@M< FE 8IK?
K?< 8JK =I@:8E ,@=K , CK?FL>? K?<I< 8I< KI8EJ=FID =8LCKI<C8K<;
J8CK 98J@EJ JL:? 8J K?< <8; -<8 I@=K QFE< 9I@<UP ;@J:LJJ<; @E *8IK 
"FMC8E; <K 8C  FECP K?< , @J @E:CL;<; ?<I<@E
4.1. The East African rift (EAR) and salt
, ILEJ =FI FM<I BD @E 8 DFI<FIC<JJ (- ;@I<:K@FE =IFD
K?< =8I KI@GC< ALE:K@FE 8 ?FK JGFKD8EKC< GCLD< KF K?< 'FQ8D9@HL<
?8EE<C '@;N8P 8CFE> K?< <8JK<IE 9I8E:? F= , @J K?< (FIK? .8E
Q8E@8E @M<I><E:< 4FE< (. N?@:? C@EBJ K?< I@=K N@K? K?< %@C@D8E
A8IF MFC:8E@: 8I<8 =LIK?<I KF K?< <8JK 1?<I< K?< <8JK<IE 9I8E:? F= ,
D8B<J K?@J C@EB K?<I< 8I< ;@JK@E:K 8E; LE@HL< MFC:8E@: 8E; UL@;I<
C8K<; =<8KLI<J @E:CL;@E> K?< 8CB8C@E< C8B<J (8KIFE 8E; '8>8;@ K?< C8I><
(>FIF>FIF I8K<I 8E; K?< :8I9FE8K@K< MFC:8EF )C FE@PF &<E>8@ 8B<I
<K 8C 
.?< ?@>? K<DG<I8KLI< ><FK?<ID8C JPJK<DJ 8CFE> K?< 8JK<IE 9I8E:?
F= K?< , 8I< :CFJ<CP I<C8K<; KF K?< MFC:8E@: :<EK<IJ N?@C< K?< 1<JK<IE
9I8E:? F= K?< I@=K @J :?8I8:K<I@Q<; 9P J<;@D<EK 8E; C8B< TCC<; >I89<EJ
8E; I<JKI@:K<; MFC:8E@JD -8<DLE;JJFE 
'8E8 <K 8C  ?8M< DF;<CC<; K?< JFLI:< F= K?< (. MFC:8E@:
IF:BJ 8E; @;<EK@T<; @K KF 9< D<K8JFD8K@Q<; JL9:FEK@E<EK8C C@K?FJG?<I@:
D8EKC< “FEK@E<EK8C C@K?FJG?<I< LE;<I>F<J JL9JK8EK@8C DF;@T:8K@FE
9FK? ;LI@E> K?< I@=K@E> GIF:<JJ 8E; 8J 8 I<JGFEJ< KF K?< @DG8:K F= 8 I@J
@E> K?<ID8C 8EFD8CP JL:? 8J 8 D8EKC< GCLD< .?< GI<J<E:< F= 8 D8E
KC< GCLD< :8E JKIFE>CP @EUL<E:< K?< :?<D@:8C :FDGFJ@K@FE F= K?< C8M8J
<ILGK<;”'8E8 <K 8C 
.?< (>FIF>FIF I8K<I @J 89FLK BD @E ;@8D<K<I  D ;<<G  @>J
 8E;  8E; ?8J ELD<IFLJ 9I@E< JGI@E>J N?@:? :FEKI@9LK< KF D8B@E>
K?< 8I<8 <OKI<D<CP =<IK@C< 8E; K?LJ 8 ?L9 =FI GC8EKJ 8E; 8E@D8CJ
4.2. Alkaline lakes and salts
::FI;@E> KF 18II<E  K?< 8CB8C@E< &8B< '8>8;@ &8B< (8
KIFE 8E; FK?<I C8B<J @E K?< , JPJK<D 8I< :?8I8:K<I@Q<; 9P J<8JFE8C
=I<J?<E@E> ?@>? GIF;L:K@M@KP C<M<CJ 8E; 9I@>?K I<; N8K<IJ  @>  .?<
:FCFI :FD<J =IFD ?8CF8CB8C@G?@C@: 8I:?8<8 EFK :P8EF98:K<I@8 .?< 8I
:?8<8C JG<:@<J 9<CFE> KF K?< ><E<I8 Natronacoccus, Natronobacterium,
Natrialba, Halorubrum, Natronorubrum 8E; Natronomonas N?@:? 8CC F:
:LI @E K?< 9I@E<J F= &8B< '8>8;@ 8E; &8B< (8KIFE .?@J 9@FK8 UFLI@J?<J
@E K?< C8B< :<EK<I 9I@E<J N?<I< KIFE8?8C@K< J8KLI8K@FE GI<M8@CJ N@K?
G" LG KF  .?@J ?@>? 8CB8C@E@KP D8P @E;@:8K< K?8K K?< ?P;IFK?<ID8C


UNCORRECTED PROOF
M. Hovland et al. Marine and Petroleum Geology xxx (2018) xxx-xxx
Fig. 10. -?8;<; I<C@<= D8G F= K?< :<EKI8C I<>@FE F= K?< <8JK<IE 9I8E:? F= K?< 8JK =I@:8E
,@=K , N@K? K?< (>FIF>FIF I8K<I (: K?< )C F@EPF &<E>8@ :8I9FE8K@K< MFC:8EF
)& 8E; &8B< (8KIFE &( '8G GIF;L:<; LJ@E> K?< '8I@E< !<FJ:@<E:< 8K8 -PJK<D
!<FD8G8GGFI>
GIF:<JJ<J I<JGFEJ@9C< D8P 9< I<C8K@M<CP CFNK<DG<I8KLI< <> J<IG<E
K@E@Q8K@FEI<C8K<;
“,<>@FE8CCP J8C@E@K@<J @E K?< <8JK =I@:8E I@=K M8CC<P C8B<J I8E>< =IFD
8IFLE; –‰KFK8C J8CKJ NM @E K?< DFI< EFIK?<ICP C8B<J F>F
I@8 (8BLIL CD<EK<@K8 8E; -FE8:?@ KF KIFE8 8E; ?8C@K< J8KLI8K@FE
‰ @E C8B<J KF K?< JFLK? '8>8;@ 8E; (8KIFE  :FD9@E8K@FE F=
?@>? 8D9@<EK K<DG<I8KLI< ?@>? C@>?K @EK<EJ@KP 8E; 8 :FEK@ELFLJ I<JLG
GCP F= )X D8B<J K?<J< JF;8 C8B<J 8DFE>JK K?< ?@>?<JK @E K?< NFIC;
@E K<IDJ F= J<8JFE8C GC8EBKFE@: 9@FD8JJ !I8EK <K 8C  8E; 8CJF
GC8:<J K?<D 8DFE> K?< NFIC;J DFJK GIF;L:K@M< <:FJPJK<DJ '<C8:B 8E;
%@C?8D ”18II<E 
L< KF K?<@I F9M@FLJ 8JJF:@8K@FE N@K? <OK<EJ@FE8C I@=K@E> ?@>?KF
M<IP?@>? ?<8KUFN ELD<IFLJ =LD8IFC<J ?FK JGI@E>J 8E; 8:K@M< MFC
:8E@: =<8KLI<J K?<I< :8E 9< EF ;FL9K K?8K K?< J8CKJ GIF;L:<; @E K?@J
EFED8I@E< <EM@IFED<EK @J ><FK?<ID8CCP 8E; ?P;IFK?<ID8CCP GIF;L:<;
8E; D8P <M<E 9< I<C8K<; KF J<IG<EK@E@Q8K@FE 8K ;<GK? <> -:I@98EF <K
8C 
1?<I<8J DFJK C8M8J @E K?< NFIC; 8I< I@:? @E J@C@:8K< D@E<I8CJ )C
F@EPF &<E>8@ @J 8 ‘JF;8 MFC:8EF’@JJL@E> :8I9FE8K@K< DFI<FIC<JJ ;<
MF@; F= J@C@:8K<J .?< :8I9FE8K@K< MFC:8EF<J 8CJF JL>><JK K?8K D8EKC<
GCLD<J DLJK 9< 8:K@M<CP =FID@E> 9<CFN :FEK@E<EK8C :ILJK “.?< @JFKFG<
J@>E8KLI<J =FLE; @E D8EP :8I9FE8K@K<J ?8M< 9<<E 8KKI@9LK<; KF @EMFCM<
D<EK F= I<:P:C<; G<I?8GJ 8><; C@D<JKFE< FI FK?<I :8I9FE8K<I@:? D8K<
I@8C ;LI@E> GCLD< 8:K@M@KP FI ><E<I8K@FE F= D8>D8J =IFD ;<<G D8EKC<
D8K<I@8C <EI@:?<; @E )X <EKI8@E<; N@K?@E 8 GCLD<”<CC 8E; .@CKFE

.?< )C F@EPF &<E>8@ C8M8 @J I@:? @E K?< I8I< JF;@LD 8E; GFK8JJ@LD
:8I9FE8K< D@E<I8CJ EP<I<I@K< 8E; >I<>FIP@K< L< KF K?@J LELJL8C :FD
GFJ@K@FE K?< C8M8 <ILGKJ 8K I<C8K@M<CP CFN K<DG<I8KLI<J F= 8GGIFO@D8K<CP
° 8 K<DG<I8KLI< JF CFN K?8K K?< DFCK<E C8M8 8GG<8IJ 9C8:B @E JLE
C@>?K I8K?<I K?8E ?8M@E> K?< I<; >CFN :FDDFE KF DFJK C8M8J #K @J 8CJF
:?8I8:K<I@Q<; 9P ?8M@E> DL:? CFN<I M@J:FJ@KP K?8E J@C@:8K< C8M8J F=K<E
C<JJ M@J:FLJ K?8E N8K<I .?< JF;@LD 8E; GFK8JJ@LD :8I9FE8K< D@E<I8CJ
F= K?< C8M8J <ILGK<; 8K )C F@EPF &<E>8@ 8I< LEJK89C< 8K K?< 8IK?J JLI
=8:< 8E; JLJ:<GK@9C< KF I8G@; N<8K?<I@E> HL@:BCP KLIE@E> =IFD 9C8:B KF
>I<P @E :FCFI .?< I<JLCK@E> MFC:8E@: C8E;J:8G< @J K?<I<=FI< ;@==<I<EK
=IFD 8EP C8E;J:8G< =FID<; 9P J@C@:8K< C8M8J
::FI;@E> KF LIB< <K 8C  K?< F::LII<E:< F= :8I9FE8K@K<J @J
N@KE<JJ F= M<IP FC; JLKLI<J K?8K D8P ?8M< <OG<I@<E:<; J<M<I8C 1@CJFE
:P:C<J N@K? 8::LDLC8K@FE F= C8I>< MFCLD<J F= ;<<GJ<8K<; ‘<OFK@:’D@E
<I8CJ =FID<; 9P GIF:<JJ<J N@K?@E K?< JL9;L:K@FE QFE< 8CJF @E FLI M@<N
@EMFCM@E> ?L>< 8DFLEKJ F= D8I@E< J8CKJ
, @J 8 :FEK@E<EK8C I@=K N@K?FLK :FEK8:K N@K? K?< F:<8E .IFE8 8E;
:8I9FE8:<FLJ J8CKJ 8I< ;FD@E8K@E> @E K?< JFLK?<IE G8IK F= K?< ,
N?@C< :?CFI@;<J ;FD@E8K< @E K?< EFIK?<IE G8IK .?@J :8E 9< <OGC8@E<;
9P M8I@FLJ JFLI:<J F= ‘?@;;<E J8CKJ’@E K?< ?P;IFK?<ID8C JPJK<DJ F= K?<
I@=K .?< :8I9FE8K@K<J 8JJF:@8K<; N@K? )C F@EPF &<E>8@ 8I< 8CJF 8 G8IK
F= K?< JFLK?<IE JPJK<D F= K?< I@=K
4.3. Salt deposits in Danakil, Afar
8ICP <OGCFI8K@FE @E K?< =8I 8I<8 9P "LK:?@EJFE 8E; E><CJ 
I<JLCK<; @E K?< ;@J:FM<IP F= K?@:B J<HL<E:<J F= *C<@JKF:<E<'@F:<E<
J8CKJ .?<P ;<J:I@9< JFD< F= K?<@I TE;@E>J 9P “… K?< 8E8B@C <GI<J
J@FE 8E; K?< JLIIFLE;@E> I<>@FE F= K?< =8I :FEK8@E K?@:B J<HL<E:<J F=
*C<@JKF:<E<'@F:<E< J8CK N@K? 8K C<8JK  D F= <M8GFI@K< ?8M@E> 8::L
DLC8K<; 9<E<8K? K?< J8CK G8E F= (FIK?<IE 8E8B@C .?@J J<HL<E:< 8CJF
@E:CL;<J C8K<I8CCP :FEK@ELFLJ ?FI@QFEJ F= :8IE8CC@K< I8E>@E> =IFD  D
KF D @E K?@:BE<JJ @E 8JJF:@8K@FE N@K? K?< ?P;IFLJ J8CK 9@J:?F=@K<
∼D @E K?@:BE<JJ F::LII@E> 8K ;<GK?J I8E>@E> =IFD  D KF  D
9<CFN K?< JLI=8:< 8J :FETID<; 9P 9FI<?FC< ;8K8”"LK:?@EJFE 8E;
E><CJ 
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J8CK U8KJ ×BD CF:8K<; EFIK? F= &8B< 8J<C< ∼ BD EFIK? F= K?<
M<IP 8:K@M< IK8 C< MFC:8EF @E K?< EFIK?<IE =8I I<>@FE F= K?@FG@8
I@KI<8 &8B< 8J<C< @J 8 G<ID8E<EKCP J8CKJ8KLI8K<; C8B< N@K? 8 JLI=8:<
<C<M8K@FE F= D 9<CFN J<8 C<M<C "< ;<J:I@9<J JFD< F= K?< JKIL:KLI<J
=FLE; FE K?< - U8EB F= 8CCFC 8J “'FLE;J FI KFN<IJ F= ?P;IFK?<ID8C
J8CK GI<:@G@K8K<; =IFD ?FK JGI@E>J …” .8C9FK  @> 
*<I?8GJ K?< DFJK @EKI@>L@E> =<8KLI< ?< ;@J:LJJ<J @J K?< JF:8CC<;
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8E; "LK:?@EJFE’J  G@FE<<I@E> ;<J:I@GK@FEJ F= K?@J =<8KLI< K?<
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

UNCORRECTED PROOF
M. Hovland et al. Marine and Petroleum Geology xxx (2018) xxx-xxx
Fig. 11. Upper image !FF>C< 8IK? J8K<CC@K< M@<N F= K?< :<EKI8C I<>@FE F= K?< <8JK<IE 9I8E:? F= K?< 8JK =I@:8E ,@=K &(&8B< (8KIFE 8E; K?< JD8CC I<; I<:K8E>C< @E K?< C8B< @J K?<
CF:8K@FE F= K?< @D8>< 9<CFN Bottom image <K8@C<; M@<N F= 8 GFIK@FE F= &8B< (8KIFE E<8I @KJ N<JK<IE 9FI;<I .?@J <CC@GK@:8C N?@K< JKIL:KLI< N@K? :FE:<EKI@: C8P<IJ FE 8 98:B>IFLE;
F= I<; J8CKJ I<GI<J<EKJ 8 JL9JLI=8:< JGI@E> N?@:? @J K?< JFLI:< F= K?< GI<:@G@K8K<; J8CKJ #KJ :<EK<I I@J<J 89FLK  D 89FM< K?< JLIIFLE;@E> I<; J8CK #D8>< GIF;L:<; N@K? !FF>C< 8IK?
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GC8:<J N?@:? :C<8ICP ;<DFEJKI8K<J ?FN :CFJ<CP K?< J8CK GIF;L:K@FE @J 8J
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DF;<C 8E; J8K@J=P J<M<I8C F= K?< Conceptual Elements >@M<E @E K?< #EKIF
;L:K@FE <> Thermo- and ?uid-dynamicsSolubility and precipitation of
saltsRe>ning of saltsSalt preservation 8E; Hidden salts
5. Continental rifting and salts
(LD<IFLJ I@=KI<C8K<; J8CK 98J@EJ 8I< BEFNE NFIC;N@;< 8E; JFD<
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I@=KI<C8K<; J8CK >@8EKJ ?8M< =FID<;


UNCORRECTED PROOF
M. Hovland et al. Marine and Petroleum Geology xxx (2018) xxx-xxx
Fig. 12. .?< Gada ‘Ale J8CK @EK<IC8P<I<; C8M8 MFC:8EF Left D8G DF;@T<; =IFD 8I9<I@ 8E; 08I<K  Right !FF>C< 8IK? @D8>< F= !8;8 ‘C< ,<; 8IIFNJ D8IB -  J8CK ;FD< N@K?
@EK<I:8C8K<; C8M8 !!8;8 ‘C< MFC:8EF .?< >I<<E JHL8I< @E K?< C<=K @D8>< J?FNJ K?< CF:8K@FE F= K?< I@>?K @D8><  FI @EK<IGI<K8K@FE F= K?< I<=<I<E:<J KF :FCFI @E K?@J T>LI< C<><E; K?<
I<8;<I @J I<=<II<; KF K?< 1<9 M<IJ@FE F= K?@J 8IK@:C<
Fig. 13. Left 8 :FE:<GKL8C ><FGIFTC< K?IFL>? &8B< 8J<C< EFK KF J:8C< 98J<; FE .8C9FK  8E; "FMC8E; <K 8C 8 J?FN@E> ?FN J8CK :8E 9< GIF;L:<; 8::FI;@E> KF K?< ?P
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5.1. Geologic history of the red sea area
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5.2. The rifting of the red sea
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8 G?8J< F= MFC:8E@JD 8K ∼ '8 N@K? 98J8CK@: ;@B<J 8E; C8P<I<; >89
9IF 8E; >I8EFG?PI< 9F;@<J 8GG<8I@E> JPE:?IFEFLJCP K?IFL>?FLK K?< <E
K@I< ,<; -<8 FJNFIK?  8E; I<=<I<E:<J K?<I<@E .?LJ K?< ,<; -<8
C@EB<; KNF M<IP 8:K@M< MFC:8E@: :<EK<IJ CF:8K<; 89FLK  BD 8G8IK
FE< @E EFIK?<IE >PGK GIF;L:@E> LG KF BDX F= MFC:8E@: D8K<I@8C
8E; FE< @E 3<D<E F= BDX @E K?< JFLK? J<< 8CJF @> 
.?@J @J 8CJF @E 8>I<<D<EK N@K? F:?I8E  N?F JK8K<J K?8K “E
<G@JF;< F= ;@B< @EKILJ@FE ;8K<; 8K  '8 @J I<:FI;<; 8CFE> K?< <E
K@I< C<E>K? F= K?< ,<; -<8 8E; K?< I89@8E D8I>@E .?@J <G@JF;< N8J


UNCORRECTED PROOF
M. Hovland et al. Marine and Petroleum Geology xxx (2018) xxx-xxx
Fig. 14.  -B<K:? F= 8 ><FCF>@:8C GIFTC< DF;@T<; =IFD .8C9FK  ?@J @>  #K J?FNJ K?< JG<:K8:LC8I J8CK MFC:8EF<J 8K 8CCFC @E K?< 8E8B@C ;<GI<JJ@FE ."- “:K@M< KFN<IJ F=
?P;IFK?<ID8C J8CK”  "-“8J@E UFFI<; 9P ?P;IFK?<ID8C J8CKJ” " “<8; ?P;IFK?<ID8C :FE<”.8C9FKJ K<ID@EFCF>P  -8K<CC@K< @D8>< F= K?< 8CCFC 8I<8 8E; G8IKJ F= &8B< 8J<C<
J8CK G8EC8B< .?< P<CCFN C@E< 1 J?FNJ K?< CF:8K@FE F= GIFTC< @E  'F;@T<; =IFD .8C9FK   -L>><JK<; ‘'<>8GFCP>FE8C :FEM<:K@FE :<CCJ’.8C9FK  8JJF:@8K<; N@K?
LGN<CC@E> 8E; J<<G8>< =<8KLI<J FE &8B< 8J<C< 8E; 8K K?< 8CCFC J8CK DFLEK8@EJ DF;@T<; =IFD .8C9FK   FI @EK<IGI<K8K@FE F= K?< I<=<I<E:<J KF :FCFI @E K?@J T>LI< C<><E; K?< I<8;<I
@J I<=<II<; KF K?< 1<9 M<IJ@FE F= K?@J 8IK@:C<
DFI< @EK<EJ< @E K?< JFLK?<IE ,<; -<8 8E; N8J K?<I< 8::FDG8E@<; @E
GC8:<J 9P @EKILJ@FE F= GCLKFE@: 9F;@<J F= >I8E@K< KF >899IF@: :FDGFJ@
K@FE”.?@J @J 8CJF N?<I< K?< TIJK F:<8E@Q8K@FE @E K?< ,<; -<8 JK8IK<;
5.3. Salt formation in the red sea
::FI;@E> KF FE8KK@ <K 8C  K?< J8CK @E K?< ,<; -<8 ?8GG<E<;
KF 8::LDLC8K< 8J =FCCFNJ “M8GFI@K< ;<GFJ@K@FE KFFB GC8:< K?IFL>?
FLK K?< <EK@I< ,<; -<8 98J@E JK8IK@E> 8K 8IFLE;  '8 @E K?< '@;
;C<'@F:<E< -<II8M8CC@8E 8E; I<8:?@E> 8 K?@:BE<JJ F= K?FLJ8E;J F= D<
K<IJ '@K:?<CC <K 8C  FJNFIK?  "8C@K< 8E; 8E?P;I@K<>PG
JLD N<I< K?< D8@E D@E<I8C G?8J<J K?<P 8I< CF:8CCP @EK<I9<;;<; N@K?
J8E;JKFE<J 8E; J?8C<J 8J N<CC 8J N@K? :8I9FE8K< GC8K=FID ;<GFJ@KJ
@E;@:8K@E> @EK<IM8CJ F= EFID8C D8I@E< ;<GFJ@K@FE” E; 8::FI;@E> KF
L>LJK@E <K 8C  “.?< J<;@D<EK :FM<I :FEJ@JKJ F= '@F:<E< <M8GFI
@K<J 8E; PFLE><I G<C8>@: :8I9FE8K< FFQ< N@K? C8I>< K?@:BE<JJ<J F= LG KF
BD <> !@I;C<I 8E; 1?@KD8IJ?  -<8IC< 8E; ,FJJ  !@I;C<I
 FEK@E<EK8C 9I<8BLG 8E; J<8UFFI JGI<8;@E> :8LJ<; K?< ;@JILG
K@FE F= K?<J< <M8GFI@K<J N?@:? @E JFD< GC8:<J ?8M< 9<<E J?FNE KF UFN
KFN8I; K?< ;<<G<I 8O@8C I@=K @E K?< =FID F= J8CK >C8:@<IJ BEFNE 8J JL9
D8I@E< E8D8B@<IJ !@I;C<I  '@K:?<CC <K 8C ”
#E 8 I<:<EK JKL;P 98J<; FE I<U<:K@FE J<@JD@: ;8K8 '@K:?<CC <K 8C
 ?8M< I<8:?<; K?< =FCCFN@E> :FE:CLJ@FEJ 98J<; FE :FEM<EK@FE8C
@EK<IGI<K8K@FE F= K?< ‘-I<U<:KFI’K?< @E=<II<; KFG F= <M8GFI@K<J I<U<:
KFI “J K?< <M8GFI@K<J :8EEFK ?8M< 9<<E ;<GFJ@K<; 89FM< J<8 C<M<C
K?<P GIFM@;< 8 :FEJKI8@EK FE K?< JL9J@;<E:< @E K?< =FCCFN@E> ;@J:LJ
J@FEJ” “J@;< =IFD ;@8G@IJ K?< LGG<I C<M<CJ F= K?< - I<U<:K@FE :FEJ@J
K<EKCP C@< J?8CCFN<I K?8E  D9JC 5D<KI<J 9<CFN J<8 C<M<C6 #E K?<
EFIK?<IE ,<; -<8 - =FIDJ 8 D ;<<G ;<GI<JJ@FE 8C@>E<; N@K? K?<
I@=K” “1< JL>><JK K?8K K?< <M8GFI@K<J FI@>@E8CCP ?8; 8 U8K ?FI@QFEK8C
JLI=8:< 8K K?< <E; F= K?< '@F:<E< 8E; ?8M< JL9J<HL<EKCP 9<<E ;@JKFIK<;
9P @JFJK8K@: <==<:KJ 8E; 8O@8C I@=K@E> N?@:? @E KLIE GIFDFK<; <M8GFI@K<
UFN8>< )V8O@J <M8GFI@K< ;<GI<JJ@FEJ :FII<JGFE; N@K? UFNJ @;<EK@T<;
N@K? DLCK@9<8D JFE8I LIK?<IDFI< 8:IFJJI@=K CFNJ @E FL>L<I >I8M
@KP 8EFD8C@<J I<GI<J<EK M8CC<PJ @E K?< LE;<ICP@E> 98J<D<EK .?< FV8O@J
<M8GFI@K< ;<GI<JJ@FEJ FM<IC@< K?FJ< M8CC<PJ 8J NFLC; 9< <OG<:K<; @=
?8CFB@E<K@: DFM<D<EKJ N<I< >I<8K<JK N?<I< K?< <M8GFI@K<J 8I< CF:8CCP
K?@:B C<8;@E> KF ;<U8K@FE F= K?< <M8GFI@K< JLI=8:<”'@K:?<CC <K 8C

.?< E8KLI< F= K?< :ILJK @E K?< :<EKI8C ,<; -<8 N8J ;@J:LJJ<; 9P
'@K:?<CC 8E; *8IB  N?F JL>><JK K?8K @K @J F= F:<8E@: :ILJK8C :FD
GFJ@K@FE .?@J @E=<I<E:< @J 98J<; G8IKCP FE K?< @EK<IGI<K8K@FE F= =I<<8@I
>I8M@KP ;8K8 9P -8E;N<CC <K 8C  8E; F= JLIT:@8C J@;< J:8E JFE8I
;8K8 @E K?< :<EKI8C ,<; -<8 '@K:?<CC 8E; L>LJK@E  “.?< >I8M
@KP T<C; J?FNJ D8EP C@E<8I =<8KLI<J :IFJJ@E> K?< :<EKI8C ,<; -<8 @E ;@
I<:K@FEJ JL9G8I8CC<C N@K? K?< GC8K< JGI<8;@E> ;@I<:K@FE .?<J< 8I< J@D
@C8I DFIG?FCF>@:8CCP @E >I8M@KP ;8K8 KF JCFNJGI<8;@E> D@;F:<8E I@;><
JGI<8;@E> :<EK<IJ” “#= :FII<:K D8>E<K@: 8EFD8C@<J D8P 9< 8KK<EL8K<;
8J 8 :FEJ<HL<E:< F= >I<8K<I ;<GK? F= K?< :ILJK 8JJF:@8K<; N@K? K?< CF8;
@E> 9P K?< <M8GFI@K<J N?@:? I<8:? J<M<I8C BD @E K?@:BE<JJ 8N8P =IFD
K?< 8O@J @E J<@JD@: ;8K8”'@K:?<CC 8E; L>LJK@E 
.?< JL>><JK@FE 9P '@K:?<CC <K 8C  K?8K “K?< <M8GFI@K<J FI@>@
E8CCP ?8; 8 U8K ?FI@QFEK8C JLI=8:< 8K K?< <E; F= K?< '@F:<E<”D8P EFK


UNCORRECTED PROOF
M. Hovland et al. Marine and Petroleum Geology xxx (2018) xxx-xxx
Fig. 15. !<FCF>@:8C D8G F= K?< ,<; -<8 8I<8 N?<I< K?< FLKC@E< F= K?< I89@8E –(L9@8E
-?@<C; (- @J :C<8ICP J<<E .?< D8@E GCLKFE@: 8E; MFC:8E@: LE@KJ JLIIFLE;@E> K?< ,<; -<8
8I< C@JK<; @E K?< D8G C<><E; 8E; 8I< >@M<E 8J ‘(<FGIFK<IFQF@: KF 8D9I@8E’–
'8 GCLKFE@: ‘IPF><E@8E 8E; ;@8:8I8E’– '8 J<;@D<EK8IP 8E; MFC:8EFJ<;@
D<EK8IP ‘*8C<F><E<’– '8 MFC:8E@: ‘+L8K<IE8IP’– '8 MFC:8E@: '8G DF;
@T<; =IFD ‘)E< !<FCF>P’?KKGGFIK8CFE<><FCF>PFI>)E<><FCF>P!CF98C  FI @EK<I
GI<K8K@FE F= K?< I<=<I<E:<J KF :FCFI @E K?@J T>LI< C<><E; K?< I<8;<I @J I<=<II<; KF K?< 1<9
M<IJ@FE F= K?@J 8IK@:C<
9< :FII<:K @= K?< ;<GFJ@K@FE F= J8CK N8J 8 I<JLCK F= ?P;IFK?<ID8C 8:K@M
@KP 8E; K<:KFE@: GIF:<JJ<J @E K?< TIJK GC8:< .?< @JFJK8K@: <==<:KJ F= J8CK
;<GFJ@KJ D8P 8CJF 9< @EK<IGI<K<; ;@==<I<EKCP #= 8 D8JJ F= <M8GFI@K<J @J
CF8;<; FEKF 8 CF:8C 8I<8 F= K?< F:<8E@: :ILJK K?< :ILJK N@CC JL9J@;<
KF D8@EK8@E @JFJK8K@: 98C8E:< "FN<M<I K?< JL9J@;<E:< N@CC 9< C@D@K<;
8E; JCFN ;L< KF K?< CFN ;<EJ@KP F= J8CK <>  >:DXW M<IJLJ –
>:DXW =FI K?< LE;<ICP@E> D8EKC< D8JJ<J
E 8CK<IE8K@M< <OGC8E8K@FE 9P K?< ?P;IFK?<ID8C J8CK DF;<C @J K?8K
J8CK @J KI8EJGFIK<; LGN8I;J =IFD K?< ;<<G 9P ?P;IFK?<ID8C UFN 8E; ;<
GFJ@K<; 8J JFC@; J8CK FEKF K?< J<8UFFI LGFE :FFC@E> @E GFE;J F= ?@>?;<E
J@KP 9I@E<J .?< I<DFM8C F= J8CK =IFD 9<CFN N@CC :8LJ< 8 J@DLCK8E<FLJ
JL9J@;<E:< F= K?< J<8UFFI KF D8@EK8@E D8JJ 98C8E:<  K<:KFE@: ‘JHL<<Q
@E>’F= J8CK JCLII@<J FI ;L:K@C< J8CK =IFD K?< ;<<G =8LCKJ 8JJF:@8K<; N@K?
?P;IFK?<ID8C UFN LG @EKF K?< 98J@E N@CC @E;L:< 8 J@D@C8I <==<:K KF D8@E
K8@E D8JJ 98C8E:<
5.4. Salt-cored ridges in half-grabens, northern red sea
#E K?< EFIK?<IE ,<; -<8 '8IK 8E; ,FJJ  ;<J:I@9<; ELD<I
FLJ ‘;@8G@IJ’F::LII@E> @E N8K<I ;<GK?J I8E>@E> =IFD  KF  D
"FMC8E; <K 8C  .?<P 8I< KPG@:8CCP <CFE>8K<; 8KK8@E@E> C<E>K?J
<O:<<;@E> BD 8E; N@;K?J F= BD 8E; K?<P 8I< <@K?<I <OGFJ<; FI
:FM<I<; 9P LG KF FE< BD F= J<;@D<EKJ .?<J< ‘;@8G@IJ’:FDDFECP ?8M<
=FID<; <@K?<I 8CFE> K?< 9FLE;8IP =8LCKJ F= ?8C=>I89<EJ =FID<; 9P <O
K<EJ@FE8C I@=K@E> FI @EJ@;< K?< I@=K UFFIJ )E< F= K?< DFJK GIFEFLE:<;
GFJ@K@M< =<8KLI<J @J ∼D N@;< 8E; I@J<J 8K C<8JK  D 89FM< K?< J<;
@D<EK:FM<I<; J<89<;
-FD< ‘;@8G@IJ’8I< 8CJF KFGG<; 9P E<>8K@M< ‘:FCC8GJ<’JKIL:KLI<J FE<
F= N?@:? D<8JLI<J ∼BD 8:IFJJ 8E; D @E ;<GK? '8IK 8E; ,FJJ
 @EK<IGI<K<; K?<J< KF I<GI<J<EK J8CK ;@JJFCLK@FE G@KJ "FMC8E; <K
8C  @EK<IGI<K<; K?<J< I@;><J 8E; ‘;@8G@IJ’KF I<GI<J<EK GI@D8IP
J8CK @EA<:K@K<J 8E; <OKI8;@K<J @< ?P;IFK?<ID8C 8E; K<:KFE@: =<8KLI<J
.?LJ K?< @EK<IGI<K8K@FE F= K?<J< ‘E<>8K@M<’JKIL:KLI<J FE KFG F= K?<
‘;@8G@IJ’8I< K?8K ?P;IFK?<ID8C M<EK@E> @J FE>F@E> N@K? ;<GFJ@K@FE F=
J8CKJ 8IFLE; K?< FG<E@E> F= K?< M<EKJ @< K?< FGGFJ@K< F= ;@JJFCLK@FE
.?@J D<8EJ K?8K K?< 8::LDLC8K@FE F= J8CK E<8I K?< J<89<; @J 8E FE>F@E>
GIF:<JJ 8J @J 8CJF <M@;<E:<; @E K?< =FCCFN@E> F9J<IM8K@FEJ 8E; =<8KLI<J
5.5. Red Sea Deeps
CFE> K?< :<EK<I F= K?< ∼BD CFE> ,<; -<8 K?<I< 8I< DFI<
K?8E  CF:8C ‘<<GJ’,8JLC <K 8C  L>LJK@E <K 8C  
.?<J< 8:K@M< JGI<8;@E> :<EK<IJ '@K:?<CC <K 8C  ?FJK ?P;IFK?<I
D8C :@I:LC8K@FE :<CCJ 8E; JFD< F= K?< ;<<G<JK KIFL>?J :FEK8@E ?FK 9I@E<J
?I?8I;K 8E; "ü9J:?<I  "FN<M<I K?< <O8:K CF:8K@FEJ F= K?< ?P
;IFK?<ID8C M<EKJ K?8K =<<; K?< 9I@E< GFE;J 8I< JK@CC EFK BEFNE 9<:8LJ<
“K?< 9I@E< JGI<8;J FM<I K?< <EK@I< 9FKKFD F= K?< 98J@E”IFFBJ <K 8C
 .?I<< F= K?< ,<; -<8 <<GJ KC8EK@J ## <<G .?<K@J <<G 8E;
'898?@JJ <<G 8I< :?FJ<E KF ;@J:LJJ K?< ?P;IFK?<ID8C GIF:<JJ<J 8E;
J8CK ;<GFJ@K@FE @E K?< ,@=K 9<:8LJ< K?<J< <<GJ 8I< N<CC :?8I8:K<I@Q<;
9P I<:<EK ;8K8
5.5.1. The Atlantis II deep
::FI;@E> KF EJ:?LKQ  “.?< KC8EK@J ## <<G @J FE< F= K?<
DFJK I<D8IB89C< J<8UFFI J<KK@E>J F= K?< GC8E<K #K @J K?< C8I><JK BEFNE
GI<J<EK;8P JL9D8I@E< ?P;IFK?<ID8C <EM@IFED<EKJ :FEJ@JK@E> F= 8
BDX KFGF>I8G?@: ;<GI<JJ@FE CF:8K<; @E K?< 8O@8C KIFL>? F= K?< ,<;
-<8 8K  D ;<GK? .?< ;<GI<JJ@FE KI8GJ ?FK 8E; ;<EJ< 9I@E<J =<; 9P
?P;IFK?<ID8C UL@;J K?< JFLI:< F= N?@:? ?8M< EFK P<K 9<<E J8DGC<;”
 @> 
Fig. 16.  J?8;<;I<C@<= 98K?PD<KIP D8G F= K?< KC8EK@J ## 8E; @J:FM<IP <<GJ DF;@T<;
=IFD L>LJK@E <K 8C  .?< KNF I<; ;FKJ D8IB<; ‘’8E; ‘’8I< K?< CF:8K@FEJ F=
K?< KNF J@K<J ;I@CC<; 9P -* <<G -<8 I@CC@E> *IFA<:K &<>  @E  .?< 9CL<KFE<;
:<EKI8C 8I<8 @E;@:8K<J K?< I<>@FE N?@:? @J ;<MF@; F= UFN@E> J8CK <M@;<E:<; 9P UFNC@E<J
FE K?< JLI=8:< F= K?< JC@;@E> G@EB J8CK J<< 8CJF E<OK @D8>< @>   FI @EK<IGI<K8K@FE
F= K?< I<=<I<E:<J KF :FCFI @E K?@J T>LI< C<><E; K?< I<8;<I @J I<=<II<; KF K?< 1<9 M<IJ@FE F=
K?@J 8IK@:C<


UNCORRECTED PROOF
M. Hovland et al. Marine and Petroleum Geology xxx (2018) xxx-xxx
.?< TIJK 8:KL8C ?<8KUFN <JK@D8K<J @E K?< ,<; -<8 <<GJ N<I< ;FE<
9P EJ:?LKQ <K 8C  8E; N<I< :8C:LC8K<; KF 9<KN<<E  8E;
D1DX .?<P 8CJF EFK<; K?8K K?< I8E>< F= ?<8KUFN M8CL<J :FI
I<JGFE;J KF 9FKKFD ?<8KUFN M8CL<J K?8K ?8M< 9<<E I<GFIK<; <8IC@<I
=FI K?< 8O@8C QFE< F= K?< ,<; -<8 1?<I<8J FK?<I 9I@E< GFFCJ @E;@
:8K< JK<8;PJK8K< JK89C< K<DG<I8KLI< 8E; J8C@E@KP :FE;@K@FEJ @K N8J
=FLE; K?8K K?< 08C;@M@8 <<G :<EKI8C ,<; -<8 9I@E< @E:I<8J<; 9P  °
8E; ‰ I<JG<:K@M<CP 9<KN<<E  8E;  .?@J JL>><JKJ K?8K K?<
<<GJ @E K?< ,<; -<8 LE;<I>F JK8><J F= ?<8K@E> <> 9P J@>E@=@:8EK ?P
;IFK?<ID8C 9I@E< ;@J:?8I>< 8CK<IE8K@E> N@K? HL@<K G<I@F;J :?8I8:K<I@Q<;
9P :FFC@E> EJ:?LKQ <K 8C  .?LJ @K @J <OG<:K<; K?8K K?< KI8EJ@
K@FE =IFD K?< :FEK@E<EK8C I@=K@E> JK8>< KF K?< F:<8E@: :ILJK8C JK8>< D8P
9< <HL@M8C<EK KF N?8K (FIKFE <K 8C  I<=<I KF 8J incipient/intrusive
oceanic crust .?<@I ELD<I@:8C DF;<C GI<;@:KJ K?8K @K @J @E K?@J JK8>< K?8K
J8CK @J =FID@E> 8E; TCC@E> K?< I@=K98J@E @E 8 M<IP I8G@; GIF:<JJ <>
JK8><  8E;  @E @>  *8IK  "FMC8E; <K 8C 
::FI;@E> KF K?< ?P;IFK?<ID8C J8CK DF;<C JL:? G<I@F;J N@K? D8J
J@M< ?P;IFK?<ID8C LGN8I;J KI8EJGFIK8K@FE F= ;<<G<ICF:8K<; ‘?@;;<E
J8CKJ’ N@CC @E;L:< ;I8D8K@: JL9J@;<E:< 8E; J<8UFFI :FCC8GJ<  @>J 
8E; 
CK?FL>? M<IP C@D@K<; M@JL8C F9J<IM8K@FEJ ?8M< 9<<E F9K8@E<; =IFD
@EJ@;< 8E; 8;A8:<EK KF K?< KC8EK@J ## <<G K?<I< N8J 8 EFK89C< 8C
K?FL>? C@D@K<; JLIM<P :FE;L:K<; @E  FN<I  .?@J :IL@J<
N8J ILE N@K? K?< M<JJ<C ,0 ‘):<8ELJ’8E; @K ;@J:FM<I<; J<<G8>< F=
9I@E<J E8D<; K?< ‘):<8ELJ -<<G’ 8CFE> K?< N<JK<IE N8CC F= K?< :<EKI8C
I@=K M8CC<P "<I< 8K D ;<GK? K?< 8D9@<EK J<8N8K<I K<DG<I8KLI<
N8J ∼° 8E; K?< K<DG<I8KLI< F= K?< ):<8ELJ J<<G N8K<I N8J ∼°
FN<I  ;A8:<EK KF K?< ):<8ELJ -<<G K?<P 8CJF ;@J:FM<I<; JFD<
;@==LJ@M< J<<GJ “K J<M<I8C GFJ@K@FEJ …8 K?@:B C8P<I F= JC@>?KCP N8ID
J8C@E< N8K<I N8J F9J<IM<; 8K K?< 9FKKFD LII<EK D<8JLI<D<EKJ @E;@
:8K< K?8K K?<J< K?@E ;<EJ< C8P<IJ N<I< UFN@E> ;FNEJCFG< .?@J JL>><JKJ
K?8K ;<EJ< 9I@EP N8K<I @J J<<G@E> FLK F= K?< N8CCJ F= K?< I@=K M8CC<P 8E;
UFN@E> ;FNE K?< N8CCJ”FN<I 
EJ:?LKQ  ;@J:LJJ<; K?< :FDGFJ@K@FE F= K?< 9I@E< @E K?< K
C8EK@J ## <<G “.?< J8KLI8K@FE @E;@:<J I<M<8C K?8K K?< 9I@E< @J LE;<IJ8K
LI8K<; N@K? I<JG<:K KF ?8C@K< >PGJLD 8E; 8E?P;I@K< 8K @E J@KL K<DG<I8
KLI< 'FEE@E 8E; ,8D9FQ  EJ:?LKQ <K 8C  JL>><JK@E> K?8K
K?< D8AFI J8CK :FE:<EKI8K@FEJ 8I< EFK :FEKIFCC<; 9P @E J@KL <HL@C@9I@LD F=
K?< 9I@E< GFFC N@K? I<JG<:K KF J8CK D@E<I8CJ .?< 9I@E< @J :CFJ< KF <HL@C@9
I@LD N@K? ?8C@K< 8K 8 K<DG<I8KLI< :CFJ< KF K?8K F= ,<; -<8 9FKKFD N8K<I
° N?@:? JLGGFIKJ K?< ?PGFK?<J@J K?8K K?< J8C@E@KP F= K?< @E:FD@E>
9I@E< ?8J 9<<E I<8:?<; K?IFL>? <HL@C@9I@LD N@K? <M8GFI@K< D@E<I8CJ 8K
J<8N8K<I K<DG<I8KLI< 9<=FI< ?<8K@E> F= K?< JFCLK@FE K?IFL>? =I8:KLI<;
,<; -<8 98J8CK@: :ILJK”EJ:?LKQ 
E 8CK<IE8K@M< @EK<IGI<K8K@FE F= K?<J< F9J<IM8K@FEJ @J K?8K ?P;IFK?<I
D8C 9I@E<J J8KLI8K<; N@K? J8CKJ 8K ?@>?<I K<DG<I8KLI<J @E K?< ;<<G D8P
GI<:@G@K8K< J8CKJ C@B< ?8C@K< LGFE :FFC@E> ;LI@E> K?< 8J:<EK 8E; 8K K?<
J<8UFFI @= EFK ;@CLK<; 9P CFN;<EJ@KP 9I@E< "FN<M<I ?@>?JFCL9@C@KP
J8CKJ N@CC EFK GI<:@G@K8K< 8E; D8@EK8@E ?@>? J8C@E@KP @E K?< 9I@E<J 8K K?<
9FKKFD F= K?< <<G .?@J @J G8IK@:LC8ICP K?< :8J< N@K? K?< ?@>?CP JFCL9C<
D8>E<J@LD 8E; GFK8JJ@LD :?CFI@;<J K?8K 8CCFNJ K?<D KF JK8P @E JFCLK@FE
@E K?< 9I@E< GFE; FI KF <J:8G< N?<E ?8C@K< GI<:@G@K8K<J
5.5.2. The Mabahiss Deep
'<KQ  @EM<JK@>8K<; K?< '898?@JJ <<G CF:8K<; 8K °( FE
K?< :<EKI8C ,<; -<8 I@=K 8O@J 8;A8:<EK KF 8 C8I>< MFC:8E@: JKIL:KLI<
ʻ'898?@JJ 'FEJʻ .?@J JL9D8I@E< MFC:8EF :FM<IJ 8E 8I<8 F= ∼ BDX
8E; I<GI<J<EKJ FE< F= K?< C8I><JK @E;@M@;L8C MFC:8E@: JKIL:KLI<J 8CFE> K?<
=I@:8E –I89@8E I@=K JPJK<D  @> 
'<KQ  J8DGC<; 98J8CK =IFD K?@J JL9J<8 MFC:8EF 8E; @;<EK@
T<; K?< E<N=FID<; D@E<I8C GLDG<CCP@K< N?@:? JKIFE>CP @E;@:8K<J @E
K<ID<;@8K< KF CFN K<DG<I8KLI< –° ?P;IFK?<ID8C 8:K@M@KP @E
K?< JLIIFLE;@E>J F= K?< MFC:8EF LIK?<IDFI< ?< :8I<=LCCP 8E8CPJ<; K?<
DFIG?FCF>P F= K?< MFC:8EF 8E; @KJ <<G 8E; I<8:?<; JFD< @EK<I<JK
@E> :FE:CLJ@FEJ =FI <O8DGC< K?8K K?< JDFFK? UFFI F= K?< '898?@JJ
<<G C@B<CP I<GI<J<EKJ K?< JLI=8:< F= K?< LGG<I F:<8E@: :ILJK “ FCCFN
@E> FLK<CC< <K 8C  K?< JK<GN@J< DFIG?FCF>P 8CFE> K?< '898?@JJ
<<G 1<JK<IE 8J@E I<JLCKJ =IFD CF:8C JL9J@;<E:< ;L< KF K?< >I8;
L8C @E@K@8K@FE F= FI>8E@Q<; J<8UFFI JGI<8;@E> K?< U8K ;<GI<JJ@FE DFJK
C@B<CP I<GI<J<EK@E> K?< FLK:IFGG@E> F:<8E@: 98J<D<EK 8E; CF:8K@FE F=
Fig. 17. <8KLI<J I<:FI;<; 9P '<KQ  8;A8:<EK KF K?< 8:K@M< :<EKI8C MFC:8EF ‘'898?@JJ 'FEJ’@E K?< :<EKI8C ,<; -<8 'F;@T<; =IFD '<KQ  (FK< ?FN J8CK @J UFN@E> ;FNE
K?< U8EBJ 8E; KFN8I;J K?< '898?@JJ <<G N?@:? @J JLJG<:K<; UFFI<; 9P F:<8E@: :ILJK LIK?<IDFI< K?< ‘( 8EPFE’ LGG<I I@>?K @J JL>><JK<; KF I<GI<J<EK 8 I8M@E< K?IFL>? J<;@D<EKJ
<M8GFI@K<J <IF;<; 9P J<<G@E> N8K<I9I@E<J <> ‘JGI@E> J8GG@E>’ )I8E>< <K 8C   FI @EK<IGI<K8K@FE F= K?< I<=<I<E:<J KF :FCFI @E K?@J T>LI< C<><E; K?< I<8;<I @J I<=<II<; KF K?< 1<9
M<IJ@FE F= K?@J 8IK@:C<


UNCORRECTED PROOF
M. Hovland et al. Marine and Petroleum Geology xxx (2018) xxx-xxx
K?< (1-JKI@B@E> I@=K 8O@J !L<EEF: <K 8C ” “"FN<M<I K?<
I<JLCK@E> 8>< F= 8K C<8JK  '8 8>I<<J N@K? G8C<FD8>E<K@: ;8K8 9P
!L<EEF: <K 8C  N?@:? JK8K< K?< FEJ<K F= F:<8E@: :ILJK 8::I<K@FE
@E K?< 8I<8 8K ∼ '8 .?<J< TE;@E>J JFD<N?8K :?8CC<E>< K?< 8JJLDG
K@FE 9P F:?I8E  K?8K 8:K@M< J<8UFFI JGI<8;@E> @E K?< '898?@JJ
<<G 8I<8 DLJK 9< PFLE><I K?8E  '8”'<KQ 
-8CK UFNJ I<GI<J<EK 8 ;FD@E8K@E> =<8KLI< @E K?@J <<G 8::FI;@E>
KF '<KQ  J<< @>  “-8CK UFNJ 8I< L9@HL@KFLJCP GI<J<EK 8CFE>
K?< D8I>@EJ F= K?< 1<JK<IE 8J@E LIK?<I ;FNEJCFG< I<GC<E@J?D<EK 8E;
JL9J<HL<EK FM<IUFN F= K?< ;<<G @J @E?@9@K<; 9P K?< 9LC>@E> GI<J<E:< F=
K?< '898?@JJ 'FEJ <;@T:< 8E; 8 GIFKIL;@E> GC8K<8LC@B< =FID8K@FE F=
K?< C18A? ;FD8@E KF K?< EFIK?N<JK 8E; EFIK?<8JK I<JG<:K@M<CP”
'<KQ  8CJF GL9C@J?<; 8 JK<I<F 8E8>CPG? D8G F= K?<
'898?@JJ <<G I<>@FE J?FN@E> ?@>?I<JFCLK@FE J<8UFFI 98K?PD<KIP
8I<=LC 8E8CPJ@J F= K?@J @D8>< :C<8ICP J?FNJ K?< F::LII<E:< F=
GF@EKJFLI:< <IFJ@FE @E K?< ‘J:8IG’8E; 8K K?< 9FKKFD F= K?< ‘( 8EPFE
I8M@E<’ @>  “.?< <J:8IGD<EK 5‘J:8IG’@E @> 6 JLI=8:< 8GG<8IJ
KF 9< ?<8M@CP TJJLI<; @E JCFG<G8I8CC<C ;@I<:K@FE 8E; ;<M<CFGJ @EKF 8E
8KI@LDJ?8G<; =FID8K@FE KFN8I;J K?< N<JK K?<I<9P :CFJ<CP I<J<D9C@E>
K?< ‘<>>9FO G8KK<IE’I<:F>E@Q<; 9P *@C:?<I 8E; CLDJK<@E  8CFE>
J8CK =IFEKJ @E K?< )I:8 8J@E !LC= F= '<O@:F”'<KQ 
5.5.3. The Thetis Deep
.?< .?<K@J <<G N8J <OGCFI<; 9P *@<II<K <K 8C  8E; '@K:?<CC <K
8C   8E; K?<P ;@J:FM<I<; 8E 8GG8I<EK 8EFD8CP @E K?@J G8IK@:
LC8I <<G <JG@K< @K 9<@E> 8 CF:8CCP <E:CFJ<; <<G KFK8CCP JLIIFLE;<;
9P ?@>?<I >IFLE; K?<I< 8I< EF ;<EJ< 9I@E<J KI8GG<; @EJ@;< @K .?@J @J I<
>8I;<; 8J 8EFD8CFLJ =FI KNF I<8JFEJ @ K?<I< 8I< D<K8CI@:? J<;@D<EKJ
8K K?< 9FKKFD F= K?< <<G JLJG<:K<; F= ?8M@E> 9<<E ;<GFJ@K<; 9P :FE
:<EKI8K<; ?P;IFK?<ID8C 9I@E<J *@<II<K <K 8C  8E; @@ K?<I< 8I<
J8CK UFNJ K?8K K<ID@E8K< @EJ@;< K?< <<G N@K?FLK @E:I<8J@E> K?< J8C@E@KP
F= K?< <E:CFJ<; 9F;P F= JK@CC N8K<I '@K:?<CC <K 8C  “/CK@D8K<CP
K?< C8:B F= 8 9I@E< C8B< ?<I< D8P K?<I<=FI< ?8M< 8 JKIL:KLI8C FI@>@E @=
K<:KFE@: DFM<D<EKJ FE 9FLE;8IP N8CC =8LCKJ 8I< KFF JD8CC 8E;FI @E=I<
HL<EK J@>E@=@:8EKCP KF FVJ<K K?< ?<D@G<C8>@: 8E; <M8GFI@K< 9<;J KF 8CCFN
;@JJFCLK@FE N?@C< <M8GFI@K< UFN8>< 8E; J<89<; GIF:<JJ<J 8:K@E> FE JLI
=8:< ?<D@G<C8>@: J<;@D<EKJ 8I< :FEK@EL8CCP ?<8C@E> JL:? FVJ<KJ KF GI<
M<EK N8K<I :@I:LC8K@FE”'@K:?<CC <K 8C 
#E K?< ;<J:I@GK@FE F= K?< .?<K@J <<G 9P '@K:?<CC <K 8C  
K?<P 8CJF @E=<I K?8K K?<I< @J 8:K@M< ?P;IFK?<ID8C 8:K@M@KP K?<I< “*<I
?8GJ 9<:8LJ< 8EP MFC:8E@: 8E;FI ?P;IFK?<ID8C 8:K@M@KP @J =FIKL@KFLJCP
CF:8K<; 8N8P =IFD K?< <M8GFI@K< 9<;J :FE<J KF K?< -1 8E; - 8E;
9<:8LJ< F= K?< ?<D@G<C8>@: :FM<I I<C8K@M<CP C@KKC< F= K?< ?8C@K< ?8J
9<<E ;@JJFCM@E> 8E; :FEKI@9LK@E> KF 8 9I@E< C8P<I @E K?< .?<K@J <<G @E
K?< ><FCF>@:8CCP I<:<EK G8JK” '@K:?<CC <K 8C 
#E :FEKI8JK KF K?@J :FE:CLJ@FE "FMC8E; <K 8C  F==<I<; 8 KFK8CCP
;@==<I<EK <OGC8E8K@FE 98J<; FE 8:K@M< ?P;IFK?<ID8C 8:K@M@KP @EJ@;< 8E;
9<E<8K? K?< .?<K@J <<G J <OGC8@E<; 9P "FMC8E; <K 8C  K?< ?P
;IFK?<ID8C J8CK DF;<C I<HL@I<J K?< G8IK@K@FE F= C8I>< HL8EK@K@<J F= :FE
;<EJ8K@FE N8K<I =IFD K?< G?8J< J<G8I8K@FE QFE< F= K?< ?P;IFK?<ID8C
JPJK<D @E K?< JL9JLI=8:< .?@J ?FK JLG<I:I@K@:8C N8K<I M8GFI 8K ;<E
J@KP 8IFLE;  >:DXW N@CC :FE;<EJ8K< 9P :FFC@E> ;LI@E> K?< LGN8I;J
8J:<EK K?LJ GIF;L:@E> ‘;@JK@CC<;’N8K<I C<8M@E> ?@>? ;<EJ@KP 9I@E< 8E;
GI<:@G@K8K<; J8CK @E K?< ;<<G (LD<I@:8C DF;<C@E> J?FNJ K?8K K?@J N8
K<I M8GFI K<E;J KF <J:8G< LGN8I; @E K?< ‘I<ULO QFE<’"FMC8E; <K 8C
8 N?@:? @J CF:8K<; @DD<;@8K<CP 89FM< K?< ?FKK<JK QFE< F= K?< JPJ
K<D K?8K @J K?IFL>? K?< ;<<G<JK G8IKJ F= K?< <<GJ  @>J  8E; 
.?@J @J 8CJF JLGGFIK<; 9P &<:LD9<II@-8E:?<Q <K 8C  N?F NI@K<
“.?< :F<O@JK@E> M8GFI G?8J< N?@:? 8J:<E;J DFI< I8G@;CP K?8E K?< C@H
L@; NFLC; KI8EJGFIK JLC=LI 8E; >FC; LGN8I;”
.?<I< @J EF ;FL9K K?8K K?@J ‘=I<J?’ ?FK N8K<I @J ?@>?CP :FIIFJ@M< KF
8EP E<8I9P 9F;P F= J8CK @E:CL;@E> K?< F9J<IM<; J8CK UFNJ’E8D8B@<IJ
@E K?< <<G .?LJ K?< M<EK@E> F= :FE;<EJ8K@FE N8K<I LG @EKF JFD< F=
K?< <<GJ @E:CL;@E> K?< .?<K@J <<G D8P ?@E;<I K?< =FID8K@FE F= 8
:FE:<EKI8K<; 9I@E< C8P<I 8E; D8P 8CJF I8G@;CP ;@JJFCM< K?< =IFEK F= K?<
J8CK UFNJ K?8K 8I< DFM@E> KFN8I;J K?< .?<K@J <<G .?@J ;PE8D@: 8E;
I<C8K@M<CP I8G@; GIF:<JJ D8P 8CJF <OGC8@E K?< JK<<G CF98K< J?8G< F= K?<
J8CK UFN K<ID@E8K@FEJ "FMC8E; <K 8C 
5.6. Salt walls and ridges inside Red Sea Deeps
CK?FL>? K?<I< 8I< ELD<IFLJ J8CK:FI<; I@;><J 8CFE> K?< U8EBJ F=
K?< EFIK?<IE ,<; -<8 '8IK 8E; ,FJJ  J@D@C8I I@;><J F= 8GG8I<EKCP
D8JJ@M< J8CK N<I< 8CJF ;@J:FM<I<; :IFJJ@E> FM<I J<M<I8C F= K?< <<GJ
F= K?< ,<; -<8 ::FI;@E> KF ?I?8I;K <K 8C  8E; ?I?8I;K 8E;
"ü9J:?<I  K?< FEI8; <<G @E K?< EFIK?<IE ,<; -<8 @J 8 GFFICP
LE;<IJKFF; 98J@E 8JJF:@8K<; N@K? I@=K@E> 8E; J?<8I 8::FDDF;8K@FE #K
?8J 8 J<I@<J F= 8EFD8CFLJ =<8KLI<J JFD< F= N?@:? ?I?8I;K <K 8C 
8E; ?I?8I;K 8E; "ü9J:?<I  JLJG<:K<; KF 9< J8CK ;@8G@I@JD 9P 8G
GCP@E> K?< :FEM<EK@FE8C <M8GFI@K< DF;<C  @> 
#EJK<8; F= @EK<IGI<K@E> K?< GI<J<EK<; I<U<:K@FE J<@JD@: ;8K8 @E
K?< ‘:FEM<EK@FE8C’D8EE<I N@K? =8LCK GC8E<J <K: 8E 8CK<IE8K@M< @EK<I
GI<K8K@FE @J JL>><JK<; N?<I<9P :LDLC@=FID J8CK 8::LDLC8K<; @E =8LCKJ
8E; =I8:KLI<J @E K?< ;<<G ?P;IFK?<ID8C JPJK<D 8I< GLJ?<; LGN8I;J KF
9< JHL<<Q<; LG 9P K<:KFE@: =FI:<J 8J ;L:K@C< J8CK D8JJ<J .?@J DF;<C
@J I<=<II<; KF 8J ‘J8CK @EA<:K@K<’ @>  "FMC8E; <K 8C  .?<
GIF:<JJ @J JL>><JK<; KF 9< 8::FDG8E@<; 9P ?P;IFK?<ID8C UFN F= J8KL
I8K<; 9I@E<J 8E; J8CK JCLII@<J
Fig. 18. Left 98J<; FE @>  F= ?I?8I;K <K 8C  .?< G@EB :FCFI I<GI<J<EKJ ‘8DFIG?FLJ CFN I<U<:K@M@KP J<@JD@: :?8I8:K<I’ .?@J J@>E8KLI< FI :?8I8:K<I @J JL>><JK<; KF I<GI<J<EK
<@K?<I  FM<IGI<JJLI<; GFI<N8K<I FI  ?@>?J8C@E@KP 9I@E<J GFJJ@9CP ;L:K@C< :LDLC8K@M< J8CK Right "@>?I<JFCLK@FE *8I8JFLE; @D8>< J?FN@E> K?8K K?< ;@8G@I@: D8K<I@8C @J M<IP JK<<G
8E; K?8K @K @J DFJK GIF989CP <OKIL;<; FLK F= K?< J<8UFFI LE;<I GI<JJLI< I8K?<I K?8E 8::LDLC8K@E> 8J 8 DL; MFC:8EF =IFD 8 ;@JK@E:K :FE;L@K "FN<M<I ;L< KF K?< GI<JJLI< I<C<8J< 8EP
JLIGCLJ 9I@E< @E K?< J8CK N@CC M<EK KF K?< J<8N8K<I 8E; N@CC GIF989CP UFN ;FNE?@CC 8E; 8::LDLC8K< @EJ@;< K?< 8;A8:<EK FEI8; <<G  FI @EK<IGI<K8K@FE F= K?< I<=<I<E:<J KF :FCFI @E K?@J
T>LI< C<><E; K?< I<8;<I @J I<=<II<; KF K?< 1<9 M<IJ@FE F= K?@J 8IK@:C<


UNCORRECTED PROOF
M. Hovland et al. Marine and Petroleum Geology xxx (2018) xxx-xxx
5.7. Massive salt ?ows
.?< -* &<>  J:@<EK@T: ;I@CC@E> I<GFIK 8:KL8CCP :FE:CL;<J K?8K
K?<P J8DGC<; UFN@E> J8CK !@I;C<I 8E; 1?@KD8IJ?  "FN<M<I @K
N8J EFK 9<=FI<  ;<:8;<J C8K<I N?<E '@K:?<CC <K 8C  TIJK D8GG<;
K?< J<8UFFI F= K?< :<EKI8C ,<; -<8 N@K? JN8K? 98K?PD<KIP K?8K K?<P ;@J
:FM<I<; K?< C8I>< J8CK UFNJ @E K?< .?<K@J <<G  @>  8E; @E K?< K
C8EK@J ## ;<<G N?<I< K?< -* ;I@CC@E> CF:8K@FEJ ‘’8E; ‘’N<I<
CF:8K<;  @>  .?@J C8KK<I CF:8K@FE @J J<<E KF 9< CF:8K<; @EJ@;< 8 J8CK
UFN 8I<8 J<<E FE @>  &8K<I DFI< ;<K8@C<; N@;<J:8C< D8GG@E> I<
M<8C<; K?8K K?<I< N<I< D8EP FK?<I :<EKI8C ,<; -<8 8I<8J K?8K ?8; UFN
JKIL:KLI<J @EK<IGI<K<; 8J DFM@E> J8CK <> L>LJK@E <K 8C 
.?< @EK<IGI<K8K@FE F= K?< UFN JKIL:KLI<J ?8J 9<:FD< DFI< ;<K8@C<;
I<:<EKCP 8E; @K ?8J 9<<E =FLE; K?8K K?< J8CK :8IG<KJ D8P UFN 8K 8 M<
CF:@KP F= DFI< K?8E  D G<I P<8I  <C;<EJ 8E; '@K:?<CC  .?<J<
JLIGI@J@E>CP C8I>< J8CK UFNJ N<I< <JK@D8K<; KF ?8M< I<C@<=J F= –
D ::FI;@E> KF <C;<EJ 8E; '@K:?<CC  K?< UFN@E> D8K<I@8C @J
JLJG<:K<; KF :FEJ@JK F= 8 ;@JG<IJ@FE F= G8IK@:LC8K< JFC@; J8CK D@O<; N@K?
:C8JK@: J<;@D<EK G8IK@:C<J @E :FE:<EKI8K<; 9I@E< <> 8 J8CK JCLIIP 8J
8CJF JL>><JK<; 9P K?< -* &<>  ;I@CC@E> I<JLCKJ .?< GFJJ@9@C@KP F=
8 :FE:<EKI8K<; :FFC@E> 8E; GI<:@G@K8K@E> 9I@E< :FLC; 8CJF 9< 8;;<;
'@K:?<CC <K 8C  8E; <C;<EJ 8E; '@K:?<CC  @EK<IGI<K K?<J<
J8CK UFNJ KF F::LI 8J 8 :FEJ<HL<E:< F= '@F:<E< <M8GFI@K< ;@JJFCLK@FE
9P ?P;IFK?<ID8C 8:K@M@KP  J@D@C8I M@<N @J 8CJF ?<C; 9P L>LJK@E <K 8C
 8CK?FL>? K?<P ;F EFK D<EK@FE K?8K ?P;IFK?<ID8C GIF:<JJ<J 8I<
@EMFCM<; 9LK @E=<I K?8K K?< KI@>><I@E> D<:?8E@JD =FI K?< J8CK UFN @J
8 :FD9@E8K@FE F= ;@JJFCLK@FE 9P J<8N8K<I 8E; K<:KFE@: <OK<EJ@FE LI
K?<IDFI< K?<P K<ID K?< J8CK UFNJ ‘submarine namakiers’ E8D<; 8=K<I
GC8JK@: JL98<I@8C DFM<D<EK F= >C8:@<IC@B< IF:B J8CK UFN@E> ;FNE K?<
‘%L?@(8D8B’J8CK ;FD< 8E; FK?<I J8CK ;FD<J @E K?< 8J?K@ I<>@FE F=
#I8E &<<J  .8C9FK  L>LJK@E <K 8C 
IFD K?<@I 8;;<; 98K?PD<KIP D8GG@E> L>LJK@E <K 8C  TE;
J@D@C8I J8CK UFNJ <JG<:@8CCP N<CC ;<M<CFG<; @E K?< ‘#EK<I .IFL>? 4FE<J’
#.4J N?<I< “… CFE>N8M<C<E>K? I<C8K@M< KF K?< ?LDDF:BP K<II8@E
@E K?< <<GJ C@E<8I I@;><J 8I< M@J@9C< @E D8EP I<>@FEJ” “1?<I< KNF
E8D8B@<IJ UFN@E> =IFD FGGFJ@K< J@;<J F= K?< I@=K D<<K 8 :<EKI8C :C<=K
FI JLKLI< @J ><E<I8CCP M@J@9C< .?< 98K?PD<KI@: ;8K8 8CJF J?FN E8D8B@<I
UFN I@;><J 8GG8I<EKCP ;<M@8K@E> 8IFLE; MFC:8EF<J 8E; MFC:8E@: I@;><J
FE K?< I@=K U8EBJ JL>><JK@E> K?8K K?<J< 8I< @EUL<E:@E> E8D8B@<I UFN”
L>LJK@E <K 8C 
#E K?< ?P;IFK?<ID8C J8CK DF;<C "FMC8E; <K 8C  GI<;@:K K?8K
C8I>< HL8EK@K@<J F= ?P;IFK?<ID8CCP GIF;L:<; G8IK@:LC8K< J8CK N@CC 8::L
DLC8K< LE;<I>IFLE; @E K?< :<EKI8C J<:K@FEJ F= K?< ,<; -<8 .?<I<=FI<
K?< F9J<IM8K@FE F= K?<J< <OK<EJ@M< J8CK UFNJ @J K8B<E 8J 8EFK?<I @E;@:8
K@FE K?8K K?< ?P;IFK?<ID8C DF;<C @J I<8C@JK@: E @EK<I<JK@E> 8JG<:K F=
K?< ?P;IFK?<ID8C GIF:<JJ @J 8CJF K?8K K?< J8CK UFNJ J<<D KF <D8E8K<
=IFD K?< J@;<J F= K?< :<EKI8C >I89<E I8K?<I K?8E =IFD GF@EK JFLI:<J @E
J@;< K?< >I89<E ::FI;@E> KF L>LJK@E <K 8C  K?< CFE><JK ;@J
K8E:< =IFD K?< :<EKI8C 8O@J F= K?< ,<; -<8 ,@=K KF K?<@I JFLI:< 8I<8 @J LG
KF BD .?@J JL>><JKJ K?8K K?< J8CK UFNJ 8I< :FDGFJ<; F= 9FK? E<NCP
GI<:@G@K8K<; J8CK JCLII@<J 8E; FC;<I J8CKJ 8E; J<;@D<EKJ K?8K ?8M< 9<<E
DF9@C@Q<; 8E; 8I< :FD@E> LG K?< D8@E =8LCKJ 8CFE> K?< U8EBJ  @> 
8J 8CJF JL>><JK<; 9P '@K:?<CC <K 8C  <C;<EJ 8E; '@K:?<CC 
8E; L>LJK@E <K 8C 
5.8. Suggested analogues to the red sea
5.8.1. The South Atlantic rifting
.?< I@=K@E> 8E; FG<E@E> F= K?< -FLK? KC8EK@: @J JL>><JK<; KF 9< 8E
8E8CF>L< KF K?< ,<; -<8 ;<M<CFGD<EK .?< C8I><JK J8CK 98J@E @E K?< -FLK?
KC8EK@: @J K?< -8EKFJ 8J@E :?8I8:K<I@Q<; 9P C8I>< J8CK N8CCJ 8C@>E<;
8CFE> 8 EFIK? –JFLK? ;@I<:K@FE @E K?< ;<<G<JK G8IK F= K?< 98J@E G8I8CC<C
KF K?< I@=K 8O@J 'F?I@8B <K 8C  'F?I@8B 8E; &<IFP  .?@J @J
J@D@C8I KF K?< F::LII<E:< F= K?< J8CK N8CCJ @E K?< EFIK?<IE ,<; -<8 '8IK
8E; ,FJJ 
Fig. 19. .FGF>I8G?@: =<8KLI<J @E K?< .?<K@J <<G 8 EFIK?<IE G8IK 9 JFLK?<IE G8IK : KI8EJ<:K 8:IFJJ K?< JFLK?<IE .?<K@J <<G CF:8K@FE J?FNE @E 9 'F;@T<; =IFD &@>@ <K 8C  8E;
L>LJK@E <K 8C 


UNCORRECTED PROOF
M. Hovland et al. Marine and Petroleum Geology xxx (2018) xxx-xxx
CJF @E K?< -8EKFJ 8J@E K?<I< @J <M@;<EKCP 8 M<IP :CFJ< I<C8K@FEJ?@G
9<KN<<E J8CK ;<GFJ@K@FE 8E; <G@JF;<J F= ?@>? ?<8KUFN <> 98J8CK@:
@EKILJ@M<J 8E; <OKILJ@M<J 8J ;<J:I@9<; 9P 8M@JFE <K 8C  “.?<
I8Q@C@8E J8> 98J@E @J TCC<; N@K? :F8IJ< :C8JK@: 8CCLM@8C =8EJ @E K?< GIFO
@D8C 8I<8 N?@:? >I8;< C8K<I8CCP @EKF J?8CCFN N8K<I :8I9FE8K<J D8@ECP
JKIFD8KFC@K< 8E; K?IFD9FC@K< .?< :8I9FE8K<J N<I< GIF989CP ;<GFJ@K<;
@E 8E 8CB8C@E< C8B< …” “8J< C8M8J N<I< <E:FLEK<I<; @E K?< ,$-
N<CC @E K?< -8EKFJ 8J@E E<8I K?< 98J< F= K?< J8> :8I9FE8K<J …” 8M@JFE
<K 8C 
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J?FIKCP 9<=FI< J8CK ;<GFJ@K@FE ;LI@E> K?< *8I8E8 MFC:8E@JD 8M@JFE <K
8C  K?<I< @J JKIFE> <M@;<E:< =FI 8 J@KL8K@FE I<D8IB89CP J@D@C8I KF
K?< GI<J<EK =8I8E8B@C&8B< J8C<IK8 C< MFC:8E@: J8CK JPJK<D E;
 @E;<<; 8M@JFE <K 8C  ;<J:I@9< 8 ?P;IFK?<ID8C J8CK =FID8K@FE
JPJK<D @E K?< -FLK? KC8EK@: :FDG8K@9C< N@K? K?< ?P;IFK?<ID8C DF;<C
“.?< K?@:B K8:?P?P;I@K< C8P<IJ GI<J<EK @E K?< <M8GFI@K< J<HL<E:< NFLC;
EFK GI<:@G@K8K< =IFD EFID8C J<8N8K<I 8E; K?< DFJK C@B<CP <OGC8E8K@FE F=
K?<J< ;<GFJ@KJ @J K?8K K?<P 8I< ;<I@M<; =IFD ?P;IFK?<ID8C 8CK<I8K@FE F=
98J8CK $8:BJFE <K 8C  .?< G<I:FC8K@FE DF;<C K?IFL>? ?FK 98J8CKJ
GIF;L:<J <EI@:?<; J<8N8K<I N?@:? @J E<:<JJ8IP =FI K8:?P?P;I@K< GI<:@G
@K8K@FE“8M@JFE <K 8C 
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:CL;@E> JKIFD8KFC@K<J 8E; D@:IF9@8C@K<J @J GIF989CP HL@K< J@D@C8I KF K?<
8CB8C@E< C8B<J @E K?< N<JK<IE 8ID F= K?< 8JK =I@:8E ,@=K , .?LJ @E
&8B< .8E>8EP@B8 K?<I< 8I< 8CJF JL:? ;<GFJ@KJ @E:CL;@E> D@:IF9@8C@K<J
>IFN@E> @E CF:8K@FEJ F= ><FK?<ID8C J<<G8><J F?<E  1< K?LJ
@E=<I K?8K K?@J C8B< @J 8K 8E <8IC@<I JK8>< F= I@=K ;<M<CFGD<EK :FDG8I<;
KF K?< 8JK<IE 8ID F= , N?<I< N< TE; DFI< 8:K@M< I@=K@E> @E:CL;@E>
?@>?<I ?<8KUFN 8E; 8:K@M< J8CK =FID8K@FE 8E; ;<GFJ@K@FE
5.8.2. The Guaymas Basin
EFK?<I :LII<EKCP 8:K@M< D8I@E< I@=K K?8K GIF989CP E<M<I N8J ;<J
@::8K<; @J K?< !L8PD8J 8J@E @E K?< :<EKI8C !LC= F= 8C@=FIE@8 -<@JD@:
KI8EJ<:KJ ?8M< I<M<8C<; 8 ∼BD× BD N@;< 8E;  BD K?@:B '@F:<E<
∼ '8 <M8GFI@K< 9F;P LE;<I K?< J?<C= F= K?< <8JK<IE D8I>@E F= K?<
98J@E '@CC<I <K 8C  .?< J<KK@E> F= K?< 98J@E @E;@:8K<J JKIFE>CP 8
?P;IFK?<ID8C =FID8K@FE F= K?@J C8I>< <M8GFI@K< 9F;P
5.8.3. Stromatolites and hydrothermal venting
E @EK<I<JK@E> 8E8CF>L< KF K?< JKIFD8KFC@K<J 8E; D@:IF9@8C@K<J @E K?<
, 8E; K?< I8Q@C@8E J8> 98J@E @J K?< ;<J:I@GK@FE F= JL:? =<8KLI<J 8K K?<
J8C@E< 8E; 8CB8C@E< &8B< -F:FDG8 J@KL8K<;  D 89FM< J<8 C<M<C @E
K?< I><EK@E<8E E;<J ::FI;@E> KF 8Ií8J <K 8C  “.?< N8K<I 8K
K?< J@K< F= JKIFD8KFC@K<J =FID8K@FE @J 8CB8C@E< ?PG<IJ8C@E< I@:? @E @EFI
>8E@: ELKI@<EKJ M<IP I@:? @E 8IJ<E@: 8E; N8ID – ° ;L< KF 8 ?P
;IFK?<ID8C @EGLK”
.?@J D<8EJ K?8K 8CC K?I<< F= K?<J< F::LII<E:<J F= JKIFD8KFC@K<J @E
, I8Q@C@8E J8> 98J@E 8E; K?< I><EK@E<8E E;<J 8I< >IFN@E> 8K CF
:8C@K@<J N?<I< ?P;IFK?<ID8C 9I@E<J 8I< M<EK@E> J8C@E< 8E; 8CB8C@E< N8K<I
8K JC@>?KCP ?@>?<I K<DG<I8KLI<J K?8E K?< JLIIFLE;@E>J @E;@:8K@E> K?8K
K?<J< <EM@IFED<EKJ 8I< 8KKI8:K@M< KF K?@J B@E; F= 98:K<I@8C >IFNK? 9FK?
8K GI<J<EK 8E; @E K?< G8JK
6. Summary and conclusions
6.1. Formation of solid salt in the deep crust is an inevitable process
.?<IDF;PE8D@:J GI<;@:KJ K?8K J8C@E< N8K<IJ N@CC @E:I<8J< @E J8C@E
@KP N?<E JL9A<:K<; KF ?@>?<I GI<JJLI<J 8E; K<DG<I8KLI<J -8C@E< N8K<IJ
N@CC K?LJ JGC@K @EKF =I<J? N8K<I M8GFI N?@C< K?< I<D8@E@E> C@HL@; 9I@E<
@E:I<8J<J @E ;<EJ@KP 8J :FETID<; 9P <OG<I@D<EK8C I<J<8I:? 8K GI<J
JLI<J 8E; K<DG<I8KLI<J I<C<M8EK =FI K?< :FE;@K@FEJ ;<<G @E K?< 8IK?J
:ILJK
%EFNC<;>< 89FLK K?< J8CKN8K<I G?PJ@:F:?<D@:8C GIFG<IK@<J :FD
9@E<; N@K? K?<IDF;PE8D@:J K?8K :FEKIFC K?<@I 9<?8M@FI 8CCFN :FD
GLK<I98J<; DF;<C@E> F= K?< ?P;IFK?<ID8C GIF:<JJ<J @E K?< ;<<G :ILJK
.?< I<JLCKJ F= JL:? DF;<C@E> J?FN K?8K K?< <M<I J8CK@<I 9I@E<J :FEK@EL<
KF D@>I8K< =LIK?<I ;FNE KFN8I;J K?< ?<8K JFLI:< LEK@C JFC@; J8CK GI<:@G@
K8K<J .?< =FID8K@FE F= JFC@; J8CK @J K?<I<=FI< 8E @E<M@K89C< GIF:<JJ :FE
KIFCC<; 9P K?<IDF;PE8D@:J N?<E J<8N8K<I :@I:LC8K<J @E =8LCKJ 8E; =I8:
KLI<J ;I@M<E 9P K?< ?<8K F= N8ID D8>D8 9F;@<J FI @>E<FLJ @EKILJ@FEJ
6.2. Hydrothermal circulation along tectonic plate boundaries
.?< DFJK 8:K@M< QFE<J =FI ?P;IFK?<ID8C :@I:LC8K@FE F= J<8N8K<I 8I<
C@EB<; KF GC8K< K<:KFE@:J N?<I< ?@>? K<DG<I8KLI<J 8E; GI<JJLI<J GI<M8@C
@E K?< I@=K@E> 8E; JL9;L:K@FE QFE<J 8CFE> K?< GC8K< 9FLE;8I@<J 8JJF:@
8K<; N@K? K?< 1@CJFE :P:C<J
6.3. Re>ning of salts
'8I@E< J8CKJ ?8M< M<IP ;@==<I<EK JFCL9@C@K@<J 8CJF 8K <C<M8K<; K<DG<I
8KLI<J ,<TE@E> F= J8CKJ K8B<J GC8:< ;L< KF K?@J ;@==<I<E:< @E GIFG<IK@<J
8CJF ;LI@E> K?< ?P;IFK?<ID8C :@I:LC8K@FE F= J<8N8K<I9I@E< "8C@K< 9<
@E> K?< C<8JK JFCL9C< :?CFI@;< F= D8I@E< J8CKJ N@CC 9< K?< TIJK KF GI<:@G
@K8K< LGFE @E:I<8J<; J8KLI8K@FE F= 9I@E<J N?@C< K?< DFI< JFCL9C< J8CKJ
?8M< 8 K<E;<E:P KF <J:8G< K?< JPJK<D .?@J K<E;<E:P KF <J:8G< D8P 9<
:FLEK<I8:K<; @= K?< DFI< JFCL9C< J8CKJ 8I< 8CCFN<; KF 8::LDLC8K< @E 8
GIFK<:K<; <EM@IFED<EK <> 9I@E< C8B<J FI 8I@; J8CK G8EJ <> 8CCFC
K?@FG@8 FI @E ?PG<IJ8C@E< GFE;J FE K?< J<8UFFI 9<KN<<E J8CK JKF:BJ
;FD<J -L:? GC8:<J ?8M< K?< I@>?K G?PJ@:F:?<D@:8C :?8I8:K<I@JK@:J =FI
K?< :IPJK8CC@Q8K@FE F= ‘<OFK@:’J8CKJ C@B< K8:?P?P;I@K< N@K? @KJ ?@>? :FE
K<EK F= :IPJK8C N8K<I .?<J< J8CKJ 8I< LEJK89C< 8K 8KDFJG?<I@: :FE;@K@FEJ
;L< KF K?< 89JFIGK@FE F= ?LD@;@KP =IFD K?< 8@I
6.4. Subduction of oceanic crust
.?< F:<8E@: :ILJKJ 8I< :?8I8:K<I@Q<; 9P ?8M@E> GFIFJ@K@<J @E K?< FI
;<I F=  D8@ECP =I8:KLI< GFIFJ@KP -<8N8K<I :@I:LC8K@E> @E K?< ;<<G<I
G8IKJ F= K?<J< :ILJKJ D8P 9< JL=T:@<EKCP ?<8K<; LE;<I JL=T:@<EKCP ?@>?
GI<JJLI<J KF LE;<I>F G?8J< J<G8I8K@FE I<JLCK@E> @E K?< JKFI8>< F= ?@>?
;<EJ@KP 9I@E<J 8E; <M<E JFC@; J8CKJ .?< ;@J:FM<IP F= 9FK? CFN 8E;
?@>?J8C@E@KP N8K<I M<EK@E> FE K?< J<8 UFFI JKIFE>CP @E;@:8K<J K?8K JL:?
G?8J< J<G8I8K@FE K8B<J GC8:< F9J<IM<; @E K?< <<GJ F= K?< ,<; -<8
.?LJ K?< JL9;L:K@E> F:<8E@: :ILJK D8P 9< CF8;<; N@K? DFI< J8CK K?8E
D<I<CP @KJ J<8N8K<ITCC<; GFIFJ@KP
6.5. Salt in the subduction zones
-8CK 8E; ?<8MP 9I@E<J =FID 8IFLE; 8E; @EJ@;< JL9;L:K@E> JC89J FE:<
K?< I<C<M8EK GI<JJLI< 8E; K<DG<I8KLI< :FE;@K@FEJ 8I< D<K .?< J8CK I<
D8@EJ ?@;;<E @E K?< ;<<G LEC<JJ ;@JJFCM<; 8E; KI8EJGFIK<; M@8 :FE;L:K
@E> =8LCKJ KF K?< JLI=8:< 9P N8K<I I<C<8J<; =IFD JK<<G JC89J FI 9P C8K<I
I@=K@E> @E K?< I<>@FE GI<=<I89CP 8CFE> K?< JLKLI< QFE<
0FC:8E@JD @J KI@>><I<; 9P K?< I<C<8J< F= N8K<I =IFD K?< JL9;L:K@E>
JC89 .?LJ J8CKJ D8P 9< KI8EJGFIK<; KF K?< JLI=8:< =8:@C@K8K<; 9P MFC
:8E@JD 8E; 8JJF:@8K<; ?P;IFK?<ID8C 8:K@M@KP 8J ;<DFEJKI8K<; 9P K?<
?L>< 8::LDLC8K@FEJ F= J8CKJ ?@>? LG @E K?< E;<8E 'FLEK8@EJ "<I<
?P;IFK?<ID8C 9I@E<J 8I< M<EK@E> FLK 8K – D 89FM< J<8 C<M<C
89FM< K?< QFE<J F= JK<<G JL9;L:K@FE .?<J< :FE:<EKI8K<; 9I@E<J 8I<
<M8GFI8K@E> @E K?< ;IP :C@D8K< N?@:? @J 8CJF GIFK<:K@E> K?< J8CK =IFD
I<;@JJFCLK@FE
.?< J8CKJ ;<GFJ@K<; 8I< K?< I<JLCK F= J<M<I8C G?8J<J F= I<TE@E> 8:
:FI;@E> KF K?< ;@==<I<EK JFCL9@C@K@<J F= K?< M8I@FLJ J8CK KPG<J 8K K?< M8I@
FLJ GI<JJLI<J 8E; K<DG<I8KLI<J K?<P ?8M< <E:FLEK<I<; #E 8;;@K@FE K?<
N8K<IIF:B @EK<I8:K@FEJ ?8M< JLGGC@<; D8EP 8;;@K@FE8C @E>I<;@<EKJ @EKF


UNCORRECTED PROOF
M. Hovland et al. Marine and Petroleum Geology xxx (2018) xxx-xxx
K?< M<EK@E> 9I@E<J @E:CL;@E> 9FIFE 8E; C@K?@LD .?@J :8E <OGC8@E K?<
?L>< ;<GFJ@KJ F= 9FI8K<J @E K?< E;<J 8E; <CJ<N?<I<
6.6. Oceanic subduction
.?< :FDGC<O JL9;L:K@FE QFE<J @E K?< '<;@K<II8E<8E =FI <O8DGC<
9<E<8K? K?< D@; '<;@K<II8E<8E ,@;>< I<GI<J<EKJ 8 :8J< =FI JKL;P
@E> F:<8E@: JL9;L:K@FE "<I< K?< =I@:8E GC8K< @J JL9;L:K@E> LE;<I K?<
<><8E GC8K<  J<I@<J F= C8I>< ?PG<IJ8C@E< 9I@E< GFE;J ?8M< 9<<E ;@J
:FM<I<; FE K?< J<8UFFI N?<I< 9I@E<J 8I< :FD@E> LG =IFD K?< JL9;L:
K@FE QFE< .?< 9I@E< C8B<J 8I< =<; 9P ?P;IFK?<ID8C 9I@E<J K?IFL>? =8LCKJ
8E; =I8:KLI<J K?8K G<E<KI8K< ;FNE @EKF K?< QFE< F= K?< JL9;L:K@E> JC89
6.7. Continental rifting and salt
FEK@E<EK8C I@=K@E> @J :?8I8:K<I@Q<; 9P K?< =FID8K@FE F= 8 M8CC<P N@K?
?8C=>I89<EJ 8E; =8LCKJ FI@<EK<; @E K?< ;@I<:K@FE F= K?< M8CC<P C@EB<;
8CFE> K?< >I89<EJ 0FC:8E@JD @J :FDDFECP <E:FLEK<I<; @E K?< I@=K JPJ
K<DJ 8E; M<EK@E> F= ?FK ?P;IFK?<ID8C 9I@E<J K?8K =<<; J8C@E< C8B<J
M<E :FEK@E<EK8C I@=K M8CC<PJ N@K?FLK :FEK8:K N@K? J<8N8K<I 8I< M<EK@E>
JF;@LD :?CFI@;< 8E; FK?<I J<8 J8CKJ -<M<I8C :8J< JKL;@<J 8I< ;@J:LJJ<;
KF JL9JK8EK@8K< K?<J< @JJL<J <:8LJ< F= 8CC K?< J8CK 8::LDLC8K@FEJ @E I@=K
M8CC<PJ @E:CL;@E> D8I@E< J8CKJ @K @J :8LK@FLJCP JL>><JK<; K?8K I@=K@E> @J
:FDDFECP K8B@E> GC8:< @E FC; JL9;L:K@FE 8I<8J N?<I< hidden salt @E K?<
JL9;L:K@FE QFE< @J 9<@E> DF9@C@Q<; ;LI@E> I@=K@E> 9P K?< :@I:LC8K@FE F=
?FK ?P;IFK?<ID8C N8K<I K?8K @J @EK<I8:K@E> N@K? K?< IF:BJ
6.7.1. Case 1: the East African Rift (EAR)
.?< , :FEK8@EJ 8CC K?< :?8I8:K<I@JK@: GIFG<IK@<J F= :FEK@E<EK8C I@=K
@E> #E K?< EFIK?<IE G8IK F= K?< I@=K @E:CL;@E> K?< 8CCFC 8I<8 @E K?@FG@8
K?< J8CKJ 8I< ;FD@E8EKCP :?CFI@;<J N@K? (8 % '> 8 <K: GF@EK@E>
8K 8 D8I@E< FI@>@E .?< ?L>< J8CK ;<GFJ@KJ @E 8CCFC K?@FG@8 8I< =FID
@E> 9P 8J:<E;@E> 9I@E<J K?8K 8I< M<EK@E> FLK FE K?< JLI=8:< N?<I< K?<
J8CK @J GI<:@G@K8K@E> @E K?< ;IP :C@D8K< #E K?<J< :8J<J K?<I< @J 8 TE8C
JK8>< F= <M8GFI8K@FE @EMFCM<; .?< J8D< ;IP :C@D8K< GIFK<:KJ K?< J8CK
=IFD I<;@JJFCLK@FE .?< :FDGFJ@K@FEJ F= K?< J8CKJ @E;@:8K< 8 D8I@E< FI@
>@E 9LK D@O<; N@K? <C<D<EKJ C<8:?<; FLK =IFD 9I@E<IF:B @EK<I8:K@FEJ
;LI@E> K?< ?P;IFK?<ID8C :@I:LC8K@FE
#E K?< JFLK?<IE G8IK F= K?< , M8CC<P N< TE; J8CK ;<GFJ@KJ 8E; C8B<J
N@K? 89LE;8EK :FEK<EKJ F= JF;@LD :8I9FE8K<J 8E; 9@:8I9FE8K<J @E 8;
;@K@FE KF :?CFI@;<J <> &8B< (8KIFE 8E; &8B< '8>8;@ N?<I< K?<I< @J
GI<:@G@K8K@FE F= JF;8 .?@J @J <OGC8@E<; 9P K?< GI<J<E:< F= )X =IFD K?<
MFC:8E@: 8:K@M@KP :FD9@E<; N@K? ?@>? G" @E K?< N8K<I G?8J< .?< ?@>?
G" F= K?< 9I@E<J @E;@:8K<J K?< GI<J<E:< F= J<IG<EK@E@Q8K@FE GIF:<JJ<J 8K
;<GK? @< @EK<I8:K@FE 9<KN<<E ?FK ?P;IFK?<ID8C N8K<I 8E; ?FK D8>
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Uncited references
$8:BJFE <K 8C  'F?I@8B <K 8C  .8C9FK 8E; $8:BJFE 
Acknowledgements
1< K?8EB KNF I<M@<N<IJ 0@KKFI@F -:I@98EF 8E; 1<9JK<I 'F?I@8B =FI
K?<@I :FEJKIL:K@M< :FDD<EKJ 8E; N< NFLC; 8CJF C@B< KF K?8EB GI<M@
FLJ :FE:<GKL8C ;@J:LJJ@FEJ 8E; ?<CG =IFD (8A<<9 ,8JLC 8E; ?8ICFKK< 
-:?I<@9<I
References
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

UNCORRECTED PROOF
M. Hovland et al. Marine and Petroleum Geology xxx (2018) xxx-xxx
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@E K?< 8DGFJ 8E; -8EKFJ J8CK 98J@EJ #E CJFG !# <K 8C ;J -8CK .<:KFE@:J -<;
@D<EKJ 8E; *IFJG<:K@M@KP MFC  !<FCF>@:8C -F:@<KP F= &FE;FE -G<:@8C *L9C@:8K@FE
GG S
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F:<8E @JC8E; 98J8CKJ =IFD I<E:? *FCPE<J@8 @DGC@:8K@FEJ =FI K?< < 8E; &@< I8K@FJ
8J KI8:<IJ F= JL9;L:K<; :FDGFE<EKJ '@E<I8C '8>  S L>LJK 
?I?8I;K  "ü9J:?<I   .?< EFIK?<IE ,<; -<8 @E KI8EJ@K@FE =IFD I@=K@E> KF ;I@=K
@E> C<JJFEJ C<8IE<; =IFD F:<8E ;<<GJ #E ,8JLC (' -K<N8IK #  ;J .?<
,<; -<8 K?< FID8K@FE 'FIG?FCF>P ):<8EF>I8G?P 8E; EM@IFED<EK F= 8 3FLE>
):<8E 8J@E -GI@E><I 8IK? -PJK<D -:@<E:<J <IC@E "<@;<C9<I> GG S
?I?8I;K  "ü9J:?<I  !8A<NJB@   FEI8; <<G (FIK?<IE ,<; -<8 ;<M<CFG
D<EK F= 8E <8ICP JK8>< F:<8E ;<<G N@K?@E K?< 8O@8C ;<GI<JJ@FE .<:KFEFG?PJ@:J 
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I@:BJ<E ! 0@E< $ 8CCóE ,  ?<D@:8C :FDGFJ@K@FE 8E; ;@JKI@9LK@FE F=
C@K?@LDI@:? 9I@E<J @E J8C8I ;< /PLE@ 8E; E<8I9P J8C8IJ @E JFLK?N<JK<IE FC@M@8 E
<I>P   S
I@:BJ<E !  /GG<I .<IK@8IP 8E; +L8K<IE8IP :FEK@E<EK8C J8C@E< ;<GFJ@KJ @E K?< E
;<8E I<>@FE !<FC -F: 8E8;8 -G<: *8G<I  S
8::<EE8  <:B<I .1 L<I & @CC@  FJ:?@ & ILE $* 8G@K8E@F  L
E@:@<CCF  "FIMàK?  $FC@M<K & *@IFD8CCF  ,FP;<E & ,FJJ<KK@  -<IG<CCFE@
  '8EKC< ;PE8D@:J @E K?< D<;@K<II8E<8E ,<M !<FG?PJ  S ?KKGJ
;F@FI>,!
8Ií8J ' ,8J:FM8E ( .FE<8KK@ ' C98II8:íE 0" CFI<J ', *F@Ié !
FCC8M@EF '' >L@C8I )' 08QHL<Q '* *FC<I<:BP &  .?< ;@J:FM<IP F=
JKIFD8KFC@K<J ;<M<CFG@E> 8K  D 89FM< J<8 C<M<C @E 8 ?@>?8CK@KL;< MFC:8E@: C8B< -F
:FDG8 I><EK@E<8E E;<J *&F- )E<   < ?KKGJ;F@FI>AFLIE8C
GFE<
<C;<EJ * '@K:?<CC (  -8CK UFN@E K?< :<EKI8C I<; J<8 #E ,8JLC (' -K<N
8IK #  ;J .?< ,<; -<8 -GI@E><I 8IK? -PJK<D -:@<E:<J <IC@E "<@;<C9<I> GG
S
!@I;C<I ,1 1?@KD8IJ? ,  '@F:<E< <M8GFI@K<J @E ,<; -<8 :FI<J K?<@I I<C<M8E:<
KF K?< GIF9C<D F= K?< N@;K? 8E; 8>< F= F:<8E@: :ILJK 9<E<8K? K?< ,<; -<8 #E 1?@K
D8IJ? , 1<J<I * ,FJJ  ;J #E@K@8C ,<GFIKJ F= K?< <<G -<8 I@CC@E>
*IFA<:K –0FCLD<  /- !FM<IED<EK *I@EK@E> )=T:< 18J?@E>KFE GG S
!@I;C<I ,  .?< <MFCLK@FE F= K?< !LC= F= 8;<E 8E; I<; J<8 @E JG8:< 8E; K@D< <<G
-<8 ,<J *8IK  ):<8EF>I ,<J *8G  S
!@I;C<I ,  *IF9C<DJ :FE:<IE@E> K?< <MFCLK@FE F= F:<8E@: C@K?FJG?<I< @E K?< EFIK?
<IE ,<; -<8 .<:KFEFG?PJ@:J  S
!I8EK - !I8EK 1 $FE<J  %8KF  &@ &  (FM<C 8I:?8<8C G?PCFKPG<J =IFD
8E 8JK =I@:8E 8CB8C@E< J8CK<IE OKI<DFG?@C<J  S
!L<EEF: * *8LKFK ! FLK<CC<   -LIT:@8C JKIL:KLI<J F= K?< EFIK?<IE ,<; -<8
8O@8C M8CC<P =IFD °( KF °( K@D< 8E; JG8:< <MFCLK@FE F= E<FF:<8E@: JKIL:KLI<J
.<:KFEFG?PJ@:J  S
!L<EEF: * *8LKFK ! &< +L<EKI<: '  FLK<CC<   -KIL:KLI< F= 8E <8ICP
F:<8E@: I@=K @E K?< EFIK?<IE I<; J<8 ):<8EFC :K8   S
!LKJ:?<I ' )C@M<K $& JC8E@8E  @JJ<E $* '8LIP ,  .?< “CFJK #E:8
*C8K<8L” :8LJ< F= U8K JL9;L:K@FE 9<E<8K? *<IL 8IK? *C8E<K -:@ &<KK  
S
!LKJ:?<I ' -G8BD8E 1 @AN88I; " E>;8?C ,  !<F;PE8D@:J F= U8K JL9
;L:K@FE J<@JD@:@KP 8E; KFDF>I8G?@: :FEJKI8@EKJ =IFD K?< E;<8E D8I>@E .<:KFE@:J
  S
"8I;@< &  .?< IFC<J F= I@=K@E> 8E; ?P;IFK?<ID8C 8CX 9I@E<J @E K?< FI@>@E F=
GFK8J? <M8GFI@K<J 8E ?PGFK?<J@J D $ -:@  S
"FMC8E; ' @:?C<I  ,L<JCåKK<E " $F?EJ<E "% 8 <<G IFFK<; G@<I:<D<EK
JKIL:KLI<J @E ;<<G J<;@D<EK8IP 98J@EJ—D8E@=<JK8K@FEJ F= JLG<I:I@K@:8C N8K<I ><E<I8
K@FE 8K ;<GK? $ !<F:?<D OGCFI  S
"FMC8E; ' %LQE<KJFM8 . ,L<JCåKK<E " %M8DD<  $F?EJ<E "% C8;D8IB !
"<98:?  9 -L9JLI=8:< GI<:@G@K8K@FE F= J8CKJ @E JLG<I:I@K@:8C J<8N8K<I 8J@E
,<J  S
"FMC8E; ' ,L<JCåKK<E "! $F?EJ<E "% %M8DD<  %LQE<KJFM8 . : -8CK =FI
D8K@FE 8JJF:@8K<; N@K? JL9JLI=8:< 9F@C@E> 8E; JLG<I:I@K@:8C N8K<I '8I *<KIFC !<FC
 S
"FMC8E; ' ,L<JCåKK<E " $F?EJ<E "%  LI@<; ?P;IFK?<ID8C JPJK<DJ K?< GF
K<EK@8C IFC< F= JLG<I:I@K@:8C N8K<I“-:I@1” @E M8I@FLJ ><FCF>@:8C GIF:<JJ<J 8E; F::LI
I<E:<J @E K?< JL9JLI=8:< D $ E8C ?<D  S
"FMC8E; ' ,L<JCåKK<E " $F?EJ<E "%  ,<; -<8 J8CK =FID8K@FEJ—8 I<JLCK F= ?P
;IFK?<ID8C GIF:<JJ<J K?< ,<; -<8 #E ,8JLC (' -K<N8IK #  ;J .?< ,<;
-<8 -GI@E><I 8IK? -PJK<D -:@<E:<J <IC@E "<@;<C9<I> GG S
"FMC8E; ' ,L<JCåKK<E " $F?EJ<E "%  &8I>< J8CK 8::LDLC8K@FEJ 8J 8 :FEJ<
HL<E:< F= ?P;IFK?<ID8C GIF:<JJ<J 8JJF:@8K<; N@K? ‘1@CJFE :P:C<J’ 8 I<M@<N *8IK  KF
N8I;J 8 E<N LE;<IJK8E;@E> '8I *<KIFC !<FC ?KKGJ;F@FI>AD8IG<K><F

"FMC8E; ' ,L<JCåKK<E " $F?EJ<E "% '8EL<CC8   *FJJ@9C< IFC< F= J8CK 8::L
DL8CK@FEJ @E 1@CJFE :P:C<J #E 89JKI8:K *IF:<<;@E>J F= K?< IK?LI "FCD<J '<<K@E>
 !<FC -F: '8P  &FE;FE
"L>L<E  ?8DFK,FFB< ( &FL9I@<L  '8J:C< $  'FIG?FCF>P F= 8 GI<:FCC@
J@FE8C J8CK9<8I@E> 8::I<K@FE8IP :FDGC<O K?< '<;@K<II8E<8E ,@;>< <8JK<IE D<;@K<I
I8E<8E '8I !<FG?PJ ,<J  S
"LK:?@EJFE , E><CJ !   ;@J:LJJ@FE FE K?< JKIL:KLI< 8E; <MFCLK@FE F= K?< ,<;
-<8 8E; K?< E8KLI< F= K?< ,<; -<8 !LC= F= ;<E 8E; K?@FG@8 I@=K ALE:K@FE  K<:KFE@:
J@>E@=@:8E:< F= I<>@FE8C ><FCF>P 8E; <M8GFI@K< C@K?F=8:@<J @E EFIK?<8JK<IE K?@FG@8
*?@C .I8EJ '8K? *?PJ E> -:@  S ?KKGJ;F@FI>IJK8
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$8:BJFE & $8:BJFE '* "L;<: ', ,F;I@>L<Q ,  E@>D8K@: JKIL:KLI<J
N@K?@E J8CK N8CCJ F= K?< -8EKFJ 8J@E  *8IK  ><FD<KIP 8E; B@E<D8K@:J =IFD  J<@J
D@: I<U<:K@FE 8E; N<CC ;8K8 $ -KIL:K !<FC  S
$8:BJFE '* I8D<Q  FE:B $'  ,FC< F= JL98<I@8C MFC:8E@: IF:BJ 8E; D8E
KC< GCLD<J @E :I<8K@FE F= -FLK? KC8EK@: D8I>@EJ @DGC@:8K@FEJ =FI J8CK K<:KFE@:J 8E;
JFLI:< IF:BJ '8I *<KIFC !<FC  S
$L;;  "FMC8E; '  -<89<; CL@; CFN #DG8:K FE !<FCF>P @FCF>P 8E; K?< '8
I@E< EM@IFED<EK 8D9I@;>< /E@M<IJ@KP *I<JJ 8D9I@;>< /%  GG
%8N8DFKF . 3FJ?@B8N8 ' %LD8>8@ 3 '@I89L<EF '". )BLEF ' %F98P8J?@
.  '8EKC< N<;>< @ETCKI8K<; N@K? J8C@E< UL@;J =IFD ;<?P;I8K@FE 8E; ;<:8I9FE
8K@FE F= JL9;L:K@E> JC89 *IF: (8KC :8; -:@ /E@K -K8K<J D  S
&8D9 -  <M@C @E K?< 'FLEK8@E 8 -<8I:? =FI K?< )I@>@E F= K?< E;<J *I@E:<KFE
/E@M<IJ@KP *I<JJ *I@E:<KFE (<N $<IJ<P
&8LDFE@<I ' !8@CC8I;  'L@I  CLE;P $ /EJNFIK? '  !@8EK D8>D8K@:
N8K<I I<J<IMF@IJ 8K D@;:ILJK8C ;<GK? @E=<II<; =IFD <C<:KI@:8C :FE;L:K@M@KP 8E; K?<
>IFNK? F= K?< :FEK@E<EK8C :ILJK 8IK? *C8E<K -:@ &<KK  S
&<:LD9<II@-8E:?<Q * -K<<C<'8:#EE@J ' 1<@J * I@<JE<I . F;E8I ,$ 
-8CK GI<:@G@K8K@FE @E D8>D8K@:?P;IFK?<ID8C JPJK<DJ 8JJF:@8K<; N@K? LGG<I :ILJK8C
GCLKFEJ !<FCF>P  S
&<<J !  -8CK JFD< ;<GFJ@K@FE8C 8E; ;<=FID8K@FE8C GIF9C<DJ JPDGFJ@LD FE J8CK
;FD<J $ #EJK *<K .<:?EFC S
&@>@ ' FE8KK@  ,8JLC ('  -<8UFFI JGI<8;@E> @E@K@8K@FE ><FG?PJ@:8C 8E; ><F
:?<D@:8C :FEJKI8@EKJ =IFD K?< .?<K@J 8E; (<I<LJ <<GJ :<EKI8C ,<; -<8 #E ,8JLC
(' -K<N8IK #  ;J .?< ,<; -<8 -GI@E><I <IC@E "<@;<C9<I> GG S
&@FL $! .JLA@DFI@ . 38E> $ 4?8E> , IEJK 1  ,<:P:C@E> F= :ILJK8C D8K<I@
8CJ K?IFL>? JKL;P F= LCKI8?@>?GI<JJLI< D@E<I8CJ @E :FCC@J@FE8C FIF><EJ FG?@FC@K<J 8E;
D8EKC< O<EFC@K?J 8 I<M@<N $ J@8E 8IK? -:@  S
&L>C@ - '8EQ@ 0 ,FM<I@ ' -:?I<@9<I   .?< ;<<G I<:FI; F= K?< '<JJ@E@8E
J8C@E@KP :I@J@J <M@;<E:< F= 8 EFE;<J@::8K<; D<;@K<II8E<8E J<8 *8C8<F><F>I *8C8<F
:C@D8KFC *8C8<F<:FC  S
'8E8 - LID8I . .LII@E  <@><EJFE ' -N@J?<I   '8>D8K@: 8:K@M@KP
8:IFJJ K?< 8JK =I@:8E EFIK? .8EQ8E@8E ;@M<I><E:< QFE< $ !<FC -F:  S
'8IK 3 ,FJJ   *FJK'@F:<E< I@=K@E> 8E; ;@8G@I@JD @E K?< EFIK?<IE ,<; -<8
'8I !<FC  S
'8IK@EF; $ "LJJFE & ,FG<I:? * !L@CC8LD<  JGLIK (  "FI@QFEK8C JL9;L:
K@FE QFE<J :FEM<I><E:< M<CF:@KP 8E; K?< 9L@C;@E> F= K?< E;<J 8IK? *C8E<K -:@ &<KK
 S
'<@C@AJFE  -K<@E9<I> $ "@C><E  @8C@B )' 18C;D8EE ( '8BFNJBP 3 
<<G98J@E <M@;<E:< I<JFCM<J 8 P<8IFC; ;<98K< 8E; ;<DFEJKI8K<J JPE:?IFEFLJ FE
J<K F= '<JJ@E@8E <M8GFI@K< ;<GFJ@K@FE @E 8 EFE;<J@::8K<; D<;@K<II8E<8E !<FCF>P
?KKGJ;F@FI>!
'<C8:B $' %@C?8D *  *?FKFJPEK?<K@: I8K<J F= G?PKFGC8EBKFE @E 8JK=I@:8E 8C
B8C@E< J8C@E< C8B<J &@DEFC ):<8EF>I  S
'<KQ   '898?@JJ 'FEJ  °( ,<; -<8 ,@=K .<:KFE@:J 8E; 0FC:8E@JD F= 8 &8I><
-L9D8I@E< FD< 0FC:8EF 8:LCKP F= '8K?<D8K@:J 8E; (8KLI8C -:@<E:< '-: ;@JJ<IK8
K@FE ?I@JK@8EC9I<:?KJ /E@M<IJ@KP F= %@<C %@<C !<ID8EP 
'@CC<I ( &@Q8II8C;<  "8I;@E>  %<EK !  FEJKI8@EKJ FE <8ICP !LC= F= 8C
@=FIE@8 I@=K@E> =IFD J<@JD@: @D8><J 8:IFJJ K?< <8JK<IE D8I>@E F= !L8PD8J 8J@E #E
9JKI8:K !/ 8CC '<<K@E> 8C@=FIE@8 <:<D9<I – *FJK<I .
'@K:?<CC ( L>LJK@E (  "8CFB@E<K@:J 8E; FK?<I =<8KLI<J F= !&),# CFE>I8E><
J@;<J:8E JFE8I ;8K8 =IFD K?< ,<; -<8 '8I@E< 8E; *<KIFC !<FC  S
'@K:?<CC ( &@>@ ' <C;<EJ * "ü9J:?<I   <=FID8K@FE F= 8 PFLE> J8CK >@8EK
I<>@FE8C KFGF>I8G?P F= K?< ,<; -<8 '@F:<E< <M8GFI@K<J 8J@E ,<J  S


UNCORRECTED PROOF
M. Hovland et al. Marine and Petroleum Geology xxx (2018) xxx-xxx
'@K:?<CC ( &@>@ ' <II8EK< 0 FE8KK@  ,'LKK<I   -L9D8I@E< J8CK UFNJ
@E K?< :<EKI8C ,<; -<8 !<FC -F: D LCC  S
'@K:?<CC ( *8IB 3  (8KLI< F= :ILJK @E K?< :<EKI8C I<; J<8 .<:KFEFG?PJ 
S
'@K:?<CC ( -:?D@;K ' &@>@ '  FDD<EK FE “ FID8K@FE F= .?<K@J <<G
D<K8CI@:? J<;@D<EKJ @E K?< 89J<E:< F= 9I@E<J ,<; -<8”9P *@<II<K <K 8C  $
!<F:?<D OGCFI  S
'F?I@8B 1/ &<IFP -  I:?@K<:KLI< F= I@=K<; :FEK@E<EK8C D8I>@EJ 8E; 9I<8BLG
<MFCLK@FE @EJ@>?KJ =IFD -FLK? KC8EK@: EFIK? KC8EK@: 8E; I<; J<8 –!LC= F= 8;<E
:FEAL>8K< D8I>@EJ #E 'F?I@8B 1/ 8E=FIK?  *FJK *$ IFNE  .8I@
! (<D:FB ' -@E?8 -. ;J !<FCF>@:8C -F:@<KP &FE;FE -G<:@8C *L9C@:8K@FEJ
 GG S
'F?I@8B 1 (<DčFB ' E:@JF !  -FLK? KC8EK@: ;@M<I><EK D8I>@E <MFCLK@FE
I@=K9FI;<I LGC@=K 8E; J8CK K<:KFE@:J @E K?< 98J@EJ F= - I8Q@C !<FC -F: &FE; -G<:@8C
*L9C  S
'F?I@8B 1/ -Q8KD8I@ * EAFJ -  -8CK ><FCF>P 8E; K<:KFE@:J F= J<C<:K<; I8Q@C
@8E 98J@EJ @E K?<@I >CF98C :FEK<OK !<FCF>@:8C -F: &FE; -G<:@8C *L9C  S
'FD<EQ8;<? '  -8C@E< ;<GFJ@KJ 8E; 8CB8C@E< D8>D8K@JD 8 ><E<K@: DF;<C $
*<KIFC !<FC  S
'FEE@E  ,8D9FQ   .?< 8E?P;I@K< J8KLI8K@FE @E;<O F= K?< ,<; -<8 GFE;<;
9I@E<J 8E; J<;@D<EK GFI< N8K<IJ F= K?< ,<; -<8 ;<<GJ ?<D !<FC  S
(FIKFE #) 8IILK?<IJ . "L;<: ',  ,@=K KF ;I@=K KI8EJ@K@FE @E K?< -FLK? K
C8EK@: J8CK 98J@EJ 8 E<N U8MFI F= F:<8E@: :ILJK !<FCF>P   S ?KKGJ;F@
FI>!
)I8E>< & !I<<E< "! ,<<;  <K 8C  1@;<JGI<8; UL@; <OGLCJ@FE FE 8
KI8EJC8K@FE8C :FEK@E<EK8C D8I>@E DL; MFC:8EF<J =8LCK QFE<J ?<8;C<JJ :8EPFEJ 8E;
FI>8E@:I@:? JL9JKI8K<J @E 'FEK<I<P 8P 8C@=FIE@8 !<FC -F: D LCC 
S
*@<II<K ' C8L<I ( FJ:?  C8E: !  =FID8K@FE F= .?<K@J ;<<G D<K8CI@:? J<;
@D<EKJ @E K?< 89J<E:< F= 9I@E<J I<; J<8 $ !<F:?<D OGCFI  S
*@C:?<I ,- CLDJK<@E ,  I@E< MFCLD< 8E; J8CK ;@JJFCLK@FE I8K<J @E )I:8 8J@E
EFIK?<8JK !LC= F= '<O@:F *! D JJF: *<K !<FC LCC   S
*@I8AEF   "P;IFK?<ID8C *IF:<JJ<J 8E; '@E<I8C -PJK<DJ !<FCF>@:8C -LIM<P F=
1<JK<IE LJKI8C@8 -GI@E><I
,8JLC (' -K<N8IK # (8N89 4  #EKIF;L:K@FE KF K?< ,<; -<8 @KJ FI@>@E JKIL:
KLI< 8E; <EM@IFED<EK #E ,8JLC (' -K<N8IK #  ;J .?< ,<; -<8 -GI@E><I
8IK? -PJK<D -:@<E:<J <IC@E "<@;<C9<I> GG S
,<KK@> -& $FE<J   ,@J8:?<I   !<F:?<D@:8C <MFCLK@FE F= 9I@E<J @E K?< J8C8I F=
/PLE@ FC@M@8 ?<D !<FC  – S 
,FM<I@ ' C<:B<I , %I@A>JD8E 1 <K 8C  .?< '<JJ@E@8E -8C@E@KP I@J@J G8JK 8E;
=LKLI< F= 8 >I<8K :?8CC<E>< =FI D8I@E< J:@<E:<J '8I !<FC  S
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