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Paleocene-Eocene Thermal Maximum and the Opening of the Northeast Atlantic

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The Paleocene-Eocene thermal maximum (PETM) has been attributed to a sudden release of carbon dioxide and/or methane. 40Ar/39Ar age determinations show that the Danish Ash-17 deposit, which overlies the PETM by about 450,000 years in the Atlantic, and the Skraenterne Formation Tuff, representing the end of 1 +/- 0.5 million years of massive volcanism in East Greenland, are coeval. The relative age of Danish Ash-17 thus places the PETM onset after the beginning of massive flood basalt volcanism at 56.1 +/- 0.4 million years ago but within error of the estimated continental breakup time of 55.5 +/- 0.3 million years ago, marked by the eruption of mid-ocean ridge basalt-like flows. These correlations support the view that the PETM was triggered by greenhouse gas release during magma interaction with basin-filling carbon-rich sedimentary rocks proximal to the embryonic plate boundary between Greenland and Europe.
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DOI: 10.1126/science.1135274
, 587 (2007); 316Science
et al.Michael Storey,
Opening of the Northeast Atlantic
Paleocene-Eocene Thermal Maximum and the
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33. This work was supported by grants in aid 17350027,
19205009, 18033041, and 18065017 (Chemistry of
Concerto Catalysis) from the Ministry of Education,
Culture, Sports, Science, and Technology, Japan; and a
Core Research for Evolutional Science and Technology
program (Nano-Structured Catalysts and Materials) by
JST. Crystallographic data for [1](OTf)
2
and [2](NO
3
) have
been deposited with the Cambridge Crystallographic Data
Center under reference numbers CCDC-617674
(x-ray), 617675 (x-ray), and 637331 (neutron
diffraction analysis).
Supporting Online Material
www.sciencemag.org/cgi/content/full/316/5824/585/DC1
Materials and Methods
Figs. S1 to S18
Tables S1 and S2
References
12 December 2006; accepted 12 March 2007
10.1126/science.1138751
Paleocene-Eocene Thermal
Maximum and the Opening of the
Northeast Atlantic
Michael Storey,
1
Robert A. Duncan,
2
Carl C. Swisher III
3
The Paleocene-Eocene thermal maximum (PETM) has been attributed to a sudden release of carbon
dioxide and/or methane.
40
Ar/
39
Ar age determinations show that the Danish Ash-17 deposit, which
overlies the PETM by about 450,000 years in the Atlantic, and the Skraenterne Formation Tuff,
representing the end of 1 ± 0.5 million years of massive volcanism in East Greenland, are coeval. The
relative age of Danish Ash-17 thus places the PETM onset after the beginning of massive flood basalt
volcanism at 56.1 ± 0.4 million years ago but within error of the estimated continental breakup time of
55.5 ± 0.3 million years ago, marked by the eruption of mid-ocean ridge basaltlike flows. These
correlations support the view that the PETM was triggered by greenhouse gas release during magma
interaction with basin-filling carbon-rich sedimentary rocks proximal to the embryonic plate boundary
between Greenland and Europe.
D
uring the Paleocene-Eocene thermal
maximum (PETM) (1), the sea surface
temperature rose by 5°C in the tropics (2)
and more than 6°C in the Arctic (3), in con-
junction with ocean acidification (4) and the
extinction of 30 to 50% of deep-sea benthic
formaminiferal species (5). The initiation of the
PETM is marked by an abrupt decrease in the
d
13
C proportion of marine and terrestrial sedi-
mentary carbon (1, 6), which is consistent with
the rapid addition of >1500 gigatons of
13
C-
depleted carbon, in the form of carbon dioxide
and/or methane, into the hydrosphere and
atmosphere (7). The PETM is thought to have
lasted only 210,000 to 220,000 years, with most
of the decrease in d
13
C occurring over a 20,000-
year period at the beginning of the event (8).
A possible trigger for the initiation of the
PETM is a period of intense flood basalt mag-
matism attending the opening of the North Atlan-
tic (9, 10), by generating metamorphic methane
from sill intrusion into basin-filling carbon-rich
sedimentary rocks (11). Here we present
40
Ar/
39
Ar
age determinations that allow the correlation of
Early Tertiary volcanic rocks of East Greenland
and the Faeroe Islands with the Danish Ash-17
deposit, which closely overlies PETM sequences
in the North Atlantic. In East Greenland, a >5-km-
thick sequence of plateau basalts formed in 1.0 ±
0.5 million years (My). A surge in magma pro-
duction, coupled with the eruption of mid-ocean
ridge basalt (MORB)like flows in the lower part
of the flood basalt sequence, indicates the initiation
of seafloor spreading at 55.5 ± 0.3 million years
ago (Ma). The onset of the PETM correlates
closely with this breakup-related magmatism.
The North Atlantic Igneous Province (NAIP)
includes the basaltic and picritic lavas of Baffin
Island and West Greenland; the ~7-km-thick,
predominantly tholeiitic lava flow sequences of
the Blosseville Kyst of East Greenland; the
seaward-dipping reflectors of the Greenland and
northwest European volcanic rifted margins; the
Faeroe Islands and British Tertiary basaltic lavas;
and the aseismic ridges connecting Iceland to
either margin of the central Northeast Atlantic
(Fig. 1). The total area of the NAIP is 1.3 × 10
6
km
2
(12) and its volume is estimated to be 5 × 10
6
km
3
to 10 × 10
6
km
3
(1214). The East Greenland
(Blosseville Kyst) and Faeroe Islands flood basalts
lie at opposite ends of the Greenland-Iceland-
Faeroes Ridge (GIFR), the postulated Iceland hot-
spot track, and record volcanic activity leading up
to, during, and after continental breakup between
Greenland and Europe (Fig. 1).
40
Ar/
39
Ar age determinations show that pre-
breakup volcanic activity in East Greenland and
the Faeroes began at ~61 Ma (1517). Seven
lava flows cover the duration of magnetochron
C25n (~500,000 years) in the uppermost part of
the Faeroes lower series (FLS), indicating a very
low eruption rate by ~57 Ma (18) (Fig. 2). The
FLS extends into earliest C24r, as the lava flow
immediately below the capping ~10-m-thick coal-
bearing sediment horizon (19) is reversely mag-
netized (18). The volcanic hiatus as represented
on the Faeroes, after the end of the initial phase of
volcanism, has an estimated duration of 0.6 ±
0.4 My (Fig. 2). In East Greenland, volcaniclastic
sediments overlie the FLS equivalent, the Nansen
Fjord Formation (20), which includes lahars that
contain coal fragments and plant imprints (21).
After the period of little or no volcanism,
flood basalt eruptions commenced on a massive
scale in East Greenland and the Faeroes (Fig. 2).
Flood basalt activity in East Greenland is rep-
resented by four regionally extensive forma-
tions with a combined stratigraphic thickness of
>5 km. The Milne Land Formation (MLF), the
oldest of these four formations, includes MORB-
like low-Ti basalts halfway up the succession
(20) that provide correlation with the Faeroes
middle series (FMS) and upper series (FUS) (Fig.
2). Paleomagnetic data suggest a high eruption
1
Quaternary Dating Laboratory, Department of Environment,
Society and Spatial Change, Roskilde University Centre, Post
Office Box 260, 4000 Roskilde, Denmark.
2
College of Oceanic
and Atmospheric Sciences, Oregon State University, Corvallis,
OR 97331, USA.
3
Department of Geological Sciences, Rutgers
University, Piscataway, NJ 08854-8066, USA.
www.sciencemag.org SCIENCE VOL 316 27 APRIL 2007 587
REPORTS
on February 3, 2008 www.sciencemag.orgDownloaded from
rate at the onset of the FMS (18). In the MLF,
East Greenland, lavas show a regular decrease in
the Dy/Yb ratio up through the section, indica-
tive of a progressive drop in the mean pressure of
partial melting (22) and consistent with rifting and
thinning of the lithosphere. A
40
Ar/
39
Ar age
determination on plagioclase from a lava flow at
the base of the MLF yielded an age of 56.1 ± 0.5
Ma (16), in agreement with age determinations
for MLF-equivalent lavas inland (17). The
weighted mean age is 56.1 ± 0.4 Ma [2s internal
standard error (SE) used throughout; all ages are
reported relative to the currently accepted age of
28.02 Ma for the
40
Ar/
39
Ar standard Fish Canyon
Tuff Sanidine (23)]. A high-precision
40
Ar/
39
Ar
age of 55.12 ± 0.06 Ma (table S1) on sanidine
from a tuff near the top of the Skraenterne For-
mation (SF), the uppermost of the four volcanic
formations, indicates that the entire sequence was
erupted in 1.0 ± 0.5 My (Fig. 2). The lowest
stratigraphic occurrence of MORB-like flows,
approximately 0.8 km above the base of the first
flood basalts, was dated to 55.1 ± 0.5 Ma (16) on
plagioclase from two samples of interlayered
Fe-Ti basalts (Fig. 2). Further and more precise
age constraints are provided by the Skaergaard
intrusion age. The parental magma of the
Skaergaard intrusion has been correlated with
Fig. 1. Map of the
North Atlantic region
showing the distribution
of igneous rocks related
to the NAIP and DSDP
site 550, where Danish
Ash-17 closely overlies
the PETM. A24, sea-floor
magnetic anomaly 24r;
BK, Blosseville Kyst; GC,
Gardiner Complex; MAR,
Mid-Atlantic Ridge.
A24
Denmark
GIFR
Baffin Bay
G
r
e
e
n
l
a
nd
N
or
th S
ea
6
0
°
N
7
0
°
N
15
°W
0
°
W
Iceland
M
A
R
A24
A24
R
o
c
k
a
l
l
P
l
a
t
e
a
u
Faeroes
V
ø
r
i
n
g
P
l
a
t
e
au
DSDP 550
G C
B K
A24
Onshore Basalt Flows & Sills
Offshore Basalt Flows & Sills
Seaward-Dipping
Reflector Sequences
Fig. 2. Correlation of a
composite marine record,
which encompasses the
PETM, Danish Ash-17,
and magnetochrons C25n
and lower C24r, with the
continental East Green-
land (68°N) and Faeroe
Islands flood basalt record.
Tie points are indicated
by dashed horizontal
lines. Tie point 1, corre-
lation between the SF
Tuff and the marine Dan-
ish Ash-17; tie point 2,
correlation of the East
Greenland and Faeroes
flood basalts, based on
the first occurrence of
MORB-like flows in
the respective volcanic
records (20); tie points
3 and 4, top and base
of C25n correlate the
Faeroes volcanic record
to the marine record.
Faeroes
55.1 ± 0.5 Ma
Coal-
bearing
sediments
Fe-Ti basalts and
MORB-like flows
25n
24r
LS
US &
MS
East Greenland (68º N)
56.1 ± 0.4 Ma
MLF
lower
GPF
SF
RF
Lahars and
fossil plant bearing
sediments
MLF
upper
NF
55.2 ± 0.4 Ma
Skaergaard
intrusion
55.75 ± 0.35 Ma
Tuff
55.12 ± 0.06 Ma
0
-0.5
+0.5
+1.0
+1.5
25n
CIE
Ash -17
MARINE RECORD
T(my)
PETM
55.12 ± 0.12 Ma
24r
25n
26n
58.0
Little or No
Volcanism
Time (Ma)
52.0
56.0
54.0
60.0
Magma Productivity
(km
3
/km/my)

53.0
55.0
57.0
59.0
Pre-Breakup
Melt Production
Faeroes &
East Greenland
CONTINENTAL RECORD
Post-Breakup
Melt Production
GIR
25r
}
7 Lava Flows
24n
23r
25r
26r

NF, Nansen Fjord Formation; RF, Rømer Fjord Formation. Faeroes: LS, lower series; MS, middle series; US, upper series. Marine
record: CIE, carbon isotope excursion. DT, change in time.
40
Ar/
39
Ar age determinations for SF Tuff and Danish Ash-17 are
given in tables S1 and S2 and Fig. 3. The
40
Ar/
39
Ar age for the MLF is from (16, 17). The
40
Ar/
39
Ar ages for the R F and Faeroes US/MS are from (16 ). The
40
Ar/
39
Ar-base d Skaergaard intrusion age is from (26). The +1.11 My between the top of C25n and the beginning of the CIE is from (29). The +1.55 My between
the top of C25n and Danish Ash-17 is based on the observation that Ash-17 occurs in the midpoint of C24r (32) and that C24r has a total duration of 3.11 My
(29). The right panel shows magnetochron ages (30) and the estimated variation in magma productivity over time [from (16)]. There is a low melt production rate
by the beginning of C25n and a surge in magmatism (curve 1) during early C24r. Curves 2 and 3 represent upper (6000 km
3
/km per My) and lower uncertainties
on magma productivity during the rift-to-drift phase. Post-breakup melt production is based on seismic images of crustal thickness for the Greenland-Iceland
Ridge (GIR) (14).
27 APRIL 2007 VOL 316 SCIENCE www.sciencemag.org
588
REPORTS
on February 3, 2008 www.sciencemag.orgDownloaded from
the Geike Plateau Formation (GPF) (24), which
overlies the level of the MORB-like flows in East
Greenland (Fig. 2).
40
Ar/
39
Ar ages on biotite and
hornblende from transgressive granophyres with-
in the Skaergaard intrusion, in combination with
models of cooling history (25), give an intrusion
age of 55.75 ± 0.35 Ma (26). The weighted
average of the Skaergaard intrusion age and
the less precise age for the FU S/FMS is 55.5 ±
0.3 Ma. This age for the MORB-like flows al-
lows for the possibility that the majority of flood
basalts were emplaced in <300,000 years as con-
cluded from a fluid inclusion study on late-stage
granophyres from the Skaergaard intrusion (27).
The average melt production rate for the flood
basalts is 3000 (+3000/1000) km
3
/km of rift per
My (Fig. 2), assuming that the hidden cumulates
have a comparable volume to the lavas (28). Al-
though there is a large degree of uncertainty, the
figure is in accord with crustal thicknessbased
estimates of magmatic productivity of 1800 ± 300
km
3
/km of rift per My for the GIFR, proximal to
the volcanic rifted margin (14) (Fig. 2). The surge
in melt production after renewed volcanism in East
Greenland and the Faeroes suggests a short-lived
rift-to-drift phase beginning at 56.1 ± 0.4 Ma, with
the eruption of MORB-like low-Ti basalts at 55.5 ±
0.3 Ma marking the opening of the northeast At-
lantic at 6N, above the ancestral Iceland hot spot.
Although the PETM has been identified glob-
ally in marine and also in some continental sed-
imentary sections, there has been uncertainty
about its timing relative to the on-land stratigra-
phy of the East GreenlandFaeroes flood basalts.
Orbital-based calibration for magnetochrons C24r
and C25n, using cores from multiple drill holes on
the Walvis Ridge in the South Atlantic, indicates
that the total duration of C24r is 3.12 ± 0.05 My
and that the base of the PETM is 1.11 ± 0.04 My
above the C24r/C25n boundary (29) (Fig. 2). This
indicates an age of approximately 55.5 to 55.6 Ma
for the onset of the PETM, relative to the geo-
magnetic polarity time scale value of 56.67 Ma for
the C24r/C25n boundary (30). Further age con-
straints are provided by Danish Ash-17, a wide-
spread stratigraphic marker horizon that is found
in Early Tertiary marine sediments from the North
Sea region and the North Atlantic. Danish Ash-17
overlies the PETM at Deep Sea Drilling Project
(DSDP) site 550 in the middle of C24r (C24r.5)
and has been used for the calibration of the PETM
(Fig. 1) (31, 32). Danish Ash-17 has been correlated
previously with an alkaline sanidine-bearing tuff in
the SF near the top of the East Greenland Tertiary
lava pile (Fig. 2), owing to similar mineralogy and a
40
Ar/
39
Ar age of 55.0 ± 0.3 Ma (33). The pyroclas-
tic deposit is believed to originate from the Early
Tertiary Gardiner melanephelinite-carbonatite vol-
canic complex on the East Greenland margin
(Fig. 1). To test the correlation, with the aim of lo-
cating the stratigraphic position of the PETM in
relation to the East Greenland and Faeroes flood
basalts, we have redated both Danish Ash-17 and
the SF Tuff, carrying out more than 50 individ-
ual age measurements (34). Figure 3 shows that
40
Ar/
39
Ar laser-fusion age determinations on sani-
dines from the SF Tuff and Ash-17 are analytically
indistinguishable. Of the 15 sanidine analyses from
the SF Tuff, 1 is anomalously young with an age of
54.2 Ma, possibly reflecting
40
Ar loss by alteration.
The remaining 14 analyses give ages ranging be-
tween 55.0 and 55.3 Ma and conform to a simple
Gaussian distribution with a mean age of 55.12 ±
0.06 Ma (Fig. 3). Sanidine from Ash-17 is finer-
grained, and overall the multiple- as well as single-
grain analyses are less precise. However, the
sanidine fusion ages for Ash-17 are mostly evenly
distributed around 55.12 ± 0.12 Ma. There is a
smaller fraction of older ages, which cluster around
56 Ma (fig. S1) and are considered to include an
inherited (xenocrystic) component.
The similar new high-precision ages for Danish
Ash-17 and the SF Tuff indicate that they are
coeval and, due to the rarity of sanidine-bearing
tuffs in this time interval in the North Atlantic, most
likely represent the same eruptive unit (33). Ash-17
occurs in the midpoint of C24r (30), which would
place it approximately 450,000 years above the
base of the PETM (29). Relative to the
40
Ar/
39
Ar
dates for the SF Tuff and Danish Ash-17, the start
of the PETM would thus correspond to an age of
55.6 Ma. The onset of the PETM was most likely
after the beginning of massive flood basalt vol-
canism at 56.1 ± 0.4 Ma, but is within error of the
estimated age of continental breakup at 55.5 ±
0.3 Ma, marked by the eruption of MORB-like
flows (Fig. 2). We suggest that rift propagation
and magmatism (above the ancestral Iceland hot
spot) during the final stages of breakup between
Greenland and Europe triggered the PETM event,
probably via the release of
12
C-enriched methane
though massive sill intrusion and contact metamor-
phism of carbon-rich sediments contained in
basins proximal to the embryonic plate boundary
between Greenland and Europe (11).
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34. Materials, methods, and argon isotopic analyses are
reported in the supporting material on Science Online.
35. The Villum Kann Rasmussen Foundation funded the
establishment of QUAD-Lab and supports its continued
operation. The U.S. NSF supported the age determi-
nations at Oregon State and Rutgers Universities.
T. A. Becker, L. Hogan, O. Stecher, J.-O. Nielsen,
O. Vagner, and R. Bitsch are thanked for technical
advice and support.
18 September 2006; accepted 21 March 2007
10.1126/science.1135274
0
5
10
15
20
25
52 53 54 55 56 57
0
2
4
6
8
10
12
Age (Ma)
Ash -17
(Denmark)
55.12 ± 0.12 Ma
SF Tuff
(East Greenland)
55.12 ± 0.06 Ma
Number of Analyses
58
Fig. 3. Probability plot for sanidine
40
Ar/
39
Ar ages
for the SF Tuff (top) and Danish Ash-17 (bottom).
With the exception of an anomalously young age, the
SF Tuff ages conform to a simple Gaussian distri-
bution. Ages are arithmetic mean ± 2 SE. Analyses
are reported in tables S2 and S3.
www.sciencemag.org SCIENCE VOL 316 27 APRIL 2007
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... Carbon sources that have received significant attention are the destabilization of surface reservoirs such as methane hydrates (Dickens et al., 60 1995), possibly triggered by orbital forcing Lourens et al., 2005). Other wellstudied sources include the direct volcanic emissions from the North Atlantic Igneous Province (NAIP) (Eldholm and Thomas, 1993;Storey et al., 2007a), and thermogenic degassing from NAIP contact metamorphism (Svensen et al., 2004). ...
... While the NAIP was active from ~63-54 Ma, the main acme (~80%) of volcanism occurred from 56 to 54 Ma (Wilkinson et al., 2017). In East Greenland, voluminous eruptions formed a ~5-6 km thick part of the flood 95 basalt province between 56.0 and 55.5 Ma (Larsen and Tegner, 2006;Storey et al., 2007a;Storey et al., 2007b), representing a basalt accumulation rate of at least 1 cm/yr for 500,000 years. There is also evidence of significant explosive volcanism across the PETM interval from the presence of hundreds of NAIP-sourced ash layers across Northern Europe (Egger and Brückl, 2006;Jones et al., 2019a;Larsen et al., 2003;Stokke et al., 2020b). ...
... High-precision 295 radiometric dating of magmatic crystals within ash deposits provides a geochronological framework into which palaeoenvironmental records can be placed (Lowe, 2011). Key felsic ash layers in the Danish strata such as Ashes -17 and +19 are important marker horizons across Greenland and Europe (Storey et al., 2007a;Westerhold et al., 2009). Some of the basaltic ash layers are up to 12 cm thick and found 700-1500 km from the known source volcanoes, 300 ...
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There is a temporal correlation between the peak activity of the North Atlantic Igneous Province (NAIP) and the Paleocene–Eocene Thermal Maximum (PETM), suggesting that the NAIP may have initiated and/or prolonged this extreme warming event. However, corroborating a causal relationship is hampered by a scarcity of expanded sedimentary records that contain both climatic and volcanic proxies. One locality hosting such a record is Fur Island in Denmark, where an expanded pre- to post-PETM succession containing hundreds of NAIP ash layers is exceptionally well preserved. We compiled a range of environmental proxies, including mercury (Hg) anomalies, paleotemperature proxies, and lithium (Li) and osmium (Os) isotopes, to trace NAIP activity, hydrological changes, weathering, and seawater connectivity across this interval. Volcanic proxies suggest that NAIP activity was elevated before the PETM and appears to have peaked during the body of the δ13C excursion, but decreased considerably during the PETM recovery. This suggests that the acme in NAIP activity, dominated by flood basalt volcanism and thermogenic degassing from contact metamorphism, was likely confined to just ~200 kyr (ca. 56.0–55.8 Ma). The hundreds of thick basaltic ashes in the post-PETM strata likely represent a change from effusive to explosive activity, rather than an increase in NAIP activity. Detrital δ7Li values and clay abundances suggest that volcanic ash production increased basaltic reactive surface area, likely enhancing silicate weathering and atmospheric carbon sequestration in the early Eocene. Signals in lipid biomarkers and Os isotopes, traditionally used to trace paleotemperature and weathering changes, are used here to track seaway connectivity. These proxies indicate that the North Sea was rapidly cut off from the North Atlantic in under 12 kyr during the PETM recovery due to NAIP thermal uplift. Our findings reinforce the hypothesis that the emplacement of the NAIP had a profound and complex impact on Paleocene–Eocene climate, both directly through volcanic and thermogenic degassing, and indirectly by driving regional uplift and changing seaway connectivity.
... A total of 179 layers have been given official numbers, whereas certain distinctive ash layers not included in the original sequence, since have been assigned numbers and added letters (Fig. 1C;Bøggild 1918;Gry 1940;Pedersen & Surlyk 1983;Pedersen & Buchardt 1996;Larsen et al. 2003;Pedersen et al. 2004). The ash layers originate from volcanic eruptions connected to the opening of the northeast Atlantic (Bøggild 1918;Andersen 1937;Pedersen & Surlyk 1983;Danielsen & Thomsen 1997;Storey et al. 2007), and the age of the formation has been determined by radiometric dating of locally numbered ash layers -17 and +19, yielding 39 Ar/ 40 Ar age determinations of c. 55.6 Ma and c. 54.4 Ma, respectively (Storey et al. 2007;Westerhold et al. 2009;Stokke et al. 2020). The Fur Formation is divided into the lower Knudeklint Member, defined by laminated beds and relatively few ash layers, and the upper Silstrup Member, which is dominated by structureless beds and an abundancy of often thick ash layers; sequences reflecting the alternating conditions of slight dysoxia and anoxia ( Fig. 1C; Pedersen & Surlyk 1983;Heilmann-Clausen et al. 1985). ...
... A total of 179 layers have been given official numbers, whereas certain distinctive ash layers not included in the original sequence, since have been assigned numbers and added letters (Fig. 1C;Bøggild 1918;Gry 1940;Pedersen & Surlyk 1983;Pedersen & Buchardt 1996;Larsen et al. 2003;Pedersen et al. 2004). The ash layers originate from volcanic eruptions connected to the opening of the northeast Atlantic (Bøggild 1918;Andersen 1937;Pedersen & Surlyk 1983;Danielsen & Thomsen 1997;Storey et al. 2007), and the age of the formation has been determined by radiometric dating of locally numbered ash layers -17 and +19, yielding 39 Ar/ 40 Ar age determinations of c. 55.6 Ma and c. 54.4 Ma, respectively (Storey et al. 2007;Westerhold et al. 2009;Stokke et al. 2020). The Fur Formation is divided into the lower Knudeklint Member, defined by laminated beds and relatively few ash layers, and the upper Silstrup Member, which is dominated by structureless beds and an abundancy of often thick ash layers; sequences reflecting the alternating conditions of slight dysoxia and anoxia ( Fig. 1C; Pedersen & Surlyk 1983;Heilmann-Clausen et al. 1985). ...
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Bony fishes are among the best represented macrofossils from the earliest Eocene Fur Formation, northern Denmark. The most abundant fish of the formation has never been formally described, in spite of its abundance throughout the formation, and only referred to as an ‘argentinoid’. This work provides a taxonomic study of this argentinoid taxon, which is described herein as Surlykus longigracilis gen. et sp. nov. The caudal skeleton shows separated first preural and first ural centra, a unique condition within the Argentiniformes. In addition, it is characterised by having a large mouth and a single supramaxilla, which suggest that Surlykus gen. nov. occupies a basal position within the Argentiniformes, representing the sister-group to all the other lineages of this clade ([Argentinidae + Opisthoproctidae] + [Bathylagidae + Microstomatidae]), and, consequently, a stem-group Argentiniformes. Mass-mortality assemblages may indicate that Surlykus longigracilis gen. et sp. nov. formed large schools in the ancient North Sea Basin, where it probably represented the trophic nucleus of the fish communities.
... The Knudeklint Member is principally laminated with relatively few ash layers, whereas the Silstrup Member is dominated by structureless beds with numerous ash layers (Pedersen & Surlyk, 1983;Heilmann-Clausen et al., 1985). The marine diatomite sediments are interbedded with a well-preserved series of more than 180 numbered ash layers originating from volcanic eruptions during the opening of the Northeast Atlantic (Bøggild, 1918;Andersen, 1937;Pedersen & Surlyk, 1983;Danielsen & Thomsen, 1997;Storey et al., 2007). However, as more ash layers are continuously identified and officially numbered, the sediments may contain well more than 200 distinct ash layers (Andersen, 1937;Pedersen et al., 2012). ...
... However, as more ash layers are continuously identified and officially numbered, the sediments may contain well more than 200 distinct ash layers (Andersen, 1937;Pedersen et al., 2012). The age of the Fur Formation is based on radiometric dating of ash layers −17 and +19, yielding 39Ar/40Ar age determinations of ∼55.6 Ma and ∼54.4 Ma, respectively (Chambers et al., 2003;Storey et al., 2007;Westerhold et al., 2009;Stokke et al., 2020). The sediments of the Fur Formation were deposited in the North Sea Basin below the storm wave base under conditions of alternating anoxia and slight dysoxia (Pedersen & Surlyk, 1983). ...
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The earliest Eocene (Ypresian) Fur Formation (Denmark) is globally renowned for its exceptionally well-preserved fossils, including birds, sea turtles, insects, plants, and fishes. Fishes, albeit abundant and diverse, however, are only superficially known and very few detailed, taxonomic studies have been realized to date. A new polymixiiform fish, Polyspinatus fluere gen. et sp. nov., from the Fur Formation is described based on seven well-preserved, nearly complete specimens. All the specimens were studied by traditional stereomicroscopy, and by micro-X-ray fluorescence-element mapping. Digital 2D-element images of strontium-, phosphorus-, and calcium distributions of each specimen were directly applied for the taxonomic descriptions presented herein. Polyspinatus fluere gen. et sp. nov. is the first known Eocene record of the family Polymixiidae based on articulated skeletal remains. Polyspinatus gen. nov. exhibits a unique combination of characters that support its recognition as a new genus of the Polymixiidae. Its specialized hyoid apparatus with the first and second branchiostegal rays being sinuous and parallel to each other, and the third being wide and plate-like, followed by four saber-like elements, is strikingly similar to that of Polymixia, supporting a possible sister-group relationship with extant beardfishes.
... The broad overall increase was a consequence of appearance of the Iceland hot spot that caused the mid-Atlantic Ridge to propagate northwards between Greenland and Europe into the Arctic (Srivastava and Tapscott, 1986). This resulted in the release of frozen methane hydrates on the Arctic continental shelf causing Early Eocene Climatic Optimum (Storey et al., 2007). During this warming there was a spike in temperature, the Palaeocene-Eocene Thermal Maximum, caused by orbital forcing of the Earth's climate (Li et al., 2022). ...
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... O processo de degaseificação oriunda de vulcanismo permanece sendo importante fonte natural de dióxido de carbono e de outros gases para atmosfera e oceanos. Este mecanismo contribui para o aporte de material gasoso na atmosfera por meio de eventos tectônicos ao longo do tempo e diretamente no oceano por hidrotermalismo em vulcões submarinos (SANTANA-CASIANO, FRAILE-NUEZ, et al., 2016) Entre os processos naturais, pode-se destacar aqueles vinculados ao vulcanismo como o responsável pelas súbitas elevações da concentração de dióxido de carbono na atmosfera durante o Ypresiano, no Eoceno (PEARSON, PALMER, 2000, STOREY, DUNCAN, et al., 2007, e aqueles ligados a processos biológicos, como a transição para o ressurgimento da formação glacial polar e sua expansão na transição para o Oligoceno (PEARSON, FOSTER, et al., 2009, SPEELMAN, VAN KEMPEN, et al., 2009. As mudanças climáticas terrestres que ocorreram ao longo dos últimos 500 milhões de anos são ilustradas na Figura 2. Como um sistema de equilíbrio no longo prazo, o ciclo do carbono tenderia a capturar CO2 da atmosfera no oceano e nos depósitos inertes marinhos na forma mineral, por processo de dissolução, o que mitigaria o efeito da concentração de dióxido de carbono na atmosfera. ...
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... The volcanism degassing process remained an important natural source of carbon dioxide and other gases to the atmosphere and the ocean. This mechanism could release volcanic gases in the atmosphere by tectonic events through time and inputs directly to the ocean by hydrothermalism in the submarine volcanos (SANTANA-CASIANO, FRAILE-NUEZ, et al., 2016) Among the natural processes, it can highlight those linked to volcanism, which is pointed out as responsible for the sudden increase in the concentration of carbon dioxide in the atmosphere during the Ypresian, in the Eocene (PEARSON, PALMER, 2000, STOREY, DUNCAN, et al., 2007, and those linked to biological processes, such as the transition to the resurgence of polar glacial formation and its expansion, in the transition to the Oligocene (PEARSON, FOSTER, et al., 2009, SPEELMAN, VAN KEMPEN, et al., 2009. The history of terrestrial climate change over the past 500 million years can be illustrated in Figure 2. On the left side, the anomalous temperature of the Earth's surface considering average relativity for the 0 ºC equivalent to the preindustrial period's baseline. ...
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A simple model is developed which explains the occurrence of volcanic continental margins and flood basalts as a consequence of their association with nearby plumes that were active at the time of rifting. In the model, asthenosphere temperatures are increased by 100-150 C over large regions of the earth by heat advected upward in mantle plumes. The amount of partial melt generated by the asthenosphere as it wells up beneath rifts in these hot areas is calculated. Observational constraints from all known examples of volcanic continental margins are reviewed and the model is used to explain these observations.
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We combine new and published 40Ar/39Ar age determinations from incremental heating experiments on whole rocks and mineral separates to assess the timing, duration and distribution of volcanic activity during construction of the North Atlantic Igneous Province. We use these ages together with volume estimates of erupted magmas and their cumulates to calculate melt production rates for the early Tertiary flood basalts of East Greenland and the Faeroes Islands. The lavas lie at opposite ends of the Greenland–Iceland–Faeroes Ridge, the postulated Iceland hotspot track, and record volcanic activity leading up to, during and following continental breakup between Greenland and Europe.
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The question of whether basaltic rocks in continental flood basalt provinces are primary magmas or whether they are descended in general from picritic parent magmas is reviewed. It is suggested that the latter is more likely to be correct on the evidence of phase relations and the relative rareness of mantle materials with appropriate Fe/Mg ratios. Major element variations in the residual liquids of fractional and equilibrium crystallization of basaltic magmas are modelled for a variety of crystallizing assemblages. It is concluded that crystallization of olivine, clinopyroxene, and plagioclase has a marked effect on buffering chemical change in many important elements. It is this effect which accounts for the apparent uniformity of large volumes of flood basalts, not, as has sometimes been supposed, a series of implausible coincidences in the amount of material fractionated from each magma batch. It is further argued that much of the variation seen in basalts may be imposed by polybaric fractionation operating throughout crustal depths, that is at pressures up to at least 12 kb. Parental picritic magmas rising from the mantle reach the surface in exceptional areas of crustal thinning. More usually, however, it is suggested that they intrude the base of the crust as a series of sills which differentiate into upper gabbroic and lower ultramafic portions. Much of the 'low pressure' fractionation of basaltic magmas may take place in this deep crustal sill complex and evolved liquids are transmitted to the surface as their density becomes sufficiently low. This implies that in areas of flood vulcanism a potentially large new contribution to the crust is made by under- plating, the volumes of concealed cumulates being at least as large as the amount of erupted surface lava.