When modeling ignores observations: The Jiloca graben (NE Spain) and the Rubielos de la Cérida impact basin

Abstract

The Iberian System in NE Spain is characterized by a distinctive graben/basin system (Calatayud, Jiloca, Alfambra/Teruel), among others, which has received much attention and discussion in earlier and very recent geological literature. A completely different approach to the formation of this graben/basin system is provided by the impact crater chain of the Rubielos de la Cérida impact basin as part of the important Middle Tertiary Azuara impact event, which has been published for about 20 years. Although the Rubielos de la Cérida impact basin is characterized by all the geological, mineralogical and petrographical impact findings recognized in international impact research, it has completely been hushed up in the Spanish geological literature to this day. The article presented here uses the example of the Jiloca graben to show the absolute incompatibility of the previous geological concepts with the impact structures that can be observed in the Jiloca graben without much effort. Digital terrain modeling and aerial photography together with structural and stratigraphic alien geology define a new lateral Singra-Jiloca complex impact structure with central uplift and an inner ring, which is positioned exactly in the middle of the Jiloca graben. Unusual topographic structures at the rim and in the area of the inner ring are interpreted as strike-slip transpression and transtension. Geological literature that still sticks to the old ideas and develops new models and concepts for the graben/basin structures, but ignores the huge meteorite impact and does not even enter into a discussion, must at best cause incomprehension.

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When!modeling!ignores!observations:!The!Jiloca!graben!(NE!
Spain)!and!the!Rubielos!de!la!Cérida!impact!basin!!
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by!Kord!Ernstson1!and!Ferran!Claudin2!
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June!2020!
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Abstract.!-!The!Iberian!System!in!NE!Spain!is!characterized!by!a!distinctive!
graben/basin!system!(Calatayud,!Jiloca,!Alfambra/Teruel),!among!others,!which!has!
received!much!attention!and!discussion!in!earlier!and!very!recent!geological!literature.!A!
completely!different!approach!to!the!formation!of!this!graben/basin!system!is!provided!
by!the!impact!crater!chain!of!the!Rubielos!de!la!Cérida!impact!basin!as!part!of!the!
important!Middle!Tertiary!Azuara!impact!event,!which!has!been!published!for!about!20!
years.!Although!the!Rubielos!de!la!Cérida!impact!basin!is!characterized!by!all!the!
geological,!mineralogical!and!petrographical!impact!findings!recognized!in!international!
impact!research,!it!has!completely!been!hushed!up!in!the!Spanish!geological!literature!to!
this!day.!The!article!presented!here!uses!the!example!of!the!Jiloca!graben!to!show!the!
absolute!incompatibility!of!the!previous!geological!concepts!with!the!impact!structures!
that!can!be!observed!in!the!Jiloca!graben!without!much!effort.!Digital!terrain!modeling!
and!aerial!photography!together!with!structural!and!stratigraphic!alien!geology!define!a!
new!lateral!Singra-Jiloca!complex!impact!structure!with!central!uplift!and!an!inner!ring,!
which!is!positioned!exactly!in!the!middle!of!the!Jiloca!graben.!Unusual!topographic!
structures!at!the!rim!and!in!the!area!of!the!inner!ring!are!interpreted!as!strike-slip!
transpression!and!transtension.!Geological!literature!that!still!sticks!to!the!old!ideas!and!
develops!new!models!and!concepts!for!the!graben/basin!structures,!but!ignores!the!
huge!meteorite!impact!and!does!not!even!enter!into!a!discussion,!must!at!best!cause!
incomprehension.!
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Key+words:!meteorite!impact,!Azuara!impact!event,!Alfambra-Teruel!graben,!Calatayud!basin,!
strike-slip!transgression,!transtension,!Singra-Jiloca!impact!
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1 University of Würzburg, 97074 Würzburg (Germany), ernstson@ernstson.de
2 Associate Geological Museum Barcelona (Spain); fclaudin@xtec.cat
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1!Introduction!
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According!to!current!geological!characterization,!the!Jiloca!Graben!in!northeastern!Spain!
is!part!of!an!important!intramontane!graben-basin!system!together!with!the!Calatayud!
Basin/Graben!and!the!Alfambra-Teruel!Basin/Graben!(Fig.!1),!both!terms!being!used!
synonymously!in!the!literature.!The!origin!of!the!remarkable!topographic!depression!is!
controversial,!and!tectonic!subsidence!(Rubio!and!Simón!2007)!and!erosive!deepening!
are!mainly!attributed!to!either!Tertiary!erosion!pediplains!or!karst!subrosion,!whereby!
combined!formation!processes!are!also!discussed!(Casas-Sainz!and!Cortés-Gracia!2002)!
Gracia!et!al.!2003).!!
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In!the!literature!(e.g.,!Sanz!de!Galdeano!et!al.!2019,!!Gutiérrez!et!al.!2012)!,!the!Jiloca!
graben!is!described!as!having!originated!in!the!Neogene!and!Quaternary,!being!limited!
by!normal!faults!(the!Menera!and!Palomera!faults)!with!measurable!several!hundred!
meters!throws,!cutting!pre-existent!NW-SE!striking!folds.!The!sedimentary!fill!consists!
of!at!least!80!m!thick!Neogene!and!Quaternary.!!
The!contradictory!interpretations!of!the!genesis!of!the!Jiloca!graben!also!find!expression!
in!the!fact!that!the!structure!is!called!both!a!graben!and!sometimes!a!half-graben!(Fig.!
5.9.!in![Sanz!de!Galdeano!et!al.!2019]).!!
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In!the!aforementioned!articles!and!even!in!the!most!recent!literature,!there!is!no!
mention!of!an!approximately!20-year-old!alternative!hypothesis!on!the!formation!of!the!
Jiloca!graben!in!the!context!of!discussions!and!publications!on!the!large!multiple!Azuara!
impact!with!the!formation!of!the!Azuara!impact!structure!and!an!associated!Rubielos!de!
la!Cérida!impact!basin!(Ernstson!et!al.!2001,!2002,!!2003,!Claudin!et!al.!2001,!2003,!
Schüssler!et!al.!2002,!Hradil!et!al.!2001,!Ernstson!and!Claudin,!http://www.impact-
structures.com/impact-spain/the-rubielos-de-la-cerida-impact-basin,!no!year).!This!is!
accompanied!by!the!observation!that!the!Azuara!impact!structure!published!since!1985!
(Ernstson!et!al.!1985,!1987,!2002,!Müller!and!Ernstson!1990,!Ernstson!and!Claudin!
1990,!Ernstson!1994,!Ernstson!and!Fiebag!1992!,!Claudin!and!Ernstson!(2012),!Ernstson!
and!Claudin!http://www.impact-structures.com/impact-spain/the-azuara-impact-
structure,!no!year)!is!not!mentioned!at!all!in!the!discussion!of!the!other!basin!structures!
mentioned!(Calatayud!and!Alfambra-Teruel),!even!in!the!latest!geological!literature!(e.g.!
Sanchez!et!al.!2017,!Casas-Sainz!et!al!2018,!Gutiérrez!et!al.!2012,!2020,!Simón!et!al.!
2019,!Sanz!de!Galdeano!et!al.!2019!).!!
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In!view!of!this!fact!in!the!newer!and!most!recent!Spanish!geological!literature,!we!feel!
compelled!to!contrast!the!conventional!ideas!about!the!intramontane!basins!mentioned!
at!the!beginning!with!the!extensive!geological,!mineralogical!and!petrographical!findings!
from!the!Rubielos!de!la!Cérida!impact!basin!with!the!result!that!the!formation!
hypotheses!discussed!so!far!can!be!geologically!coherently!replaced!by!the!formation!of!
the!region!in!a!massive!impact!event.!We!start!here!with!a!first!article!focusing!on!the!
Jiloca!graben,!which!will!be!followed!by!further!articles!on!the!geological!structure!and!
the!extensive!impact!finds!and!features!of!the!entire!Rubielos!de!la!Cérida!impact!basin,!
which!is!not!known!on!earth!as!its!equal.!
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Fig.1.!Standard!graben/basin!configuration!on!the!Digital!Terrain!Modell!(DTM!source!M.!Cabedo).!
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Fig.!2.!The!Azuara!multiple!impact!event!produced!the!more!circular!Azuara!impact!structure!
together!with!the!elongated!Rubielos!de!la!Cérida!impact!basin.!
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2!The!Rubielos!de!la!Cérida!impact!basin!
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Originally,!the!Rubielos!de!la!Cérida!basin!was!defined!by!an!approximately!circular!
uplift!of!Mesozoic!rocks!(Fig.!2,!3),!surrounded!by!a!semi-circular!to!elliptical!depression!
of!Quaternary!and!post-impact!Neogene!deposits!(Fig.!4;!simplified!and!modified!from!
the!geological!maps!1:!200.000;!ITGE,!1991;!IGME,!1986).!This!circular!uplift!with!rocks!
of!the!Muschelkalk!Fm.!in!the!very!center!at!the!village!of!Rubielos!de!la!Cérida!and!!
tectonically!very!surprising!in!the!region,!was,!after!abundant!impact!findings!with!clear!
shock!metamorphism!and!structural!abnormalities!(Fig.!4),!quickly!recognized!as!a!
companion!to!the!then!already!established!Azuara!impact!structure!(Ernstson!et!al!
(2002).!Continuing!geological!investigations!soon!showed!that!from!the!central!uplift!
there!was!an!unmistakable!extension!of!the!structure!towards!Teruel,!which!continued!
to!provide!ample!impact!findings!(Abb.!4)!and!led!to!the!definition!of!a!Rubielos!de!la!
Cérida!impact!basin!(Ernstson!et!al.!2003).!
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Fig.!3.!Map!for!general!orientation!in!the!multiple!impact!field!of!the!Azuara!impact!structure!and!
the!Rubielos!de!la!Cérida!impact!basin.!CAL.!=!Calamocha,!CAM!=!Caminreal,!CAR!=!Cariñna,!MUN!=!
Muniesa;!A-23!=!Autovía!Mudéjar.!
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Fig.!4.!Simplified!geologic!map!of!the!Rubielos!de!la!Cérida!impact!basin!and!major!occurrences!of!
impact!features.!1!=!Paleozoic,!Mesozoic!and!Lower!Tertiary,!2!=!Upper!Tertiary!and!Quaternary,!3!
=!Pelarda!Formation!ejecta,!4!=!Muschelkalk,!5!=!Keuper,!6!=!Rhaethian!and!Liassic,!7!=!Dogger,!8!=!
Malmian,!9!=!Cretaceous,!10!=!drainage!pattern.!A!=!basal!suevite!breccia,!B!=!breccia!dikes,!C!=!
megabreccias!and!monomictic!movement!breccias,!D!=!shock!metamorphism,!E!=!shatter!cones,!F!
=!impact!melt!rocks,!suevites!(Barrachina!type)!and!suevite-like!breccias,!G!=!impact!glass!
(pseudotachylite?).!Also!shown!a!WSW-ENE!section!of!the!central!uplift.!

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It!soon!became!clear!during!the!mapping!of!the!geology!in!the!basin!that,!apart!from!the!
Palomera!steeply!raised!block!(Figs.!5,!6),!we!were!dealing!with!extreme!structural!
compression!along!and!within!the!Central!uplift!chain!(Figs.!7-9),!which!goes!against!all!
assumptions!of!direct!contact!graben!structures!postulated!west!(Jiloca)!and!east!
(Alfambra/Teruel),!but!would!provide!a!very!strong!argument!for!impact!cratering!
processing!(Fig.!10).!
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!!Fig.!5.!Location!of!the!exposures!in!Figs.!6-8.!
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Fig.!6.!Part!of!the!central!uplift!chain!(Sierra!Palomera)!emerging!from!the!Quaternary!of!the!
impact!basin!(continuation!of!the!Rubielos!de!la!Cérida!central!uplift!to!the!south;!see!Fig.!2).!
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Fig.!7.!Megabreccia!near!Bueña.!Intense!criss-cross!layering!of!Jurassic!limestones!in!the!central!
uplift!chain!indicates!extreme!compression.!
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Fig.!8.!!Folding!and!megabrecciation!of!Jurassic!limestones!in!the!central-uplift!chain!(between!
Bueña!and!Caminreal).!Note!that!only!some!“ghost”!layering!has!survived!the!intense!brecciation.!
As!in!Fig.!7!an!extreme!compression!is!indicated.!

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Fig.!9.!The!image!shows!part!of!an!extended!megabreccia!deposit!in!the!southern!central!uplift!
near!Caudé.!Within!a!chaotic!accumulation!of!limestone!blocks!and!fragments,!a!large!surface!
displaying!prominent!striae!and!polish!occurs!(hammer!length!40!cm).!Any!relation!to!tectonic!
structures!is!clearly!missing.!It!is!assumed!that!the!peculiar!deformations!formed!in!the!highly!
compressive!process!of!the!central!uplift!development!(modification!stage!of!impact!cratering).!
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Fig.!10.!Simple!models!of!graben!tectonics!and!impact!cratering.!
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3!The!Mesozoic!uplift!in!the!middle!of!the!Jiloca!graben!
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In!the!course!of!the!field!work!in!the!Rubielos!de!la!Cérida!impact!basin,!the!special!
stratigraphic!constellation!with!the!Buntsandstein!hill!northeast!of!Singra!in!the!middle!
of!the!plain!of!the!Neogene-Tertiary!Jiloca!Graben!(Fig.!11)!understandably!attracted!
attention.!As!a!silicate!lithostratigraphic!unit,!it!was!an!invitation!to!look!for!shock-
metamorphic!rocks,!which!led!quite!quickly!to!success!(Fig.!4).!The!accompanying!
investigations!on!the!stratigraphic!outcrop!of!the!Singra!hill!provided!extensive!further!
impact-specific!evidence!in!the!form!of!the!suevite!basal!breccia,!dike!breccias!and!
monomictic!movement!breccias,!so!that!the!whole!complex!together!with!the!adjacent!
rising!arch!of!Rhaetian!and!Liassic!rocks!were!classified!as!impact-related.!!
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Since!this!situation!does!not!even!exist!in!the!latest!geological!literature,!the!basic!
discrepancy!between!conventional!and!impact-related!interpretation!is!shown!below,!
followed!by!a!structural!model,!which!also!includes!the!morphological!situation!with!the!
Digital!Terrain!Model!(DTM).!
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Fig.!11.!Map!section!of!the!Jiloca!graben!in!the!Digital!Terrain!Model.!The!rectangle!spans!the!
generalized!geologic!map!of!the!Mesozoic!structure!(arrow)!in!the!middle!of!the!Jiloca!graben!(Fig.!
11).!
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Fig.!12.!Geological!sketch!of!the!Mesozoic!uplift!in!the!middle!of!the!graben.!!Legend!of!the!
stratigraphic!units!in!Fig.!12.!Copied!from!the!maps!1!:!200!000,!sheets!Daroca!and!Teruel,!and!the!
maps!1!:!50!000,!sheets!Monreal!del!Campo!(IGME!1983)!and!Santa!Eulalia!(IGME!1959).!Because!of!
its!exotic!stratigraphic!position,!the!Upper!Malmian!(Kimmeridgian)!block!(C)!must!be!considered!
as!a!dislocated!megablock!or!assigned!to!downward!"elevator"!tectonics!over!enormous!drop.!The!
layer!dip!has!been!copied!from!the!1!:!50!000!maps.!
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Fig.!13.!Geological!profile!(see!Fig.!12)!of!the!uplift.!The!sketched!dip!of!the!units!refers!to!Fig.!12.!
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As!can!be!seen!in!Fig.!11,!the!unusual!topographical!situation!of!the!structure!can!
already!be!seen!in!the!DTM,!which!will!also!be!discussed!later.!Fig.!12!shows!a!highly!
simplified!geological!map!for!the!rectangle!with!a!restriction!to!an!indexing!of!the!
Mesozoic!units.!For!the!white!profile!line!Fig.!13!shows!a!corresponding!section!with!the!
corresponding!legend.!In!principle!the!structural!situation!is!roughly!half!of!the!circular!
central!uplift!of!Rubielos!de!la!Cérida!(Fig.!4).!!The!impossibility!of!a!Jiloca!graben!in!its!
previous!interpretation!in!this!area!cannot!be!better!characterized!than!by!this!
stratigraphically!and!structurally!completely!alien!situation.!!
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The!position!of!this!structure!within!the!formation!of!the!entire!impact!basin!can!only!be!
conjectured.!The!most!plausible!explanation!is!the!formation!of!a!smaller!side!crater!in!
the!chain!of!adjacent!central!craters,!with!an!inner!ring!and!its!own!central!uplift.!The!
diameter!may!be!estimated!to!roughly!10!km!(see!5).!
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4!Transpression!and!transtension!in!complex!impact!structures!
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Transpression!and!transtension!are!strike-slip!deformations!that!deviate!from!simple!
shear,!when!!a!component!of!shortening!or!extension!orthogonal!to!the!deformation!
zone!occurs.!These!three-dimensional!non-coaxial!strains!develop!principally!in!
response!to!obliquely!convergent!or!divergent!relative!motions.!For!complex!impact!
structures,!Kenkmann!and!Dalwigk!(2000)!have!shown!that!such!deformations!can!be!a!
new!and!noteworthy!feature!that!arises!in!the!modification!phase!of!impact!cratering!
during!converging!and!diverging!gravitational!collapse!movements.!
Very!simple!models!of!these!strike-slip!deformations!have!been!sketched!in!Fig.!14,!
which!should!serve!to!classify!the!very!unusual!morphological!conditions!in!the!Singra!
area!(Fig.!15).!
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Fig.!14.!Simple!models!of!strike-slip!transpression!and!transtension!structures!in!complex!impact!
craters.!
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A!look!at!the!DTM!in!Fig.!15!suggests!that!the!postulated!side!crater!with!the!uplift!and!a!
partially!formed!inner!ring!could!be!the!result!of!exactly!this!strike-slip!deformation.!It!
is!important!to!understand!that!these!structures!have!not!been!noticed!in!previous!
mapping,!where!only!a!more!or!less!elongated!Rhaetian-Liassic!stripe!with!partial!
anticlinal!character!was!registered.!Only!with!the!DGM!this!quite!unusual!pattern!of!

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almost!equally!spaced!narrow!morphological!bars!is!recognized,!where!the!individual!
bars!also!show!a!certain!elongation!orthogonal!to!the!postulated!inner!ring.!
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Fig.!15.!Interpretation!of!unusual!topographic!features!in!the!middle!of!the!Jiloca!graben!as!impact-
related!transpression!and!transtension!structures.!!
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5!The!Singra-Jiloca!crater!!
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With!the!topographical!and!geological!features!discussed!above!and!in!view!of!the!
impact-related!observations!in!the!Singra!uplift!and!on!the!neighboring!Buntsandstein!
hill!(Fig.!4),!a!remarkable!lateral!extension!of!the!central!uplift!chain!right!through!the!
middle!of!the!Jiloca!graben,!as!it!has!always!been!interpreted!so!far,!becomes!evident.!
Apart!from!the!geologically!fundamentally!alien!stratigraphic!elevations!in!the!middle!of!
the!graben,!this!insight!is!made!possible!above!all!by!the!high-resolution!DTM!(Fig.!15)!
and!aerial!imagery!(Google!Earth,!Fig.!16)!,!which!clearly!show!impact-related!features.!!
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Fig.!16.!Aerial!photograph!(Google!Earth)!in!which!the!special!topographic!position!of!the!Singra-
Jiloca!structure!with!postulated!transpression!and!transtension!is!also!clearly!visible.!For!the!
white!lines!marked!in!the!small!image!inset,!Fig.!17!shows!the!profiles!of!the!terrain!elevations!
taken!from!the!Google!map.!
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The!topographical!peculiarities!should!not!be!overstressed!here,!especially!since!the!
geological!maps!give!practically!no!better!stratigraphic!itemization!of!a!transpression!at!
the!crater!rim,!but!the!conspicuous!correspondence!of!the!peculiar!structures!exactly!in!
this!area!(Figs.!16,!17)!strongly!supports!the!reality!of!this!Singra-Jiloca!complex!impact!
structure!as!a!lateral!companion!to!the!main!impact!chain!extending!between!the!
Rubielos!de!la!Cérida!uplift!and!Teruel.!
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Fig.!17.!The!terrain!forms!along!the!profiles!in!Fig.!16!interpreted!as!transpression!and!
transtension!support!this!point!of!view,!whereby!almost!periodically!occurring!ridges!of!a!
transpression!and!troughs!of!a!transtension!appear!to!be!formed.!Source!Google!Earth.!
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For!the!time!being,!questions!remain!unanswered!regarding!the!extension!of!the!Singra-
Jiloca!structure!in!the!form!of!the!inner!ring!to!the!north!(Figs.!15,!16)!and!a!certain!
topographic!west-east!asymmetry!at!the!edge!of!the!Sierra!Palomera!(Figs.!16).!From!
the!point!of!view!of!a!complex!impact!cratering,!the!formation!of!the!central!mountain!
chain!with!primary!compression!and!subsequent!partial!collapse!and!laterally!strong!
pressure!to!the!outside!-!here!especially!in!the!area!of!the!Palomera!uplift!-!cannot!have!
remained!without!influence!on!the!more!or!less!simultaneous!formation!of!the!Singra-
Jiloca!structure,!and!a!consequently!formed!asymmetry!is!not!necessarily!surprising.!A!
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Fig.!18.!!A!diametrical!elevation!profile!through!the!structure!across!the!Jiloca!graben!provides!an!
appropriate!interpretation!and!at!the!same!time!once!again!highlights!the!contrast!between!the!
traditional!geological!approach!on!the!one!hand!and!the!coherent!results!of!impact!research!on!the!
other.!
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6!Discussion!and!conclusions!
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The!starting!point!for!this!article!was!described!at!the!beginning!and!refers!to!the!fact!
that!the!great!multiple!impact!that!the!Azuara!impact!structure!and!the!associated!
Rubielos!de!la!Cérida!impact!basin!does!not!occur!in!the!newer!and!most!recent!Spanish!
geological!literature,!and!even!these!terms!do!not!appear!in!the!indexes!of!textbooks!on!
Spanish!geology.!We!have!taken!this!as!an!opportunity!to!show!by!means!of!an!example!
how!ignoring!the!extensively!published!impact!material!on!the!impacts!means!that!old!
and!long!outdated!views!on!the!Tertiary!geology!of!the!Iberian!system!are!being!
perpetuated,!and!also!very!special!aspects!of!tectonics!and!geophysical,!e.g.!
seismological,!conditions!are!necessarily!misleading.!!
!
The!structure!of!the!Jiloca!Graben!taken!here!as!an!example!is!symptomatic!for!this!
conflict,!which!in!the!conventional!view!works!with!model!conceptions!(here:!tectonic!
graben!lowering!or!erosion!with!subrosion!and!karst)!of!a!whole!graben/basin!system,!
but!ignores!simple!geological!observations.!We!have!already!made!similar!experience!in!
connection!with!the!ejecta!of!the!Azuara!impact!structure!(Pelarda!Formation)!and!the!
remarkable!impact!thrust!of!Daroca!(Claudin!and!Ernstson!2019,!2020,!and!references!
therein).!
!
With!regard!to!the!Jiloca!graben,!we!would!like!to!concede!that!this!striking!depression,!
in!a!relatively!cursory!view!and!discussion,!has!certainly!offered!itself!as!a!graben!
formation,!and!even!with!regard!to!the!impact,!the!Jiloca!graben!and!the!
Alfambra/Teruel!graben!belong!to!graben-like!depressions!between!Rubielos!de!la!
Cérida's!central!uplift!and!the!basin!rim.!That!the!discrepancy!between!tectonic!graben!
subsidence!and!impact!interpretation!due!to!the!enormous!stratigraphic!uplift!at!Singra!
and!the!enormous!subsidence!of!the!Kimmeridgian!block!directly!next!to!it,!and!all!that!
in!the!middle!of!the!Jiloca!graben,!should!have!given!food!for!thought.!This!should!be!put!
aside!here,!as!should!the!published!impact!shock-metamorphic!effects!throughout!the!
entire!impact!basin.!
!
The!new!view!of!an!independent!lateral!crater!with!a!central!uplift!and!inner!ring!with!a!
diameter!of!perhaps!10!km,!which!is!now!located!exactly!in!the!middle!of!the!formerly!
interpreted!Jiloca!graben,!results!mainly!from!the!use!of!the!DTM!digital!terrain!model!
and!the!so!very!informative!historical!aerial!photographs!of!Google!Earth,!which!have!
been!changing!over!30!years.!Both!strongly!reinforce!the!interpretation!as!a!new!impact!
structure!belonging!to!the!multiple!Azuara!impact!event!and!should!not!allow!the!
tectonic!or!subrosion-affected!Jiloca!graben!to!continue!to!exist!geologically.!This!should!
also!apply!without!restriction!to!the!Alfambra/Teruel!graben!as!part!of!the!Rubielos!de!
la!Cérida!impact!basin!and!all!related!geotectonic!work!and!processing!in!the!region!
(e.g.,!Anchuela!et!al.!2016,!Arlegui!2006,!Casas-Sainz!&!Cortés-Gracia!2002,!Casas-Sainz!
et!al.!2018,!Casas!et!al.!2000,!Ezquerro!et!al.!2019,!2020,!Gutiérrez!et!al!2012,!2020,!Sanz!
de!Galdeano!et!al!2019,!Simón!et!al!2005,!2012,!2017).!
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