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Journal ArticleDOI

A revised age-model for the Eocene deep-marine siliciclastic systems, Aínsa Basin, Spanish Pyrenees

01 Jan 2021-Journal of the Geological Society (Geological Society of London)-Vol. 178, Iss: 1
TL;DR: Using new palaeomagnetic and biostratigraphic data, the authors revise the age model for the Ainsa Basin (Spanish Pyrenees), a tectonically active basin formed at a convergent-plate margin.
Abstract: Using new palaeomagnetic and biostratigraphic data, we revise the age-model for the middle Eocene, deep-marine, Ainsa Basin (Spanish Pyrenees), a tectonically active basin formed at a convergent-plate margin. This new age model provides a framework for evaluating the depositional history and sediment accumulation rates. New integrated magneto- and biostratigraphy data identifies two normal and two reverse chrons of the geomagnetic polarity timescale (C21r, C21n, C20r, C20n) and place these Upper Hecho Group deposits in the middle Eocene (Lutetian). Nannofossil analysis identifies a biostratigraphic range from Subzone NP14b in the Gerbe System to Subzone NP15b at the top of the Ainsa System using key, age-diagnostic marker species such as Blackites inflatus, Blackites piriformis and Coccolithus gigas. We also present new nannofossil biostratigraphy from the Lower Hecho Group. This new Ainsa Basin chronostratigraphy enables inter-basinal correlations between the proximal fluvio-deltaic Tremp-Graus Basin and the more distal Jaca Basin, thereby providing a better understanding of the basin evolution. Supplementary material:https://doi.org/10.6084/m9.figshare.c.5083076

Summary (3 min read)

Jump to: [Introduction][Geological setting][Methodology][Results][Discussion] and [Conclusions]

Introduction

  • Using new palaeomagnetic and biostratigraphic data, the authors revise the age-model for the middle Eocene, deep-marine, Aínsa Basin (Spanish Pyrenees), a tectonically active basin formed at a convergent-plate margin.
  • The authors also present new nannofossil biostratigraphy from the Lower Hecho Group.
  • Through the integration of new palaeomagnetic and biostratigraphic data, the authors refine the existing age model of Scotchman et al. (2015) for the middle Eocene Hecho Group deposits of the deep-marine Aínsa Basin (Spanish Pyrenees), which was a tectonically active basin that formed at convergent-plate margin (Pickering and Cantalejo, 2015, and references therein).
  • The deep-marine environments of the Aínsa Basin represent slope, base-of-slope and proximal basin-floor sediments (Pickering and Cantalejo, 2015, and references therein) linked to the proximal fluvio-deltaic Tremp Basin to the east and the more distal deep-marine Jaca basin to the west .
  • Inter-basinal correlations are also complicated by the lack of consensus on lithostratigraphic nomenclature used for the various formation names.

Geological setting

  • The Aínsa Basin is located in the western part of the South Central Pyrenean Unit (SCPU) within the South Pyrenean Thrust System (Fernández et al., 2012).
  • Rotation in the Aínsa Basin area was coeval with the formation of 3-km in length N–S trending anticlines (Mediano, Añisclo and Boltaña anticlines), and with the growth of extensional faults in the Montsec thrust sheet (Muñoz et al., 2013).
  • Such growth structures during deposition of the deep-marine sediments show the importance of synsedimentary tectonics in controlling basin configuration both prior to, and during, deposition.
  • The infill of the Aínsa Basin consists of ~4 km of deep-marine structurally-confined, syntectonic, delta-fed lower basin-slope and base-of-slope clastic depositional systems that accumulated during the Ypresian and the Lutetian stages of the Eocene (Barnolas and Teixell, 1994; Remacha and Fernández, 2003; Fernández et al., 2004; Pickering and Corregidor, 2005; Pickering and Bayliss. 2009).
  • Each of these systems contains two to six sandbodies interpreted as sand-prone channelised submarine fans and related deposits (Pickering and Corregidor, 2005; Pickering and Bayliss, 2009).

Methodology

  • The average sediment accumulation rates (SARs) for the interfan fine-grained sediments in the Upper Hecho Group in the Aínsa Basin has been estimated to be between 24 and 50 cm/kyr with an average of 30cm/kyr (Cantalejo and Pickering, 2015).
  • New sampling for biostratigraphic analysis was taken every 10 m in all sections with the exception of the Aínsa section that is fully sampled in the Scotchman et al. (2015) study.
  • The map also shows 10 additional sample sites completed in the highly deformed Lower Hecho Group (FO1-FO10) to complement previous sampling and to complete the age model of the entire Aínsa Basin stratigraphy.
  • The samples were heated rapidly at a rate of 30°C/min until a temperature of ~30°C below the desired peak temperature was achieved.
  • The polarity of these samples was inferred from demagnetisation trends of other samples from the same site or from samples immediately above or below the sampling site.

Results

  • The results of this magnetostratigraphic study have identified four polarity chrons (from oldest to youngest): reverse-1 (R1), normal-1 (N1), reverse-2 (R2) and normal-2 (N2) .
  • The R2–N2 reversal appears to be just above the M-III fan between sample sites MG9 and MG10 (Aínsa section).
  • The key, age-diagnostic marker species are Blackites inflatus, Blackites piriformis and Coccolithus gigas (Table 1) but a range of additional taxa support these subzonal assignments (e.g., Lanternithus minutus, Pemma spp., Nannotetrina cristata, Sphenolithus furcatolithoides, S. spiniger).
  • The nannofossiliferous samples from the Lower Hecho samples range from Zone NP13 in the Fosado System to Subzone NP14a in the Arro System.
  • Similar problems are found when shifting the identified reversals to an older part of the stratigraphy, which is inconsistent within their biostratigraphy framework and with previous published work (i.e., Bentham and Burbank, 1996; Dreyer et al.

Discussion

  • The age of the older part of the Lower Hecho Group (Fosado and Los Molinos systems) is poorly constrained due to the severe tectonic deformation with numerous thrusts that likely duplicate and/or excise stratigraphy (Millington and Clark, 1995; Castelltort et al., 2017); there are also many MTDs/MTCs.
  • Fig. 12. Magnetostratigraphic correlation between Mochales et al. (2012a) and this study.
  • Oms et al. (2003) suggested that the reversed polarity observed in the lower "Cotefablo Allogroup", in agreement with biostratigraphy, can be associated with Chron C20r.
  • The Lower Hecho Group is not present in the western part of the Aínsa Basin, meaning that in the order of 3-4 million years of stratigraphy is absent due to non-deposition or as very condensed sections on the flanks of the Boltaña Anticline, and/or gravitational sliding and slumping (Pickering and Corregidor, 2005; Mochales et al., 2012a).
  • The Banastón and the Aínsa systems appear coeval with the sediments of the Capella Formation in the Upper Montañana Group, and the Morillo and Guaso systems are likely to correlate with the conglomeratic units of the Pano Formation .

Conclusions

  • This paper presents the first magnetostratigraphic study of the deep-marine sediments of the Upper Hecho Group in the Aínsa Basin, including most of the Gerbe System and the Banastón, Aínsa, Morillo, and part of the lower Guaso, systems.
  • The authors identified four main polarity chrons: R1, N1, R2 and N2 that they have interpreted as chrons C21r, C21n, C20r and C20n, using primarily nannofossil biostratigraphy.
  • The SARs during the deposition of the Upper Hecho Group average ~39 cm/kyr.
  • In the Boltaña Anticline, the shallowmarine retrogressive sequence of the lower part of the Paules Member has been linked with the deposition of the Gerbe and the Banastón systems whilst the progradational sequence of the upper part of the Paules Member is correlated with the deposition of the Aínsa and Morillo systems.

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A revised age-model for the Eocene deep-marine siliciclastic systems,
Aínsa Basin, Spanish Pyrenees
Blanca Cantalejo
1
*, Kevin T. Pickering
1
, Conall McNiocaill
2
, Paul Bown
1
,
Kyrre Johansen
2
, Melissa Grant
2
1
Department of Earth Sciences, University College London (UCL), Gower Street, London,
WC1E 6BT, U.K.
2
Department of Earth Sciences, University Oxford, South Parks Road, Oxford, OX1 3AN,
U.K.
*Correspondence (ucfbbca@ucl.ac.uk)
Keywords magnetostratigraphy, biostratigraphy, nannofossils, deep-marine, Middle Eocene,
Aínsa Basin
Abstract
Using new palaeomagnetic and biostratigraphic data, we revise the age-model for the middle
Eocene, deep-marine, Aínsa Basin (Spanish Pyrenees), a tectonically active basin formed at a
convergent-plate margin. This new age model provides a framework for evaluating the
depositional history and sediment accumulation rates. New integrated magneto- and
biostratigraphy data identifies two normal and two reverse chrons of the geomagnetic polarity
timescale (C21r, C21n, C20r, C20n) and place these Upper Hecho Group deposits in the
middle Eocene (Lutetian). Nannofossil analysis identifies a biostratigraphic range from
Subzone NP14b in the Gerbe System to Subzone NP15b at the top of the Aínsa System using
key, age-diagnostic marker species such as Blackites inflatus, Blackites piriformis and
Coccolithus gigas. We also present new nannofossil biostratigraphy from the Lower Hecho
Group. This new Aínsa Basin chronostratigraphy enables inter-basinal correlations between
the proximal fluvio-deltaic Tremp-Graus Basin and the more distal Jaca Basin, thereby
providing a better understanding of the basin evolution.
A robust age-model is a prerequisite for understanding the interplay of tectonic, climatic and
autocyclic processes in controlling stratigraphic architecture, and resolving source to sink

configurations in deep time (e.g., Cecil, 2003; Allen, 2008; Romans et al., 2016; Matengo
and Haq, 2020).
Through the integration of new palaeomagnetic and biostratigraphic data, we refine the
existing age model of Scotchman et al. (2015) for the middle Eocene Hecho Group deposits
of the deep-marine Aínsa Basin (Spanish Pyrenees), which was a tectonically active basin
that formed at convergent-plate margin (Pickering and Cantalejo, 2015, and references
therein). The Middle Eocene stratigraphy of the Pyrenees and adjoining areas is one of the
best natural laboratories worldwide for understanding a connected sedimentary system from
terrestrial, through shelf and submarine slope, to deep-marine environments in a tectonically-
active basin. The Aínsa Basin occupies a critical position within the source-to-sink system,
between the non-marine, marginal-marine and shallow-marine environments that acted as the
sediment supply and transfer areas for sediment-transfer processes into the deep-marine
environments of the Aínsa Basin, and the more distal Jaca and Pamplona basinal sinks.
There are few published chronostratigraphic studies based on the deep-marine sediments of
the Aínsa Basin. Some of these studies are limited to a specific stratigraphic interval, e.g.,
biostratigraphy studies restricted to the Aínsa submarine-fan and related system undertaken
by Pickering and Corregidor (2005), and in the Guaso System by Sutcliffe and Pickering
(2009). The most complete study is that of Scotchman et al. (2015), based on calcareous
nannofossil and larger benthic foraminifera age determination through ~2 km of Upper
Hecho Group stratigraphy. Previous magnetostratigraphic work has been undertaken in
shallow-marine sediments around the margins of the basin (e.g., Mochales et al.,2012a, b in
the Boltaña Anticline, Holl and Anastasio,1993 in the Mediano Anticline), with a synthesis
and new measurements by Muñoz et al. (2013).
The deep-marine environments of the Aínsa Basin represent slope, base-of-slope and
proximal basin-floor sediments (Pickering and Cantalejo, 2015, and references therein) linked
to the proximal fluvio-deltaic Tremp Basin to the east and the more distal deep-marine Jaca
basin to the west (Figure 1). Intra-basinal regional correlations have been attempted between
the Tremp and Aínsa basins (Serra-Kiel et al., 1994; Bentham and Burbank, 1996; Nijman,
1998; Das Gupta and Pickering, 2008) and between the Aínsa and Jaca basins (Labaume et
al., 1985; Payros et al., 1999; Oms et al., 2003). However, some correlations have proved to
be controversial and contradictory, as discussed below. Inter-basinal correlations are also
complicated by the lack of consensus on lithostratigraphic nomenclature used for the various

formation names. In addition, the Aínsa and Jaca basins are separated by the Boltaña
Anticline across which Hecho Group sediments are not represented, making it considerably
more difficult to establish correlations across these two basin-fills (cf. Das Gupta and
Pickering, 2008; Caja et al., 2010; Clark et al., 2017).
Fig. 1. Schematic geological map of the Pyrenees showing the position of the Aínsa Basin
and the main tectonic structures. NPFT = North Pyrenean Frontal Thrust; NPF = North
Pyrenean Fault; SPFT = South Pyrenean Frontal Thrust; SCPU = South-Central Pyrenean
Unit (modified after Vergés et al. (2002).
The main aim of this paper is to provide an integrated magneto- and biostratigraphically
constrained high-resolution age model for the Aínsa Basin. This new age model: (i) presents
new magnetostratigraphy in the basin to help tie the magnetostratigraphic work of Mochales
et al. (2012a), Holl and Anastasio (1993) in the sediments of the Boltaña and Mediano basin
flank anticlines, respectively, and also integrate the work by Muñoz et al. (2013), to the Aínsa
Basin stratigraphy, (ii) provides new micropalaeontological observations across the entire

basin deep-marine stratigraphy and incorporates the previously published biostratigraphic
work of Scotchman et al. (2015) in the Upper Hecho Group, and (iii) proposes new
correlations with updip (Tremp) and downdip (Jaca) stratigraphy to refine the source-to-sink
configurations.
The age model presented constitutes a time framework to its companion manuscript
(Cantalejo et al. in review) where we investigate the role of climate change versus tectonics
in modulating coarse-grained sediment flux to the basin. This manuscript discusses the
temporal span of deep-marine channel and related depositional systems, and demonstrates the
complex nature of drivers on deep-marine sandy fans in a tectonically-active basin.
Geological setting
The Aínsa Basin is located in the western part of the South Central Pyrenean Unit (SCPU)
within the South Pyrenean Thrust System (Fernández et al., 2012). It initially developed as a
foreland basin during the Ypresian-Lutetian, due to flexural subsidence caused by the
advancement of the Montsec-Cotiella thrust sheet (Dreyer et al., 1999). In the middle
Lutetian and Bartonian, thrust sheets propagated westwards towards the foreland and a
number of north-south trending anticlines and synclines developed in the basin (Muñoz et al.,
1998; Fernández et al., 2004; Muñoz et al., 2013). The Boltaña and Mediano anticlines define
the western and eastern sides of the Aínsa Basin, respectively.
Palaeomagnetic studies of the Gavarnie thrust sheet by Muñoz et al. (2013) suggest regional
clockwise rotations of up to 80° in sediments throughout the Lutetian with a decreasing
amount of rotation. Rotation in the Aínsa Basin area was coeval with the formation of 3-km
in length NS trending anticlines (Mediano, Añisclo and Boltaña anticlines), and with the
growth of extensional faults in the Montsec thrust sheet (Muñoz et al., 2013). Such growth
structures during deposition of the deep-marine sediments show the importance of
synsedimentary tectonics in controlling basin configuration both prior to, and during,
deposition. Thus, although important synsedimentary seafloor growth structures have been
identified in the area of the Mediano, Añisclo and Boltaña anticlines, and associated
synclines (Puigdefábregas, 1975; Holl and Anastasio, 1993; Muñoz et al., 1994; Poblet et al.,
1998; Dreyer et al., 1999; Pickering and Corregidor, 2000, 2005; Fernández et al., 2004;
Mochales et al., 2012a, b; Fernández et al., 2012; Muñoz et al. 2013; Bayliss and Pickering,
2015a, b; Pickering et al., 2015), the present orientation of these tectonic features most likely

developed obliquely to the orientation of the seafloor topographic ridges that were growing
during sedimentation.
The infill of the Aínsa Basin consists of ~4 km of deep-marine structurally-confined,
syntectonic, delta-fed lower basin-slope and base-of-slope clastic depositional systems that
accumulated during the Ypresian and the Lutetian stages of the Eocene (Figure 2) (Barnolas
and Teixell, 1994; Remacha and Fernández, 2003; Fernández et al., 2004; Pickering and
Corregidor, 2005; Pickering and Bayliss. 2009). These sediments constitute the Hecho
Group, defined by Mutti et al. (1972) as comprising all the syntectonic Eocene sediment
gravity-flow (SGF) and pelagic/hemipelagic deposits of the south-central Pyrenees that
accumulated from the early Ypresian (Remacha et al., 1998) to the late Lutetian/early
Bartonian (Oms et al., 2003). The deposits consist of a succession of mudstones (commonly
marlstones) and coarser-grained sandbodies. The mudstones are characterised by thick
intervals (up to several hundred metres thick) of thin-bedded laminated siltstones and
marlstones that constitute both interfan and fan lateral-margin facies (Pickering and
Corregidor, 2005; Pickering and Bayliss, 2009). Eight sand-rich, deep-marine systems have
been recognised, from the oldest: Fosado, Los Molinos, Arro, Gerbe, Banastón, Aínsa,
Morillo and Guaso (Pickering and Corregidor, 2005). Each of these systems contains two to
six sandbodies interpreted as sand-prone channelised submarine fans and related deposits
(Pickering and Corregidor, 2005; Pickering and Bayliss, 2009).

Citations
More filters
01 May 2014
TL;DR: In this article, temperature gradients measured in 10 holes at 6 sites were used to generate the first high fidelity heat flow measurements from Integrated Ocean Drilling Program drill holes across the northern and central Lesser Antilles arc and back arc Grenada basin.
Abstract: Using temperature gradients measured in 10 holes at 6 sites, we generate the first high fidelity heat flow measurements from Integrated Ocean Drilling Program drill holes across the northern and central Lesser Antilles arc and back arc Grenada basin. The implied heat flow, after correcting for bathymetry and sedimentation effects, ranges from about 0.1 W/m2 on the crest of the arc, midway between the volcanic islands of Montserrat and Guadeloupe, to 15 km from the crest in the back arc direction. Combined with previous measurements, we find that the magnitude and spatial pattern of heat flow are similar to those at continental arcs. The heat flow in the Grenada basin to the west of the active arc is 0.06 W/m2, a factor of 2 lower than that found in the previous and most recent study. There is no thermal evidence for significant shallow fluid advection at any of these sites. Present-day volcanism is confined to the region with the highest heat flow.

11 citations

Journal ArticleDOI
TL;DR: In an attempt to understand the relative importance of climate and tectonics in modulating coarse-grained sediment flux to a tectonically active basin during what many researchers believe to be a greenhouse period, this paper studied the Middle Eocene deep-marine Ainsa Basin, Spanish Pyrenees.
Abstract: In an attempt to understand the relative importance of climate and tectonics in modulating coarse-grained sediment flux to a tectonically active basin during what many researchers believe to be a greenhouse period, we have studied the Middle Eocene deep-marine Ainsa Basin, Spanish Pyrenees. We use orbital tuning of many spectral gamma-ray-logged fine-grained siliciclastic sections, already shown to contain Milankovitch frequencies, in conjunction with a new high-resolution palaeomagnetic study through the basin sediments, to identify polarity reversals in the basin as anchor points to allow the conversion of a depth-stratigraphy to a chronostratigraphy. We use these data, in conjunction with a new age model incorporating new biostratigraphic data, to pace the development of the deep-marine sandy submarine fans over c. 8 million years. Timing for the sandy submarine fans shows that, unlike for the fine-grained interfan sediments, coarse-grained delivery to the basin was more complex. Approximately 72% of the sandy fans are potentially coincident with the long-eccentricity (400 kyr) minima and, therefore, potentially recording changing climate. The stratigraphic position of some sandy fans is at variance with this, specifically those that likely coincide with a period of known increased tectonic activity within the Ainsa Basin, which we propose represents the time when the basin was converted into a thrust-top basin (Gavarnie thrust sheet), presumably associated with rapid uplift and redeposition of coarse clastics into deep-marine environments. We also identify sub-Milankovitch climate signals such as the c. 41.5 Ma Late Lutetian Thermal Maximum. This study demonstrates the complex nature of drivers on deep-marine sandy fans in a tectonically active basin over c. 8 Myr. Findings of this study suggest that, even during greenhouse periods, sandy submarine fans are more likely linked with times of eccentricity minima and climate change, broadly consistent with the concept of lowstand fans. However, hysteresis effects in orogenic processes of mountain uplift, erosion and delivery of coarse siliciclastics via fluvial systems to coastal (deltaic) and shallow-marine environments likely contributed to the complex signals that we recognize, including the 2–3 Myr time gap between the onset of deep-marine fine-grained sediments in the early development of the Ainsa Basin and the arrival of the first sandy fans. Supplementary Materials: Filtered records for each of the analysed gamma-ray logged sections. Anchor points, SARs tables and graphs and alternative tuning sections are available at: https://doi.org/10.6084/m9.figshare.c.5132975

9 citations


Cites background or methods from "A revised age-model for the Eocene ..."

  • ...Magnetostratigraphic studies show reverse polarity throughout the Forcaz section (Cantalejo et al. 2020), interpreted to be chron C20r (45.72–43.43 Ma, Gradstein et al. 2012)....

    [...]

  • ...The Gerbe, Labuerda 2, Boltaña, Forcaz and Morillo sections have a good chronostratigraphic age control from recent biostratigraphic and magnetostratigraphic studies (Scotchman et al. 2015; Cantalejo et al. 2020)....

    [...]

  • ...Our new palaeomagnetic study and age model for the Aínsa Basin (Cantalejo et al. 2020) using a higher-resolution eustatic sea-level curve (Fig....

    [...]

  • ...Magnetostratigraphic studies (Cantalejo et al. 2020) show reverse polarity throughout the Boltaña section tied with chron C20r....

    [...]

  • ...Cantalejo et al. (2020) use magnetostratigraphy in combination with calcareous nannofossil identification through the same gamma-ray-logged sections (Cantalejo and Pickering 2015)....

    [...]

25 Apr 2014
TL;DR: Hodgson et al. as discussed by the authors present an analisi of the sedimentologia, geometria, and trajectoria of diverses clinoformes deltaiques successively en estudis d'aflorament or en bases of dades de sismica de reflexio.
Abstract: L'analisi de la sedimentologia, geometria i trajectoria de diverses clinoformes deltaiques successives en estudis d'aflorament o en bases de dades de sismica de reflexio han estat ampliament utilitzats com una eina per a (1) inferir canvis en el nivell del mar i per a (2) interpretar els factors de control a curt i llarg termini sobre la evolucio dels marges de conca, aixi com en la durada i tipus de transport de sediment groller des dels continents fins als oceans. Els models deposicionals, majoritariament enfocats en la influencia de l'eustatisme (acomodacio) i l'aport de sediment, principalment a partir de dades sismiques de gran escala, mostren un menor interes/focus en l'analisi de facies i els procesos deposicionals que s'en infereixen, els quals operen en diferents posicions al llarg dels clinotemes individuals, i en l'estudi de com aquests procesos canvien amb la trajectoria i el temps. Les sequencies deposicionals de Castissent, de l'Eoce inferior (alogrup de Castissent, Pirineus sud-centrals, Espanya) consisteixen principalment, a la conca d'Ainsa, en diposits de barra de desembocadura i lobuls sorrencs de front deltaic en transicio a turbidites de talus, formats en un sistema de river-delta dominat per avingudes. La deposicio d'aquests cossos sedimentaris va estar fortament controlada per la interaccio entre fluxos hiperpicnics d'origen continental, la influencia dels processos litorals sobre aquests fluxos, i l'activitat tectonica, tant local com regional, la cinematica sinsedimentaria de la qual encara no ha estat explicada en suficient detall. La cartografia i correlacio de cicles sedimentaris d'alta frequencia evidencia que aquests poden ser considerats clinotemes deltaics limitats per les seves relatives superficies limit o clinoformes (discordances sigmoidals), la formacio de les quals estaria estrictament controlada per l'activitat tectonica. Per altra banda, els perfils sismics d'alta resolucio vinculats a dades de pou i sondejos proporcionen els mitjans necessaris per a lligar l'arquitectura deposicional (trajectoria de clinoformes) amb els processos i patrons de dispersio de sediment. L'Expedicio 313 de l'IODP (Integrated Ocean Drilling Program) va perforar un grup de clinotemes del Mioce a l'offshore de Nova Jersey per tal de capturar un registre complet de varacions del nivell del mar a traves de la integracio d'estratigrafia sismica, dades de pou i sondejos, i cronostratigrafia. En la base de dades de l'Expedicio 313, aquesta valoracio es pot efectuar a traves de diferents clinotemes successius, amb els respectius analisis de facies i interpretacions de processos i ambients deposicionals al llarg d'un mateix clinotema (Poyatos-More and Hodgson, 2012; Hodgson et al., in prep.). No obstant, estudis d'aflorament com el de les sequencies de Castissent o de subsol com el de Nova Jersey tracten sovint l'acomodacio i l'aport sedimentari com un problema bidimensional, mitjancant l'analisi d'un perfil de marge de conca paral·lel a la direccio principal de l'aport. Els resultats d'aquests estudis han estat comparats amb la part inferior de la Formacio Waterford (Conca de Karoo, Sud-africa), un cas d'estudi d'aflorament tridimensional d'un sistema de talus-plataforma exhumat, que permet la identificacio de la posicio del rollover de la clinoforma i de les associacions de facies al llarg de tres perfils deposicionals paral·lels a l'aport (Jones, 2013; Jones et al., 2013a and b). Aquests perfils de marge de conca de la Fm Waterford mostren tots ells trajectories similars, tot i que amb una significativa variabilitat lateral pel que fa a la presencia de sorra al talus. D'aquesta manera, aquest estudi demostra que la variabilitat lateral en la fisiografia dels marges de conca afecta significativament a la dispersio de sediment entre ambients de plataforma, talus i fons de conca, i ha de ser per tant considerada, juntament amb el regim de processos, com a factor de control clau quan s'intenten elaborar prediccions de bypass de sediment en successions de marge de plataforma.

6 citations

Journal ArticleDOI
TL;DR: In this article, a combination of newly acquired and legacy geochemical datasets (carbon and oxygen stable isotopes, organic matter content, major and trace elements and the mineralogical composition of bulk hemipelagic sediments) tuned by a new age model to global “target” curves were compared to discuss the possible drivers of the stratigraphic cycles found in the deep marine sediment gravity flow deposits of the Hecho Group.

4 citations


Cites background or methods or result from "A revised age-model for the Eocene ..."

  • ...5 Ainsa stack The compilation of Castelltort et al., (2017) and this study data generates an isotopic and geochemical dataset for the complete Hecho Group in the Ainsa basin (Fig. 11). Correlation between the Pueyo offaxis section (Castelltort et al., 2017, Fig. 11) and the Labuerda section (this study) was assessed with geological map and supported by lateral isotopic records correlation (LB021=GB33, in B-II?, Fig. 11). In this work, Banaston I was placed in the turbidite stack previously identified as Gerbe II by Castelltort et al., 2017. Our interpretation is in accordance with the map of Cornard and Pickering (2019) and set the correlation between both section in the lateral equivalents of Banaston I (Fig....

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  • ...The N1 normal zone is identified as belonging to the C21n chron in accordance with Castelltort et al. (2017) age model. This interpretation is consistent with Cantalejo et al. (2020) age model based on magnetostratigraphy acquired in different sections in the basin....

    [...]

  • ...The N1 normal zone is identified as belonging to the C21n chron in accordance with Castelltort et al. (2017) age model. This interpretation is consistent with Cantalejo et al. (2020) age model based on magnetostratigraphy acquired in different sections in the basin. Both models have slight differences regarding the exact position of two reversals found in the succession of the upper Hecho Group. First, Cantalejo et al. (2020) place more precisely the transition from C21n to C20r between BV and BIV and secondly, the transition from C20r to C20n is placed before the second member of Morillo (M-II) in this study while Cantalejo et al. (2020) place it during M-III member....

    [...]

  • ...4, 6 and 7) in the deep marine sediments of the Ainsa basin to provide together with existing isotope records in Castelltort et al. (2017) a new chronostratigraphic framework for a near complete profile in the Ainsa basin deep marine succession....

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  • ...The N1 normal zone is identified as belonging to the C21n chron in accordance with Castelltort et al. (2017) age model. This interpretation is consistent with Cantalejo et al. (2020) age model based on magnetostratigraphy acquired in different sections in the basin. Both models have slight differences regarding the exact position of two reversals found in the succession of the upper Hecho Group. First, Cantalejo et al. (2020) place more precisely the transition from C21n to C20r between BV and BIV and secondly, the transition from C20r to C20n is placed before the second member of Morillo (M-II) in this study while Cantalejo et al....

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Journal ArticleDOI
TL;DR: In this article , the authors describe two outcrop examples of deepwater, predominantly turbiditic, deposits overlying masstransport deposits, from the Eocene slope succession of the Aínsa Basin (Spanish Pyrenees).
Abstract: Erosional scars, slumps, slides and debrites (mass‐transport deposits) on submarine slopes form relief that influences turbidity current behaviour. However, the interaction of mass‐transport deposit emplacement kinematics (i.e. rapid emplacement versus creep), the morphology of the evolving seafloor topography and subsequent flow types is complicated. This study describes two outcrop examples of deep‐water, predominantly turbiditic, deposits overlying mass‐transport deposits, from the Eocene slope succession of the Aínsa Basin (Spanish Pyrenees). In both examples, the mass‐transport deposit substrate continued to creep contemporaneously with turbidity current deposition and bypass. In the first case study, structures in the mass‐transport deposits are extensional and oriented parallel to flow. In the second, structures are compressional and oriented perpendicular to flow. Mudstones dominate the slope succession, but deposits overlying mass‐transport deposits form sandstone‐prone accumulations. Lateral confinement by flow‐parallel extensional faults enhanced channel‐formation. Channel incision occurred close to the exhumed fault plane on the hangingwall. Incision ceased as the fault gradually locked‐up, and channels avulsed to the hangingwall of a newly active normal fault, while the abandoned channel was filled by a thinning and fining‐upward succession. Barriers formed where the long axes of compressional anticlines developed in mass‐transport deposits formed perpendicular to flow. Here, turbidites filled the bathymetric lows in the axes of synclines. Continued tightening of synclinal depocentres led to repeated stoss side trapping and upslope accretion of coarse‐grained sediment accumulation. This generated thickening and coarsening‐up, followed by thinning and fining‐upward successions, tracking the decreasing, then increasing flow bypass associated with topographic expression on the mass‐transport deposit. This study shows how post‐emplacement creep, and orientation of topographic features on mass‐transport deposits, influence the routing and deposition of contemporaneous turbidity currents, and illustrates examples of facies successions that could be misinterpreted as the product of other autogenic submarine slope processes, such as lateral migration of sinuous channels, or compensational lobe stacking.
References
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01 Jan 1971

2,100 citations


"A revised age-model for the Eocene ..." refers methods in this paper

  • ...Biostratigraphy is described with reference to the Paleogene NP zones of Martini (1971) and age calibrations for individual biohorizons are sourced fromGradstein et al. (2012)/Time Scale Creator 6.1, unless otherwise stated....

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Book
01 Jan 2012
TL;DR: The Geologic Time Scale (GTS) as mentioned in this paper is an international geologic time scale for deciphering the history of our planet Earth and has been widely used in the literature.
Abstract: The Geologic Time Scale 2012, winner of a 2012 Prose Award Honorable Mention for Best Multi-volume Reference in Science from the Association of American Publishers, is the framework for deciphering the history of our planet Earth. The authors have been at the forefront of chronostratigraphic research and initiatives to create an international geologic time scale for many years, and the charts in this book present the most up-to-date, international standard, as ratified by the International Commission on Stratigraphy and the International Union of Geological Sciences. This 2012 geologic time scale is an enhanced, improved and expanded version of the GTS2004, including chapters on planetary scales, the Cryogenian-Ediacaran periods/systems, a prehistory scale of human development, a survey of sequence stratigraphy, and an extensive compilation of stable-isotope chemostratigraphy. This book is an essential reference for all geoscientists, including researchers, students, and petroleum and mining professionals. The presentation is non-technical and illustrated with numerous colour charts, maps and photographs. The book also includes a detachable wall chart of the complete time scale for use as a handy reference in the office, laboratory or field. This is the most detailed international geologic time scale available that contextualizes information in one single reference for quick desktop access. It gives insights in the construction, strengths, and limitations of the geological time scale that greatly enhances its function and its utility. It aids understanding by combining with the mathematical and statistical methods to scaled composites of global succession of events. It meets the needs of a range of users at various points in the workflow (researchers extracting linear time from rock records, students recognizing the geologic stage by their content).

1,596 citations

Book ChapterDOI
01 Jan 1992
TL;DR: In this paper, a balanced cross-section of the Pyrenean chain has been constructed, showing a minimum shortening of 147 km, 112 km of which are related to stacking of basement thrust sheets in the southern Pyrenees.
Abstract: Construction of a crustal balanced cross-section across the Pyrenean chain shows a minimum shortening of 147 km, 112 km of which are related to stacking of basement thrust sheets in the southern Pyrenees. Metamorphic conditions of the basement rocks, as well as thrust geometry, indicate the maximum depth for the detachment level to be at 15 km. In the restored cross-section, the upper crust is 110 km longer than the lower layered crust. The lower crust was subducted together with the lithospheric mantle into the asthenospheric mantle and has not been imaged by geophysical data probably because an increase of density through eclogitic meta-morphism. The upper crust constitutes an orogenic lid mainly deformed by thrust structures. The balanced cross-section has been constrained by the ECORS deep reflection seismic profile as well as detailed surface data and available commercial seismic and oil well data. The restored cross-section provides a better picture of the middle Cretaceous combined strike-slip and extensional fault system as well as of the Hercynian crust. Hercynian geological features have been used as an additional tool for the restoration of the basement thrust sheets.

798 citations


"A revised age-model for the Eocene ..." refers background or methods in this paper

  • ...The rotation was likely linked to movement along the base of the Gavarnie thrust sheet detached at lower Triassic Keuper evaporites below the Tethyan carbonates (Farrell et al. 1987; Muñoz 1992; Teixell 1996)....

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  • ...lower Triassic Keuper evaporites below the Tethyan carbonates (Farrell et al. 1987; Muñoz 1992; Teixell 1996)....

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  • ...Stratigraphy of the Aínsa Basin in the context of the Gavarnie thrust sheet, modified from Muñoz et al. (2013). Lithostratigraphic units: Es,...

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  • ...systems (=San Vicente Formation of Muñoz et al. (2013))....

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Journal ArticleDOI
TL;DR: In this article, the authors evaluate environmental signal propagation across sediment-routing systems with emphasis on sediment supply, Qs, as the carrier of up-system forcings, and provide a set of conceptual and practical tools for evaluating sediment supply within a source-to-sink context, which can inform interpretations of signals from the sedimentary record.

370 citations

Journal ArticleDOI
TL;DR: In this paper, the authors reconcile records of warm high latitudes with glacio-eustasy by proposing that Late Cretaceous-early Eocene ice sheets generally reached maximum volumes of 8 −12 −10 6 km 3 (20 −30 m glacioeustatic equivalent), but did not reach the Antarctic coast; hence, coastal Antarctica remained relatively warm even though there were significant changes in sea level as the result of glaciation.

359 citations


"A revised age-model for the Eocene ..." refers methods in this paper

  • ...…used the bulk δ13Ccarb signal, correlated with the coeval eustatic curve from the New Jersey (USA) passive margin based on the backstripped curves of Miller et al. (2005), in an attempt to provide an independent record of global sea-level changes for the Arro, Gerbe and lower Banastón systems…...

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  • ...The age-model presented in this study allows us to correlate the deep-marine stratigraphy of the basin with the stratigraphy at the flanks of the basin where Mochales et al. (2012a) and Holl and Anastasio (1993) completed a palaeomagnetic study in the western and eastern flanks, respectively....

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Frequently Asked Questions (1)
Q1. What contributions have the authors mentioned in the paper "A revised age-model for the eocene deep-marine siliciclastic systems, aínsa basin, spanish pyrenees" ?

This new age model provides a framework for evaluating the depositional history and sediment accumulation rates. The authors also present new nannofossil biostratigraphy from the Lower Hecho Group. The main aim of this paper is to provide an integrated magnetoand biostratigraphically constrained high-resolution age model for the Aínsa Basin. This new age model: ( i ) presents new magnetostratigraphy in the basin to help tie the magnetostratigraphic work of Mochales et al. ( 2012a ), Holl and Anastasio ( 1993 ) in the sediments of the Boltaña and Mediano basin flank anticlines, respectively, and also integrate the work by Muñoz et al. ( 2013 ), to the Aínsa Basin stratigraphy, ( ii ) provides new micropalaeontological observations across the entire basin deep-marine stratigraphy and incorporates the previously published biostratigraphic work of Scotchman et al. ( 2015 ) in the Upper Hecho Group, and ( iii ) proposes new correlations with updip ( Tremp ) and downdip ( Jaca ) stratigraphy to refine the source-to-sink configurations. The age model presented constitutes a time framework to its companion manuscript ( Cantalejo et al. in review ) where the authors investigate the role of climate change versus tectonics in modulating coarse-grained sediment flux to the basin. This manuscript discusses the temporal span of deep-marine channel and related depositional systems, and demonstrates the complex nature of drivers on deep-marine sandy fans in a tectonically-active basin. Through the integration of new palaeomagnetic and biostratigraphic data, the authors refine the existing age model of Scotchman et al. ( 2015 ) for the middle Eocene Hecho Group deposits of the deep-marine Aínsa Basin ( Spanish Pyrenees ), which was a tectonically active basin that formed at convergent-plate margin ( Pickering and Cantalejo, 2015, and references therein ).