Orbital forcing as principal driver for fine-grained deep-marine siliciclastic sedimentation, Middle-Eocene Ainsa Basin, Spanish Pyrenees

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

“…For example, FO B. inflatus a key marker at 47.84 Ma identified in sample AR4 within the Gerbe system produces a large time offset (~4 Myr) if we associate the R1/N1 reversal also found in the Gerbe system to the C20r/C20n reversal (43.432 Ma). In addition, the short time duration of the C19 chrons would then result in unrealistically high SARs during the deposition of the Aínsa, Morillo and Guaso systems which is inconsistent with previous publications (Cantalejo and Pickering, 2015). Similar problems are found when shifting the identified reversals to an older part of the stratigraphy, which is inconsistent within our biostratigraphy framework and with previous published work (i.e., Bentham and Burbank, 1996;Dreyer et al 1999;Mochales et al 2012a;Muñoz et al 2013).…”

“…This ~3-m thick dark mudstone unit is likely to be the ~30-kyr Late Lutetian Thermal Maximum (LLTM) that is recognised as a global transient warming event, dated from Atlantic deep-sea cores at 41.52 Ma by Westerhold et al (2018). Time-series analysis of the mudrocks in the Aínsa Basin indicate sediment accumulation rates of ~30 cm/kyr (Cantalejo and Pickering, 2015), consistent with the thickness of the dark mudstone/claystone as the LLTM.…”

“…Samples were collected at 10 m intervals over ~2 km of stratigraphy in order to achieve sufficient resolution to capture every polarity reversal. 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). The sampling interval must span an interval of time >10 kyr to average out secular variation.…”

Detrital zircon (U‐Th)/(He‐Pb) double‐dating constraints on provenance and foreland basin evolution of the Ainsa Basin, south‐central Pyrenees, Spain

“…The structural control of the shelf slope break restricted the size of the shallow marine and coastal zones, affecting the ability of shelf systems to modulate sediment supply to the deep marine [in the sense of Romans et al , ]. The highly variable climatic [ Zachos et al , ] and eustatic [ Kominz et al , ] regimes in the Eocene contemporaneous with the initiation of Pyrenean exhumation [ Muñoz , ; Puigdefàbregas et al , ] make the Ainsa Basin an ideal setting to investigate source to sink sedimentary dynamics, including sediment budgeting [ Michael et al , ], grain size fractionation [ Parsons et al , ; Allen et al , ], and climatic cyclicity [ Cantalejo and Pickering , ] in response to allogenic forcing.…”

Magnetostratigraphy and stable isotope stratigraphy of the middle-Eocene succession of the Ainsa basin (Spain): new age constraints and implications for sediment delivery to the deep waters

“…San Lino level) supports this hypothesis. In addition, a decrease in the oxygenation of the basin was suggested by the Th/U values of Cantalejo and Pickering (2015) for Morillo and Guaso SGF systems. Finally, our Hi values show negative values during the Guaso SGF suggesting a higher input of terrestrial organic matter.…”