High-Resolution C-isotope, TOC and Biostratigraphic Records of OAE1a (Aptian) from an Expanded Hemipelagic Cored Succession, Western Tethys: a New Stratigraphic Reference for Global Correlation and Paleoenvironmental Reconstruction

José M Castro*, Pedro A Ruiz-Ortiz, Ginés A de Gea, Roque Aguado, Ian Jarvis, Helmut Weissert, José M Molina, Luis M Nieto, Richard D Pancost, María L Quijano, Matías Reolid, Peter W Skelton, Carmina López-Rodríguez, Rafael Martínez-Rodríguez

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

Abstract

A high-resolution carbonate C-isotope stratigraphy for the Aptian is presented for the Cau core (Spain). The biostratigraphically calibrated C-isotope stratigraphy of the core is used to refine the previously defined C-isotope segments of the Aptian. Fourteen C-isotope segments have been identified and correlated, and further subdivisions are presented. Correlation with other sections worldwide demonstrates the robustness of the C-isotope stratigraphy of the Cau core. The studied succession includes a continuous record of the early Aptian Oceanic Anoxic Event (OAE 1a). Its onset has been studied at an ultra-high-resolution scale (0.2–0.5 kyr spacing), revealing a succession of sharp δ13 Ccarb negative spikes, interpreted as the record of pulses in volcanism and methane emissions. The largest spike was rapid (< 10 kyr) and marks the base of OAE 1a, which occurs within a longer-term falling δ13 Ccarb trend. The C-isotope profile across OAE 1a perfectly records the negative (C3/Ap3), positive (C4/Ap4), steady (C5/Ap5) and positive (C6/Ap6) segments that were defined from Cismon (Italy) and subsequently identified worldwide. The Ap7 to Ap14 segments record a C-isotope negative excursion, coupled with high TOC contents, probably related to regional paleogeography. The links with global environmental changes, episodes of widespread deposition of organic matter, and ultimately to major volcanic episodes are discussed. We propose the Cau core as a new reference section for the Aptian, and specifically for OAE 1a, based on its expanded and well-preserved sedimentary, geochemical and biotic archives, which provide further insights into the environmental and biotic changes that occurred during this time interval.
Original languageEnglish
Article numbere2020PA004004
Number of pages75
JournalPaleoceanography and Paleoclimatology
Volume36
Issue number3
Early online date8 Mar 2021
DOIs
Publication statusPublished - Mar 2021

Bibliographical note

Funding Information:
The authors wish to express special thanks to the municipality of Llíber (Alicante) and its mayor, D. José Juan Reus, who provided us with all kinds of facilities for carrying out the drilling. Javier Jáimez and Emilio Peñalver, the two technicians, who conducted the drilling are also acknowledged. David Gallego‐Torres greatly contributed with the sampling and description of the cores. This work has been funded by the Spanish Government, Ministry of Science and Technology (research project CGL2014‐55274‐P), Research Group RNM‐200 (Junta de Andalucía), and University of Jaén (FEDER‐UJA 1265149). Laboratory technicians A. Piedra, A. Carrillo, M. J. Campos, and Inés Sanchís are acknowledged for their help in processing of micropaleontology samples and technical support. Support from Equinor (formerly Statoil) research contract 4502299156 to I. Jarvis is gratefully acknowledged. The authors are very grateful to Elisabetta Erba and R. Mark Leckie, whose constructive comments led to significant improvements in the final version of this paper, and to Ursula Röhl and Matthew Huber for their helpful editorial assistance.

Funding Information:
The authors wish to express special thanks to the municipality of Ll?ber (Alicante) and its mayor, D. Jos? Juan Reus, who provided us with all kinds of facilities for carrying out the drilling. Javier J?imez and Emilio Pe?alver, the two technicians, who conducted the drilling are also acknowledged. David Gallego-Torres greatly contributed with the sampling and description of the cores. This work has been funded by the Spanish Government, Ministry of Science and Technology (research project CGL2014-55274-P), Research Group RNM-200 (Junta de Andaluc?a), and University of Ja?n (FEDER-UJA 1265149). Laboratory technicians A. Piedra, A. Carrillo, M. J. Campos, and In?s Sanch?s are acknowledged for their help in processing of micropaleontology samples and technical support. Support from Equinor (formerly Statoil) research contract 4502299156 to I. Jarvis is gratefully acknowledged. The authors are very grateful to Elisabetta Erba and R. Mark Leckie, whose constructive comments led to significant improvements in the final version of this paper, and to Ursula R?hl and Matthew Huber for their helpful editorial assistance.

Publisher Copyright:
© 2021. American Geophysical Union. All Rights Reserved.

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