Climate changes as recorded in stable carbon isotopic compositions of the Late Jurassic marine sedimentary succession in the Qiangtang Basin, Northern Tibet

Autor(en)

Gaojie Li, Guoqing Xia, Haisheng Yi, Chihua Wu, Michael Wagreich

Abstrakt

The Jurassic oceanographic and climatic evolution is considered to be related to the breakup of Pangaea. As a crucial component of the carbon cycle, atmospheric CO

₂ concentration (pCO

₂) has been postulated as a main driver for climate change during the Jurassic, and concomitant changes in paleo-oceanographic conditions occurred as a result. In this study, we present a high-resolution organic matter (kerogen) carbon isotope dataset (δ

¹³C

_kerogen) from Upper Jurassic marine sedimentary rocks in the Qiangtang Basin, Tibet. The δ

¹³C

_kerogen result contains a genuine record concerning the response of the eastern Tethys to exogenic carbon cycle perturbations in both marine and atmospheric reservoirs and is also consistent with the high-resolution bulk carbonate and organic matter carbon-isotope records from the Atlantic and western Tethys. The relative fractionation of carbon isotopes in organic matter vs. carbonate species, defined as Δ

¹³C (δ

¹³C

_carb-δ

¹³C

_kerogen), and the secular trend of atmospheric pCO

₂ over the Late Jurassic that is calculated from the high-resolution δ

¹³C

_kerogen values indicate a cold Callovian-Oxfordian transition, a long-term increasing but fluctuating Kimmeridgian and a prominent early Tithonian cooling event (ETCE). The pronounced temperature plateau during the late Kimmeridgian-early Tithonian was contemporaneous with the occurrence of major magmatic events during the Late Jurassic, while the ETCE has been possibly attributed to major changes in oceanic circulation patterns. Additionally, reconstructed atmospheric pCO

₂ values show very small differences to values using phytane- and stomatal density-based pCO

₂ calculations, providing an alternative estimate for accurate identification of the paleoclimatic framework of this enigmatic interval in the Mesozoic.

Organisation(en)

Institut für Geologie

Externe Organisation(en)

Mianyang Teachers' College, Chengdu University of Technology, Southwest Petroleum University

Journal

Journal of Asian Earth Sciences

Band

236

Anzahl der Seiten

13

ISSN

1367-9120

DOI

https://doi.org/10.1016/j.jseaes.2022.105317

Publikationsdatum

09-2022

Peer-reviewed

Ja

ÖFOS 2012

105105 Geochemie, 105123 Stratigraphie

Schlagwörter

ASJC Scopus Sachgebiete

Earth-Surface Processes, Geology

Sustainable Development Goals

SDG 14 – Leben unter Wasser, SDG 13 – Maßnahmen zum Klimaschutz

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/320bc8c8-0f86-48eb-8e2c-84707e5025cd