Climate change evidence from stable carbon isotope records of the Late Jurassic marine sedimentary succession in the Qiangtang Basin, Northern Tibet

• A high-resolution organic matter δ 13 C record is present in the Upper Jurassic marine sedimentary rocks from the Qiangtang Basin, Tibet. • An alternative to phytane- and stomatal density-based p CO 2 reconstructions is used with the net carbon isotope fractionation between δ 13 C values of primary producers and atmospheric CO 2 levels. • Δ 13 C (δ 13 C carb -δ 13 C kerogen ) and atmospheric p CO 2 calculation reveal a cooling event in the Early Tithonian. 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 ( p CO 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 13 C kerogen ) from Upper Jurassic marine sedimentary rocks in the Qiangtang Basin, Tibet. The δ 13 C 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 13 C (δ 13 C carb -δ 13 C kerogen ), and the secular trend of atmospheric p CO 2 over the Late Jurassic that is calculated from the high-resolution δ 13 C 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 p CO 2 values show very small differences to values using phytane- and stomatal density-based p CO 2 calculations, providing an alternative estimate for accurate identification of the paleoclimatic framework of this enigmatic interval in the Mesozoic.