https://doi.org/10.5194/cp-2020-152 Preprint. Discussion started: 21 December 2020 c Author(s) 2020. CC BY 4.0 License. Aptian-Albian clumped isotopes from northwest China: Cool temperatures, variable atmospheric pCO2 and regional shifts in hydrologic cycle Dustin T. Harper1, Marina B. Suarez1,2, Jessica Uglesich2, Hailu You3,4,5, Daqing Li6, Peter Dodson7 5 1 Department of Geology, The University of Kansas, Lawrence, KS, U.S.A. 2 Department of Geological Sciences, University of Texas, San Antonio, TX, U.S.A. 3 Key LaBoratory of VerteBrate Evolution and Human Origins, Institute of VerteBrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, P.R.C. 10 4 Chinese Academy of Science Center for Excellence in Life and Paleoenvironment, Beijing, P.R.C. 5 College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, P.R.C. 6 Institute of VerteBrate Paleontology and College of Life Science and Technology, Gansu Agricultural University, Lanzhou, P.R.C. 7 Department of Biomedical Sciences, The University of Pennsylvania, Philadelphia, U.S.A. 15 Correspondence to: Dustin T. Harper (
[email protected]) Abstract. The Early Cretaceous is characterized by warm background temperatures (i.e., greenhouse climate) and carbon cycle perturbations that are often marked by Ocean Anoxic Events (OAEs) and associated shifts in the hydrologic cycle. Higher-resolution records of terrestrial and marine δ13C and δ18O (Both carBonates and organics) suggest climate shifts 20 during the Aptian-AlBian, including a warm period associated with OAE 1a in the early Aptian and subsequent “cold snap” near the Aptian-AlBian Boundary prior to the Kilian and OAE 1B.