title: Triassic-Jurassic climate in continental high-latitude Asia was dominated by obliquity-paced variations (Junggar Basin, Ürümqi, China).
abstract: Empirical constraints on orbital gravitational solutions for the Solar System can be derived from the Earth's geological record of past climates. Lithologically based paleoclimate data from the thick, coal-bearing, fluvial-lacustrine sequences of the Junggar Basin of Northwestern China (paleolatitude ∼60°) show that climate variability of the warm and glacier-free high latitudes of the latest Triassic-Early Jurassic (∼198-202 Ma) Pangea was strongly paced by obliquity-dominated (∼40 ky) orbital cyclicity, based on an age model using the 405-ky cycle of eccentricity. In contrast, coeval low-latitude continental climate was much more strongly paced by climatic precession, with virtually no hint of obliquity. Although this previously unknown obliquity dominance at high latitude is not necessarily unexpected in a high CO2 world, these data deviate substantially from published orbital solutions in period and amplitude for eccentricity cycles greater than 405 ky, consistent with chaotic diffusion of the Solar System. In contrast, there are indications that the Earth-Mars orbital resonance was in today's 2-to-1 ratio of eccentricity to inclination. These empirical data underscore the need for temporally comprehensive, highly reliable data, as well as new gravitational solutions fitting those data.
authors.affiliation: State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Paleontology, Nanjing 210008, China; polsen@ldeo.columbia.edu jgsha@nigpas.ac.cn.
authors.forename: Jingeng
authors.initials: J
authors.lastname: Sha
authors.affiliation: Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY 10968; polsen@ldeo.columbia.edu jgsha@nigpas.ac.cn.
authors.forename: Paul E
authors.initials: PE
authors.lastname: Olsen
authors.affiliation: State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Paleontology, Nanjing 210008, China;
authors.forename: Yanhong
authors.initials: Y
authors.lastname: Pan
authors.affiliation: Institute of Geology, China Earthquake Administration, Beijing 100029, China;
authors.forename: Daoyi
authors.initials: D
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Paleontology, Nanjing 210008, China;
authors.forename: Yaqiang
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Chinese Academy of Sciences Key Laboratory of Crust-Mantle Materials and Environments, School of Earth and Space Sciences, University of Science and Technology of China, Heifei 230026, China;
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Paleontology, Nanjing 210008, China;
authors.forename: Xiaogang
authors.initials: X
authors.lastname: Yao
authors.affiliation: Department of Geology, Lund University, 223 62 Lund, Sweden; and Department of Palaeobiology, Swedish Museum of Natural History, 104 05 Stockholm, Sweden.
authors.forename: Vivi
authors.initials: V
authors.lastname: Vajda
keywords: Triassic–Jurassic; lacustrine sediments; obliquity cycle; orbital forcing; solar system chaos