Triassic–Jurassic climate in continental high-latitude Asia was dominated by obliquity-paced variations (Junggar Basin, Ürümqi, China)
2015 (English)In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 112, no 12, 3624-3629 p.Article in journal (Refereed) Published
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.
Place, publisher, year, edition, pages
National Academy of Sciences of the United States of America, 2015. Vol. 112, no 12, 3624-3629 p.
orbital forcing; obliquity cycle; Triassic–Jurassic; lacustrine sediments; solar system chaos; palynology
Other Earth and Related Environmental Sciences
Research subject The changing Earth
IdentifiersURN: urn:nbn:se:nrm:diva-1396DOI: 10.1073/pnas.1501137112OAI: oai:DiVA.org:nrm-1396DiVA: diva2:867190
FunderSwedish Research Council, LUCCI 349-2007-8705