Orbital forcing of climate 1.4 billion years ago

Summary, in English

Fluctuating climate is a hallmark of Earth. As one transcends deep into Earth time, however, both the evidence for and the causes of climate change become difficult to establish. We report geochemical and sedimentological evidence for repeated, short-term climate fluctuations from the exceptionally well-preserved ∼1.4-billion-year-old Xiamaling Formation of the North China Craton. We observe two patterns of climate fluctuations: On long time scales, over what amounts to tens of millions of years, sediments of the Xiamaling Formation record changes in geochemistry consistent with long-term changes in the location of the Xiamaling relative to the position of the Intertropical Convergence Zone. On shorter time scales, and within a precisely calibrated stratigraphic framework, cyclicity in sediment geochemical dynamics is consistent with orbital control. In particular, sediment geochemical fluctuations reflect what appear to be orbitally forced changes in wind patterns and ocean circulation as they influenced rates of organic carbon flux, trace metal accumulation, and the source of detrital particles to the sediment.

• Author: Shuichang Zhang; Xiaomei Wang; Emma U Hammarlund; Huajian Wang; M Mafalda Costa; Christian J Bjerrum; James N Connelly; Baomin Zhang; Lizeng Bian; Donald E Canfield
• Publishing year: 2015-03-24
• Language: English
• Pages: 13-1406
• Publication/Series: Proceedings of the National Academy of Sciences of the United States of America
• Volume: 112
• Issue: 12
• Links: http://dx.doi.org/10.1073/pnas.1502239112
• Document type: Journal article
• Publisher: National Academy of Sciences
• Keywords: Journal Article; Research Support, Non-U.S. Gov't
• Status: Published
• ISBN/ISSN/Other: ISSN: 1091-6490