title: Orbital forcing of climate 1.4 billion years ago.
abstract: 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.
authors.affiliation: Key Laboratory of Petroleum Geochemistry, Research Institute of Petroleum Exploration and Development, China National Petroleum Corporation, Beijing 100083, China;
authors.forename: Shuichang
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Petroleum Geochemistry, Research Institute of Petroleum Exploration and Development, China National Petroleum Corporation, Beijing 100083, China;
authors.forename: Xiaomei
authors.initials: X
authors.lastname: Wang
authors.affiliation: Institute of Biology and Nordic Center for Earth Evolution, University of Southern Denmark, 5230 Odense M, Denmark;
authors.forename: Emma U
authors.initials: EU
authors.lastname: Hammarlund
authors.affiliation: Key Laboratory of Petroleum Geochemistry, Research Institute of Petroleum Exploration and Development, China National Petroleum Corporation, Beijing 100083, China;
authors.forename: Huajian
authors.initials: H
authors.lastname: Wang
authors.affiliation: Centre for Star and Planet Formation, Natural History Museum of Denmark, University of Copenhagen, 1350 Copenhagen K, Denmark;
authors.forename: M Mafalda
authors.initials: MM
authors.lastname: Costa
authors.affiliation: Department of Geosciences and Natural Resource Management, Section of Geology, and Nordic Center for Earth Evolution, University of Copenhagen, 1350 Copenhagen K, Denmark; and.
authors.forename: Christian J
authors.initials: CJ
authors.lastname: Bjerrum
authors.affiliation: Centre for Star and Planet Formation, Natural History Museum of Denmark, University of Copenhagen, 1350 Copenhagen K, Denmark;
authors.forename: James N
authors.initials: JN
authors.lastname: Connelly
authors.affiliation: Key Laboratory of Petroleum Geochemistry, Research Institute of Petroleum Exploration and Development, China National Petroleum Corporation, Beijing 100083, China;
authors.forename: Baomin
authors.initials: B
authors.lastname: Zhang
authors.affiliation: Department of Geosciences, Nanjing University, Nanjing 210093, China.
authors.forename: Lizeng
authors.initials: L
authors.lastname: Bian
authors.affiliation: Institute of Biology and Nordic Center for Earth Evolution, University of Southern Denmark, 5230 Odense M, Denmark; dec@biology.sdu.dk.
authors.forename: Donald E
authors.initials: DE
authors.lastname: Canfield
keywords: Hadley Cell; ITCZ; Mesoproterozoic; Milankovitch; Xiamaling