Publication Date:
2016-01-23
Description:
The Archean Eon witnessed the production of early continental crust, the emergence of life, and fundamental changes to the atmosphere. The nature of the first continental crust, which was the interface between the surface and deep Earth, has been obscured by the weathering, erosion, and tectonism that followed its formation. We used Ni/Co and Cr/Zn ratios in Archean terrigenous sedimentary rocks and Archean igneous/metaigneous rocks to track the bulk MgO composition of the Archean upper continental crust. This crust evolved from a highly mafic bulk composition before 3.0 billion years ago to a felsic bulk composition by 2.5 billion years ago. This compositional change was attended by a fivefold increase in the mass of the upper continental crust due to addition of granitic rocks, suggesting the onset of global plate tectonics at ~3.0 billion years ago.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Tang, Ming -- Chen, Kang -- Rudnick, Roberta L -- New York, N.Y. -- Science. 2016 Jan 22;351(6271):372-5. doi: 10.1126/science.aad5513.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Geology, University of Maryland, College Park, MD 20742, USA. Corresponding author. E-mail: tangmyes@gmail.com. ; Department of Geology, University of Maryland, College Park, MD 20742, USA. State Key Laboratory of Geological Processes and Mineral Resources, School of Earth Sciences, China University of Geosciences, Wuhan 430074, China. ; Department of Geology, University of Maryland, College Park, MD 20742, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26798012" target="_blank"〉PubMed〈/a〉
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
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Chemistry and Pharmacology
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Computer Science
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Medicine
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Natural Sciences in General
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Physics
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