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Secular trends in the composition of sedimentary rock assemblages—Archean through Phanerozoic time

1978; Geological Society of America; Volume: 6; Issue: 9 Linguagem: Inglês

10.1130/0091-7613(1978)6 2.0.co;2

1943-2682

Frederic L. Schwab,

Geology and Paleoclimatology Research

Research Article| September 01, 1978 Secular trends in the composition of sedimentary rock assemblages—Archean through Phanerozoic time Frederic L. Schwab Frederic L. Schwab 1Department of Geology, Washington and Lee University, Lexington, Virginia 24450 Search for other works by this author on: GSW Google Scholar Geology (1978) 6 (9): 532–536. https://doi.org/10.1130/0091-7613(1978)6 2.0.CO;2 Article history first online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Frederic L. Schwab; Secular trends in the composition of sedimentary rock assemblages—Archean through Phanerozoic time. Geology 1978;; 6 (9): 532–536. doi: https://doi.org/10.1130/0091-7613(1978)6 2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract The bulk composition of the sedimentary rock-cover in several regions was estimated by using published chemical analyses of the component rock types. This composition changes as a function of age. Archean sedimentary assemblages are comparatively richer in Al2O3, Na2O, and MgO than most Proterozoic and Phanerozoic assemblages. The younger rock assemblages are progressively richer in SiO2, K2O, and (generally) CaO. These compositional differences define secular trends that probably reflect evolutionary changes in the composition of the Earth's upper crust, atmosphere, and hydrosphere, although the trends may partly be the result of either secondary processes (such as diagenesis, metamorphism, and sediment recycling) or selective preservation of particular rock types because of structural and stratigraphic position. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.