Nd-Sr isotopic provenance analysis of Upper Cretaceous Great Valley fore-arc sandstones

Abstract

Research Article| August 01, 1991 Nd-Sr isotopic provenance analysis of Upper Cretaceous Great Valley fore-arc sandstones Anne M. Linn; Anne M. Linn 1Department of Earth and Space Sciences, University of California, Los Angeles, California 90024 Search for other works by this author on: GSW Google Scholar Donald J. DePaolo; Donald J. DePaolo 2Berkeley Center for Isotope Geochemistry, Department of Geology and Geophysics, University of California and Earth Sciences Division, Lawrence Berkeley Laboratory, Berkeley, California 94720 Search for other works by this author on: GSW Google Scholar Raymond V. Ingersoll Raymond V. Ingersoll 1Department of Earth and Space Sciences, University of California, Los Angeles, California 90024 Search for other works by this author on: GSW Google Scholar Author and Article Information Anne M. Linn 1Department of Earth and Space Sciences, University of California, Los Angeles, California 90024 Donald J. DePaolo 2Berkeley Center for Isotope Geochemistry, Department of Geology and Geophysics, University of California and Earth Sciences Division, Lawrence Berkeley Laboratory, Berkeley, California 94720 Raymond V. Ingersoll 1Department of Earth and Space Sciences, University of California, Los Angeles, California 90024 Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1991) 19 (8): 803–806. https://doi.org/10.1130/0091-7613(1991)019<0803:NSIPAO>2.3.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 Anne M. Linn, Donald J. DePaolo, Raymond V. Ingersoll; Nd-Sr isotopic provenance analysis of Upper Cretaceous Great Valley fore-arc sandstones. Geology 1991;; 19 (8): 803–806. doi: https://doi.org/10.1130/0091-7613(1991)019<0803:NSIPAO>2.3.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 provenance of fore-arc sandstones of the Upper Cretaceous Great Valley Group was investigated by using measurements of Sm-Nd and Rb-Sr isotope ratios and major and trace element concentrations. The objective was to elucidate the erosional history of the adjacent Sierra Nevada arc and its relation to magmatism and fore-arc sedimentation. Relatively detailed provenance information is obtainable because the currently exposed plutonic rocks of the arc (and, by inference, the Cretaceous volcanic rocks) have large geographic gradients in isotopic composition, mainly from west to east across the arc. The relation of ϵNd to ϵSr and to major and trace elements in Great Valley sandstones is the same as in the plutonic rocks of the Sierra Nevada; this observation confirms that the arc was the primary source of sediment and that the chemistry of the detritus was not significantly disturbed by sedimentary processes. With decreasing ϵNd, there is an increase in K2O, Rb, Pb, Ba, La, and U, and MgO, Ni, and Cr decrease. The ϵNd of sandstones decreases with decreasing depositional age from -0.7 to -5.0 in 97 to 73 Ma strata. The ϵNd and age of the sandstones closely match those of the plutonic rocks of the Sierra Nevada. This observation indicates that the location of the mean sandstone source and the active volcanic front were nearly coincident in time and space; thus, the isotopic compositions of the sandstones directly record the temporal and geographic variations in arc magmatism. The volcanic "roof" of the Sierra Nevada arc was evidently chemically and isotopically equivalent to its plutonic roots. Prearc metasedimentary rocks did not significantly contribute to the isotopic or geochemical composition of the fore-arc sandstones. 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.