Journal ArticleDOI
Geochemical classification of terrigenous sands and shales from core or log data
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In this article, a means of relating geochemical concentrations to existing sandstone classification schemes is proposed based on three chemical parameters: the SiO2/Al2O3 ratio, the Fe 2O3/K2O ratio, and the Ca content.Abstract:
A means of relating geochemical concentrations to existing sandstone classification schemes is based on three chemical parameters: the SiO2/Al2O3 ratio, the Fe2O3/K2O ratio, and the Ca content. In terrigenous sands and shales, the SiO2/Al2O3 ratio separates Si-rich quartzarenites from Al-rich shales, with other sand types showing intermediate values. The ratio of total iron (as Fe2O3) to K2O separates lithic sands (litharenites and sublitharenites) from feldspathic sands (arkoses and subarkoses). In addition, very high Fe2O3/K2O ratios indicate Fe-rich shales (e.g., pyritic, sideritic, hematitic) or Fe-rich sands (e.g., gl uconitic) depending on the silica/alumina ratio. The Ca content is used to differentiate noncalcareous from calcareous sandstones and shales and to separate siliciclastic from carbonate rocks. Sandstones are classified the same by this scheme as by petrographic analysis about 84% of the time, and shales are effectively discriminated from sandstones. The requisite input data can be accurately supplied by geochemical well-logging measurements, enabling unbiased sandstone classification to be displayed on a continuous basis with depth.read more
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Dissertation
Ossa-Morena Zone Variscan "calc-alkaline" hybrid rocks: interaction of mantle-and crustal-derived magmas as a result of intra-orogenic extension-related intraplanting
TL;DR: In this paper, the authors investigate the petrogenesis of rocas ''calco-alcalinas'' in the Zona de Ossa-Morena, a region of Orogenia Varisca.
Journal ArticleDOI
Insights into the Acadian orogeny, New England Appalachians: a provenance study of the Carrabassett and Kittery formations, Maine
TL;DR: The early Devonian Carrabassett and Kittery formations have major and trace element compositions indicative of a passive continental margin provenance, not unlike the older formations of the Central Maine Basin that are thought to have been derived from Laurentian sources.
Dissertation
The geology, sedimentology, geochronology and palaeo-environmental reconstruction of the Heelbo hillslope deposit, Free State Province, South Africa
TL;DR: Thesis submitted in fulfillment of the requirements for the degree of Doctor of Philosophy degree at the University of the Witwatersrand in South Africa as discussed by the authors, 2015, was submitted in 2015.
Journal ArticleDOI
Tajik Basin and Southwestern Tian Shan, Northwestern India-Asia Collision Zone: 3. Preorogenic to Synorogenic Retro-foreland Basin Evolution in the Eastern Tajik Depression and Linkage to the Pamir Hinterland
Ralf Dedow,Matthias Franz,Matthias Franz,Adam Szulc,Jörg W. Schneider,Jörg W. Schneider,Jan Brückner,Lothar Ratschbacher,Łukasz Gągała,Jean‐Claude Ringenbach,Negmat Rajabov,Mustafo Gadoev,Ilhomjon Oimahmadov +12 more
Journal ArticleDOI
Provenance, weathering, and paleoenvironment of the Upper Cretaceous Duwi black shales, Aswan Governorate, Egypt
TL;DR: In this paper, the authors investigated the mineralogy and geochemistry of the Upper Cretaceous Duwi black shales of Nile Valley district, Aswan Governorate, Egypt, have been investigated to identify the source rock characteristics, paleoweathering, and paleoenvironment of the source area.
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