Journal ArticleDOI
Geochemical classification of terrigenous sands and shales from core or log data
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TLDR
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
Citations
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Journal ArticleDOI
Provenance of the Cretaceous Debre Libanos Sandstone in the Blue Nile Basin, Ethiopia: Evidence from petrography and geochemistry
TL;DR: In this paper, the Debre Libanos Sandstone in the Blue Nile Basin, Ethiopia from its petrographic and geochemical signatures was analyzed. But the authors focused on the provenance, depositional tectonic setting and source area weathering of the cretaceous debre libanos sandstone.
Chemostratigraphy: a method to improve interwell correlation in barren sequences — a case study using onshore Duckmantian=Stephanian sequences (West Midlands, U.K.)
TL;DR: Chemostratigraphy has been applied to onshore Duckmantian=Stephanian successions encountered in outcrop and penetrated by two boreholes from the West Midlands (U.K.) as mentioned in this paper.
Journal ArticleDOI
Zircon U-Pb ages and Hf isotopes of Paleozoic metasedimentary rocks from the Habahe Group in the Qinghe area, Chinese Altai and their tectonic implications
Zengchan Dong,Zengchan Dong,Yigui Han,Guochun Zhao,Guochun Zhao,Feng Pan,Kai Wang,Botao Huang,Juanlu Chen +8 more
TL;DR: In this paper, the authors used U-Pb data for detrital zircons from the Habahe Group in the Qinghe region of the eastern Chinese Altai to indicate that the strata were deposited from the late Silurian to early Devonian and experienced regional metamorphism in the middle Devonian (383 ± 9 Ma).
Journal ArticleDOI
Petrography, geochemistry, and geochronology of Lower Jurassic sedimentary rocks from the Northern Tianshan (West Bogda area), Northwest China: Implications for provenance and tectonic evolution
Journal ArticleDOI
Lithological control on the occurrence of chlorite in the diagenetic Wealden complex of the Bilbao anticlinorium (Basco-Cantabrian Basin, Northern Spain)
TL;DR: In this article, a detailed sedimentological, mineralogical and geochemical study of sandstones and shales from the southern flank of the Bilbao anticline in the Gordexola and Orozko valleys, northwestern Spain, has been conducted.
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