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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Journal ArticleDOI
Geochemistry of fine-grained clastic sedimentary rocks of the Neoproterozoic Ikorongo Group, NE Tanzania: Implications for provenance and source rock weathering
TL;DR: In this article, geochemical data for the mudrocks (i.e., shales and siltstones) from the Ikorongo basin in an attempt to constrain their provenance and source rock weathering are reported.
Journal ArticleDOI
Geochemistry and Nd isotopic composition of the Early Paleozoic flysch sequence in the Chinese Altai, Central Asia: Evidence for a northward-derived mafic source and insight into Nd model ages in accretionary orogen
TL;DR: Li et al. as mentioned in this paper used Nd isotopic composition of sedimentary rocks to trace the provenance of the Early Paleozoic flysch sequence in the Chinese Altai and adjacent western Mongolian terranes.
Journal ArticleDOI
Geochemistry of Mansar Lake sediments, Jammu, India: Implication for source-area weathering, provenance, and tectonic setting
TL;DR: The sediment geochemistry, including REE, of surface and core samples from Mansar Lake, along with mineralogical investigations, have been carried out in order to understand the provenance, source area weathering, hydrolic sorting and tectonic setting of the basin this paper.
Journal ArticleDOI
A fresh approach to investigating CO2 storage: Experimental CO2-water-rock interactions in a low-salinity reservoir system
S. M. Farquhar,Julie K. Pearce,Julie K. Pearce,G. K. W. Dawson,Alexandra N. Golab,Silvano Sommacal,Dirk Kirste,Dirk Kirste,D. Biddle,Suzanne D. Golding +9 more
TL;DR: In this paper, core samples and sub-plugs from five Jurassic-aged Surat Basin sandstones and siltstones of varying mineralogy have been experimentally reacted in low-salinity water with supercritical CO2 at simulated in situ reservoir conditions (P=12MPa and T=60°C) for 16 days (384h).
Journal ArticleDOI
Detrital zircon U-Pb dating, Hf isotopes and whole-rock geochemistry from the Songshan Group in the Dengfeng Complex: constraints on the tectonic evolution of the Trans-North China Orogen
TL;DR: In this article, the Songshan Group is interpreted as having deposited in a retroarc foreland basin, which is consistent with the model that the collision between the Eastern and Western Blocks to form the Trans-North China Orogen occurred at ∼1.85 ǫ Ga after long-lived subduction.
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