Michigan Basin, USA

If substantial arsenic is present in a sandstone or conglomerate, it may occur in hematite or other iron (oxy)(hydr)oxide cements or coatings on mineral grains. Arsenic may also be enriched in sandstones, conglomerates, and other clastic sedimentary rocks if hydrothermal or other secondary sulfide minerals are present (e.g. St. Peter Sandstone, (Gotkowitz et al., 2001) arsenian pyrite cement in the Marshall Sandstone of the Michigan Basin, USA, (Kolker et al., 2000 Szramek, Walter and McCall, 2004)). Sections of the St. Peter Sandstone in eastern Wisconsin, USA, are enriched in sulfide minerals and contain about 500 mg kg-1 of arsenic. In contrast, unmineralized portions typically have <10 mg kg-1 (Gotkowitz et al., 2001). If present in sedimentary rocks, hydrothermal sulfide deposits often tend to concentrate in veins and faults more than the rock matrices. 

Wilson T. P. and Long D. T. (1993) Geochemistry and isotope chemistry of Ca-Na-Cl brines in Silurian strata, Michigan Basin, USA. Appl. Geochem. 8, 81-100. 

Taylor, T.R.. Sibley, D.F. (1986) Petrographic and geochemical characteristics of dolomite types and the origin of ferroan dolomite in the Trenton Formation, Ordovician, Michigan Basin, USA. Sedimentology, 33, 61-86. 

USA Indiana Dugger Formation Danville Member 2 bituminous samples USA Michigan Basin Michigan 3 bituminous coals... 

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