Organic-Rich Sedimentary Rocks

Dinur D., Spiro B. and Aizenshtat Z. (1980) The distribution and isotopic composition of sulfur in organic rich sedimentary rocks. Chem. Geol. 31, 37-51. 

In this paper organically-bound sulfur in three types of high-molecular-weight organic matter (kerogen, asphaltenes and resins) obtained from three organic sulfur-rich sedimentary rock samples has been studied. Kerogen, asphaltene and resin fractions were isolated and characterised by the two described techniques. 

Sedimentary rocks with the highest arsenic concentrations largely consist of materials that readily sorb or contain arsenic, such as organic matter, iron (oxy)(hydr)oxides, clay minerals, and sulfide compounds. Arsenian pyrite and arsenic-sorbing organic matter are especially common in coals and shales. Ironstones and iron formations are mainly composed of hematite and other iron (oxy)(hydr)oxides that readily sorb or coprecipitate arsenic. Iron compounds also occur as cements in some sandstones. Although almost any type of sedimentary rock could contain arsenic-rich minerals precipitated by subsurface fluids (Section 3.6.4), many sandstones and carbonates consist almost entirely of minerals that by themselves retain very little arsenic namely, quartz in sandstones and dolomite and calcite in limestones. 

The organic material in both tar sands and high-grade oil shale has a carbon-to-hydrogen mass ratio of about 8, which is close to that of cmde oil. However, the mineral content of rich tar sands in the form of sand or sandstone is about 85 mass%, and that of high-grade oil shale, in the form of sedimentary rock, is about the same. Therefore, very large volumes of solids must be handled to recover... 

Demaison G. (1991) Anoxia vs. productivity what controls the formation of organic-carbon-rich sediments and sedimentary rocks discussion. Am. Assoc. Petrol. Geol. Bull. 75(3), 499. 

The Phosphoria Formation was deposited in a foreland basin between the Continental margin and the North American cratonic shelf. This foreland basin, which is here defined by the area of deposition of the two organic-ncarbon-rich mudstone members of the Phosphoria (fig. 1), has been named the Sublett basin (8)5 and it covers an extensive area of approximately 400,000 knr (about 700 km by 600 km). The basin has a northwest-southeast-trending axis and seems to have been deepest in central Idaho where deep-water sedimentary rocks equivalent to the Phosphoria Formation are exceptionally thick. The depth decreased toward the shelves and land areas indicated in figure 1. The deepest part of the Sublett... 

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