Low carbon black shales of South and parts of Central and Northern Urals: new geochemical characterization data

We analyzed the distribution of wide range of trace elements in low-carbon shales of various Riphean, Vendian and Lower Paleozoic lithostratigraphic units of the South, Central, and southern part of the Northern Urals (Satka, Bolshoy Inzer, Suran, Yusha, Zigazino-Komarovo, Vels, Buton, Bezgodovo, and other suites). It was determined that they significantly differ in content of the trace elements. In the most cases, the concentration of trace elements in these shales is roughly comparable with those found in well-known geochemical units, such as the Post-Archean Australian Shale (PAAS), or is lower. Alternatively, obtained data showed significant differences between the Urals low-carbon black shales and the Ven-dian and Cambrian black shales from China, and other black shale formations, characterized by higher concentration of many trace elements. We consider the probable important role of the geodynamic position of black shale formation, variation in the bioproductivity, association with specific rock complexes, and extent of secondary transformations in variability of geo-chemical composition of the black shale sediments.