Bone Detritus in Sediments of the Tethys Ocean

Resumo

Comparative studies of the geochemistry of bone detritus were performed for the bottom of the Melovoe deposit (south of the Mangyshlak Peninsula; Oligocene–Miocene) and for the recent uranium-bearing sediments at the shelf of Namibia in which the concentrations of trace elements were determined. The similarity of trace-elemental compositions of bones and enclosing sediments was revealed for both cases, as well as a partial similarity of ancient and recent sediments and bones. Moreover, the similarity of uranium mineralization in Maikop bones and in the bone matter of the recent shelf was found. Paleographic data on the Maikop basin showed that the ore bodies were formed in shoal productive shelf zone characterized by frequent mass die-offs of fauna similarly to occasional events at the recent oceanic shelves. Certain geochemical differences in mineral and chemical compositions of ancient and recent bones are related to the increased concentrations of uranium and other trace elements in the Tethys waters owing to the evaporation of seawaters and associated concentrating of dissolved metals under the ocean regression.