Uranium and yttrium accumulation in the bone debris in carbonaceous rocks of the Kamchatsky Mys Peninsula

Abstract

The carbonaceous rocks composing the beds in the Cretaceous carbonate-siliceous paleoceanic sediments of the Kamchatsky Mys Peninsula (Eastern Kamchatka) were studied using a scanning electron microscope. In the matrix, which consists of organic and siliceous matter, abundant bone debris and phosphate coprolites have been revealed. In the fragments of fish bones, the authors have revealed microinclusions enriched with uranium and, to a lesser extent, yttrium. The accumulation of these elements is associated with their sorption from seawater and from sediment in bone debris. The concentration of uranium was boosted by euxinic conditions in the near-bottom waters caused by high biological productivity in the surface waters of the ocean, as well as low sedimentation rate, which prevented the dilution of organic matter and biogenic phosphates by terrigenous material and promoted long-term exposure of bone debris at the bottom.

Keywords

• uranium
• yttrium
• bone debris
• Kamchatka
• carbonaceous rocks