Pleistocene walrus on the Pechora River: mineralogical and geochemical data and paleoecological reconstructions

Abstract

Left tusk’s fragments of the Pleistocene walrus were studied. Its fossil remains were found on the bank of the Pechora River in 2009. The analyses covered granulometric, chemical and normative-mineral composition of grounds inside the bones; thermal properties, chemical and microelemental composition of the tusk; X-ray diffraction parameters and chemical composition of bone bioapatite; macrostructure, elemental and amino acid composition of bone organic matter; isotopic composition of carbon, oxygen in bioapatite and carbon, nitrogen in bone collagen. Bioapatite was identified for moderately isotopically light carbon, characteristic of extracave fossil bones of the Pleistocene animals, and isotopically heavy oxygen, typical of seawater bicarbonate. The isotopic data for the organic matter of the Pechora walrus correlated with the similar characteristics of marine animals but simultaneously indicated not a mollusk diet, typical of modern walruses, but a fish diet. The latter fact evidenced the habitat and the diet of the Pechora walrus being untypical for marine predators.