Vestnik Permskogo Universiteta: Seriâ Geologiâ (Dec 2020)
Mineralogical and Geochemical Features of Cave Fossilization of Bone Detritus on the Example of Imanay Cave (South Urals)
Abstract
First time, the results of complex mineralogical and geochemical studies of fossil bone detritus of Pleistocene mammals from the Imanay Cave (South Urals) were obtained using optical and scanning electron microscopy, a statistical volumetric method for nanoporosity determination, thermal, X-ray structural and X-ray fluorescence analyzes, gas chromatography, IR, Raman and x-ray luminescent spectroscopy, ICP MS, and isotope mass spectrometry. The aim of the research was to obtain experimental data on the nature and degree of fossilization of bone remains in caves, and to assess the possibilities of paleoecological reconstructions from cave fossil bones. The data on the microstructure of bone remains, nanoporosity, chemical composition and concentration of trace elements, X-ray structural and thermal properties, isotopic composition of the mineral, and organic components in bones are discussed. According to the data obtained, fossilization of bone remains in caves is fundamentally different at all levels of structure and composition of fossil bones from those outside caves environments. In particular, cave bones are distinguished by intense epigenetic calcitization, 3—5 times higher CO2 content and abnormally high Ca/P atomic ratios, but they are many times inferior in terms of the content of illuminated mineral impurities, enrichment in microelements of the host geological environment, content of Corg and collagen. According to the isotopic composition of carbon and oxygen in bioapatite, cave bone detritus is abnormally heavy, approaching the isotopic composition of carbon and oxygen in marine limestones. Some paleoecological reconstructions are presented and evidence of the habitation of the late Neanderthals in the Imanai cave is considered.
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