Nonpyrogenic charring of Late Pleistocene large mammal remains in northeastern Russia

Mammal remains preserved in the permafrost zone often bear traces of postmortem transformations, reflecting aspects of the palaeoenvironment and the processes that took place during the accumulation of host sediments. Multidisciplinary studies including radiocarbon dating, infrared spectroscopy, and microfossil analyses and grain size of infilling sediments from remains allow recognition of their stratigraphical and palaeogeographical origins and facilitate reconstructions of taphonomic pathways and the pre-burial environments. Here, as exemplified by skulls of woolly rhinoceros, cave lion, and ancient bison, some distinct features of postmortem changes such as nonpyrogenic charring and vivianite encrustation indicate that the remains have undergone a complex range of burial processes in aerobic and anaerobic conditions in the Pleistocene landscapes of Arctic northeastern Russia. We hypothesize that these processes were mainly confined to the warmer intervals in the Late Pleistocene.