Micromorphology and origin of an unusual bear fur-bearing deposit in Bàsura Cave (Toirano, NW Italy)

AROBBA, DANIELE; CITTON, PAOLO; AVANZINI, MARCO; RELLINI, IVANO; STARNINI, ELISABETTA; SALVADOR, ISABELLA; ZUNINO, MARTA; FIRPO, MARCO; ROMANO, MARCO; NEGRINO, FABIO

QUATERNARY INTERNATIONAL

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2021

1040-6182

The B`asura Cave (Toirano, Savona, NW Italy) hosts important cave bear bone assemblages and a numerous andvaried, tracks and traces record left by humans and other producers. An outstanding element of the analysedmaterial is represented by fossil bear fur fragments, which were found in the inner deposits of the cave, and that,to date, are virtually unknown in the cave global record. After analysing and discussing micromorphologicalfeatures of the inedited material, we integrate and interpret new radiocarbon data, along with taphonomic,sedimentological, geochemical and mineralogical evidences, with the aim of improving our understanding aboutthe nature and chronology of the bear fur-bearing deposit. The bear fur fragments are included in a stratigraphicsuccession corresponding to a secondary deposit, formed after the dismantling, reworking and redeposition of aformer bear-bearing deposit, as a result of short but intensive flooding events that most probably took place atthe end of the Last Glacial Maximum. After sediments redeposition, important diagenetic changes have occurredand probably driven by guano deposits, whose pre-existence, in absence of record, is inferred from corrosionfeatures, nutrient concentrations, mineral species identified (REE bearing hydroxyapatite), and claw traces leftby bats on the cave ceiling and walls. Diagenetic imprint derived by guano deposits caused mineralization of bearfur fragments by replacement with apatite, which faithfully copied the form and structure of hairs but also ofvegetal tissues, phytoliths and pollen found within them. Our study demonstrates for the first time that the bearfur is one of the main vectors in introducing botanical microremains into the interior of the ?Old World? caves.