Malacological sequence from profile of calcareous tufa in Grori (Podhale Basin, southern Poland) as an indicator of the Late Glacial/Holocene boundary

摘要

Rich assemblages of subfossil malacofauna were discovered in the profile of slope deposits and calcareous tufas at the Grori site in the Podhale Basin in southern Poland. The detailed analysis of the composition of this fauna has made it possible to distinguish four types of assemblages. Their age was established by radiocarbon dating as well as by comparisons with other profiles. The malacofauna represented almost exclusively by terrestrial species, was used for the reconstruction of the changes in the environment during the sedimentation of the deposits. The assemblages distinguished in the study provided the basis for stratigraphic considerations. The oldest fauna, characterized by a high proportion of cold-loving species, is typical of the Younger Dryas. The remaining three assemblages are correspondingly linked with the Early and Middle Holocene. The evident differences in the composition and structure of the identified malacocoenoses enabled definition of the Late Glacial/Holocene boundary. The wide geographical distribution of the selected molluscan assemblages enables supra-regional correlation and provides an important premise for defining the regional malacostratigraphic subdivisions, which can be successfully used to determine the age of deposits. From this viewpoint, the profile of calcareous tufas in Gron represents a model location for Central Europe.