Conversely, the few geological studies that focused on the geomorphological evolution of the Ach and Lone valleys were mostly designed to answer questions unrelated to the study of the human occupation of this region. The current understanding of the relationship between caves, cave deposits, human occupation and landscape evolution in the Ach and Lone valleys relies on data coming almost exclusively from cave sites and rockshelters. From the excavation of these Prehistoric cave deposits generations of archaeologists have discovered deep sequences and spectacular finds that help to illuminate the evolution of our species and the extinction of Neanderthals. In the Swabian Jura (Southwest Germany) the Ach and Lone valleys host a number of cave sites, which have been repeatedly occupied by groups of hominins since at least the last interglacial. The hypothesis that cave erosion was triggered by regional landscape changes seems to be supported by geochronological data from the Danube Valley, which show that terrace formation at the end of the Pleistocene moved westwards throughout southern Germany with a time lag of few millennia. Furthermore, we argued that the time difference across the two valleys show that the erosion of cave deposits began and terminated earlier in the Lone Valley, resulting in a more intensive removal of Gravettian-aged deposits. Based on geoarchaeological data from previous studies and presented in this paper, we interpreted these gaps in radiocarbon data as indicating of cave erosion. Ages from the Lone Valley show increasing multimillennial gaps between 36 and 18 Kcal BP, while a similar gap is present in the Ach Valley between 28 and 16 Kcal BP. We conclude that the second hypothesis is most likely. ii) Erosion of cave deposits did not occur at the same time in the two valleys. To investigate on the causes responsible for the dearth of Gravettian materials in the Lone Valley we test two alternative hypotheses: i) Gravettian humans occupied less intensively this part of the Swabian Jura. We argued that the rate of cave erosion was higher after phases of downcutting, when hillside erosion was more intensive. In this paper we present ERT, EC-logging and GPR data showing that in both Ach and Lone valleys sediments and archaeological materials eroded from caves and deposited above river incisions after 37-32 Kcal BP. It is debated whether this gap is due to a phase of human depopulation, or taphonomic issues related with landscape changes. On the other hand, traces of contemporaneous occupations in the nearby Lone Valley are sparse. Unlike other Upper Paleolithic industries, Gravettian assemblages from the Swabian Jura are documented solely in the Ach Valley (35-30 Kcal BP).
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |