Presence of cave bears in western Austria before the onset of the Last Glacial Maximum: new radiocarbon dates and palaeoclimatic considerations

Tischoferhohle and Pendling-Barenhohle near Kufstein, Tyrol, are among the only locations where remains of cave bear, Ursus spelaeus-group, were found in the western part of Austria. One sample from each site was radiocarbon-dated four decades ago to ca. 28 C-14 ka BP. Here we report that attempts to date additional samples from Pendling-Barenhohle have failed due to the lack of collagen, casting doubts on the validity of the original measurement. We also unsuccessfully tried to date flowstone clasts embedded in the bone-bearing sediment to provide maximum constraints on the age of this sediment. Ten cave bear bones from Tischoferhohle showing good collagen preservation were radiocarbon-dated to 31.1-39.9 C-14 ka BP, again pointing towards an age underestimation by the original radiocarbon-dated sample from this site. These new dates from Tischoferhohle are therefore currently the only reliable cave bear dates in western Austria and constrain the interval of cave occupation to 44.3-33.5 cal ka BP. We re-calibrate and re-evaluate dates of alpine cave bear samples in the context of available palaeoclimate information from the greater alpine region covering the transition into the Last Glacial Maximum, eventually leading to the demise of this megafauna.

Geomorfologia del giacimento di orso delle caverne nella grotta di Govjestica, Valle di Praca, Bosnia-Ercegovina

In 2011 the GSB/USB caving group of Bologna has discovered, in the southern fossil branches of Govjestica cave (Valle di Praça, Bosnia) a fossil deposit of vertebrates containing bones of Ursus spelaeus, Capra ibex, Cricetulus migratorius and Microtus. On the basis of the U/Th ages of the bones, teeth and carbonate flowstone covering the fossils (60 ka), datings carried out in the laboratories of U-Series at Bologna, and on the disposition of the bones, a past connection between Govjestica and the nearby Banja Stjena cave is hypothesised. The closure of this passage has occurred suddenly through a collapse that has forced the last cave bears awakened from their winter sleep to stay blocked in Govjestica, and die. The connecting passage has later been covered with calcite flowstones and is no longer visible. This hypothesis is sustained by the rather scarce number of skeletons of cave bears found in Govjestica (a dozen of skulls against the often large amounts of cave bears found in similar caves): Govjestica cave, and especially the Room of the Bones in its southern part, has been used by cave bears only for a couple of centuries before these parts became inaccessible. Furthermore, the entrance of Banja Stjena cave was probably located close to or at the level of the Praça river, that has excavated its thalweg for around 20 metres in the last 60 ka.

Texturas de espeleotemas calcíticos recientes en la Cueva del Canelobre (Alicante, SE España)

Se describen las características texturales y composicionales de los espeleotemas recientes en la cueva del Canelobre.

Point clouds of measurements in the Dechen Cave near Iserlohn, Germany

Modeling natural phenomena from 3D information enhances our understanding of the environment. Dense 3D point clouds are increasingly used as highly detailed input datasets. In addition to the capturing techniques of point clouds with LiDAR, low-cost sensors have been released in the last few years providing access to new research fields and facilitating 3D data acquisition for a broader range of applications. This letter presents an analysis of different speleothem features using 3D point clouds acquired with the gaming device Microsoft® Kinect. We compare the Kinect sensor with terrestrial LiDAR reference measurements using the KinFu pipeline for capturing complete 3D objects (< 4m**3). The results demonstrate the suitability of the Kinect to capture flowstone walls and to derive morphometric parameters of cave features. Although the chosen capturing strategy (KinFu) reveals a high correlation (R2=0.92) of stalagmite morphometry along the vertical object axis, a systematic overestimation (22% for radii and 44% for volume) is found. The comparison of flowstone wall datasets predominantly shows low differences (mean of 1 mm with 7 mm standard deviation) of the order of the Kinect depth precision. For both objects the major differences occur at strongly varying and curved surface structures (e.g. with fine concave parts).