[Zurück]

G. Steinhauser, W. Hujer, J.H. Sterba, R. Seemann, M. Bichler, N. Symeonidis:
"On strontium and barium anomalies in the sediments of Charkadio Cave (Tilos Islang, Dodekanese, Greece)";
Journal of Radioanalytical and Nuclear Chemistry, 276 (2008), 1; S. 167 - 173.

The sediments of Charkadio Cave (Island of Tilos) have been object of chemical and mineralogical investigation. Sampling the speleothems of Charkadio Cave, it is possible to look back into the island´s younger geological history. Tilos is of non-volcanic origin but neighbored to several volcanoes of the Aegean (Kos, Nisyros, and Giali). We observed a certain coincidence of increased Ba nd Sr values in such samples and volcanic activity. Some of the layers of these fine-grained sediments contain volcanic particles (ash grains and lapilli). Interestingly, these strata have the highest content of Ba and Sr, as determined by neutron activation analysis. Additionally to this discovery, Sr-rich barite crystals were found in some of these layers. Thus, Ba and Sr must either exist on the surface of tephra particles in volatile and water-soluble compounds and/or were released by weathering from Ba and Sr containing feldspars (originating from pumice) in the cave sediment environment. Since other cave sediments from Tilos, which were not exposed to volcanic products, contain very much lesser quantities of Ba and Sr, we conclude that mobile Ba and Sr compounds are contributet to the sediment by volcanic fallout.

http://dx.doi.org/10.1007/s10967-007-0427-3

http://publik.tuwien.ac.at/files/PubDat_166324.pdf