ALBERT

Description: To identify modern and past sediment transport from the siberian hinterland to the Laptev Sea, mineralogical and sedimentological investigations (e. g. heavy minerals) were performed. These analyses concentrated on recent and Holocene sediments as weil as on sea-ice sediments from the Laptev Sea. The distribution of heavy minerals in surface sediments allows a subdivision of the Laptev Sea into three different provinces. The western Laptev Sea is dominated by a local garnet enrichment and a high concentration of pyroxene. In the central and the eastern part of the Laptev Sea the amphiboles dominate among the heavy minerals. whereas the minerals of mica, rock fragments and opaque minerals determine the spectrum of heavy minerals in the south-eastern Laptev Sea with a relatively low con­centration of pyroxene and amphiboles. These distribution patterns are mainly attributed to the fluvial input of float debris from the Siberian hinterland. The coastal erosion and the processes of sediment redeposition significantly contribute to the recent sedimenta­tion in the Laptev Sea, however, these processes play only a minor role for the distribu­tion of heavy minerals. The composition of heavy minerals in sea-ice sediments generally reflect their as­semblages in the areas of ice formation. A slight shift in the spectrum of heavy minerals in favour of relatively light and fine-grained components, which should be considered by comparing sea-ice- and shelf sediments, allows conclusions on the prevailing incorpora­tion mechanism during freeze-up favouring fine-grained sediment particles. Heavy mineral and sediment petrographical analysis of four sediment cores from the eastern and western Laptev Sea testify changing sedimentary conditions due to a change of climatic conditions after the last glacial optimum. Large amounts of sand and terrige­nious plantdebris, which occur in the lowermost core-section of Khatanga and Yana Valley, as weil as the composition of heavy minerals, which corresponds to the recent Khatanga and Lena sediments, prove the activity of these rivers before the beginning of transgression, as consequently the shelves began to be flooded around 10.000 y. b. p. The increasing amounts of garnet and opaque minerals in the western Laptev Sea during this time show the increasing drainage of the Anabar-shield due to the climatic change. Owing to the rising sea-level the depocenters of the Khatanga Valley shifted landward. The erosive character of transgression is noticeable because of high bulk sediment accu­mulation rates in the north-eastern Laptev Sea. After reaching the recent sea-level around 6.000 y. b. p., the sedimentation in the Laptev Sea is determined considerably by fluvial input of sediments. coastal erosion and the prevailing ice conditions. Large amounts of mica in the sediments of the eastern Laptev Sea around 5.000 y. b. p. re­present short-term an intensive influence of Yana river, while the amphibols signal the prevailing input of Lena sediments. Locally restricted enrichments of carbonate nearby the New Siberian Islands confirm the still remaining influence of the coastal erosion remaining until today on the sediment budget of the Laptev Sea.

Description: Lake Ohrid (Macedonia / Albania) is probably the oldest lake in Europe (2-5 Ma), and is considered an important sedimentary archive to study the evolution of a graben system over several million years. Multichannel seismic profiles were acquired in 2007 and 2008 showing that the lake can be divided into two main parts, the slope areas and a large, deep central basin. The basin is bordered by the major eastern and western graben fault, additional faults were identifi ed in the northern part of the lake. These faults are active, as we can trace them from the basement up to the lake floor. Clinoforms mainly found in the southern part of the lake indicate that the Lake has undergone major lake level fluctuations. The central basin shows widespread areas with thick, undisturbed sedimentary successions. No indications for a dry lake are found in this part of the lake, hence, offering the possibility to recover long, continuous archives for the entire lifetime of Lake Ohrid in the frame of the proposed SCOPSCO(Scientific Collaboration On Past Speciation Conditions in Lake Ohrid)-ICDP(International Continental Drilling Program) campaign. Five primary drilling locations have been chosen as ICDP sites. One 680 m long record in the central part will provide substantial information on age and origin of the lake, as well as a complete record of environmental history (incl. e.g. tephra deposition, evolutionary changes and their relation to geological events). Furthermore, four additional drill sites closer to the shore of the lake will provide information on major changes of the hydrological regime, the age of ancient foresets, lake level changes, the tectonic activity, and mass movements. The drilling proposal is approved by ICDP and will be realized in summer 2011 or 2012.