Die postglaziale Sedimentationsgeschichte der Laptewsee: schwermineralogische und sedimentpetrographische Untersuchungen = Postglacial depositional history of the Laptev sea: mineralogy and sedimentology

• Main Author: Peregovich, Bernhard
• Format: Thesis
• Language: German; English
• Published: 1998
• Subjects: Laptev Sea; Yana Valley; Berichte zur Polarforschung; khatanga; laptev; Polarforschung; Sea ice
• Online Access: https://oceanrep.geomar.de/id/eprint/49883/; https://oceanrep.geomar.de/id/eprint/49883/1/Diss.%20Peregovich.pdf; https://oceanrep.geomar.de/id/eprint/49883/3/BerPolarforsch1999316.pdf

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 ...