Browsing by Author "Alatarvas, Raisa"

The Landsort Deep is the deepest part of the Baltic Sea. It is located just south from the postulated margins of the early Weichselian glacial, and the deep displays a high-resolution sediment sequence from late Weichselian and Holocene. The physical properties and characterisation of late and postglacial sediments from the Landsort Deep enabled the interpretation of the sediment responses to late Weichselian and Holocene glacial settings. The sediment stratigraphy of the Landsort Deep reflects variations of salinity in the Baltic Sea Basin, and it enables the identification of four major stages in the history of the Baltic Sea: Baltic Ice Lake, Yoldia Sea, Ancylus Lake and Littorina Sea. The samples studied are from cores from Hole M0063C. The cores were recovered during the Integrated Ocean Drilling Program (IODP) Expedition 347, “Baltic Sea Paleoenvironment”. Site M0063 is divided into seven lithostratigraphic units, and the samples are from Unit VI (54–93 ambsf) and Unit V (48–54 ambsf). Sediment analyses and the interpretation of the sedimentary environment of Units VI and V are based on grain-size analysis by laser diffractometry, loss on ignition (LOI) determination, and on the IODP Expedition 347 physical properties dataset. The uniquely long varved glacial clay sequence of Units VI and V gives indications of the Scandinavian Ice Sheet and the sedimentation of the Baltic Sea Basin responded to climate fluctuations. The lowermost part of the thick sediment column comprising Units VI and V, displays ice-proximal settings, and the upper part represents ice-distal settings. The correlation of the sedimentary features to well-known geological events in the Baltic Sea region enabled the relative age determination of the Units VI and V. The sediments are deposited during the Baltic Ice Lake stage and the transition into the Yoldia Sea stage, roughly estimated between 13.5 and 11.5 ka. Comparison to different late and postglacial settings e.g. marine and terrestrial, illustrated conformities in various glacial sedimentary settings.