LU konference
At 12:30-14:00
Ice flow pattern and extent of the last Scandinavian ice sheet southeast of the Baltic sea.
This lecture presents preliminary results of the ongoing research that aims to build a GIS-based model on extent and timing of the last SIS in the area between its maximum extent and the Baltic Sea. Digitized subglacial bedforms, ice marginal and other glacial landforms and features are compared and validated against digital elevation model (DEM). This has allowed specifying, revising and in places to questioning the location of the LGM, and to interpret and correlate the post-LGM ice streams with marginal positions. Morphological evidence persisted from large ice streams in length of 100 to 300 km that operated at the time of formation Middle and North Lithuanian endmorains that is ca 2-3 ka after the LGM. Ice streams from the Onega and White Sea basins had high lateral slopes and clearly channelled flow while the ice streams that drained the ice sheet through the Ladoga – Ilmen depression and in the eastern Baltic had usually fan-shape flow pattern and morphologically unclear lateral slopes. In elevated areas and highlands that are located between ice streams a crossing of lineated bedforms is common.
At 14:30-16:00 Modern methods in Quaternary stratigraphy and Pleistocene Chronostratigraphy of SE Baltic Region Age and stable isotope composition of freshwater tufa and ostracods refers to CO2 concentration and decay of permafrost, and can be applied for reconstruction of deglaciation history in the SE area of Scandinavian ice sheet. Freshwater lacustrine tufa is widely distributed within and outside of the limits of LGM of the southeastern sector of the Scandinavian glaciation. Most intensive tufa deposition ocurred during rapid temperature increase at early Holocene, when CO2 concentration has reached post-glacial level of ca 260 ppmv. Permafrost hindered carbonate-rich groundwater outflow and tufa precipitation at LGM and in periglacial zone. There was no permafrost in the East Baltic area (?) and tufa precipitation started up to 700 yrs after deglaciation.
At 14:30-16:00 Modern methods in Quaternary stratigraphy and Pleistocene Chronostratigraphy of SE Baltic Region Age and stable isotope composition of freshwater tufa and ostracods refers to CO2 concentration and decay of permafrost, and can be applied for reconstruction of deglaciation history in the SE area of Scandinavian ice sheet. Freshwater lacustrine tufa is widely distributed within and outside of the limits of LGM of the southeastern sector of the Scandinavian glaciation. Most intensive tufa deposition ocurred during rapid temperature increase at early Holocene, when CO2 concentration has reached post-glacial level of ca 260 ppmv. Permafrost hindered carbonate-rich groundwater outflow and tufa precipitation at LGM and in periglacial zone. There was no permafrost in the East Baltic area (?) and tufa precipitation started up to 700 yrs after deglaciation.