Thesis (Ph. D.)--Lehigh University, 2000. / Includes bibliographical references and vita.

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The prospect of sea level rise due to melting ice sheets affirms the urgency of gaining knowledge on ice sheet dynamics during deglaciation. The Fennoscandian Ice Sheet serves as an analogue, whose retreat can be reconstructed from the geomorphological record. The recent development of a high-resolution LiDAR-derived elevation model can reveal new relationships between landforms, even for well-studied areas such as the Torneträsk region in northwestern Sweden. Therefore, this study aims to refine the reconstruction of the deglaciation in this region based on an updated glacial geomorphological map. A range of glacial landforms were mapped, which by means of an inversion model were utilized to form swarms representing spatially and temporally coherent ice sheet flow systems. Additionally, glacial lake traces allowed for the identification of ice margins that dammed lakes in Torneträsk, Rautasjaure, and other (former) lake basins. Eight glacial lake stages were identified for the Torneträsk basin, where final drainage occurred through Tornedalen. Over 20 glacial lake stages were identified for the Rautasjaure basin, where drainage occurred along the margins of a thinning ice lobe. The disparity between the glacial lake systems results from different damming mechanisms in relation to the contrasting topography of the basins. A strong topographic control on the retreat pattern is evident, as the ice sheet retreated southward in an orderly fashion in the premontane region, but disintegrated into ice lobes in the montane region. The temporal resolution of current dating techniques is insufficient to constrain the timing of ice retreat at the spatial scale of this study. Precise dating of the Pärvie fault would pinpoint the age of the ice margin which at the time of rupture was located between two glacial lake stages of Torneträsk. Collectively, this study provides data for better understanding the final retreat of the ice sheet and associated processes, such as interactions between glacial lakes and ice dynamics.

The prospect of sea level rise due to melting ice sheets affirms the urgency of gaining knowledge on ice sheet dynamics during deglaciation. The Fennoscandian Ice Sheet serves as an analogue, whose retreat can be reconstructed from the geomorphological record. The recent development of a high-resolution LiDAR-derived elevation model can reveal new relationships between landforms, even for well-studied areas such as the Torneträsk region in northwestern Sweden. Therefore, this study aims to refine the reconstruction of the deglaciation in this region based on an updated glacial geomorphological map. A range of glacial landforms were mapped, which by means of an inversion model were utilized to form swarms representing spatially and temporally coherent ice sheet flow systems. Additionally, glacial lake traces allowed for the identification of ice margins that dammed lakes in Torneträsk, Rautasjaure, and other (former) lake basins. Eight glacial lake stages were identified for the Torneträsk basin, where final drainage occurred through Tornedalen. Over 20 glacial lake stages were identified for the Rautasjaure basin, where drainage occurred along the margins of a thinning ice lobe. The disparity between the glacial lake systems results from different damming mechanisms in relation to the contrasting topography of the basins. A strong topographic control on the retreat pattern is evident, as the ice sheet retreated southward in an orderly fashion in the premontane region, but disintegrated into ice lobes in the montane region. The temporal resolution of current dating techniques is insufficient to constrain the timing of ice retreat at the spatial scale of this study. Precise dating of the Pärvie fault would pinpoint the age of the ice margin which at the time of rupture was located between two glacial lake stages of Torneträsk. Collectively, this study provides data for better understanding the final retreat of the ice sheet and associated processes, such as interactions between glacial lakes and ice dynamics.

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The Black Sea becomes periodically isolated from the global ocean during each glacial period. This occurs when the elevation of the global ocean is lower than the Bosporus sill, putting a stop to inflow of salt water to the Black Sea. This phenomenon allows the Black Sea to evolve from a marine environment to a freshwater one. It is also evident that the depth of the Bosporus sill does not remain at the same elevation, and instead is dynamic. The sill becomes filled with sediments during periods of its sub-aerial exposure but is subsequently eroded to its bedrock during periods of outflow from the Black Sea-Lake to the global ocean. This interpretation comes from the observations that during the last glacial period, the Black Sea-Lake was in a positive hydrological balance, fresh, and predominantly outflowing to the global ocean over a deep Bosporus sill, at approximately 80 meters below sea level (mbsl). It is highly likely that there were brief periods when the lake froze and the outflow suspended, such as during the extreme stadial conditions associated with the North Atlantic iceberg-discharge Heinrich Event 2 (HE 2) at ~24 kyr before present, when there is also no evident carbonate accumulation in stalagmites that receive water from evaporated Black Sea surface water. Upon the onset of deglaciation, large floods originating from the Fennoscandinavian Ice Sheet and the Alps, delivered meltwater so as to fully ventilate the Black Sea-Lake and even potentially replace all of the water in the basin. These floods occurred near the time of the deglacial iceberg-discharge Heinrich Event 1 (HE 1 at ~17 kyr before present), and left pulses of red-colored sediment everywhere on the western half of the Black Sea basin.