Geologos, 2009, 15, 3-4.
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Browsing Geologos, 2009, 15, 3-4. by Subject "NE Poland"
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Item Neotectonics induced by ice-sheet advances in NE Poland(Bogucki Wydawnictwo Naukowe, 2009) Morawski, WojciechDifferences in the geological structure of the hard-rock substratum of the Warmia and Mazury regions (NE Poland) resulted during the Pleistocene in different reactions on the load exerted by the land-ice masses. In the (western) Warmia province, vertical glacio-isostatic movements caused cyclic erosional events affecting the relatively thick sedimentary cover, which became more compacted. In contrast, the thinner sedimentary cover of the rigid crystalline basement favoured quiet sedimentation in the (eastern) Mazury province. The zone in between these two areas runs NNE-SSW for some 80 km. It is several kilometres wide and is composed of landforms that owe their origin to the sedimentary infilling of crevasses. This intermediate zone formed an interlobe are between the two huge ice lobes that covered the Warmia and Mazury areas during the last ice age. The basement of the zone coincides with the crystalline craton slope, which is accompanied to the west by a parallel marginal trough. Cyclic advances and retreats of the Pleistocene ice sheet induced neotectonic mobility. Glacio-isostatic processes resulted in the intermediate zone in block movements (uplift and subsidence) that affected the whole Cenozoic succession, creating mainly vertical discontinuity zones. Glacio-isostasy also induced vertical tectonic movements within the older deposits, reaching down to the crystalline basement. A tectonic graben thus developed. It is bounded by flexures accompanied on both sides by positive structures that may indicate transpressional movements with a strike-slip stress component.Item Palynology of the Palaeogene and Neogene from the Warmia and Mazury areas (NE Poland)(Bogucki Wydawnictwo Naukowe, 2009) Słodkowska, BarbaraPollen, phytoplankton and microfauna from the Palaeogene and Neogene of two boreholes in NE Poland have been studied. Borehole Klucznik 1 is located in the Warmia area, and borehole Sąpłaty 3 borehole in the Mazury area. The oldest palynomorph assemblage comes from the Klucznik sediments; it consists of phytoplankton from the Early Palaeocene (Danian) D1 and D2 dinocyst zone, and from the Selandian D3 zone. The Eocene is present in the both the Klucznik and the Sąpłaty successions. The Middle Eocene assemblage has been dated as late Bartonian and belongs to the D11 dinocyst zone. The Late Eocene (Priabonian) D12 dinocyst zone is also present in both boreholes. Sporomorphs of a Late Eocene palynomorph assemblage point on the proximity of land and on terrestrial vegetation. The dinocyst zone D13, characteristic for the earliest Oligocene (‘Latdorfian’) has been found in both profiles as well. A Neogene sporomorph assemblage dating from the Middle Miocene (Early Serravallian) occurs only in the Sąpłaty profile. This sporomorph assemblage is correlated with pollen zone VIII. Pollen zone IX is present in the uppermost part of the Middle Miocene (Middle Serravallian). Late Miocene deposits (Late Tortonian) with pollen zone XI are present, too. The Miocene deposits accumulated in densely vegetated swamps, resulting now in the occurrence of lignite. The sedimentary conditions in the Warmia and Mazury regions were identical during the Neogene and Palaeogene, implying that both provinces belonged at the time to one sedimentary basin.