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Miocene quartz sands redeposited on subaqueous and alluvial fans during the Saalian: Interpretation of the depositional scenario at Ujście, western Poland

Mleczak Mateusz, Pisarska-Jamroży Małgorzata

Geologos

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2019

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Vol. 25, No. 2

125--137

EN

The 14-m-thick sandy succession at Ujście in western Poland formed during the Odranian stadial of the Saalian glaciation, is exceptional in being very well sorted, almost mono-fractional (fine-grained sands) and mono-mineral (mainly quartz grains) and in lacking Scandinavian erratics. The lower sequence (5 metres in thickness) consists of three stacked packages of clinoforms (inclined cross-stratified sands) and is interpreted as having been deposited on a subaqueous fan in a shallow lake during two phases of rising water levels. The upper sand (9 metres in thickness) with (sub) horizontal stratification was redeposited on a subaerial alluvial fan. Distinctive distributary channels that occur in the uppermost part of the subaqueous fan and in the lowermost portion of the alluvial fan may indicate a change in sedimentation style from subaqueous to subaerial. Moreover, the subaerial position of the fan supports the presence of ice-wedge casts that developed under periglacial conditions in the upper part of alluvial fan. The results of granulometric analysis, rounding and frosting of grains and mineral analysis indicate that the sands are derived from Gorzów Formation of Early Miocene age. The only feasible explanation is that the 14-m-thick unit must have been redeposited during the Saalian glaciation.

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Deglaciation chronology of the Pandivere and Palivere ice-marginal zones in Estonia

Saarse L., Heinsalu A., Veski S.

Geological Quarterly

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2012

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Vol. 56, No 2

353-362

EN

Accelerator mass spectrometry (AMS) 14

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Proglacial lake shorelines of Estonia and adjoining areas

Rosentau A., Vassiliev J., Saarse L., Miidel A.

Polish Geological Institute Special Papers

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2008

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Vol. 23

81-86

EN

A uniform database of the proglacial lake coastal landforms of Estonia, Latvia and NW Russia was created and used to reconstruct the spatial distribution of proglacial lakes using the kriging point interpolation and GIS approaches. Correlation of the Late Glacial coastal landforms confirms that the proglacial lake stage A1 in Estonia is synchronous with the BglI level in Latvia and with one level in NW Russia of undefined index. Proglacial lake A1 was formed concurrently with the Pandivere-Neva ice-margin about 13,300 cal. yrs BP. Proglacial lake A2 level formed probably about 12,800 cal. yrs BP and correlates with the level of BglII in Latvia and GIII in NW Russia. Simulated isobases of proglacial lake water-levels show a relatively regular pattern of the land uplift along the eastern coast of the Baltic and in the northern part of the Lake Peipsi basin, with a steeper tilt towards the northwest. Isobases in the southern part of the Lake Peipsi basin are curving towards SE and are up to 14 m higher than expected from the regional trend. This phenomenon can reflect the forebulge effect during the deglaciation and its later collapse. Shoreline reconstruction suggests that proglacial lakes in the Peipsi and Baltic basins were connected via strait-like systems and had identical water levels. Our reconstructions also show that after the glacier halted at the Pandivere-Neva ice margin about 13,300 cal. yrs BP, there was a connection with the initial Baltic Ice Lake in the west of the Gulf of Riga.

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Simulation of proglacial lake shore displacement in Estonia

Vassiljev J., Saarse L., Miidel A.

Geological Quarterly

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2005

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Vol. 49, No. 3

253-262

EN

The Late Glacial shoreline database compiled for Estonia covers 149 sites on the proglacial lakes A1 (Voose) and A2 (Kemba). Eighty-two sites were used in further simulations. Point kriging interpolation with a linear trend approach was applied to create interpolated surfaces of water levels for checking the spatial correctness of data. The sites with altitudes visually not matching with sites nearby were discarded, as well as those with residuals of more than 1 mand 0.7 mrespectively. The final surfaces were analysed geostatistically by simulating isobases, direction of tilting, and shoreline gradient. The simulated isobases suggest that both proglacial lakes A1 and A2 were connected with the glacial lake in the Lake Peipsi basin. The interpolated surface aspect shows that the direction of tilting varies between 320° and 340°. The surface gradient of lake A1 is highest in the NW and SE parts of the study area (50 and 25 cm km-1, respectively), and that of lake A2 is highest in the NWand SE parts (40 and 20 cm km-1, respectively). Using the modelling data, the shoreline correlation between the two proglacial lakes has been revised.