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River response to climate and sea level changes during the Late Saalian/Early Eemian in northern Poland – a case study of meandering river deposits in the Chłapowo cliff section

Moskalewicz D., Sokołowski R. J., Fedorowicz S.

Geologos

2016

Vol. 22, No. 1

1--14

Fluvial sediments in the Chłapowo cliff section were studied in order to reconstruct their palaeoflow conditions and stratigraphical position. Lithofacies, textural and palaeohydraulic analyses as well as luminescence dating were performed so as to achieve the aim of study. Sedimentary successions were identified as a record of point bar cycles. The fluvial environment probably functioned during the latest Saalian, shortly after the retreat of the Scandinavian Ice Sheet. Discharge outflow was directed to the northwest. The river used the older fluvioglacial valley and probably was directly connected to the Eem Sea. Good preservation and strong aggradation of point-bar cycles were related to a rapid relative base level rise. The meandering river sediments recognised showed responses to climate and sea level changes as illustrated by stratigraphical, morphological and sedimentological features of the strata described. The present study also revealed several insights into proper interpretation of meandering fluvial successions, in which the most important were: specific lithofacies assemblage of GSt (St, Sp) → Sl → SFrc → Fm (SFr) and related architectural elements: channel/sandy bedforms CH/SB → lateral accretion deposits LA → floodplain fines with crevasse splays FF (CS); upward-fining grain size and decreasing content of denser heavy minerals; estimated low-energy flow regime with a mean depth of 1.6–3.3 m, a Froude number of 0.2–0.4 and a sinuosity of 1.5.

Identification of the fluvial-channel tracts based on thickness analysis : Zabrze Beds (Namurian B) in the Main Anticline and Bytom-Dąbrowa Trough of Upper Silesia Coal Basin, Poland

Kędzior A.

Annales Societatis Geologorum Poloniae

2001

Vol. 71, No 1

21-34

The studied area of ca. 500 km2 lies within the Main Anticline and the Bytom-Dąbrowa Trough of the Upper Silesia Coal Basin. During the deposition of the fluvial Zabrze Beds, this area was subject to differential subsidence which resulted in gradual eastward thinning of this unit from ca. 250 m near Zabrze to ca. 4 m near Sosnowiec. Maps of net sandstone and coal contents in two stratigraphical intervals selected within the Zabrze Beds point to the presence of four channel tracts. The main tract is parallel to the NE-SW trending axis of maximum subsidence, and the other three are perpendicular to it. During deposition of the Zabrze Beds the main, NE-SW trending channel tract has shifted westward.