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Wpływ przerostów piaszczystych w węglu brunatnym na działalność górniczą : przykład ze złoża „Pątnów IV” (okolice Konina) w środkowej Polsce

Dziamara Mariusz, Glacová Veronika, Klęsk Jakub, Marschalko Marian, Wachocki Robert, Widera Marek

Przegląd Geologiczny

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2022

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Vol. 70, nr 5

376--383

EN

Lignite from the “‘Pątnów IV” deposit is mined in the Jóźwin IIB opencast by the Konin Lignite Mine. Within the exploited 1st Mid-Polish lignite seam, there are layers of sand with a thickness of over 5 m. Based on field observations and geological mapping, these sandy interbeddings are interpreted as deposits of two or three crevasse splays of different ages. Due to such a large thickness of sands, only the upper bench of the lignite seam is currently mined in the Jóźwin IIB opencast. On the other hand, the exploitation of the lower and middle lignite benches of this seam is unprofitable at present.

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Ptychoplasma conica isp. nov. - a new bivalve locomotion trace fossil from the Lower Jurassic (Hettangian) alluvial sediments of Sołtyków, Holy Cross Mountains, Poland

Pienkowski G., Uchman A.

Geological Quarterly

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2009

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Vol. 53, No 4

397-406

EN

A new locomotion (repichnion) trace fossil, Ptychoplasma conica isp. nov., which is composed of chains of hypichnial mounds, is described from Hettangian alluvial sediments in Central Poland. Its occurrence is limited to amalgamated crevasse sand stones. The trace fossil is associated with freshwater bivalves belonging probably to Unionidae. This trace fossil reflects rhythmic (?diurnal) movement of the tracemaker in accordance with the direction of flow in the crevasse channel, where the forward movement took place in the shallow part of a sandstone layer and was interrupted by resting episodes in deeper sediment layer along the mud-sand inter ace. Episodic flood events forced bivalves to produce escape structures, moving from deeper (previous) to upper (later) levels of lateral movements. Some vertical burrows with bivalve body fossils preserved at the bottom suggest a taphonomic burial. P. conica ranges from Late Triassic to Hettangian.

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Sedimentological interpretation of crevasse splays formed during the extreme 1997 flood in the upper Vistula river valley (South Poland)

Gębica P., Sokołowski T.

Annales Societatis Geologorum Poloniae

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2001

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Vol. 71, No 1

53-62

EN

The paper describes scours and crevasse splays formed at the breaks in embankments of the upper Vistula river valley during the summer 1997 flood. The scours cut into the floodplain composed of fining upward channel and overbank deposits. Erosional furrows have developed locally around the scours. In their vicinity, a thin layer of channel-ag gravel was locally laid down. Variously shaped crevasse splays were formed: finger-like, deltoidal and tongue-like. Surface relief, vege-tation and buildings controlled their geometry and sedimentary features. The lower parts of the deposits consist of fine and medium sands with horizontal and low-angle stratification. Higher in the sequences medium and coarse sands with pebbles display planar cross-stratification. Mud balls and black oak trunks redeposited from older alluvia are common. The whole succession represents sheet-flow sediments with partly channelized flow. Locally, at the top, coarse sands, pebbles, mud balls and boulders embedded in silty-sandy matrix occur, representing slurry-flow deposits. Also present were sediments composed of alternating sands and mud pebbles. The vanishing flow phase is marked by occasional ripple marks encountered in the top part of the sequence. Around the flow obstacles (plants, buildings) sand shadows were formed, composed of fine and medium sands with horizontal stratification in the lower parts and ripple cross-lamination along with climbing cross-lamination in the upper parts. The top part included medium and coarse sands with planar cross-stratification. Most of the studied sequences showed coarse-upward grading which is not the effect of changes in the energy of flood waters but originates from the supply of all the time coarser material from the successively deepening scours.