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Coexistence of algae and a graptolite-like problematicum: a case study from the late Silurian of Podolia (Ukraine)

Skompski Stanisław, Kozłowski Wojciech, Łuczyński Piotr, Kozłowska Anna

Acta Geologica Polonica

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2023

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Vol. 73, no. 2

115--133

EN

This contribution presents the record of an abundant assemblage of well-preserved, thallophytic noncalcified algae and of an epibiotic form that has been recognised as a putative graptolite from the upper Silurian (Ludlow, Gorstian–Ludfordian) of Podolia (western part of Ukraine). The sediments represent a shallow peritidal zone of the shelf. A new genus and species, Voronocladus dryganti, belonging to the Dasycladales Pascher, 1931, is established. Most of the specimens representing the algal thallus are overgrown by problematical epibiotic graptolites, described as Podoliagraptus algaeoides gen. et sp. nov. This phenomenon is explained as an epiphytic mode of life of the putative graptolite on algae, and is herein compared to recently known coexistences of algae with other organisms. The excellent state of preservation, and the abundance of studied Dasycladales algae and epibiotic problematics indicate that the investigated mudstone layer can be treated as a ‘Konservat Lagerstätte’ sensu Seilacher (1970).

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Professor Piotr Roniewicz (1936-2019) : in memoriam

Wysocka Anna, Głowniak Ewa, Szulczewski Michał, Rudowski Stanisław, Giżejewski Jerzy, Karnkowski Paweł Henryk, Pinińska Joanna, Pieńkowski Grzegorz, Skompski Stanisław, Słaby Ewa, Kalinowska Anna, Sawicki Gerard

Acta Geologica Polonica

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2020

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Vol. 70, no. 4

435--452

EN

Piotr Roniewicz was born in 1936 in Warsaw, however his family roots were in Stanisławów (nowadays Ivano-Frankivsk, Ukraine). He completed his university studies at the Faculty of Geology of the University of Warsaw in 1959, gaining a Master’s Degree. He began his geological career at this Faculty already as a 4th year student. In 1981-1984 he was the Vice-Dean and later in 1984-1990 - the Dean of the Faculty. Professor Roniewicz worked there until his retirement in 2006.

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The squamation of “Ctenacanthus” costellatus (Chondrichthyes: Ctenacanthiformes) from the Carboniferous of Lublin area, south-eastern Poland

Ginter Michał, Skompski Stanisław

Acta Geologica Polonica

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2019

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Vol. 69, no. 4

571--582

EN

A sample of late Viséan limestone from the Włodawa IG-4 borehole, east of Lublin, Poland, yielded a piece of a tooth and a few hundred well-preserved scales comparable to those of “Ctenacanthus” costellatus Traquair, 1884 from Glencartholm, Scotland, UK. Most of the scales are typical compound body scales of the ctenacanthid type. Their crowns are composed of several separate odontodes whose distal ends are turned backwards and bases are characterised by concave undersides. In the material, there are also sparse scales with similar crowns but with flat or convex bulbous bases, as well as ornamented plates and single, star-like denticles, probably from the head region. The taxonomic status of “Ctenacanthus” costellatus was analysed and a new generic name for that species, viz. Glencartius gen. nov., is proposed.

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Evidence of Late Cretaceous/Cenozoic strike-slip faulting within the late Palaeozoic Holy Cross Mts. Fold Belt, Poland: Józefka releasing stepover

Skompski Stanisław, Konon Andrzej, Wysocka Anna, Czarniecka Urszula

Acta Geologica Polonica

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2019

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Vol. 69, no. 1

89--105

EN

The aim of this study was to reconstruct the location mechanism of a Triassic sandstone wedge within folded Palaeozoic rocks. A vertically oriented Buntsandstein succession (Lower Triassic) from Józefka Quarry (Holy Cross Mountains, central Poland), steeply wedged within folded Devonian carbonates, is recognised as an effect of normal faulting within a releasing stepover. The sandstone succession, corresponding to the Zagnańsk Formation in the local lithostratigraphic scheme, is represented by two complexes, interpreted as deposits of a sand-dominated alluvial plain (older complex), and coarse-grained sands and gravels of a braided river system (younger complex). The sandstone complex was primarily formed as the lowermost part of the several kilometres thick Mesozoic cover of the Holy Cross Mountains Fold Belt (HCFB), later eroded as a result of the Late Cretaceous/Paleogene uplift of the area. Tectonic analysis of the present-day position of the deformed sandstone succession shows that it is fault-bounded by a system of strike-slip and normal faults, which we interpret as a releasing stepover. Accordingly, the formation of the stepover in the central part of the late Palaeozoic HCFB is evidence of a significant role of strike-slip faulting within this tectonic unit during Late Cretaceous/Paleogene times. The faulting was probably triggered by reactivation of the terminal Palaeozoic strike-slip fault pattern along the western border of the Teisseyre–Tornquist Zone.