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First discovery of Mississippian trace fossils in the Świebodzice Unit from the Witoszów region (SW Poland)

Muszer Jolanta

Geological Quarterly

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2020

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Vol. 64, No. 4

838--860

EN

Abundant and moderately diverse trace fossil assemblage have been discovered for the first time in mudstones of the Pogorzała Formation from the Witoszów region, SW Poland. Fifteen ichnospecies including fourteen ichnogenera are described. The ichnofauna is dominated by Dictyodora liebeana and contains numerous Palaeophycus tubularis, rarer Archaeonassa fossulata, Archaeonassa isp., Chondrites cf. intricatus, Curvolithus simplex, Diplopodichnus biformis, Lockeia isp., ?Lophoctenium isp., Nereites isp., Phycosiphon isp., Protovirgularia isp., ?Psammichnites isp., Taenidium isp. and one ichnospecies of fish swimming trails, Undichna cf. britannica. Some other structures (wave ripples influenced by microbial mats and zigzag structures) also occur. The trace fossil assemblages differ in various exposures, but three of them are similar and display the Dictyodora liebeana ichnoassemblage. It is represented mostly by the ethological categories fodinichnia and repichnia, with fewer pascichnia, domichnia and cubichnia. This new data from the Świebodzice Unit sheds light on the palaeontology, age and palaeoenvironment of the Pogorzała Formation. The occurrence of D. liebeana and U. cf. britannica indicates the Mississippian age of most mudstones studied, formerly considered Upper Devonian. The trace fossil assemblage belongs to the non-standard Nereites ichnofacies, without graphoglyptids. The lithological features of mudstones, trace fossil assemblage and poverty of macrofauna, testify to their deposition in a deeper sedimentation zone below storm wave base, most likely in dysaerobic, pro-delta conditions. This study suggests that rocks containing D. liebeana may form a correlative horizon in the Świebodzice Unit.

2

Coal-bearing capacity of the Petřkovice Member (Ostrava Formation, Serpukhovian, Mississippian) of the Upper Silesian Basin (Czech Republic and Poland)

Hýlová L., Jirásek J., Sivek M., Jureczka J.

Geological Quarterly

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2016

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Vol. 60, No. 3

637--649

EN

The Petřkovice Member is the basal unit of the paralic succession of the Ostrava Formation of the Upper Silesian Basin. This member is a valuable source of information about the transition from a marine basin filled with siliciclastic sediments into a paralic basin with the beginning of coal-bearing sedimentation. Models of: (1) the number of coal seams, (2) their total thickness, and (3) the coal content with respect to the total thickness of the succession were created to describe and assess the coal-bearing capacity of the Petřkovice Member. The authors present models for coal seam thicknesses exceeding either 10 or 40 cm. The coal-bearing capacity of the Petřkovice Member is very low. The average share of coal seams thicker than 0.1 m is 3%. The share of coal seams with a thickness that exceeds 0.4 m is only 1.66%. Moreover, in large areas of the basin, in the N and NE parts, the coal-bearing capacity is close to zero, because coal seams of greater thickness were detected only locally there. Based on these models and on other geological data, it is obvious that the onset of coal sedimentation was gradual and limited to particular sites showing the greatest subsidence of the basin floor. In places where minor subsidence took place, there were likely unfavorable conditions for accumulation of organic matter.

3

Morphology and palaeoecology of new, non-marine microconchid tubeworm from Lower Carboniferous (Upper Mississippian) of West Virginia, USA

Zatoń M., Peck R. L.

Annales Societatis Geologorum Poloniae

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2013

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Vol. 83, No. 1

37--50

EN

A new species of a non-marine microconchid (Tentaculita) tubeworm, Microconchus hintonensis, from the Lower Carboniferous (Upper Mississippian, Chesterian) of West Virginia, USA, is described. Non-marine microconchids occur abundantly in the deposits of the Bluefield, lower Hinton, Princeton and Bluestone Formations of the Mauch Chunk Group, where they are either associated with land plant remains and bivalve shells, or are preserved loose in the host sediment. The specimens attached to plant remains and bivalve shells, are poorly preserved, but those occurring loose in the deposits are well-preserved in three dimensions. The interpretation pre sented here, is that the loose specimens of Microconchus hintonensis sp. nov. also originally encrusted plants (land plants, algae) and bivalve shells, but became detached after substrate degradation and dissolution. The association of land plant remains, charophyte gyrogonites, bivalves, ostracodes, conchostracans, and fish teeth and scales, and the concomitant lack of strictly marine fossils indicate that the microconchid-bearing deposits of the lower Hinton, Princeton and Bluestone Formations were deposited in fresh-water environments. Microconchus hintonensis sp. nov. is regarded as a highly fecund, opportunistic species that in large numbers colonized every available substrate in its habitat. Its abundance in the deposits investigated indicates that the species was welladapted to the environments it occupied, even during episodes of higher sedimentation rates and/or competition with other soft-bodied encrusters. During such episodes, microconchids were able to grow vertically by uncoiling and elevating their tubes, in order to escape potential burial and/or overgrowth by other encrusters.

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Vojnovskytesidae – a new family of Mississippian Rugosa (Anthozoa)

Fedorowski J., Kullmann J.

Acta Geologica Polonica

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2013

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Vol. 63, no. 4

657--679

EN

Two new species of the genus Vojnovskytes Fedorowski, 2009, namely V. marcinowskii and V. arcuatus, and a new genus, Vojnimitor, based on the new species V. proiectus, all from Mississippian strata of northern Spain, are described. Vojnovskytes variabilis (Vojnovsky-Krieger, 1934), the type species for the genus from the lowermost Viséan strata of southern Urals, also is discussed and illustrated. Characters displayed by the taxa mentioned permit introduction of a new family Vojnovskytesidae.

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Do partly outdated palaeontological data produce just a noise? An assessment of the Middle Devonian-Mississippian biodiversity dynamics in central Asia on the basis of Soviet-time compilations

Ruban Dmitry A.

Geologos

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2011

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Vol. 17, No. 1

29--47

EN

Interregional tracing of trends and events in the biotic evolution is an important task of modern palaeobiology. In Soviet times (1917-1991), numerous palaeontological data have collected for the territory of Russia and neighbouring U.S.S.R. countries. Later, these data were compiled and published in a series of reference volumes. Although this information cannot be updated in a conventional way, it remains valuable for quantitative analyses, particularly because of its comprehensive and unique character. Assessment of the previously collected data on the stratigraphic distribution of Middle Devonian-Mississippian marine invertebrates in three regions of central Asia (central Kazakhstan, Uzbekistan and Tajikistan) reveals some general patterns of biodiversity dynamics. The total number of genera generally declined during the Givetian-Famennian, whereas a remarkable diversity peak occurred in the Visean. This is consistent with the global pattern and, thus, permits to hypothesize a regional signature of the global trends. Changes in the extinction rate differ, however, between central Asia and the Earth in its entirety, which may be explained particularly by biases in either the regional or the global records. Evidence of the Givetian and Frasnian/Famennian mass extinctions is found in the three regions under study. Results of this tentative study indicate important directions for further research and suggest that central Asia is a highly important domain for studies of mid-Palaeozoic biodiversity dynamics.

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Stratigraphy, palynology and organic geochemistry of the Devonian-Mississippian metasedimentary Albergaria-a-Velha Unit (Porto-Tomar shear zone, W Portugal)

Machado G., Francu E., Vavrdová M., Flores D., Fonseca P. E., Rocha F. T., Pereira L. C. G., Gomes A., Fonseca M., Chaminé H.

Geological Quarterly

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2011

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Vol. 55, No. 2

139-164

EN

The Albergaria-a-Velha Unit is one of several tectonostratigraphic out-of-sequence units of the metamorphic belt associated with the Porto-Tomar shear zone (Ossa-Morena Zone, W Portugal). It is composed of considerably deformed - very low grade - metasediments, namely shales, siltstones and rare fine sandstones. In this work we present new sedimentological and biostratigraphical data that suggest the Albergaria-a-Velha Unit was deposited from the (?)early Frasnian to the Serpukhovian in a distal marine environment, where turbiditic and basinal sedimentation prevailed. Palynofacies analysis and lithological data point to a gradual increase of terrestrial input, suggesting a prograding system. Detrital framework data is indicative of a stable cratonic sediment source area composed of low grade metamorphic rocks. The timing of the onset of the Porto-Tomar shear zone activity and consequently its influence on the sedimentation of this unit is discussed. Organic petrology and geochemistry data indicate that the Albergaria-a-Velha Unit is within the dry gas window in terms of hydrocarbon generation ranges.