The late Frasnian rhynchonellid genus Pammegetherhynchus (Brachiopoda) in Poland, and its relevance to the Kellwasser Crisis

The rhynchonellid species, Pammegetherhynchus kowalaensis sp. n. occurs in the late Frasnian (Early to Late Palmatolepis rhenana, and possibly early Palmatolepis linguiformis conodont zones) marly-bituminous succession at Kowala (various outcrops) in the Gałęzice Syncline, south of Kielce in the Holy Cross Mountains, Poland. The only other known species of this genus is the type species, Pammegetherhynchus merodae Sartenaer, 1977 ,from the late Frasnian (somewhere in the Early and Late Palmatolepis rhenann Zones) of the French Fagne (dark shales of 'Matagne' aspect), and, probably, of the Eifel ('Biidesheimer Goniatitenschiefer'). P kowalaensls sp. n. occurred in level-bottom pioneer assemblages, thriving in reef downslope, mostly poorĘ-oxygenated habitats of the Kellwasser interval. The species finally disappeared near the Frasnian-Famennian boundary. The genus Pammegetherhynchus seems to be particularly suited to stressed deep-water shelf environments in the European part of the Laurussian shelf, widely distributed in this crisis time

Early Frasnian bioherms in the Holy Cross Mts

The Frasnian bioherms exposed along the southern limb of the Gałęzice syneline in the Holy Cross Mts, Central Poland, occur in the highest part of the stromatoporoid-coral sequence, and their facies equivalent are chiefly the·coral biostromes·of the Upper Sitkówka Beds. In spite of small bathymetric differences between bioherms and biostromes, they contrast in ecology of the contained invertebrates, especially in brachiopod assemblages. The bioherms have developed in the belt on a gentle southern slope of the-early Frasnian shallow-water carbonate bank of the Kielce region in the central part of the Holy Cross Mts

Influence of palaeoweathering on trace metal concentrations and environmental proxies in black shales

The mineralogical and chemical compositions of Lower Carboniferous (Tournaisian) marine black shale from the Kowala quarry, the Holy Cross Mountains, Poland, were investigated. This study focuses on disturbances in palaeoenvironmental proxies caused by palaeoweathering, which progressively changed the major and trace element abundances. Palaeomagnetic investigations reveal that the Devonian – Carboniferous succession was weathered during the Permian-Triassic by the infiltration of oxidizing fluids related to karstification following post-Variscan exhumation. The weathering process led to vermiculitization of chlorite, partial dissolution of calcite and replacement of pyrite by hematite and goethite. Moreover, the concentrations of some trace metals, including Co, Cu, Pb, Mo, Ni, As and U, significantly decreased. Consequently, some elemental abundance ratios that are used as environmental proxies, including U/Th, Ni/Co and V/Cr, were altered. Elements that are bound to iron sulphides (e.g., Mo) appear to be especially prone to mobilization by even a lightly weathered black shale. The documented weathering, including changes in elemental concentrations, can potentially create misinterpretations of the original palaeoenvironmental conditions. In addition, the palaeoweathering of the studied samples appears to have substantially changed the carbon, oxygen, nitrogen and molybdenum stable isotope values. The nitrogen and molybdenum stable isotope ratios, in particular, appear to be most sensitive to the effects of weathering and therefore are good indicators of (palaeo)weathering processes. The major cause of these changes is the decay of organic matter and pyrite. For the organic carbon stable isotopes ratios, the main factor that controlls this process appears to be the preferential degradation of labile organic matter. A combination of the total organic carbon (TOC), total sulphur (TS) content, Mo concentration and stable isotope compositions seems to be the most useful for identify (palaeo)weathering. Our results suggest that reductions in TS and Mo in tandem with diminished Mo stable isotope values in the absence of obvious changes to the TOC content provide the most compelling evidence of (palaeo)weathering

Professor Piotr Roniewicz (1936-2019) In memoriam

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