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Palaeoenvironmental reconstruction of Bathonian (Middle Jurassic) ore-bearing clays at Gnaszyn, Kraków-Silesia Homocline, Poland

Gedl P., Kaim A., Leonowicz P., Boczarowski A., Dudek T., Kędzierski M., Rees J., Smoleń J., Szczepanik P., Sztajner P., Witkowska M., Ziaja J.

Acta Geologica Polonica

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2012

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Vol. 62, no. 3

463-484

EN

Multidisciplinary studies of the Middle-Upper Bathonian ore-bearing clays at Gnaszyn revealed variable palaeoenvironmental conditions during the deposition of this seemingly monotonous sequence. We interpret the conditions in the bottom environment and the photic zone, and also evaluate the influence of the adjacent land areas, based on sedimentology, geochemistry, sporomorphs and palynofacies composition, benthic (foraminifera, gastropods, bivalves, scaphopods, echinoderms), planktonic (calcareous nannoplankton, dinoflagellate cysts), and nektonic (sharks) fossils. The Gnaszyn succession originated relatively close to the shore, within reach of an intense supply of terrestrial fine clastic and organic particles. The latter are mainly of terrestrial origin and range from 1.5 to 2.5 wt.%. The precise water depth is difficult to estimate but most likely ranges from several tens of metres to a few hundred metres. All fossil groups show minor changes throughout the succession. As the climate seems to have been quite stable during this period we consider sea-level fluctuations to have been the main factor responsible for the changes. The terrestrial input, including freshwater and land-derived clastic and organic particles (sporomorphs and cuticles), increased during periods of sea-level lowstand. As a consequence, stress conditions (lower salinity, higher nutrient availability, lower water transparency) in the photic zone caused blooms of opportunistic planktonic taxa. Furthermore, a faster sedimentation rate led to oxygen depletion and deterioration of the living conditions in the bottom environment due to an increased accumulation of organic matter. As a result, the benthic biota became taxonomically impoverished and commonly dominated by juvenile forms. During periods of high sea level, the source areas were shifted away from the basin, resulting in a decrease in the terrestrial influx, increase in the salinity of surface waters, the appearance of more diverse phytoplankton assemblages, a lower sedimentation rate, and an improvement of living conditions at the bottom.

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Palaeoenvironmental interpretation of echinoderm assemblages from Bathonian ore-bearing clays at Gnaszyn (Kraków-Silesia Homocline, Poland)

Boczarowski A.

Acta Geologica Polonica

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2012

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Vol. 62, no. 3

351-366

EN

This paper presents the results of an investigation into the variability of echinoderm assemblages from Bathonian ore-bearing clays from Gnaszyn. Remains of Crinoidea, Asteroidea, Ophiuroidea, Echinoidea, and Holothuroidea have been studied from 38 rock samples. The most common echinoderms represented are the crinoids Balanocrinus berchteni and Chariocrinus andreae and a few species of the holothurian genera Priscopedatus, Calclamna, Staurocaudina, Eocaudina, Achistrum, Theelia and Hemisphaeranthos. The echinoderms from Gnaszyn show various life strategies: benthic or epibenthic forms, sessile sestonophages (Crinoidea), motile macrophages (Asteroidea) and detritivores (Asteroidea, Ophiuroidea, Echinoidea), infaunal and epifaunal detritus feeders, sediment feeders or rake-feeders (Holothuroidea). Their presence suggests well oxygenated and presumably relatively cold bottom marine waters. The parts of the Gnaszyn section around concretion horizons and characterized by the ubiquitous occurrence of the holothurian Theelia and echinoids were deposited during phases of optimal living conditions with sufficient influx of plant detritus and good oxygenation of the sea bottom. These parts commonly host echinoderm associations dominated by crinoid remains, which occasionally are still articulated (or disarticulated but remaining intact) - this points to a quiet environment with normal oxygenation of the bottom waters but anaerobic/dysaerobic conditions in the sediment.

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A preliminary report on dinosaur track assemblages from the Middle Jurassic of the Imilchil area, Morocco

Gierliński G. D., Menducki P., Janiszewska K., Wicik I., Boczarowski A.

Geological Quarterly

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2009

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Vol. 53, No 4

477-482

EN

Dinosaur tracks are reported from three new localities near Imilchil, in the Central High Atlas of Morocco. New dinosaur track assemblages are recognized in Bathonian and Bajocian beds. The Bathonian track assemblage comprises theropod, sauropod and ornithopod footprints. The Bajocian deposits contain a sauropod-thyreophoran track assemblage.

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Chromo-stereoscopy as a tool in micropalaeontological investigations : echinoderms as a case study

Boczarowski A.

Studia Geologica Polonica

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2005

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Vol. 124

21-35

EN

An anaglyph technique, as a variety of chromo-stereoscopy, is presented and adapted for the investigation purpose. This method allows perfect documentation of 3-dimensional objects, including all types of 3D micro/fossils. Anaglyphs are especially recommended for describing type collections and make them available worldwide. The methods of stereogram preparation by means of a scanning electron microscope and adaptation of the technique to micropalaeontology are described. This useful technique is tested on SEM images of complex echinoid structures (organs) called pedicellariae. The obtained stereograms document their anatomy and help identification of the fossil material as well as their comparison to Recent specimens. Numerous echinoid pedicellariae from Bajocian and Bathonian deposits of the ore-bearing clays of the Częstochowa formation have been analysed. Two separate methods of anaglyph image preparation are described (for RGB and grayscale image mode). The samples come from several brickyards located in the area of the Kraków-Często- chowa Upland, Central Poland. Pedicellariae are represented by globiferous and ophicephalous types. It has been proved that Jurassic echinoids already had very well developed defence strategies, which applied pedicellariae, quite often equipped with a venom-bearing system similar to the one in Recent specimens. Large morphological similarity of the investigated Jurassic specimens to the Recent representatives of the Parechinidae family, especially to the genus Paracentrotus Mortensen has been proved. However, no representatives of this type of echinoid have been found in Jurassic sediments so far.

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Pedicellarie ze środkowojurajskich iłów rudonośnych i ich znaczenie w strategii życiowej jeżowców

Boczarowski A.

Volumina Jurassica

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2004

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Vol. 2, no. 1

141-150

EN

Numerous, well-preserved globiferous and ophiocephalous pedicellariae of echinoids have been found in samples from several brickyards of Central Poland: Gnaszyn and Kawodrza (Częstochowa), Blanowice (Zawiercie), Wrzosowa. This is the first study of the uppermost Bajocian and Bathonian pedicellariae from the Ore Bearing Częstochowa Clay Formation. Four new morphotypes are described. Effectiveness of the defensive echinoid strategy is discussed; the structures observed indicate the presence of poison in some but not all spines and pedicellariae of both living and fossil species. All main morphological types of pedicellariae are compared. Morphotype I of globiferous pedicellariae and morphotype III of ophiocephalous pedicellariae are similar to those from the recent family Parechinidae. Jurassic echinoid Pelanechinus has ophiocephalous pedicellariae reminding morphotype II, as described from the Polish Bathonian.

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Rekonstrukcja paleośrodowiska sedymentacji środkowojurajskich iłów rudonośnych Gnaszyna (Częstochowa) - wyniki wstępne

Gedl P., Kaim A., Boczarowski A., Kędzierski M., Smoleń J., Szczepanik P., Witkowska M., Ziaja J.

Volumina Jurassica

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2003

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Vol. 1, no. 1

19-28

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The first record of Aspiduriella (Ophiuroidea) in the Upper Muschelkalk of Poland

Salamon M. A., Boczarowski A.

Geological Quarterly

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2003

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Vol. 47, No 3

307-310

EN

The ophiuroid Aspiduriella sp. is recorded for the first time from the Upper Muschelkalk (Ceratites Beds), at Nietulisko, northern margin of the Holy Cross Mountains, central Poland.