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Wyszukujesz frazę "Racki, G" wg kryterium: Autor


Wyświetlanie 1-6 z 6
Tytuł:
Influential Polish publications in sedimentary geology 1996-2016
Autorzy:
Racki, G.
Powiązania:
https://bibliotekanauki.pl/articles/2059868.pdf
Data publikacji:
2016
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
sedimentary geology
hot papers
citation analysis
Polish geology
Opis:
The list of thirty highest cited recent Polish publications (after 1995) on diverse themes resulted from study of sedimentary rocks, usually referred as sedimentary geology, is presented. The progressively successful fields include in first order large-scale palaeogeographic and lithofacies analyses in supra-regional geotectonic framework (by Golonka), and also tectonic-regional varieties of basin analysis, developed by several research groups in Cracow, Warsaw and Wrocław, in agreement with one of the leading research front in worldwide geosciences. Ecological and Integrative stratigraphic-event characteristics of sedimentary successions are another well-known Polish specialties, the best exemplified by flysch ichnology (Uchman) and Devonian studies at University of Silesia. On the other hand, sedimentary geochemistry is still in infancy in Poland, despite a big progress in last years (in particular organic topics - Marynowski). The dominance of Cracow geological school is obvious, derived from a long-lasting tradition of mostly Carpathian studies in Jaggielonian University, even if this research is well advanced as well in many other institutions in Poland. For example, a newly emerging Polish specialty in tsunami hazard studies (Szczuciński) is markedly located at Adam Mickiewicz University. Nevertheless, Carpathian and post-Palaeozoic stratigraphic-sedimentological themes were still the most popular, although simultaneously an evolution toward effective cooperation in largely international groups (also outside of Poland, especially in Ukraine) appears to be the most significant tendency in modern Polish geosciences.
Źródło:
Geological Quarterly; 2016, 60, 2; 537--546
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Very large stromatoporoid indicating Early Frasnian reef core (Holy Cross Mts., Poland)
Autorzy:
Racki, G.
Sobstel, M.
Powiązania:
https://bibliotekanauki.pl/articles/2058751.pdf
Data publikacji:
2004
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Stromatoporoidea
Dyminy Reef
Frasnian
Holy Cross Mountains
Polska
Opis:
A large stromatoporoid Actinostroma cf. crassepilatum Lecompte, 1951, at least 8.5 m in diameter and 0.85 m in height, occurs in the Śluchowice quarry in Kielce, Holy Cross Mountains. This sponge occurs in growth position within Early Frasnian (transitans Zone) intraclast-rich reef-rubble deposits. A unique preservation of the reef-builder close to a reef core is implied for the northern flank of the developing Dyminy Reef during its maximum expansion northward into the Kostomłoty intrashelf basin.
Źródło:
Geological Quarterly; 2004, 48, 1; 83--88
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Proliferation of abnormal palynoflora during the end-Devonian biotic crisis
Autorzy:
Filipiak, P.
Racki, G.
Powiązania:
https://bibliotekanauki.pl/articles/2059045.pdf
Data publikacji:
2010
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Devonian-Carboniferous transition
mutation
palynomorphs
tetrads
mass extinction
volcanism
Opis:
The dispersed miospore assemblage of the Retispora lepidophyta-Verrucosisporites nitidus (LN) Zone from the Holy Cross Mountains(Poland) is marked by enrichment (above 4%) in abnormal spore morphotypes during a terrestrial flora turnover close to the Devonian-Carboniferous boundary, recorded just above the Hangenberg Black Shale level. Incomplete and complete tetrads represent mostly Vallatisporites spp., supplemented by Grandispora, Retusotriletes and Apiculiretusispora. Additional peculiar morphotypes, marked byanomalous overall shape and ornamentation, are interpreted as mutated varieties of Vallatisporites based on intermediate morphologicalstages, connecting them with this well known genus. This relatively high aberrant palynomorph frequency is accompanied by volcanicash intercalations, as well as by charcoal debris and polycyclic aromatic biomarkers indicative of forest wildfire. Thus, the anomalousspore morphology could reflect the mutagenic effect of regional acidification due to explosive volcanism. However, palynological literature data from NW France and Canada highlight the possibility of a supra-regional mutated miospore signal near the Devonian-Carboniferous boundary, and there is need for high-resolution studies of the LN Zone to examine this. The end-Permian scenario of abnormalfloral growth in immensely stressed habitats may therefore apply to other potentially volcanically-induced biotic turnovers.
Źródło:
Geological Quarterly; 2010, 54, 1; 1-14
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Anomalous Upper Devonian mercury enrichments : comparison of Inductively Coupled Plasma – Mass Spectrometry (ICP-MS) and Atomic Absorption Spectrometry (AAS) analytical data
Autorzy:
Racki, G.
Rakociński, M.
Marynowski, L.
Powiązania:
https://bibliotekanauki.pl/articles/2060451.pdf
Data publikacji:
2018
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Mercury anomalies
analytical methods
geochemistry
Frasnian-Famennian boundary
Devonian-Carboniferous boundary
volcanism
Opis:
Mercury geochemistry is emerging recently as a hot topic in chemostratigraphical and facies research, owing to the diagnostic character of Hg enrichments as a proxy of volcanic activity (crucial in the context of assumed causal links between volcanic cataclysms and mass extinctions). Thus, as a prerequisite to such far-reaching interpretations, reliable analytical determinations of Hg concentrations are necessary. In conventionally performed analyses in sedimentary geochemistry, Inductively Coupled Plasma – Mass Spectrometry (ICP-MS) is usually applied, as an analytical standard for trace elements, including Hg. However, with a detection limit (DL) of 10 ppb, such measured values have been questioned as a conclusive geochemical indicator of Hg anomalies, and, instead, far more accurate techniques, such as Atomic Absorption Spectrometry (AAS; DL = 0.2 ppb), are requested. As a preliminary test of this view, we present comparative analysis of 91 samples from three sections encompassing the key Frasnian-Famennian and Famennian-Tournaisian boundary intervals in Morocco (Lahmida), Germany (Kahlleite) and Uzbekistan (Novchomok), for which Hg concentrations were determined by both methods in the same samples. Despite some differences, especially at low Hg concentrations, both analytical methods reveal the same 12 extraordinarily enriched samples in excess of 1 ppm (with one exception, the determination error is <20%), as well as similar overall chemostratigraphic patterns characterized by a few prominent Hg spikes, with a top value of 5.8 ppm. The Hg concentrations determined by ICP-MS and AAS are significantly correlated, as high as r = 0.98 (Novchomok), even if the first method reveals a general tendency toward slightly heightened values (by ~15 to 30% for medians). Therefore, ICP-MS results can conclusively be used in mercury chemostratigraphy in order to recognize extraordinary volcanic (or other) signals, at least in the Devonian geological record. False Hg anomalies were not generated by these conventional ICP-MS determinations.
Źródło:
Geological Quarterly; 2018, 62, 3; 487--495
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Geochemical and ecological aspects of lower Frasnian pyrite-ammonoid level at Kostomłoty (Holy Cross Mountains, Poland)
Autorzy:
Racki, G.
Piechota, A.
Bond, D.
Wignall, P. B.
Powiązania:
https://bibliotekanauki.pl/articles/2060630.pdf
Data publikacji:
2004
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Holy Cross Mountains
Frasnian
pyritic fossils
geochemical proxies
anoxia
Timan Event
Opis:
The lower Frasnian (transitans Zone with Ancyrodella priamosica = MN 4 Zone) rhythmic basin succession of marly limestones and shales (upper Szydłówek Beds) at Kostomłoty, western Holy CrossMts., Central Poland, contains a record of the transgressive-hypoxic Timan Event in this drowned part of southern Laurussian shelf. The unique facies consists of organic-rich marly shales and a distinctive pyritic, goniatite level, 1.6mthick. The faunal assemblage is dominated by pyritized shells of diminutivemollusks with cephalopods (including goniatites Epitornoceras and Acanthoclymenia), buchioline bivalves (Glyptohallicardia) and styliolinids. This interval is marked by moderately low Th/U ratios and pyrite framboid size distributions suggestive of dysoxic rather than permanent euxinic conditions. The scarcity of infauna and bioturbation resulted in finely laminated sedimentary fabrics, as well as the low diversity of the presumed pioneer benthos (mostly brachiopods). In the topmost part of the Szydłówek Beds, distinguished by the Styliolina coquina interbedded between limestone-biodetrital layers, the above geochemical proxies and C-isotope positive shift indicate a tendency to somewhat increased bottom oxygen deficiency and higher carbon burial rate linked with a bloom of pelagic biota during high-productivity pulse. The geochemical and community changes are a complex regional record of the initial phase of a major perturbation in the earth-ocean system during a phase of intermittently rising sea level in the early to middle Frasnian, and associated with the highest positive C-isotope ratios of the Devonian.
Źródło:
Geological Quarterly; 2004, 48, 3; 267--282
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparative oxygen and carbon isotopic records of Miocene and recent lacustrine unionid bivalves from Poland
Autorzy:
Błażejowski, B.
Racki, G.
Gieszcz, P.
Małkowski, K.
Kin, A.
Krzywiecka, K.
Powiązania:
https://bibliotekanauki.pl/articles/2060015.pdf
Data publikacji:
2013
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
sclerochronology
stable isotopes
fresh water
Miocene and recent Unionidae
Bełchatów
Gil Wielki Lake.
Opis:
The δ13C and δ18O isotope data from both fossil (Miocene) and modern freshwater bivalve shells of family Unionidae from Poland (species Margaritifera flabellatiformis and Unio tumidus, respectively) show a similar, truncated sinusoidal pattern.. The isotopic profiles of the whole shell are visibly marked by three growth stages, linked with a progressive loss of environmental record because of declining intra-annual biocarbonate accretion rate. The juvenile and gerontic phases exhibit generally more positive and stable (plateau) isotopic pattern than the mid-age stage. An increasing δ13C trend is typical for the final life stage, likely influenced by nutrient overloading, reversing the tendency towards δ13C depletion throughout the individual’s life induced by metabolic processes. Due to the progressive loss of environmental signals through ontogeny, these initial and final isotopic profile segments probably correspond to, respectively, an instant signature of the first season growth, and a multiyear value set of summer maxima during geriatric stage. Vague seasonal cyclic record is the striking feature of the mid-age δ18O and δ13C profile slices. In case of low-amplitude δ18O curve, this is probably promoted by a sensitivity of the lake ecosystem to many dynamic intra-annual factors affecting water budget balance. This consistent signature mode seems to be typical for lake-dwelling unionid shells at least since Miocene from different climatic zones, as confirmed by coeval lacustrine low-latitude mussels from Amazonia. Thus, this isotope record is relevant to obtain information on the habitat and life cycle of the fossil freshwater bivalves, as well as could help understand modern environmental change.
Źródło:
Geological Quarterly; 2013, 57, 1; 113--122
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-6 z 6

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