Temat: Ediacaran - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Organic microfossil assemblages from the late Ediacaran rocks of the Małopolska Block, southeastern Poland
Autorzy:: Jachowicz-Zdanowska, M.
Powiązania:: https://bibliotekanauki.pl/articles/2059153.pdf
Data publikacji:: 2011
Wydawca:: Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:: southern Poland
Małopolska Block
Ediacaran
acritarchs
Opis:: The results of palynological investigations of the oldest siliciclastic strata recognized in the Małopolska Block, situated in southeastern Poland, within the Trans-European Suture Zone (TESZ), are summarized in this paper. Siliciclastic flysch-type rocks without macrofossils have been encountered in over 1000 boreholes within the Małopolska Block, below Paleozoic, Mesozoic, and Cenozoic deposits of various ages (from Ordovician up Miocene). The lithostratigraphy of the pre-Ordovician basement in the Małopolska Block is not fully known. Thin tuffs or tuffites layers have been found in many sections of these rocks. In some of the boreholes (e.g., Książ Wielki IG 1), a late Ediacaran age has been determined for a tuffite interlayer of the rocks underlying Ordovician strata, by U-Pb dating of zircons recovered from that tuffite, that indicated 549 š3 Ma. This article describes the palynology of samples from twelve selected profiles which contained recognizable organic microfossils, in various states of preservation. The associations recovered are dominated by small spherical forms, without any ornamentation, belonging to the Leiosphaeridia, and by fossil cyanobacteria represented by straight or coiled thread-like fragmentary specimens. Similar organic microfossil associations, with poorly differentiated species and genera, are known from many late Ediacaran occurrences.
Źródło:: Geological Quarterly; 2011, 55, 2; 85-94
1641-7291
Pojawia się w:: Geological Quarterly
Dostawca treści:: Biblioteka Nauki

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Tytuł:: Ediacaran-Paleozoic subsidence history of the Volyn-Podillya-Moldavia Basin (W and SW Ukraine, Moldova, NE Romania)
Autorzy:: Poprawa, P.
Radkovets, N.
Rauball, J.
Powiązania:: https://bibliotekanauki.pl/articles/2060431.pdf
Data publikacji:: 2018
Wydawca:: Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:: Ediacaran-Early Paleozoic
Volyn-Podillya-Moldavia basin
tectonic subsidence
backstripping
Opis:: Tectonic subsidence history was analysed for the Ediacaran-Paleozoic Volyn-Podillya-Moldavia Basin, by performing 1D backstripping for 21 boreholes located in western and SW Ukraine, Moldova and NE Romania. Tectonic subsidence history is coherent across the area studied. Development of the basin commenced with an Ediacaran phase of extension, initiated with the emplacement of rift-related volcanic rocks and associated with rapid syn-rift tectonic subsidence. During this event, tectonic subsidence increased towards the SW, i.e. towards the edge of the East European Craton, where the Ediacaran rift zone was located. At that time, a rift developed along the whole SW margin of the East European Craton from Scandinavia to the Black Sea. Development of this large extensional basin was related to the latest stages of break-up of the Precambrian supercontinent Rodinia/Pannotia and ultimately the formation of the Tornquist Ocean. The latest Ediacaran to Late Ordovician tectonic subsidence pattern was characteristic of the post-rift thermal sag stage of extensional basins. The SW margin of the newly formed Baltica, including the area studied, became a passive continental margin. The late Cambrian uplift and erosion was presumably related to a far-field effect of contractional events or intra-plate stresses. Since the Late Ordovician, a gradual change to a collisional tectonic setting is observed across the SW margin of Baltica. In the study area, this is indicated by a systematic increase in subsidence rate from Wenlock to Early Devonian time, creating subsidence curves with convex shapes typical of foreland basin development. The Silurian to Early Devonian Volyn-Podillya-Moldavia Basin is interpreted here as a flexural foredeep related to a Caledonian collision zone located further to the SW. The prominent diachroneity in the initiation of the foredeep basin development at a scale of the whole SW margin of Baltica is coherent with a model of oblique collision of Avalonia and Baltica. During the Pragian-Emsian, the basin was part of a system of post-collisional Old Red basins, with subsidence driven presumably by lithospheric isostatic imbalance resulting from the Caledonian collision and development of an accretionary wedge. Middle to Late Devonian short-term phases of rapid subsidence in small depocentres might be regarded as an indication of a transtensional tectonic regime.
Źródło:: Geological Quarterly; 2018, 62, 3; 459--486
1641-7291
Pojawia się w:: Geological Quarterly
Dostawca treści:: Biblioteka Nauki

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Tytuł:: Development of Trans-European Suture Zone in Poland: from Ediacaran rifting to Early Palaeozoic accretion
Autorzy:: Nawrocki, J.
Poprawa, P.
Powiązania:: https://bibliotekanauki.pl/articles/2058943.pdf
Data publikacji:: 2006
Wydawca:: Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:: Early Palaeozoic
Trans-European Suture Zone
Ediacaran, terrane
rifting
accretion
Opis:: This contribution summarizes selected results of the “Palaeozoic Accretion of Poland” Project. Emphasis is placed on geochronological, geochemical and palaeomagnetic constraints on the Late Neoproterozoic to Early Palaeozoic development of the Trans-European Suture Zone (TESZ). During the Late Neoproterozoic break-up of Rodinia, a major rift developed in the area of the future TESZ along which Baltica was separated from peri-Gondwana and Laurentia, resulting in opening of the Tornquist Ocean and development of the southwestern Baltica passive margin. This was paralleled by the development of the Cadomian orogenic system along the margin of Gondwana and the eastern and southern margins of Baltica. Some tectonic units involved in the TESZ, such as the Brunovistulian Terrane and the Małopolska Massif characterized by Cadomian basement, were derived fromthe internal and external parts of the Cadomian Orogen, presumably somewhere at the SE or SW corners of Baltica. Determination of areas where these terrains were originally located depends strongly on the Ediacaran plate model that is adopted for Baltica. The Małopolska Massif was reaccreted to Baltica, presumably due to latest Ediacaran strike-slip tectonics, during the late Middle to Late Cambrian, causing at that time an interruption of its passive margin subsidence pattern and minor erosion. During Late Ordovician to Silurian times, the Caledonian collision of Gondwana-derived East Avalonia Terrane with Baltica gave rise to the development of a foredeep basin along the southwestern margin of Baltica. The proximal part of this foredeep corresponds to the Pomeranian region to the Koszalin-Chojnice Zone, and its distal parts to the Baltic Basin, both of which developed on Baltica basement. During Ordovician and Silurian times clastics were shed into the Koszalin-Chojnice Zone and the Baltic Basin from the evolving Caledonian orogenic wedge, consisting of a subduction-related volcanic arc, obducted ophiolites and accretionary prism, as well as crustal units that were detached from basement of Baltica and Avalonia. The Brunovistulian Terrane was accreted to theMałopolskaMassif at the turn from the Silurian to the Devonian. Proximal terranes, such as the Pomerania and Łysogóry units remained after Late Neoproterozoic rifting in a position close to the relatively mobile SW margins of Baltica.
Źródło:: Geological Quarterly; 2006, 50, 1; 59-76
1641-7291
Pojawia się w:: Geological Quarterly
Dostawca treści:: Biblioteka Nauki

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