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Wyświetlanie 1-2 z 2
Tytuł:
Basement structure of the Paleozoic Platform in Poland
Autorzy:
Narkiewicz, M.
Petecki, Z.
Powiązania:
https://bibliotekanauki.pl/articles/2060386.pdf
Data publikacji:
2017
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
potential fields
seismics
basement units
Paleozoic Platform
Polska
Caledonides
Opis:
The Paleozoic Platform comprises the southwestern half of the Polish territory, separated from the Precambrian East European Platform (EEP) by a NW–SE trending subvertical lithospheric-scale discontinuity – the Teisseyre-Tornquist Zone. In the present study, the Paleozoic Platform basement is subdivided based on geological and geophysical evidence acquired during the last decades, including deep seismic refraction and reflection results, as well as gravity, magnetic and magnetotelluric data. The units adjacent to the EEP, the Mid-Polish Domain (comprising the Łysogóry Block) and the Pomeranian Block, are characterized by a thinned three-layer EEP-type crystalline crust (age 1.7–3.7 Gy). Their oldest platform cover is probably composed of thick Ediacaran syn-rift sedimentary and volcanic rocks. Their western extension in the contiguous German and Baltic area can be traced as far as the East Elbian Massif and Thor Suture based mainly on magnetic anomaly patterns. The Upper Silesian and Małopolska blocks located in SE Poland are characterized by Cadomian (660–600 My) basement overlain by the thick deformed Ediacaran foredeep deposits. Whereas the units with the EEP-type basement are interpreted as proximal terranes displaced along the EEP margin during the late Early Paleozoic, the blocks with a Cadomian basement are conceived as exotic terranes of a possible Gondwanan provenance. All these terranes were accreted ultimately during the final, latest Silurian stages of the Caledonian deformation although the exact scenario of the amalgamation remains hypothetical. The Sudetic Domain in SW Poland is a collage of different crustal units juxtaposed ultimately in the Pennsylvanian (ca. 310 Ma) during the final episodes of the Variscan Orogeny. Their northern boundary corresponds to the Rheic Suture traceable in magnetic and gravity anomalies pattern along the northern margin of the Wolsztyn–Leszno High, and continuing westwards along the Mid-German Crystalline High. The arcuate trace of the suture in the NE is dextrally displaced along the Odra Fault, and continues southwards where it is mapped as the Moravian–Silesian Suture.
Źródło:
Geological Quarterly; 2017, 61, 2; 502--520
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Strefa Teisseyre’a-Tornquista : dawne koncepcje a nowe dane
Teisseyre-Tornquist Zone : evolving approaches and new data
Autorzy:
Narkiewicz, Marek
Petecki, Zdzisław
Powiązania:
https://bibliotekanauki.pl/articles/2075897.pdf
Data publikacji:
2019
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Strefa Tornquist-Teisseyre
pola potencjalne
sondowanie sejsmiczne
modelowanie grawitacyjne
skorupa kratoniczna
platforma paleozoiczna
Teisseyre-Tornquist Zone
potential fields
deep seismic sounding
gravity modelling
cratonic crust
Paleozoic Platform
Opis:
Concepts prevailing among the Polish geoscientists during the last decades assumed that the Teisseyre-Tornquist Zone is a major tectonic discontinuity separating the pre-Ediacaran East European Craton (EEC) crust from the Paleozoic Platform composed of terranes accreted during the Caledonian and Variscan orogenic processes. The recent interpretations of the TTZ by Mazur and collaborators, basedon gravity modelling and new PolandSPAN seismic reflection data, revive earlier ideas of the EEC crust extending to the western Poland and NE Germany. These authors propose that the TTZ is in fact a Sveconorwegian (ca. 1 Ga old) collisional suture marked by a crustal keel expressed as the Pomeranian and Kuiavian gravity lows in northern and central Poland. However, the present review of seismic data available, as well as a closer evaluation of the modelling results, do not confirm the keel/suture concept. On the other hand, the idea of the TTZ as an Early Paleozoic tectonic discontinuity is supported by several lines of evidence, including a strong regional magnetic gradient and a contrast in the crustal structure. The latter is revealed by seismic velocity distribution from the refraction data, in the results of magnetotelluric profiling and in recent seismicity patterns. The interpretation of the PolandSPAN data attempting to prove the continuity of the cratonic crust and its Ediacaran-Lower Paleozoic cover across the TTZ appears questionable. At the same time the POLCRUST-01 deep seismic profile in SE Poland documents that the zone is associated with the subvertical Tomaszów Fault. The basement top displacement by ca. 0,5 km and associated change in its slope are related to the fault whose deep crustal roots are further documented by reflectivity patterns in the lower crust. The recent modelling exercise by Krzywiec and collaborators aimed at questioning the thick-skinned nature of this fault does not present compelling results, being based on a poorly constrained geological model. The general conclusion from the present review is that the recently published data either support or at least do not contradict the concept of the TTZ as a tectonic zone separating the continuous EEC crust from several allochtonous blocks - mostly proximal Early Paleozoic terranes to the south-west. Thelithospheric memory of the TTZ echoed in successive stages of its reactivation in different intra-plate tectonic regimes - transpressive Variscan, mostly extensional or transtensional Permian through Early Cretaceous, compressional Late Cretaceous and finally Neogene, related to the Carpathian orogenic compression.
Źródło:
Przegląd Geologiczny; 2019, 67, 10; 837--848
0033-2151
Pojawia się w:
Przegląd Geologiczny
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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