Baltica and the Cadomian orogen in the Ediacaran–Cambrian: a perspective from SE Poland

Abstract

In the supercontinent of Rodinia, Baltica occurred next to Amazonia, then the two drifted away when Rodinia broke up. By the end of the Neoproterozoic, Baltica became an independent continent. At that time, Timanide orogen developed at its modern northeastern margin. In most paleogeographical reconstructions, the opposite (SW, Tornquist) edge faced the Tornquist Ocean and remained just a passive margin till the arrival of the Gondwana-born East Avalonia in the late Ordovician. However, preliminary isotopic studies of detrital zircons from the Tornquist passive margin succession hinted that rock components of Gondwana derivation reached Baltica already in the early Cambrian. In this paper, we examine 18 drill-cores of Ediacaran-Cambrian and Ordovician siliciclastic rocks from the tectonostratigraphic units along the SW-NE transect from Upper Silesia (USB) via Małopolska (MB) and the Holy Cross Mts (HCM) to the East European Platform (EEP), SE Poland, in terms of the provenance data gained from the LA-ICP-MS and SHRIMP analyses of 32 zircon samples. Rocks from all the units revealed abundant Cadomian 0.7-0.55 Ga detrital zircons (15-50% of the total analyzed grains) and other grains that yielded peaks at 0.9-1.2, 1.4-1.6, 1.8-2.2, 2.7-3.0 Ga assignable to Baltica rather than Amazonia. Such age spectra in the USB, HCM and EEP prove the proximity of peripheral (peri-Gondwanan) fragments of the Cadomian orogen to Baltica. These fragments formed the Teissyere-Tornquist Terrane Assemblage (TTA) that obliquely docked and overrode the thinned southwestern edge of Baltica which earlier accumulated Neoproterozoic rift and passive margin deposits. Our data show that in the late Ediacaran-early Cambrian, parts of the Cadomian orogenic belt became accreted to Baltica.

Provenance of lower Palaeozoic metasediments of the East Odenwald (Mid-German-Crystalline Zone, Variscides)—a correlation with the East European Platform (Poland)

“…The provenance analysis of metasediments of the Mid-German-Crystalline Zone displays two different Baltica related source areas. The age spectrum with Ediacaran zircons together (a) with Mesoproterozoic input (1.0-1.6 Ga, Spessart, Kirchner and Albert 2020) and (b) with an age peak at 1.5 Ga (East Odenwald) could be located at the EEP and the Trans-European-Suture-Zone (Poland, Pharaoh 1999;Żelaźniewicz et al 2020), where zircons of a giant intrusive complex (Mazury High, 1.5 Ga) were mixed with Ediacaran (probably from the Volyn volcanoclastic rocks) and Sveconorwegian related zircons.…”

“…12, TTA, purple colour), which received their detritus from the Proterozoic basement of the Baltic craton (Fig. 1) and from the The tectonostratigraphic units of the TTA were probably separated from each other by the NW-trending faults, parallel to the EEP margin, that coincide with the Teisseyre-Tornquist Line (Znosko 1977;Żelaźniewicz et al 2020). Probably, at a similar NW trending fault starts further to the south the separation from the EEP.…”

“…This could be interpreted as recycling of the zircons from Fig. 11 Facies of the lower Palaeozoic sandstone (late Cambrian to Ordovician) of the East European Craton (modified after Jaworowski 1997) and their detrital zircon age spectra (Lorentzen et al 2018;Żelaźniewicz et al 2009 Żelaźniewicz et al 2020Żelaźniewicz et al , Porębski et al 2019: sample Syczyn QU 1) and from Belarus (Paszkowski et al 2019).…”

First Evidence of the Post-Variscan Magmatic Pulse on the Western Edge of East European Craton: U-Pb Geochronology and Geochemistry of the Dolerite in the Lublin Podlasie Basin, Eastern Poland

“…In this part of the EEC the dominant evidence of igneous activity remains, the volcanogenic Sławatycze Formation, in E Poland, being analogous to the Volyn Series, in Ukraine [6,7]. [7,33,45] are also indicated. Polish chrono-and lithostratigraphy after [49,50] Ukrainian and Belarusian lithostratigraphy after [15].…”

“…The Volyn Series passes disconformably up-section into the uppermost Ediacaran siliciclastic complex, represented by riverine-estuarine sediments deposited in a transgressive cycle, divided into the Siemiatycze, Białopole, Łopiennik and Włodawa Formations [48][49][50]. In some of these clastic rock layers (Figure 3), the age of the detrital zircon populations has been identified [45]. The thickness of this complex locally exceeds 600 m. It gradually passes up into the Cambrian marine clastic sequence [51].…”