| 1. |
- Krzeminska, Ewa, et al.
(författare)
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Basement correlation across the southernmost Baltic Sea: Geochemical and geochronological evidence from onshore and offshore deep drill cores, northern Poland.
- 2021
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Ingår i: Precambrian Research. - : Elsevier. - 0301-9268 .- 1872-7433. ; 362, s. 1-20
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Tidskriftsartikel (refereegranskat)abstract
- New zircon U-Pb age measurements, whole rock major and trace element geochemistry, and Sr and Nd isotopicanalyses of samples from fourteen deep drill holes that penetrated the hidden Precambrian basement of the southernmost Baltic Sea and the coastal area of northern Poland (Pomerania), make it possible to identify a two episodes of Proterozoic magmatism in that area. The basement consists of late Palaeoproterozoic deformed calc-alkaline, magnesian, I-type to A-type diorites to granites of volcanic arc affinity. U-Pb zircon geochronology documents their magmatic crystallization ages to be between 1791 ± 8 Ma and 1750 ± 5 Ma, with an episode of syn- to late-magmatic deformation recorded in thin overgrowths on zircons at about 1740 Ma. These rocks from Pomerania and its offshore area broadly correlate with the bedrock of Blekinge in southern Sweden, where most of the crust was formed at 1.77–1.75 Ga. They may thus be part of the same geological domain, extending on both sides of the present-day southern Baltic Sea, formed along a late Palaeoproterozoic active continental margin. A subordinate suite of undeformed, significantly younger A-type granites was emplaced at 1477 ± 6 Ma, 1449 ± 7 Ma and 1450 ± 9 Ma. This time interval is concurrent with emplacement of A-type granitoids on the Danish island of Bornholm as well as in Blekinge and other parts of southern Fennoscandia. However, their geochemical and isotopic data highlight a genetic diversity of these granites.
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| 2. |
- Szrek, Piotr, et al.
(författare)
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A glimpse of a fish face : An exceptional fish feeding trace fossil from the Lower Devonian of the Holy Cross Mountains, Poland
- 2016
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Ingår i: Palaeogeography, Palaeoclimatology, Palaeoecology. - : Elsevier BV. - 0031-0182 .- 1872-616X. ; 454, s. 113-124
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Tidskriftsartikel (refereegranskat)abstract
- An exceptionally well-preserved assemblage of numerous invertebrate and vertebrate trace fossils is described from the Lower Devonian of the Holy Cross Mountains, southern Poland. Two trace-bearing horizons occur in the shallow-marine sequence that is exposed in a small outcrop near Ujazd village. One of the trace fossils is preserved as a bilobate, generally elliptical, epichnial pit is described as Osculichnus tarnowskae isp. nov. and interpreted as a unique example of praedichnia. Neoichnologic experiments and observations indicate that the ichnogenus Osculichnus was produced by feeding fish. The fish producing O. tarnowskae probably hunted bivalves, polychaetes and arthropods, which are represented by invertebrate trace fossils in the same horizons. The overall shape and morphological details of O. tarnowskae suggest that it was made by a lungfish broadly similar to Dipnorhynchus. The trace provides the first direct evidence for Devonian lungfish feeding behaviour, as well as the first record of three-dimensional soft-tissue morphology of the snout area of an Emsian representative of this group. The trace fossils from Ujazd provide new insight into the palaeoecology and taphonomy of the Lower Devonian of the Holy Cross Mountains.
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| 3. |
- Szrek, Piotr, et al.
(författare)
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A plant-root system in the Lower Devonian of the Holy Cross Mountains, Poland
- 2015
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Ingår i: Estonian journal of earth sciences. - : Estonian Academy Publishers. - 1736-4728 .- 1736-7557. ; 64:1, s. 95-98
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Tidskriftsartikel (refereegranskat)abstract
- The depositional environment of the Lower Devonian of the Holy Cross Mountains has only been studied and interpreted in part, particularly for the lower portion of the profile. Recent fieldwork findings suggest a considerable change with regard to earlier hypotheses. Apart from the sedimentological observations that indicate marginal marine and very shallow-water conditions, horizons with plant-root traces and layers interpreted as palaeosols showing different stages of pedogenesis have been documented. The presence of palaeosols in some areas of the Holy Cross Mountains is the first direct evidence for the existence of terrestrial conditions during the Lower Devonian in this area. This plant-root system is one of the oldest fossil records ever described globally.
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