Nauki Ścisłe i Nauki o Ziemi

Acta Geologica Polonica

Zawartość

Acta Geologica Polonica | 2022 | vol. 72 | No 3

Abstrakt

A detailed analysis of the upper Viséan, Serpukhovian and Bashkirian Rugosa of the Donets Basin confirms their Mississippian/Pennsylvanian turnover during the Eumorphoceras / Homalophyllites–Hudsonoceras Zone, as postulated earlier (Fedorowski 1981a). The deterioration of rugose corals, globally diverse in time and space in the late Viséan and Serpukhovian, has resulted in the patchy distribution of survivors and newcomers, present in the Bashkirian. Difficulties in inter-basinal communication and the isolation of some sites have resulted in a different content of Bashkirian Rugosa in particular patches, with only rare genera in common. New data has made it possible to document the appearance of the first late Carboniferous genera in the Donets Basin as early as the lower Voznessenkian Horizon (= lower Chokierian Substage), i.e., close to the beginning of the Bashkirian Stage. The two stages of diversification, established in the Bashkirian rugose corals of the Donets Basin, cannot find their counterparts elsewhere. A palaeogeographic overview of the most important sites of diversified rugose corals documents the need to re-examine many taxa, which should be based on complete specimen studies. This and the precise placement of taxa in the modern stratigraphy must be done in order to make rugose corals globally comparable. Simple repetitions of names, commonly used in general summaries, is strongly misleading in both stratigraphic and palaeogeographic reconstructions.
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Autorzy i Afiliacje

Jerzy Fedorowski
1

  1. Institute of Geology, Adam Mickiewicz University, Bogumiła Krygowskiego 12, 61-680 Poznań, Poland

Abstrakt

The first recognition of a tracemaker responding to a temporary shift in the redox boundary is recognized. This is recorded by a new trace fossil, Sursumichnus orbicularis igen. et isp. nov., which is established for mound-like structures on the upper surfaces of sandstone beds from the Borjomi Flysch (upper Paleocene–lower Eocene) in the Lesser Caucasus (Georgia). It is connected with the spatangoid echinoid burrow Scolicia de Quatrefages, 1849 and interpreted as a resting trace of the same tracemaker produced after moving up from a deeper position within the sediment. The resting is caused by an episode of unfavourable conditions related to shallowing of the redox boundary. The trace fossil is a component of the Nereites ichnofacies.
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Autorzy i Afiliacje

Alfred Uchman
1
Zurab Lebanidze
2
Nino Kobakhidze
3
Tamar Beridze
3
Davit Makadze
4
Koba Lobzhanidze
3
Sophio Khutsishvili
3
Rusudan Chagelishvili
5
Kakha Koiava
2
Nino Khundadze
4

  1. Faculty of Geography and Geology, Institute of Geological Sciences, Jagiellonian University, Gronostajowa3a, 30-387 Kraków, Poland
  2. Department of Geology, Faculty of Exact and Natural Sciences, Iv. Javakhishvili Tbilisi State University, University str. 13, 0186 Tbilisi, Georgia
  3. Alexander Janelidze Institute of Geology, Iv. Javakhishvili Tbilisi State University, Politkovskaia 31, 0186 Tbilisi, Georgia
  4. Alexander Tvalchrelidze Caucasian Institute of Mineral Resources, Tbilisi State University, 12 Mindeli str., 0186 Tbilisi, Georgia
  5. Department of Geology and Paleontology, Georgian National Museum, 3 Purtseladze str., 0105 Tbilisi, Georgia

Abstrakt

Biostratigraphic analysis of calcareous nannofossils from the Pełczyska section in the Miechów Trough (southern Poland) has revealed that the entire section covers the lowermost Maastrichtian. The UC16bTP Tethyan subzone is designated based on the presence of Broinsonia parca constricta Hattner, Wind and Wise, 1980, reworked remains of Uniplanarius trifidus (Stradner) Hattner and Wise in Wind and Wise, 1983 and the simultaneous lack of Eiffellithus eximius (Stover) Perch-Nielsen, 1968. The studied section spans also the interval between the LO of Zeugrhabdotus praesigmoides Burnett, 1997 and the FO of Prediscosphaera mgayae Lees, 2007 (UC16 S3 Boreal subzone). Quantitative analysis of nannofossil assemblages has shown the dominance of cold water species (up to 50%), e.g., Micula decussata Vekshina, 1959, Prediscosphaera spp., Arkhangelskiella spp., Calculites obscurus (Deflandre) Prins and Sissingh in Sissingh, 1977 and Lucianorhabdus cayeuxii Deflandre, 1959. In the early Maastrichtian, the studied area was more influenced by cool water masses from the Boreal Province rather than by warm water from the Tethyan Province. The significant predominance of cold water taxa and the elevated presence of Prediscosphaera cretacea (Arkhangelsky) Gartner, 1968 also supports the hypothesis of climate cooling in the early Maastrichtian.
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Autorzy i Afiliacje

Urszula Ciołko
1
Elżbieta Gaździcka
2

  1. Institute of Geological Sciences, Polish Academy of Sciences, Twarda 51/55, 00-818 Warszawa, Poland
  2. Faculty of Geology, University of Warsaw, Żwirki i Wigury 93, 02-089 Warszawa, Poland

Abstrakt

In this paper cation arrangement in two samples of aluminoceladonite, emerald‑green and dark-green were studied by Mössbauer, Raman and X-ray photoelectron spectroscopies. The X-ray photoelectron spectroscopy (XPS) spectra obtained in the region of the Si2p, Al2p, Fe2p, K2p, and O1s core levels provided information, for the first time highlighting a route to identify the position of Si, Al, K, and Fe cations in a structure of layered silicates. The XPS analysis showed the presence of Al in tetrahedral and octahedral coordination while the K2p line indicated the possibility of K+ substitution by other cations in interlayer sites. Mössbauer spectroscopy provided information about crystal chemistry with respect to the local electronic and geometric environment around the Fe atom and to distortions of the polyhedra. It turned out that iron was located mostly in the cis-octahedra position wherein about 75% of iron appeared in the form of Fe 3+. The most preferred cation combinations around Fe corresponded to 3Fe 3+ ions and MgFe 2+Fe 3+/2MgFe 3+. Raman spectroscopy illustrated aluminium substitution in silicon and iron positions wherein the concentration of the aluminium determined the degree of structural distortion within the layered system. These isomorphic substitutions implied a typical band arrangement in the hydroxyl region, which has not been observed in celadonites so far.
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Autorzy i Afiliacje

Mariola Kądziołka-Gaweł
1
Mateusz Dulski
2
Maria Czaja
3
Tomasz Krzykawski
3
Magdalena Szubka
1

  1. Institute of Physics, University of Silesia, 75 Pułku Piechoty 1, 41-500 Chorzów, Poland
  2. Institute of Material Science, University of Silesia, 75 Pułku Piechoty 1a, 41-500 Chorzów, Poland
  3. Faculty of Earth Sciences, University of Silesia, Będzińska 60, 41-200 Sosnowiec, Poland

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