Science and earth science

Acta Geologica Polonica

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Acta Geologica Polonica | 2025 | No 2

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Abstract

Vinn, O., Isakar, M., El Hedeny, M., Almansour, M.I. and Alfarraj, S. 2025. First record of agglutinated worm tubes from the uppermost Cambrian of Estonia. Acta Geologica Polonica, 75 (2), e41.

A new species of agglutinated tube, Cryptosiphon oboloides sp. nov., is described from the Furongian of Estonia. The agglutinated tubes are composed of pieces of lingulate shells that are placed to form an overall pattern. The studied agglutinated tube strongly resembles cases of modern caddisfly larvae, though we do not suggest any phylogenetic affinity to caddisflies. The tubes originally contained an organic inner lining with a sticky external surface that enabled worms to glue on shell fragments and sand grains. The relatively well-arranged grains in the tube wall suggest that the animal actively assisted in gluing the shell fragments, orienting, and finding the right place for them. It is possible that worms capable of building agglutinated tubes from shell material originated in Baltica and later dispersed to the Armorican Terrane Assemblage and other regions in the Early to Middle Ordovician.
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Authors and Affiliations

Olev Vinn
1
Mare Isakar
2
Magdy El Hedeny
3
Mansour I. Almansour
4
Saleh Alfarraj
4

  1. Department of Geology, University of Tartu, Ravila 14A, 50411 Tartu, Estonia
  2. Natural History Museum, University of Tartu, Vanemuise 46, Tartu, Estonia
  3. Geology Department, Faculty of Science, Alexandria University, Egypt
  4. College of Science, King Saud University, Riyadh, Kingdom of Saudi Arabia
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Abstract

Celestine is a rather common mineral in epigenetic native sulphur deposits and seems to be a very valuable
indicator of some of the geological processes forming these deposits. This paper presents the results of investigation
of fluid inclusions in celestine from the Tarnobrzeg native sulphur deposits (SE Poland). Several different
morphological types of celestine were selected from Machów open-pit mine. Study of the fluid inclusions has
been carried out using microscopic and microthermometic methods. The data show that two types of chloride
fluids were responsible for the formation of celestine and native sulphur and further transformation of the native
sulphur deposits. The first type of fluid, containing a relatively higher salt content and lower NaCl/CaCl2 ratio,
also points to the role of hydrocarbons during the formation of native sulphur deposits. The second type of fluid
contains a relatively lower amount of salt and a higher NaCl/CaCl2 proportion and reflects the subsequent evolution
of the chemistry of the fluids forming the deposits. The results of the study of fluid inclusions in celestine
are in good agreement with its stable isotope composition.

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Authors and Affiliations

Jan Parafiniuk
1
Arkadiusz Gąsiński
2
Andrzej Kozłowski
1

  1. Department of Geology, University of Warsaw, Żwirki i Wigury 93, 02-089 Warsaw, Poland
  2. Institute of Ceramics and Building Materials, Postępu 9, 02-676 Warsaw, Poland
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Abstract

In this study, seven core carbonate samples were collected from the marine Upper Cretaceous (Turonian– Coniacian) limestone in two wells in the East Baghdad Oilfield of the Mesopotamian Basin. The Turonian– Coniacian period is regarded as the archetypal warm interval as well as a pivotal epoch in biological evolution. The carbonate strata of the Khasib Formation in the East Baghdad Oilfield of the Mesopotamian Basin were chosen as a model. The paleoenvironment was reconstructed using petrological characteristics and concentrations of major, trace, and rare earth elements (REEs), as well as carbon, oxygen, and strontium isotopic studies. The data suggest that the paleotemperature of the seawater was 28ºC, that suboxic-anoxic paleoredox conditions were present, that the paleosalinity of the seawater was minimal, and a biological explosion occurred when the temperature dropped to a point where life could survive. Dolomite dissolution, influenced by early meteoric water, established the groundwork for high-quality reservoirs, and leftover dolomite also protected natural oil. This research adds to the paleoenvironmental record and offers a theoretical foundation for future natural oil exploitation.
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Authors and Affiliations

Rana Abbas Ali
1

  1. Department of Geology, College of Science, University of Baghdad, Iraq
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Abstract

A wide stratigraphic gap spanning the middle Miaolingian to early Tremadocian in the succession of the northern Małopolska Block, exposed in the southern Kielce Region of the Holy Cross Mountains in south-central Poland, was hitherto indicated as the key argument for its different tectonic evolution compared to the adjacent northern Łysogóry Block. As these two blocks form part of the Trans-European Suture Zone, deciphering their early Palaeozoic history has profound impact on our understanding of the evolution of this major Central European tectonic domain. Based on data from the Lenarczyce PIG 1 well (Kielce Region), we analyse here the stratigraphy and sedimentary record of the upper Cambrian in the Holy Cross Mountains. Rich acritarch assemblages coupled with rare macrofossil specimens from this well indicate the presence of a Miaolingian and Furongian succession showing different tectonic styles and separated by a stratigraphic gap. The stratigraphic gap separating these successions spans the middle to late Miaolingian and the early to middle Furongian, and it has proved to be much narrower than previously considered. The upper Furongian siliciclastic succession recognised here can be defined as a shallow-water flood-dominated delta system, developed after the tectonic event responsible for the intense deformation of the lower and middle Cambrian strata. In the latest Furongian, this sedimentary system passed rapidly upwards into an offshore mud belt produced by a relative sea-level rise (transgressive event). The unconformity at the Cambrian–Ordovician boundary in the southern Holy Cross Mountains is shown to be of a complex nature resulting from pre-Furongian folding and thrusting, and post-Furongian changes of relative sea-level/accommodation space.
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Authors and Affiliations

Wiesław Trela
1
Zbigniew Szczepanik
1
Anna Żylińska
2

  1. Polish Geological Institute – National Research Institute, Holy Cross Branch, Zgoda 21, 25-378 Kielce,Poland
  2. University of Warsaw, Faculty of Geology, Żwirki i Wigury 93, 02-089 Warszawa, Poland

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