Results 21 to 30 of about 1,517 (200)
Chitinozoans from the Ordovician-Silurian Boundary Beds in the Eastern Cincinnati Region in Ohio and Kentucky [PDF]
, 1985 Author Institution: Geological Survey of Sweden ; Department of Geology and Mineralogy, The Ohio State UniversityRepresentatives of seven species of chitinozoans, one of which is new (Ancyrochitina belfastensis n.
Bergstrom, Stig M., Grahn, Yngve
core +2 more sources
Chitinozoans from the Telychian (Llandovery, Silurian) Shenxuanyi Member, upper Ningqiang Formation of the northwestern Yangtze Platform, China [PDF]
Swiss Journal of PalaeontologySilurian strata are well-developed in the northwest margin of Yangtze Platform. A total of 117 densely spaced argillaceous samples were taken from the Shenxuanyi Member, upper Ningqiang Formation to the lowermost Chejiaba Formation of the Majia section ...
Yangui Li +10 more
openalex +2 more sources
Boundary between the Porkuni and Juuru regional stages in the Neitla section, Estonia [PDF]
Estonian Journal of Earth Sciences, 2023 Conodonts and chitinozoans were studied from the Neitla section, which exposes the boundary between the Porkuni and Juuru regional stages. This level, although not proved biostratigraphically, has been traditionally considered to correspond to the ...
Peep Männik, Jaak Nõlvak
doaj +1 more source
The detailed Middle to early Late Ordovician faunal succession and δ13Ccarbon chemistry of the Kårehamn drill core, offshore eastern Öland, Sweden: implications for stratigraphy and correlation [PDF]
Estonian Journal of Earth Sciences, 2023 The Middle to lower Upper Ordovician stratigraphy of the KÃ¥rehamn core, drilled ca 7 km offshore to the east of the KÃ¥rehamn village, northeastern Ãland, is presented. The investigated core is one of four drill cores obtained during the preparation of
Svend Stouge +4 more
doaj +1 more source
The role of clay minerals in the preservation of Precambrian organic‐walled microfossils
Geobiology, Volume 21, Issue 6, Page 708-724, November 2023., 2023 Abstract Precambrian organic‐walled microfossils (OWMs) are primarily preserved in mudstones and shales that are low in total organic carbon (TOC). Recent work suggests that high TOC may hinder OWM preservation, perhaps because it interferes with chemical interactions involving certain clay minerals that inhibit the decay of microorganisms.
C. R. Woltz +3 more
wiley +1 more source
Paleoceanography and Paleoclimatology, Volume 38, Issue 2, February 2023., 2023 Abstract New δ34Spy (pyrite) and δ34SCAS (carbonate‐associated sulfate) across the Llandovery‐Wenlock boundary (∼432 Ma) provide evidence for the expansion of reduced marine environments during the Ireviken Biogeochemical Event. This event consists of a major positive carbon isotope excursion, increased biotic turnover, and other major perturbations ...
Brittany M. Stolfus +7 more
wiley +1 more source
AGU Advances, Volume 3, Issue 1, February 2022., 2022 Abstract The Ordovician (Hirnantian; 445 Ma) hosts the second most severe mass extinction in Earth history, coinciding with Gondwanan glaciation and increased geochemical evidence for marine anoxia. It remains unclear whether cooling, expanded oxygen deficiency, or a combination drove the Late Ordovician Mass Extinction (LOME).
Nevin P. Kozik +4 more
wiley +1 more source
Lethaia, Volume 54, Issue 5, Page 610-630, December 2021., 2021 The Mora 001 and Solberga 1 drill cores provide the best available overview on the early Silurian (Llandovery, Rhuddanian to Telychian) graptolite succession available for the Siljan Ring impact structure of central Sweden. The Solberga 1 succession includes a nearly complete graptolite succession from the Pernerograptus revolutus Biozone (late ...
Jörg Maletz
wiley +1 more source
Latest Ordovician age of the Spinachitina fragilis Chitinozoan Biozone in Baltoscandia [PDF]
Estonian Journal of Earth Sciences, 2023 The global Spinachitina fragilis Chitinozoan Biozone has been considered the lowermost Silurian zone in most publications. S. fragilis was first described from the Ohesaare drill core, Estonia, and utilised as a Baltic regional zonal taxon together with ...
Jaak Nõlvak, Yan Liang, Olle Hints
doaj +1 more source
Geofluids, Volume 2021, Issue 1, 2021., 2021 Organic pores play an important role in shale reservoirs. Organic pores occur where shale gas was produced and accumulated. However, there is little scientific understanding of the distribution and connectivity of organic pores. Organic pore types and their structural characteristics were studied using a total organic carbon (TOC), thin section ...
Tao Jiang +6 more
wiley +1 more source