Results 1 to 10 of about 275 (175)
Different controls on the Hg spikes linked the two pulses of the Late Ordovician mass extinction in South China [PDF]
Scientific Reports, 2022 The Late Ordovician mass extinction (LOME, ca. 445 Ma; Hirnantian stage) is the second most severe biological crisis of the entire Phanerozoic. The LOME has been subdivided into two pulses (intervals), at the beginning and the ending of the Hirnantian ...
Zhen Qiu +5 more
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The late Katian Elkhorn event: precursor to the Late Ordovician mass extinction [PDF]
Estonian Journal of Earth Sciences, 2023 The late Katian Elkhorn event is a biogeochemical perturbation preceding the Late Ordovician mass extinction (LOME) with an exceptional record in the United States (U.S.).
Patrick I. McLaughlin +8 more
doaj +2 more sources
Chitinozoan biozonation in the upper Katian and Hirnantian of the Welsh Basin, UK
Review of Palaeobotany and Palynology, 2014 AbstractHere we present a chitinozoan biostratigraphical framework for the South Wales upper Katian and Hirnantian (Ashgill) succession. The current study indicates that three of the six Avalonian Ashgill chitinozoan biozones are recognised in the Welsh Basin; the bergstroemi, fossensis and umbilicata biozones.
Thijs R A Vandenbroucke
exaly +2 more sources
Petroleum Exploration and Development, 2021 Based on the lithologies, sedimentary structures, graptolite zones, inorganic geochemical characteristics, electrical data of 110 shale gas wells in southern Sichuan Basin and the mineral quantitative analysis technology of scanning electron microscope ...
Yiqing Zhu, Chao Luo, Yuran Yang
exaly +3 more sources
New Early Katian species of Leptestiidae and Hesperorthidae (Brachiopoda) from Lithuania [PDF]
Estonian Journal of Earth Sciences, 2016 A new leptestiid brachiopod species of the genus Sampo and a hesperorthid species of the genus Dolerorthis are described from the Early Katian Oandu Stage of southern Lithuania.
Juozas Paškevičius, Linda Hints
doaj +3 more sources
AGU Advances, 2022 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.
Nevin P. Kozik +4 more
doaj +2 more sources
Pathways and mechanisms of Late Ordovician (Katian) faunal migrations of Laurentia and Baltica [PDF]
Estonian Journal of Earth Sciences, 2015 Late Ordovician strata within the Cincinnati Basin record a mass faunal migration event during the C4 and C5 depositional sequences. The geographic source region for the invaders and the paleoceanographic conditions that facilitated dispersal into the ...
Adriane R. Lam, Alycia L. Stigall
doaj +2 more sources
Conodont biostratigraphy of the Oandu Stage (Katian, Upper Ordovician) in NE Estonia [PDF]
Estonian Journal of Earth Sciences, 2017 Conodonts from the type region of the Oandu Regional Stage (Katian, Upper Ordovician) in NE Estonia were studied. Here, the lower boundary of the stage corresponds to a discontinuity surface at the base of the Hirmuse Formation and, in conodont ...
Peep Männik
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Three-dimensionally preserved siphuncle in an actinoceratid cephalopod from the late Katian of Bohemia [PDF]
Estonian Journal of Earth Sciences, 2023 The Ordovician to Carboniferous cephalopods of the order Actinoceratida (Teichert, 1933) are distinguished from all other cephalopods by their large siphuncles, which typically contain heavy, calcareous deposits enclosing a complex system of canals ...
Martina Aubrechtová, Vojtěch Turek
doaj +2 more sources
Upper Sandbian–lower Katian bio- and chemostratigraphy in the Pajevonys-13 core section, Lithuania [PDF]
Estonian Journal of Earth Sciences, 2016 The succession of five formations (Auleliai, Vilučiai, Alvitas, Šakiai, Jakšiai) corresponding to the upper Sandbian and lower Katian in southern Lithuania is dated based on new bio- and chemostratigraphical data from the Pajevonys-13 core section.
Linda Hints +4 more
doaj +3 more sources