Results 21 to 30 of about 29,037 (201)
Echinoderm Lagerstätten from high-latitude Gondwana – filling the gap in the Ordovician diversification of the phylum [PDF]
Estonian Journal of Earth Sciences, 2023 The phylum Echinodermata is a major component of marine ecosystems since the first appearance of echinoderms in the Cambrian. Like other metazoan phyla, echinoderms underwent two major evolutionary pulses in early Palaeozoic times: the Cambrian Explosion
Martina Nohejlová +4 more
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Population structure of graptolite assemblages [PDF]
, 1998 Graptolite rhabdosomes display a diverse suite of morphologies. The range of morphotypes present within most moderate to high diversity assemblages from the Ordovician and Silurian is similar, despite the different taxonomic composition of the faunas at ...
Underwood, Charlie J.
core +4 more sources
Oil and gas sources in Shunbei Oilfield, Tarim Basin
Shiyou shiyan dizhi, 2020 The hydrocarbon sources in the Middle and Lower Ordovician in the Shunbei area of the Tarim Basin were studied based on the geochemical characteristics of oil and gas samples.
Rong GU, Lu YUN, Xiuxiang ZHU, Meng ZHU
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Changes in shelf phosphorus burial during the Hirnantian glaciation and its implications [PDF]
Estonian Journal of Earth Sciences, 2023 The Late Ordovician mass extinction occurred during an icehouse interval, accompanied by the glaciation of the supercontinent Gondwana, which was located at the South Pole at that time.
Johann Müller +4 more
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An Ordovician ostracod palaeopsychrosphere? [PDF]
Estonian Journal of Earth Sciences, 2023 Ostracods are tiny bivalved crustaceans with a fossil record extending into rocks of the Lower Ordovician. They occupy almost all aquatic environments today, from the ocean abyssal planes to damp forest leaf litter.
Anna McGairy +6 more
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The Ordovician System: From overlapping unit stratotypes to Global Boundary Stratotype Sections and Points [PDF]
Estonian Journal of Earth Sciences, 2023 For nearly a century the Ordovician System was hidden as Murchison and Sedgwick tussled over the overlapping ground between their Silurian and Cambrian systems.
David A. T. Harper +2 more
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Shiyou shiyan dizhi, 2023 From the eastern to the western part of Shunbei area in the Tarim Basin, the accumulations of marine oil and gas obviously decrease with the exploration risks significantly increasing.
Lixin QI, Yong DING
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Early Tremadocian graptolites from the Arivechi area, Sonora, northern Mexico [PDF]
Estonian Journal of Earth Sciences, 2023 Graptolites from the early Tremadocian Anisograptus matanensis Biozone are identified from east-central Sonora, northwestern Mexico, within a carbonate-shelf succession deposited on the southwestern continental shelf margin of Laurentia.
Dulce Raquel Reyes-Montoya +5 more
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Shiyou shiyan dizhi, 2023 In recent years, some progress has been made in the exploration of Ordovician natural gas in the western Ordos Basin, among which, the Ordovician Kelimoli Formation has the highest degree of natural gas accumulation.
Huimin LI +7 more
doaj +1 more source
The Evae transgression: a major event? [PDF]
Estonian Journal of Earth Sciences, 2023 The most extensive sea-level event of the Early Ordovician is known as the Evae transgression. During the highstand of this event, the conodont index species Oepikodus evae reached its acme and often coincided with the peak in conodont generic diversity.
Gisella M. Della Costa +1 more
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