scholarly journals The Dawangou auxiliary GSSP (Xinjiang autonomous region, China) of the base of the Upper Ordovician Series: putting global chitinozoan biostratigraphy to the test

2010 ◽  
Vol 29 (2) ◽  
pp. 93-113 ◽  
Author(s):  
Jan Hennissen ◽  
Thijs R. A. Vandenbroucke ◽  
Xu Chen ◽  
Peng Tang ◽  
Jacques Verniers

Abstract. The Dawangou section, an auxiliary Global Stratoype Section and Point (GSSP) for the base of the Upper Ordovician Series, was sampled for chitinozoans. The 32 samples taken from the black shales of the Saergan Formation, spanning the Pterograptus elegans, Didymograptus murchisoni and Nemagraptus gracilis graptolite biozones, yielded 6536 chitinozoan vesicles. In addition to a diverse endemic assemblage, species important for international correlation were recovered, which enables the subdivision of the Saergan Formation into two chitinozoan biozones, one subzone and one provisionally recognized biozone: the Baltoscandian Laufeldochitina striata Biozone and the Laurentian Lagenochitina sp. A (sensu Achab, 1984) (/Belonechitina hirsuta) Biozone, and the Belonechitina tuberculata Subzone are recognized based on the presence of the index species, while the Baltoscandian Laufeldochitina stentor Biozone is provisionally recognized on the presence of Laufeldochitina sp. A aff. striata sensu Grahn et al., 1996 which has a range confined to the latter biozone. One new chitinozoan species is described: Cyathochitina giraffa sp. nov. and two species were assigned to a different genus: Belonechitina tuberculata comb. nov. and Hercochitina seriespinosa comb. nov.

2018 ◽  
Vol 18 (1) ◽  
Author(s):  
Haimei Jia ◽  
Chao Ma ◽  
Mengting Lu ◽  
Jianping Fu ◽  
Lance E. Rodewald ◽  
...  

2021 ◽  
pp. M57-2016-27
Author(s):  
Denis Lavoie ◽  
Nicolas Pinet ◽  
Shunxin Zhang

AbstractThe Foxe Platform and Basin Tectono-Sedimentary Element is an ovoid-shaped, predominantly marine basin located in the Canadian Arctic. The Paleozoic sedimentary succession (Cambrian to Silurian) unconformably overlies the Precambrian basement and reaches a maximum measured thickness of slightly over 500 metres in the only exploration well drilled in this basin. The Lower Paleozoic Foxe Platform and Basin Tectono-Sedimentary Element is surrounded by Precambrian basement and by the Paleozoic Arctic Platform to the north and by the Paleozoic-Mesozoic (?) Hudson Bay Strait Platform and Basin to the south. The Paleozoic succession consists of a Cambrian clastic-dominated interval overlain by Ordovician to lower Silurian predominantly shallow marine carbonate. Other than a single well drilled in the northern part of the basin, no subsurface information is available. Thermally immature Upper Ordovician organic matter rich calcareous black shales have been mapped on the onshore extension of the basin to the southeast. Potential hydrocarbon reservoirs consist of Cambrian porous coarse-grained clastics as well as Upper Ordovician dolostones and reefs.


2012 ◽  
Vol 33 (12) ◽  
pp. 3886-3906 ◽  
Author(s):  
F. Veroustraete ◽  
Q. Li ◽  
W. W. Verstraeten ◽  
X. Chen ◽  
J. Li ◽  
...  

1986 ◽  
Vol 23 (4) ◽  
pp. 504-526 ◽  
Author(s):  
Lewis H. King ◽  
Gordon B. J. Fader ◽  
W. A. M. Jenkins ◽  
Edward L. King

Analyses of seismic reflection profiles supported by lithological and palynological studies of core samples from submarine outcrops indicate that the lower Paleozoic succession of the Avalon Terrane, southeast Newfoundland, is continuous offshore. The succession crops out over an area greater than 30 000 km2 and is approximately 8 km thick. The sequence is dominantly siltstone and is of Late Cambrian to ?Devonian or younger age. It is relatively unmetamorphosed, underlain by Hadrynian acoustic basement, and overlain along its eastern and southern margins by a Mesozoic–Cenozoic succession that is economically important from an oil and gas perspective.Lithofacies studies indicate that in Early Ordovician time restricted shallow-marine conditions probably prevailed over a vast area of the Avalon Terrane. Upper Ordovician and Silurian siltstones show evidence of deposition under more-dynamic and well-oxygenated conditions and probably represent a normal shallow-marine environment. Redbeds of possible Devonian or younger age are interpreted to be of continental origin. Black shales of Ordovician age are potential source rocks for the generation of hydrocarbons.


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