Upper Canadian to Whiterockian (Ordovician) conodont biostratigraphy of the Upper St. George Group, western Newfoundland
The St. George Group of western Newfoundland is a sequence of limestones and dolostones deposited on the North American platform margin of the Lower Ordovician Iapetus Ocean. The upper half of this sequence records a shoaling-upwards megacycle of deposition, which is found in the upper Boat Harbour,...
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| Format: | Thesis |
| Language: | English |
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Memorial University of Newfoundland
1989
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| Online Access: | https://research.library.mun.ca/6716/ https://research.library.mun.ca/6716/1/KathleenAnneStrait.pdf https://research.library.mun.ca/6716/3/KathleenAnneStrait.pdf |
| Summary: | The St. George Group of western Newfoundland is a sequence of limestones and dolostones deposited on the North American platform margin of the Lower Ordovician Iapetus Ocean. The upper half of this sequence records a shoaling-upwards megacycle of deposition, which is found in the upper Boat Harbour, Catoche and Aguathuna formations. -- Much of this megacycle was sampled for conodonts in order to establish a refined biostratigraphy and to shed light upon lithostratigraphic problems within Catoche and Aguathuna formations. Over 130 core samples from the Daniel's Harbour mine and approximately 110 outcrop samples from localities throughout western Newfoundland yielded approximately 5,000 conodonts. -- In total, 72 species from 43 genera are herein described from the upper megacycle of the St. George Group. Striatodontus n. gen. is described, with S. kakivangus n. sp. and S. carlae (Repetski) both found in the St. George Group. Elements probably forming part of a previously unknown apparatus (?New Genus 1) are described, but remain unnamed. New species are Bergstroemognathus alus, Clavohamulus cavus, Diaphorodus gravelsensis, D. stevensi, Leptochirognathus planus, Parapanderodus aequalis and Rossodus symmetricus. In addition, species of Ansella Fåhraeus & Hunter, ?Erismodus Branson & Mehl, Protoprioniodus McTavish, ?Reutterodus Serpagli, and new species of Scalpellodus Dzik, Variabiliconus Landing et al. and the unnamed new (?) genus remain in open nomenclature pending the availability of more abundant material. -- Seven successive informal conodont assemblages are recognised within the faunal succession. These are based upon morphological changes within species of Parapanderodus Stouge and Diaphorodus Kennedy, and concurrent ranges of a number of species. -- Assemblage I correlates with North American trilobite Zone H, which is equivalent to early Midcontinent Province Fauna E of the North American conodont zonation; coeval Baltic Province conodonts are found in the Prioniodus elegans Zone. Assemblage II ... |
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