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Upper Ordovician conodont biostratigraphy and revised lithostratigraphy and geological map, Akpatok Island, Ungava Bay, Nunavut

Shunxin Zhang
Upper Ordovician conodont biostratigraphy and revised lithostratigraphy and geological map, Akpatok Island, Ungava Bay, Nunavut
Canadian Journal of Earth Sciences = Revue Canadienne des Sciences de la Terre (January 2018) 55 (1): 52-69

Abstract

Stratigraphic units exposed on Akpatok Island, Ungava Bay, Nunavut, were previously recognized as Boas River and Akpatok formations; their biostratigraphic ages and correlations, in particular the stratigraphic position and age of the organic rich "Boas River" Formation, were largely based on limited data. New detailed field observations have recognized three stratigraphic units, namely the Amadjuak, Akpatok, and Foster Bay formations, in which extensive microfossil sampling recovered over 22 000 conodont elements from 66 productive samples from both outcrops and rubble at over 20 localities in four areas. Four Upper Ordovician conodont zones and one unzoned interval are established for the three redefined formations: Belodina confluens and Oulodus velicuspis Interval zones are confined to the exposed Amadjuak Formation and correlated to Edenian and Maysvillian; Amorphognathus ordovicicus - Plegagnathus dartoni Concurrent-range Zone occurs with the Akpatok Formation and correlated to lower Richmondian; Rhipidognathus symmetricus Taxon-range Zone is retained in the Foster Bay Formation and correlated to upper Richmondian; and an "Unzoned Interval" is defined between the last two zones in the lower Foster Bay Formation. The conodont Amorphognathus ordovicicus occurs in both Akpatok and lower Foster Bay formations, and it is also recovered from the bituminous, argillaceous limestone rubble, based on which the stratigraphic position of the previously named "Boas River" Formation is most likely positioned within the lower Foster Bay Formation. The biostratigraphy and lithostratigraphy are combined with geographic information systems (GIS) to establish the thicknesses of the three formations and revise the geologic map of the island.


ISSN: 0008-4077
EISSN: 1480-3313
Coden: CJESAP
Serial Title: Canadian Journal of Earth Sciences = Revue Canadienne des Sciences de la Terre
Serial Volume: 55
Serial Issue: 1
Title: Upper Ordovician conodont biostratigraphy and revised lithostratigraphy and geological map, Akpatok Island, Ungava Bay, Nunavut
Author(s): Zhang, Shunxin
Affiliation: Nunavut Geoscience Office, Iqaluit, NU, Canada
Pages: 52-69
Published: 201801
Text Language: English
Summary Language: French
Publisher: National Research Council of Canada, Ottawa, ON, Canada
References: 33
Accession Number: 2018-036954
Categories: Stratigraphy
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. sect., strat. cols., 3 plates, geol. sketch maps
N60°25'00" - N60°31'60", W68°19'60" - W67°49'60"
Country of Publication: Canada
Secondary Affiliation: GeoRef, Copyright 2018, American Geosciences Institute. Reference includes data from Canadian Science Publishing, NRC Research Press, Ottawa, ON, Canada. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 201809
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