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Taxonomy and biostratigraphy of Middle Ordovician (Llanvirn) graptolites from the Table Cove and Black Cove formations, western Newfoundland

Posted on:1998-08-23Degree:M.ScType:Thesis
University:Memorial University of Newfoundland (Canada)Candidate:Taylor, Rod StephenFull Text:PDF
GTID:2460390014478386Subject:Geology
Abstract/Summary:
This thesis provides the first full taxonomic treatment of graptolites from the Middle Ordovician (Llanvirn) Table Head and Goose Tickle groups of western Newfoundland. These rocks represent the upper portion of an autochthonous sedimentary and volcanic sequence that was deposited in a shallow water, near-shore environment during the rifting and passive drifting of the continental margin. Seventeen taxa from these strata are discussed in detail, based almost exclusively on flattened material, including Glossograptus sp. nov. Specimen preservation is best in the Port au Port region, quality decreasing to the east and the north.;There is good correlation between graptolite assemblages at the various exposures of the Table Cove and Black Cove formations, but there appears to be insufficient vertical change through the sequences to permit faunal subdivision of this interval (equivalent to the Australian Darriwilian 3).;The graptolite assemblages found in these rocks suggest a low latitude, warm water setting (Pacific Province) at the time of formation. However, the increased number of pandemic species compared to neighbouring Early Ordovician (Arenig) sequences in western Newfoundland suggests that provincialism was becoming less pronounced at this time.
Keywords/Search Tags:Ordovician, Table, Western, Cove
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