Origin of a glacially influenced shallow marine chromite placer, Port au Port Bay, western Newfoundland, Canada
Detrital chromite is currently accumulating in the wave-influenced gravel-dominated shoreface of eastern Port au Port Bay of western Newfoundland adjacent to the mouth of Fox Island River. Chromium (Cr) concentrations of up to 7485 ppm occur in modern cross-bedded shallow marine gravel and pebbly sa...
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crcansciencepubl:10.1139/cjes-2023-0095 2024-05-19T07:41:57+00:00 Origin of a glacially influenced shallow marine chromite placer, Port au Port Bay, western Newfoundland, Canada Duyan, Mehmet Eyles, Nick Natural Sciences and Engineering Research Council of Canada Milli Eğitim Bakanliği 2024 http://dx.doi.org/10.1139/cjes-2023-0095 https://cdnsciencepub.com/doi/full-xml/10.1139/cjes-2023-0095 https://cdnsciencepub.com/doi/pdf/10.1139/cjes-2023-0095 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Earth Sciences volume 61, issue 5, page 620-639 ISSN 0008-4077 1480-3313 journal-article 2024 crcansciencepubl https://doi.org/10.1139/cjes-2023-0095 2024-05-02T06:51:24Z Detrital chromite is currently accumulating in the wave-influenced gravel-dominated shoreface of eastern Port au Port Bay of western Newfoundland adjacent to the mouth of Fox Island River. Chromium (Cr) concentrations of up to 7485 ppm occur in modern cross-bedded shallow marine gravel and pebbly sand facies sourced from rapidly eroding coastal cliffs cut in a lateglacial and early postglacial fan delta and raised beach facies. These sediments fill a broad coastal embayment and were deposited by a glacially influenced Fox Island River during a phase of low relative sea level following final deglaciation of the Newfoundland Ice Cap between approximately 13 700 years B.P. (ybp) and 9500 ybp. Since then, coastal outcrops of these raised sediments have undergone rapid erosion in response to ongoing postglacial sea level rise outpacing the rate of crustal recovery. Geochemical analysis of 1149 sediment samples across the entire Fox Island River watershed identifies relatively low Cr concentrations (maximum 1860 ppm) in glacial and fluvial sediments, including those areas adjacent to chromite-bearing rocks of the Bay of Islands Ophiolite Complex. Conversely, uplifted lateglacial shallow marine gravels and associated raised beach/nearshore deposits along the coast show elevated Cr concentrations up to 5400 ppm, highlighting the importance of marine concentration of glacially derived sediment during deglaciation. At the present day, chromite-bearing lateglacial sediment is being reworked and transported southwards by shore-parallel littoral currents resulting in reconcentration of Cr within a nearshore placer about 8 km long and 2 km wide, though the deposit may be more extensive offshore where it is likely covered by transgressive marine muds. The glacial and postglacial history of the Port au Port Bay area was widely replicated in other areas of ultrabasic rock along the western coast of Newfoundland and the results of this investigation may aid the search for other nearshore glacially influenced marine placers. Article in Journal/Newspaper Ice cap Newfoundland Canadian Science Publishing Canadian Journal of Earth Sciences |
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Open Polar |
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Canadian Science Publishing |
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crcansciencepubl |
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English |
description |
Detrital chromite is currently accumulating in the wave-influenced gravel-dominated shoreface of eastern Port au Port Bay of western Newfoundland adjacent to the mouth of Fox Island River. Chromium (Cr) concentrations of up to 7485 ppm occur in modern cross-bedded shallow marine gravel and pebbly sand facies sourced from rapidly eroding coastal cliffs cut in a lateglacial and early postglacial fan delta and raised beach facies. These sediments fill a broad coastal embayment and were deposited by a glacially influenced Fox Island River during a phase of low relative sea level following final deglaciation of the Newfoundland Ice Cap between approximately 13 700 years B.P. (ybp) and 9500 ybp. Since then, coastal outcrops of these raised sediments have undergone rapid erosion in response to ongoing postglacial sea level rise outpacing the rate of crustal recovery. Geochemical analysis of 1149 sediment samples across the entire Fox Island River watershed identifies relatively low Cr concentrations (maximum 1860 ppm) in glacial and fluvial sediments, including those areas adjacent to chromite-bearing rocks of the Bay of Islands Ophiolite Complex. Conversely, uplifted lateglacial shallow marine gravels and associated raised beach/nearshore deposits along the coast show elevated Cr concentrations up to 5400 ppm, highlighting the importance of marine concentration of glacially derived sediment during deglaciation. At the present day, chromite-bearing lateglacial sediment is being reworked and transported southwards by shore-parallel littoral currents resulting in reconcentration of Cr within a nearshore placer about 8 km long and 2 km wide, though the deposit may be more extensive offshore where it is likely covered by transgressive marine muds. The glacial and postglacial history of the Port au Port Bay area was widely replicated in other areas of ultrabasic rock along the western coast of Newfoundland and the results of this investigation may aid the search for other nearshore glacially influenced marine placers. |
author2 |
Natural Sciences and Engineering Research Council of Canada Milli Eğitim Bakanliği |
format |
Article in Journal/Newspaper |
author |
Duyan, Mehmet Eyles, Nick |
spellingShingle |
Duyan, Mehmet Eyles, Nick Origin of a glacially influenced shallow marine chromite placer, Port au Port Bay, western Newfoundland, Canada |
author_facet |
Duyan, Mehmet Eyles, Nick |
author_sort |
Duyan, Mehmet |
title |
Origin of a glacially influenced shallow marine chromite placer, Port au Port Bay, western Newfoundland, Canada |
title_short |
Origin of a glacially influenced shallow marine chromite placer, Port au Port Bay, western Newfoundland, Canada |
title_full |
Origin of a glacially influenced shallow marine chromite placer, Port au Port Bay, western Newfoundland, Canada |
title_fullStr |
Origin of a glacially influenced shallow marine chromite placer, Port au Port Bay, western Newfoundland, Canada |
title_full_unstemmed |
Origin of a glacially influenced shallow marine chromite placer, Port au Port Bay, western Newfoundland, Canada |
title_sort |
origin of a glacially influenced shallow marine chromite placer, port au port bay, western newfoundland, canada |
publisher |
Canadian Science Publishing |
publishDate |
2024 |
url |
http://dx.doi.org/10.1139/cjes-2023-0095 https://cdnsciencepub.com/doi/full-xml/10.1139/cjes-2023-0095 https://cdnsciencepub.com/doi/pdf/10.1139/cjes-2023-0095 |
genre |
Ice cap Newfoundland |
genre_facet |
Ice cap Newfoundland |
op_source |
Canadian Journal of Earth Sciences volume 61, issue 5, page 620-639 ISSN 0008-4077 1480-3313 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/cjes-2023-0095 |
container_title |
Canadian Journal of Earth Sciences |
_version_ |
1799481569571766272 |