Enigmatic deep-water mounds on the Orphan Knoll, Labrador Sea
Deep-sea mounds can have a variety of origins and may provide hard-substrate features in depths that are normally dominated by mud. Orphan Knoll, a 2 km high bedrock horst off northeast Newfoundland, hosts more than 200 mounds, or mound complexes, of unknown composition, in water depths of 1720–2500...
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2020
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Online Access: | http://nora.nerc.ac.uk/id/eprint/526702/ https://nora.nerc.ac.uk/id/eprint/526702/1/fmars-06-00744.pdf https://doi.org/10.3389/fmars.2019.00744 |
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ftnerc:oai:nora.nerc.ac.uk:526702 2023-05-15T17:06:13+02:00 Enigmatic deep-water mounds on the Orphan Knoll, Labrador Sea Meredyk, Shawn P. Edinger, Evan Piper, David J. W. Huvenne, Veerle A. I. Hoy, Shannon Ruffman, Alan 2020-01-30 text http://nora.nerc.ac.uk/id/eprint/526702/ https://nora.nerc.ac.uk/id/eprint/526702/1/fmars-06-00744.pdf https://doi.org/10.3389/fmars.2019.00744 en eng https://nora.nerc.ac.uk/id/eprint/526702/1/fmars-06-00744.pdf Meredyk, Shawn P.; Edinger, Evan; Piper, David J. W.; Huvenne, Veerle A. I. orcid:0000-0001-7135-6360 Hoy, Shannon; Ruffman, Alan. 2020 Enigmatic deep-water mounds on the Orphan Knoll, Labrador Sea. Frontiers in Marine Science, 6. https://doi.org/10.3389/fmars.2019.00744 <https://doi.org/10.3389/fmars.2019.00744> cc_by_4 CC-BY Publication - Article PeerReviewed 2020 ftnerc https://doi.org/10.3389/fmars.2019.00744 2023-02-04T19:50:05Z Deep-sea mounds can have a variety of origins and may provide hard-substrate features in depths that are normally dominated by mud. Orphan Knoll, a 2 km high bedrock horst off northeast Newfoundland, hosts more than 200 mounds, or mound complexes, of unknown composition, in water depths of 1720–2500 m. Most mounds are 10–600 m high, with average mound height 187 m, and 1–3 km wide. The study objective was to characterize the size, shape, orientation, and composition of the enigmatic Orphan Knoll mounds, in order to determine their age and origin. Archival ship-based side-scan sonar, multibeam sonar, airgun, high-resolution sparker and 3.5 kHz acoustic sub-bottom profiling, and newly acquired ship-based multibeam sonar, video transects by remotely operated vehicle (ROV), rock samples, and near-bottom multibeam sonar data were analyzed. Four mounds were studied during two ROV dives. Archival sidescan sonar data show > 200 mounds. Sparker profiles show that the mound crests are covered by condensed stratified Quaternary sediment and airgun seismic data show faults reaching near the seafloor. New multibeam sonar data show mounds are dominantly conical to elliptical in shape, but without preferred orientation or alignment. Remotely operated vehicle (ROV) transects and near-bottom multibeam showed that three mounds were rounded and symmetrically arranged, while a fourth was more asymmetrical, with steep faces on the southwestern and southeastern flanks, where finely bedded to massive sedimentary bedrock outcropped dipping 15–45°SW. Rock samples from the mounds include Eocene calcareous ooze and mid-Miocene bedded pelagic limestone. Thick ferromanganese crusts were found on many surfaces, obscuring possible outcrops from physical sampling. Polymetallic nodules were found on the slope of one mound. Ice-rafted detritus, including igneous and metamorphic rocks and Paleozoic limestone and dolostone, was common in the sediments immediately surrounding the mounds. Quaternary sub-fossil solitary scleractinian corals ... Article in Journal/Newspaper Labrador Sea Newfoundland Natural Environment Research Council: NERC Open Research Archive Newfoundland Orphan Knoll ENVELOPE(-46.500,-46.500,50.500,50.500) Frontiers in Marine Science 6 |
institution |
Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
English |
description |
Deep-sea mounds can have a variety of origins and may provide hard-substrate features in depths that are normally dominated by mud. Orphan Knoll, a 2 km high bedrock horst off northeast Newfoundland, hosts more than 200 mounds, or mound complexes, of unknown composition, in water depths of 1720–2500 m. Most mounds are 10–600 m high, with average mound height 187 m, and 1–3 km wide. The study objective was to characterize the size, shape, orientation, and composition of the enigmatic Orphan Knoll mounds, in order to determine their age and origin. Archival ship-based side-scan sonar, multibeam sonar, airgun, high-resolution sparker and 3.5 kHz acoustic sub-bottom profiling, and newly acquired ship-based multibeam sonar, video transects by remotely operated vehicle (ROV), rock samples, and near-bottom multibeam sonar data were analyzed. Four mounds were studied during two ROV dives. Archival sidescan sonar data show > 200 mounds. Sparker profiles show that the mound crests are covered by condensed stratified Quaternary sediment and airgun seismic data show faults reaching near the seafloor. New multibeam sonar data show mounds are dominantly conical to elliptical in shape, but without preferred orientation or alignment. Remotely operated vehicle (ROV) transects and near-bottom multibeam showed that three mounds were rounded and symmetrically arranged, while a fourth was more asymmetrical, with steep faces on the southwestern and southeastern flanks, where finely bedded to massive sedimentary bedrock outcropped dipping 15–45°SW. Rock samples from the mounds include Eocene calcareous ooze and mid-Miocene bedded pelagic limestone. Thick ferromanganese crusts were found on many surfaces, obscuring possible outcrops from physical sampling. Polymetallic nodules were found on the slope of one mound. Ice-rafted detritus, including igneous and metamorphic rocks and Paleozoic limestone and dolostone, was common in the sediments immediately surrounding the mounds. Quaternary sub-fossil solitary scleractinian corals ... |
format |
Article in Journal/Newspaper |
author |
Meredyk, Shawn P. Edinger, Evan Piper, David J. W. Huvenne, Veerle A. I. Hoy, Shannon Ruffman, Alan |
spellingShingle |
Meredyk, Shawn P. Edinger, Evan Piper, David J. W. Huvenne, Veerle A. I. Hoy, Shannon Ruffman, Alan Enigmatic deep-water mounds on the Orphan Knoll, Labrador Sea |
author_facet |
Meredyk, Shawn P. Edinger, Evan Piper, David J. W. Huvenne, Veerle A. I. Hoy, Shannon Ruffman, Alan |
author_sort |
Meredyk, Shawn P. |
title |
Enigmatic deep-water mounds on the Orphan Knoll, Labrador Sea |
title_short |
Enigmatic deep-water mounds on the Orphan Knoll, Labrador Sea |
title_full |
Enigmatic deep-water mounds on the Orphan Knoll, Labrador Sea |
title_fullStr |
Enigmatic deep-water mounds on the Orphan Knoll, Labrador Sea |
title_full_unstemmed |
Enigmatic deep-water mounds on the Orphan Knoll, Labrador Sea |
title_sort |
enigmatic deep-water mounds on the orphan knoll, labrador sea |
publishDate |
2020 |
url |
http://nora.nerc.ac.uk/id/eprint/526702/ https://nora.nerc.ac.uk/id/eprint/526702/1/fmars-06-00744.pdf https://doi.org/10.3389/fmars.2019.00744 |
long_lat |
ENVELOPE(-46.500,-46.500,50.500,50.500) |
geographic |
Newfoundland Orphan Knoll |
geographic_facet |
Newfoundland Orphan Knoll |
genre |
Labrador Sea Newfoundland |
genre_facet |
Labrador Sea Newfoundland |
op_relation |
https://nora.nerc.ac.uk/id/eprint/526702/1/fmars-06-00744.pdf Meredyk, Shawn P.; Edinger, Evan; Piper, David J. W.; Huvenne, Veerle A. I. orcid:0000-0001-7135-6360 Hoy, Shannon; Ruffman, Alan. 2020 Enigmatic deep-water mounds on the Orphan Knoll, Labrador Sea. Frontiers in Marine Science, 6. https://doi.org/10.3389/fmars.2019.00744 <https://doi.org/10.3389/fmars.2019.00744> |
op_rights |
cc_by_4 |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.3389/fmars.2019.00744 |
container_title |
Frontiers in Marine Science |
container_volume |
6 |
_version_ |
1766061252646273024 |