Paleoceanography and dinoflagellate cyst record of northwestern North Pacific ODP Site 882 during the Pliocene–Pleistocene transition
A palynological study of the Pliocene–Pleistocene transition (2761 to 2497 ka) at Ocean Drilling Program Site 882, located on the Detroit Seamount in the western Subarctic Gyre of the northern North Pacific, provides a detailed record from 68 productive samples of dinoflagellate cysts (dinocysts) an...
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Brock University
2022
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ftbrockuniv:oai:dr.library.brocku.ca:10464/15654 2023-07-16T03:59:57+02:00 Paleoceanography and dinoflagellate cyst record of northwestern North Pacific ODP Site 882 during the Pliocene–Pleistocene transition Farmani, Taghi Department of Earth Sciences 2022-03-16T13:13:35Z http://hdl.handle.net/10464/15654 eng eng Brock University http://hdl.handle.net/10464/15654 Dinoflagellate Acritarch Pacific Pliocene Pleistocene Electronic Thesis or Dissertation 2022 ftbrockuniv 2023-06-27T22:10:30Z A palynological study of the Pliocene–Pleistocene transition (2761 to 2497 ka) at Ocean Drilling Program Site 882, located on the Detroit Seamount in the western Subarctic Gyre of the northern North Pacific, provides a detailed record from 68 productive samples of dinoflagellate cysts (dinocysts) and acritarchs with preservation varying from good to moderate. Dinocyst assemblages are characterized by an overwhelming dominance of round brown cysts, scarcity of phototrophs including Impagidinium species, and low taxonomic richness (a total of 11 dinocyst taxa for the entire study), reflecting the elevated nutrient levels but harsh conditions and reduced salinities of the North Pacific Subarctic Gyre. Cool, saline surface waters characterize the interval from 2761 to 2.72 Ma, as indicated by relatively abundant Impagidinium species including I. pallidum. Following the establishment of the modern halocline at ~2.72 Ma, significant shifts are recorded in both dinocyst concentrations and abundances of the acritarch Cymatiosphaera? invaginata. Productivity evidently remained fairly high even during glacial cycles, including the intense glacial Marine Isotope Stage (MIS) G4 at 2.70 Ma marked by common Habibacysta tectata and Pyxidinopsis reticulata, implying ice-free conditions at least during the summer. Dinocyst concentrations, and by inference productivity, are at their lowest during MIS 104 (2.6 Ma) which is associated with pronounced cooling in the northern North Atlantic and across the higher latitudes of the Northern Hemisphere. Low abundances of Cymatiosphaera? invaginata throughout the interval 2600–2565 ka, which includes interglacial MIS 103, unusually suggest reduced precipitation and hence elevated salinities at this time. The interval 2558–2497 ka registers a return to sporadically abundant Cymatiosphaera? invaginata in glacial MIS 100 and interglacial MISs 101 and 99, suggesting the return of reduced salinities and perhaps enhanced nutrient levels. In general, productivity seems to remain relatively ... Thesis North Atlantic Subarctic Brock University Digital Repository Detroit ENVELOPE(-60.000,-60.000,-64.167,-64.167) Pacific |
institution |
Open Polar |
collection |
Brock University Digital Repository |
op_collection_id |
ftbrockuniv |
language |
English |
topic |
Dinoflagellate Acritarch Pacific Pliocene Pleistocene |
spellingShingle |
Dinoflagellate Acritarch Pacific Pliocene Pleistocene Farmani, Taghi Paleoceanography and dinoflagellate cyst record of northwestern North Pacific ODP Site 882 during the Pliocene–Pleistocene transition |
topic_facet |
Dinoflagellate Acritarch Pacific Pliocene Pleistocene |
description |
A palynological study of the Pliocene–Pleistocene transition (2761 to 2497 ka) at Ocean Drilling Program Site 882, located on the Detroit Seamount in the western Subarctic Gyre of the northern North Pacific, provides a detailed record from 68 productive samples of dinoflagellate cysts (dinocysts) and acritarchs with preservation varying from good to moderate. Dinocyst assemblages are characterized by an overwhelming dominance of round brown cysts, scarcity of phototrophs including Impagidinium species, and low taxonomic richness (a total of 11 dinocyst taxa for the entire study), reflecting the elevated nutrient levels but harsh conditions and reduced salinities of the North Pacific Subarctic Gyre. Cool, saline surface waters characterize the interval from 2761 to 2.72 Ma, as indicated by relatively abundant Impagidinium species including I. pallidum. Following the establishment of the modern halocline at ~2.72 Ma, significant shifts are recorded in both dinocyst concentrations and abundances of the acritarch Cymatiosphaera? invaginata. Productivity evidently remained fairly high even during glacial cycles, including the intense glacial Marine Isotope Stage (MIS) G4 at 2.70 Ma marked by common Habibacysta tectata and Pyxidinopsis reticulata, implying ice-free conditions at least during the summer. Dinocyst concentrations, and by inference productivity, are at their lowest during MIS 104 (2.6 Ma) which is associated with pronounced cooling in the northern North Atlantic and across the higher latitudes of the Northern Hemisphere. Low abundances of Cymatiosphaera? invaginata throughout the interval 2600–2565 ka, which includes interglacial MIS 103, unusually suggest reduced precipitation and hence elevated salinities at this time. The interval 2558–2497 ka registers a return to sporadically abundant Cymatiosphaera? invaginata in glacial MIS 100 and interglacial MISs 101 and 99, suggesting the return of reduced salinities and perhaps enhanced nutrient levels. In general, productivity seems to remain relatively ... |
author2 |
Department of Earth Sciences |
format |
Thesis |
author |
Farmani, Taghi |
author_facet |
Farmani, Taghi |
author_sort |
Farmani, Taghi |
title |
Paleoceanography and dinoflagellate cyst record of northwestern North Pacific ODP Site 882 during the Pliocene–Pleistocene transition |
title_short |
Paleoceanography and dinoflagellate cyst record of northwestern North Pacific ODP Site 882 during the Pliocene–Pleistocene transition |
title_full |
Paleoceanography and dinoflagellate cyst record of northwestern North Pacific ODP Site 882 during the Pliocene–Pleistocene transition |
title_fullStr |
Paleoceanography and dinoflagellate cyst record of northwestern North Pacific ODP Site 882 during the Pliocene–Pleistocene transition |
title_full_unstemmed |
Paleoceanography and dinoflagellate cyst record of northwestern North Pacific ODP Site 882 during the Pliocene–Pleistocene transition |
title_sort |
paleoceanography and dinoflagellate cyst record of northwestern north pacific odp site 882 during the pliocene–pleistocene transition |
publisher |
Brock University |
publishDate |
2022 |
url |
http://hdl.handle.net/10464/15654 |
long_lat |
ENVELOPE(-60.000,-60.000,-64.167,-64.167) |
geographic |
Detroit Pacific |
geographic_facet |
Detroit Pacific |
genre |
North Atlantic Subarctic |
genre_facet |
North Atlantic Subarctic |
op_relation |
http://hdl.handle.net/10464/15654 |
_version_ |
1771548334824095744 |