Anomalous carbonate preservation in the abyssal North Pacific, ODP sites 882 and 1179: planktonic foraminiferal analysis, climate change and palaeogeomagnetism /
Samples for this study were obtained from the abyssal western North Pacific Ocean at Ocean Drilling Project Sites 882 (50°21.797'N, 167°35.999^E) and 1179 (41°4.787^N, 159°58.786'E). Despite their depth below the present day calcite compensation depth, ~250m and ~ 1.5km respectively, these...
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ftbrockuniv:oai:dr.library.brocku.ca:10464/1474 2024-06-09T07:47:46+00:00 Anomalous carbonate preservation in the abyssal North Pacific, ODP sites 882 and 1179: planktonic foraminiferal analysis, climate change and palaeogeomagnetism / Findlay, Duncan John. Department of Earth Sciences 2009-06-01T19:30:15Z http://hdl.handle.net/10464/1474 eng eng Brock University http://hdl.handle.net/10464/1474 Foraminifera Fossil Carbonate minerals Plankton Climatic changes Paleogeophysics Geomagnetic reversals Paleoclimatology Electronic Thesis or Dissertation 2009 ftbrockuniv 2024-05-16T06:42:42Z Samples for this study were obtained from the abyssal western North Pacific Ocean at Ocean Drilling Project Sites 882 (50°21.797'N, 167°35.999^E) and 1179 (41°4.787^N, 159°58.786'E). Despite their depth below the present day calcite compensation depth, ~250m and ~ 1.5km respectively, these late Pliocene-Pleistocene cores contained large quantities of carbonate, a small proportion of which is composed of well-preserved foraminiferal tests with minor to no signs of dissolution. This excellent preservation is unusual in light of their positions below the current calcite compensation depth. Globigerina bulloides, Globigerina quinqueloba, and Neogloboquadrina pachyderma are the dominant species at the more northerly Site 882, whereas A^. pachyderma, Globorotalia inflata, and G. bulloides dominate Site 1179. This species distribution is a direct reflection of their respective ambient oceanographic conditions. Cluster analysis of the identified foraminifera reveals four groups within Site 882, which are largely temperature and dissolution-controlled, documenting a fluctuating calcite compensation depth and lysocline as well as indicating a switch to cooler conditions at about 2 Ma. The ODP fauna, although similar to those collected in nearby sediment traps, have a slightly lower diversity, and are enriched in thick walled, non-spinose taxa. Abundance peaks of foraminifera throughout the cores agree well with the timing of brief suppression of the calcite compensation depth. These suppressions of the calcite compensation depth are related to increased surface water productivity commensurate with terrestrial fertilization of otherwise nutrient-poor gyre areas. Furthermore, these events sequestered CO2 from the atmosphere, contributing to late Cenozoic global cooling. The majority of the peaks correlate with times of incursions of cold deep Pacific water and rapid declines of continental ice volume, suggesting that North Atlantic Deep Water interference may change the source dominance of Pacific deepwater, leading to less ... Thesis Neogloboquadrina pachyderma North Atlantic Deep Water North Atlantic Brock University Digital Repository Pacific |
institution |
Open Polar |
collection |
Brock University Digital Repository |
op_collection_id |
ftbrockuniv |
language |
English |
topic |
Foraminifera Fossil Carbonate minerals Plankton Climatic changes Paleogeophysics Geomagnetic reversals Paleoclimatology |
spellingShingle |
Foraminifera Fossil Carbonate minerals Plankton Climatic changes Paleogeophysics Geomagnetic reversals Paleoclimatology Findlay, Duncan John. Anomalous carbonate preservation in the abyssal North Pacific, ODP sites 882 and 1179: planktonic foraminiferal analysis, climate change and palaeogeomagnetism / |
topic_facet |
Foraminifera Fossil Carbonate minerals Plankton Climatic changes Paleogeophysics Geomagnetic reversals Paleoclimatology |
description |
Samples for this study were obtained from the abyssal western North Pacific Ocean at Ocean Drilling Project Sites 882 (50°21.797'N, 167°35.999^E) and 1179 (41°4.787^N, 159°58.786'E). Despite their depth below the present day calcite compensation depth, ~250m and ~ 1.5km respectively, these late Pliocene-Pleistocene cores contained large quantities of carbonate, a small proportion of which is composed of well-preserved foraminiferal tests with minor to no signs of dissolution. This excellent preservation is unusual in light of their positions below the current calcite compensation depth. Globigerina bulloides, Globigerina quinqueloba, and Neogloboquadrina pachyderma are the dominant species at the more northerly Site 882, whereas A^. pachyderma, Globorotalia inflata, and G. bulloides dominate Site 1179. This species distribution is a direct reflection of their respective ambient oceanographic conditions. Cluster analysis of the identified foraminifera reveals four groups within Site 882, which are largely temperature and dissolution-controlled, documenting a fluctuating calcite compensation depth and lysocline as well as indicating a switch to cooler conditions at about 2 Ma. The ODP fauna, although similar to those collected in nearby sediment traps, have a slightly lower diversity, and are enriched in thick walled, non-spinose taxa. Abundance peaks of foraminifera throughout the cores agree well with the timing of brief suppression of the calcite compensation depth. These suppressions of the calcite compensation depth are related to increased surface water productivity commensurate with terrestrial fertilization of otherwise nutrient-poor gyre areas. Furthermore, these events sequestered CO2 from the atmosphere, contributing to late Cenozoic global cooling. The majority of the peaks correlate with times of incursions of cold deep Pacific water and rapid declines of continental ice volume, suggesting that North Atlantic Deep Water interference may change the source dominance of Pacific deepwater, leading to less ... |
author2 |
Department of Earth Sciences |
format |
Thesis |
author |
Findlay, Duncan John. |
author_facet |
Findlay, Duncan John. |
author_sort |
Findlay, Duncan John. |
title |
Anomalous carbonate preservation in the abyssal North Pacific, ODP sites 882 and 1179: planktonic foraminiferal analysis, climate change and palaeogeomagnetism / |
title_short |
Anomalous carbonate preservation in the abyssal North Pacific, ODP sites 882 and 1179: planktonic foraminiferal analysis, climate change and palaeogeomagnetism / |
title_full |
Anomalous carbonate preservation in the abyssal North Pacific, ODP sites 882 and 1179: planktonic foraminiferal analysis, climate change and palaeogeomagnetism / |
title_fullStr |
Anomalous carbonate preservation in the abyssal North Pacific, ODP sites 882 and 1179: planktonic foraminiferal analysis, climate change and palaeogeomagnetism / |
title_full_unstemmed |
Anomalous carbonate preservation in the abyssal North Pacific, ODP sites 882 and 1179: planktonic foraminiferal analysis, climate change and palaeogeomagnetism / |
title_sort |
anomalous carbonate preservation in the abyssal north pacific, odp sites 882 and 1179: planktonic foraminiferal analysis, climate change and palaeogeomagnetism / |
publisher |
Brock University |
publishDate |
2009 |
url |
http://hdl.handle.net/10464/1474 |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
Neogloboquadrina pachyderma North Atlantic Deep Water North Atlantic |
genre_facet |
Neogloboquadrina pachyderma North Atlantic Deep Water North Atlantic |
op_relation |
http://hdl.handle.net/10464/1474 |
_version_ |
1801379146529505280 |