Silt grain-size analysis of ODP holes from the western equatorial Atlantic
Grain-size records of the terrigenous and calcareous silt fraction, preservation of planktic foraminifera, and benthic foraminiferal stable-isotope data (delta13C, delta18O values of C. wuellerstorfi) at ODP Site 927 on the Ceará Rise (5°27.7'N, 44°28.8'W), are used to reconstruct variatio...
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ftpangaea:oai:pangaea.de:doi:10.1594/PANGAEA.736009 2023-05-15T17:25:29+02:00 Silt grain-size analysis of ODP holes from the western equatorial Atlantic Gröger, M Henrich, Rüdiger Bickert, Torsten MEDIAN LATITUDE: 5.719435 * MEDIAN LONGITUDE: -44.110200 * SOUTH-BOUND LATITUDE: 5.462660 * WEST-BOUND LONGITUDE: -44.480500 * NORTH-BOUND LATITUDE: 5.976210 * EAST-BOUND LONGITUDE: -43.739900 * DATE/TIME START: 1994-02-28T06:30:00 * DATE/TIME END: 1994-03-12T20:00:00 2003-03-31 application/zip, 2 datasets https://doi.pangaea.de/10.1594/PANGAEA.736009 https://doi.org/10.1594/PANGAEA.736009 en eng PANGAEA Gröger, M (2002): Deep-water circulation in the western equatorial Atlantic: inferences from carbonate preservation studies and silt grain-size analysis. Berichte aus dem Fachbereich Geowissenschaften der Universität Bremen, 195, 95 pp, urn:nbn:de:gbv:46-00103059-12 https://doi.pangaea.de/10.1594/PANGAEA.736009 https://doi.org/10.1594/PANGAEA.736009 CC-BY-3.0: Creative Commons Attribution 3.0 Unported Access constraints: unrestricted info:eu-repo/semantics/openAccess CC-BY Supplement to: Gröger, M; Henrich, Rüdiger; Bickert, Torsten (2003): Glacial-interglacial variability in lower North Atlantic deep water: inference from silt grain-size analysis and carbonate preservation in the western equatorial Atlantic. Marine Geology, 201(4), 321-332, https://doi.org/10.1016/S0025-3227(03)00263-9 154-927A 154-929A DRILL Drilling/drill rig GeoB Geosciences University of Bremen Joides Resolution Leg154 North Atlantic Ocean Ocean Drilling Program ODP Dataset 2003 ftpangaea https://doi.org/10.1594/PANGAEA.736009 https://doi.org/10.1016/S0025-3227(03)00263-9 2023-01-20T07:31:43Z Grain-size records of the terrigenous and calcareous silt fraction, preservation of planktic foraminifera, and benthic foraminiferal stable-isotope data (delta13C, delta18O values of C. wuellerstorfi) at ODP Site 927 on the Ceará Rise (5°27.7'N, 44°28.8'W), are used to reconstruct variations in the history of bottom current strength, ventilation, and carbonate corrosiveness of deep waters during the time interval from 0.8 to 0.3 Ma. Glacial periods are characterized by generally smaller mean sizes of the terrigenous sortable silt fraction (mean(SS)), lower delta13C values, and poorer preservation of planktic foraminifera compared to interglacials. This indicates lower bottom current speeds, larger nutrient contents and more corrosive deep water. By contrast, larger mean(SS) sizes, higher delta13C values, and well preserved planktic foraminifera indicate strong circulation and a well ventilated deep-water mass during interglacials. The observed changes are most likely related to the weakening and strengthening of circulation of Lower North Atlantic Deep Water (LNADW). Cross-spectral analysis between the mean(SS) and benthic delta18O records reveals that minima in mean(SS) occur about 7.6 k.y. after the maximum in ice volume. This indicates a considerable lag time between ice-shield induced changes in LNADW production and subsequent changes in the velocity of LNADW flow in the western equatorial Atlantic. Striking changes in bottom current speed occur regularly during glacial to interglacial transitions. Extremely fine mean(SS) minima point to an almost complete shutdown of bottom current vigor in response to a cessation of LNADW production caused by an enhanced melt water release during the initial phases of deglaciation. However, each of the fine minima extremes is followed by a rapid shift to very high mean(SS) values that indicate strong bottom currents, and hence, vigorous LNADW flow during the early interglacials. After the onset of glacial Stage 12, generally poorer carbonate preservation and higher ... Dataset North Atlantic Deep Water North Atlantic PANGAEA - Data Publisher for Earth & Environmental Science ENVELOPE(-44.480500,-43.739900,5.976210,5.462660) |
institution |
Open Polar |
collection |
PANGAEA - Data Publisher for Earth & Environmental Science |
op_collection_id |
ftpangaea |
language |
English |
topic |
154-927A 154-929A DRILL Drilling/drill rig GeoB Geosciences University of Bremen Joides Resolution Leg154 North Atlantic Ocean Ocean Drilling Program ODP |
spellingShingle |
154-927A 154-929A DRILL Drilling/drill rig GeoB Geosciences University of Bremen Joides Resolution Leg154 North Atlantic Ocean Ocean Drilling Program ODP Gröger, M Henrich, Rüdiger Bickert, Torsten Silt grain-size analysis of ODP holes from the western equatorial Atlantic |
topic_facet |
154-927A 154-929A DRILL Drilling/drill rig GeoB Geosciences University of Bremen Joides Resolution Leg154 North Atlantic Ocean Ocean Drilling Program ODP |
description |
Grain-size records of the terrigenous and calcareous silt fraction, preservation of planktic foraminifera, and benthic foraminiferal stable-isotope data (delta13C, delta18O values of C. wuellerstorfi) at ODP Site 927 on the Ceará Rise (5°27.7'N, 44°28.8'W), are used to reconstruct variations in the history of bottom current strength, ventilation, and carbonate corrosiveness of deep waters during the time interval from 0.8 to 0.3 Ma. Glacial periods are characterized by generally smaller mean sizes of the terrigenous sortable silt fraction (mean(SS)), lower delta13C values, and poorer preservation of planktic foraminifera compared to interglacials. This indicates lower bottom current speeds, larger nutrient contents and more corrosive deep water. By contrast, larger mean(SS) sizes, higher delta13C values, and well preserved planktic foraminifera indicate strong circulation and a well ventilated deep-water mass during interglacials. The observed changes are most likely related to the weakening and strengthening of circulation of Lower North Atlantic Deep Water (LNADW). Cross-spectral analysis between the mean(SS) and benthic delta18O records reveals that minima in mean(SS) occur about 7.6 k.y. after the maximum in ice volume. This indicates a considerable lag time between ice-shield induced changes in LNADW production and subsequent changes in the velocity of LNADW flow in the western equatorial Atlantic. Striking changes in bottom current speed occur regularly during glacial to interglacial transitions. Extremely fine mean(SS) minima point to an almost complete shutdown of bottom current vigor in response to a cessation of LNADW production caused by an enhanced melt water release during the initial phases of deglaciation. However, each of the fine minima extremes is followed by a rapid shift to very high mean(SS) values that indicate strong bottom currents, and hence, vigorous LNADW flow during the early interglacials. After the onset of glacial Stage 12, generally poorer carbonate preservation and higher ... |
format |
Dataset |
author |
Gröger, M Henrich, Rüdiger Bickert, Torsten |
author_facet |
Gröger, M Henrich, Rüdiger Bickert, Torsten |
author_sort |
Gröger, M |
title |
Silt grain-size analysis of ODP holes from the western equatorial Atlantic |
title_short |
Silt grain-size analysis of ODP holes from the western equatorial Atlantic |
title_full |
Silt grain-size analysis of ODP holes from the western equatorial Atlantic |
title_fullStr |
Silt grain-size analysis of ODP holes from the western equatorial Atlantic |
title_full_unstemmed |
Silt grain-size analysis of ODP holes from the western equatorial Atlantic |
title_sort |
silt grain-size analysis of odp holes from the western equatorial atlantic |
publisher |
PANGAEA |
publishDate |
2003 |
url |
https://doi.pangaea.de/10.1594/PANGAEA.736009 https://doi.org/10.1594/PANGAEA.736009 |
op_coverage |
MEDIAN LATITUDE: 5.719435 * MEDIAN LONGITUDE: -44.110200 * SOUTH-BOUND LATITUDE: 5.462660 * WEST-BOUND LONGITUDE: -44.480500 * NORTH-BOUND LATITUDE: 5.976210 * EAST-BOUND LONGITUDE: -43.739900 * DATE/TIME START: 1994-02-28T06:30:00 * DATE/TIME END: 1994-03-12T20:00:00 |
long_lat |
ENVELOPE(-44.480500,-43.739900,5.976210,5.462660) |
genre |
North Atlantic Deep Water North Atlantic |
genre_facet |
North Atlantic Deep Water North Atlantic |
op_source |
Supplement to: Gröger, M; Henrich, Rüdiger; Bickert, Torsten (2003): Glacial-interglacial variability in lower North Atlantic deep water: inference from silt grain-size analysis and carbonate preservation in the western equatorial Atlantic. Marine Geology, 201(4), 321-332, https://doi.org/10.1016/S0025-3227(03)00263-9 |
op_relation |
Gröger, M (2002): Deep-water circulation in the western equatorial Atlantic: inferences from carbonate preservation studies and silt grain-size analysis. Berichte aus dem Fachbereich Geowissenschaften der Universität Bremen, 195, 95 pp, urn:nbn:de:gbv:46-00103059-12 https://doi.pangaea.de/10.1594/PANGAEA.736009 https://doi.org/10.1594/PANGAEA.736009 |
op_rights |
CC-BY-3.0: Creative Commons Attribution 3.0 Unported Access constraints: unrestricted info:eu-repo/semantics/openAccess |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1594/PANGAEA.736009 https://doi.org/10.1016/S0025-3227(03)00263-9 |
_version_ |
1766116927369904128 |