Geochemistry of middle Eocene-lower Oligocene pelagic sediments of ODP Hole 105-647A
Geochemical analyses of the middle Eocene through lower Oligocene lithologic Unit IIIC (260-518 meters below seafloor [mbsf]) indicate a relatively constant geochemical composition of the detrital fraction throughout this depositional interval at Ocean Drilling Program (ODP) Site 647 in the southern...
Main Authors: | , , , , , |
---|---|
Format: | Dataset |
Language: | English |
Published: |
PANGAEA
1989
|
Subjects: | |
Online Access: | https://doi.pangaea.de/10.1594/PANGAEA.745209 https://doi.org/10.1594/PANGAEA.745209 |
id |
ftpangaea:oai:pangaea.de:doi:10.1594/PANGAEA.745209 |
---|---|
record_format |
openpolar |
spelling |
ftpangaea:oai:pangaea.de:doi:10.1594/PANGAEA.745209 2023-05-15T17:06:13+02:00 Geochemistry of middle Eocene-lower Oligocene pelagic sediments of ODP Hole 105-647A Arthur, Michael A Dean, Walter E Zachos, James C Kaminski, Michael Anthony Hagerty Rieg, S Elmstrom, K LATITUDE: 53.331300 * LONGITUDE: -45.262000 * DATE/TIME START: 1985-10-15T04:10:00 * DATE/TIME END: 1985-10-23T18:15:00 1989-09-14 application/zip, 4 datasets https://doi.pangaea.de/10.1594/PANGAEA.745209 https://doi.org/10.1594/PANGAEA.745209 en eng PANGAEA https://doi.pangaea.de/10.1594/PANGAEA.745209 https://doi.org/10.1594/PANGAEA.745209 CC-BY-3.0: Creative Commons Attribution 3.0 Unported Access constraints: unrestricted info:eu-repo/semantics/openAccess CC-BY Supplement to: Arthur, Michael A; Dean, Walter E; Zachos, James C; Kaminski, Michael Anthony; Hagerty Rieg, S; Elmstrom, K (1989): Geochemical expression of early diagenesis in Middle Eocene-Lower Oligocene Pelagic sediments in the southern Labrador Sea, Site 647, ODP Leg 105. In: Srivastava, SP; Arthur, M; Clement, B; et al. (eds.), Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 105, 111-135, https://doi.org/10.2973/odp.proc.sr.105.157.1989 105-647A DRILL Drilling/drill rig Joides Resolution Leg105 North Atlantic Ocean Ocean Drilling Program ODP Dataset 1989 ftpangaea https://doi.org/10.1594/PANGAEA.745209 https://doi.org/10.2973/odp.proc.sr.105.157.1989 2023-01-20T07:31:53Z Geochemical analyses of the middle Eocene through lower Oligocene lithologic Unit IIIC (260-518 meters below seafloor [mbsf]) indicate a relatively constant geochemical composition of the detrital fraction throughout this depositional interval at Ocean Drilling Program (ODP) Site 647 in the southern Labrador Sea. The main variability occurs in redox-sensitive elements (e.g., iron, manganese, and phosphorus), which may be related to early diagenetic mobility in anaerobic pore waters during bacterial decomposition of organic matter. Initial preservation of organic matter was mediated by high sedimentation rates (36 m/m.y.). High iron (Fe) and manganese (Mn) contents are associated with carbonate concretions of siderite, manganosiderite, and rhodochrosite. These concretions probably formed in response to elevated pore-water alkalinity and total dissolved carbon dioxide (CO2) concentrations resulting from bacterial sulfate reduction, as indicated by nodule stable-isotope compositions and pore-water geochemistry. These nodules differ from those found in upper Cenozoic hemipelagic sequences in that they are not associated with methanogenesis. Phosphate minerals (carbonate-fluorapatite) precipitated in some intervals, probably as the result of desorption of phosphorus from iron and manganese during reduction. The bulk chemical composition of the sediments differs little from that of North Atlantic Quaternary abyssal red clays, but may contain a minor hydrothermal component. The silicon/ aluminum (Si/Al) ratio, however, is high and variable and probably reflects original variations in biogenic opal, much of which is now altered to smectite and/or opal CT. An increase in the sodium/potassium (Na/K) ratio in the upper Eocene corresponds to the beginning of coarsergrained feldspar flux to the site, possibly marking the onset of more vigorous deep currents. Although the Site 647 cores provide a nearly complete high-resolution, high-latitude Eocene-Oligocene record, the high sedimentation rate and somewhat unusual diagenetic ... Dataset Labrador Sea North Atlantic PANGAEA - Data Publisher for Earth & Environmental Science ENVELOPE(-45.262000,-45.262000,53.331300,53.331300) |
institution |
Open Polar |
collection |
PANGAEA - Data Publisher for Earth & Environmental Science |
op_collection_id |
ftpangaea |
language |
English |
topic |
105-647A DRILL Drilling/drill rig Joides Resolution Leg105 North Atlantic Ocean Ocean Drilling Program ODP |
spellingShingle |
105-647A DRILL Drilling/drill rig Joides Resolution Leg105 North Atlantic Ocean Ocean Drilling Program ODP Arthur, Michael A Dean, Walter E Zachos, James C Kaminski, Michael Anthony Hagerty Rieg, S Elmstrom, K Geochemistry of middle Eocene-lower Oligocene pelagic sediments of ODP Hole 105-647A |
topic_facet |
105-647A DRILL Drilling/drill rig Joides Resolution Leg105 North Atlantic Ocean Ocean Drilling Program ODP |
description |
Geochemical analyses of the middle Eocene through lower Oligocene lithologic Unit IIIC (260-518 meters below seafloor [mbsf]) indicate a relatively constant geochemical composition of the detrital fraction throughout this depositional interval at Ocean Drilling Program (ODP) Site 647 in the southern Labrador Sea. The main variability occurs in redox-sensitive elements (e.g., iron, manganese, and phosphorus), which may be related to early diagenetic mobility in anaerobic pore waters during bacterial decomposition of organic matter. Initial preservation of organic matter was mediated by high sedimentation rates (36 m/m.y.). High iron (Fe) and manganese (Mn) contents are associated with carbonate concretions of siderite, manganosiderite, and rhodochrosite. These concretions probably formed in response to elevated pore-water alkalinity and total dissolved carbon dioxide (CO2) concentrations resulting from bacterial sulfate reduction, as indicated by nodule stable-isotope compositions and pore-water geochemistry. These nodules differ from those found in upper Cenozoic hemipelagic sequences in that they are not associated with methanogenesis. Phosphate minerals (carbonate-fluorapatite) precipitated in some intervals, probably as the result of desorption of phosphorus from iron and manganese during reduction. The bulk chemical composition of the sediments differs little from that of North Atlantic Quaternary abyssal red clays, but may contain a minor hydrothermal component. The silicon/ aluminum (Si/Al) ratio, however, is high and variable and probably reflects original variations in biogenic opal, much of which is now altered to smectite and/or opal CT. An increase in the sodium/potassium (Na/K) ratio in the upper Eocene corresponds to the beginning of coarsergrained feldspar flux to the site, possibly marking the onset of more vigorous deep currents. Although the Site 647 cores provide a nearly complete high-resolution, high-latitude Eocene-Oligocene record, the high sedimentation rate and somewhat unusual diagenetic ... |
format |
Dataset |
author |
Arthur, Michael A Dean, Walter E Zachos, James C Kaminski, Michael Anthony Hagerty Rieg, S Elmstrom, K |
author_facet |
Arthur, Michael A Dean, Walter E Zachos, James C Kaminski, Michael Anthony Hagerty Rieg, S Elmstrom, K |
author_sort |
Arthur, Michael A |
title |
Geochemistry of middle Eocene-lower Oligocene pelagic sediments of ODP Hole 105-647A |
title_short |
Geochemistry of middle Eocene-lower Oligocene pelagic sediments of ODP Hole 105-647A |
title_full |
Geochemistry of middle Eocene-lower Oligocene pelagic sediments of ODP Hole 105-647A |
title_fullStr |
Geochemistry of middle Eocene-lower Oligocene pelagic sediments of ODP Hole 105-647A |
title_full_unstemmed |
Geochemistry of middle Eocene-lower Oligocene pelagic sediments of ODP Hole 105-647A |
title_sort |
geochemistry of middle eocene-lower oligocene pelagic sediments of odp hole 105-647a |
publisher |
PANGAEA |
publishDate |
1989 |
url |
https://doi.pangaea.de/10.1594/PANGAEA.745209 https://doi.org/10.1594/PANGAEA.745209 |
op_coverage |
LATITUDE: 53.331300 * LONGITUDE: -45.262000 * DATE/TIME START: 1985-10-15T04:10:00 * DATE/TIME END: 1985-10-23T18:15:00 |
long_lat |
ENVELOPE(-45.262000,-45.262000,53.331300,53.331300) |
genre |
Labrador Sea North Atlantic |
genre_facet |
Labrador Sea North Atlantic |
op_source |
Supplement to: Arthur, Michael A; Dean, Walter E; Zachos, James C; Kaminski, Michael Anthony; Hagerty Rieg, S; Elmstrom, K (1989): Geochemical expression of early diagenesis in Middle Eocene-Lower Oligocene Pelagic sediments in the southern Labrador Sea, Site 647, ODP Leg 105. In: Srivastava, SP; Arthur, M; Clement, B; et al. (eds.), Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 105, 111-135, https://doi.org/10.2973/odp.proc.sr.105.157.1989 |
op_relation |
https://doi.pangaea.de/10.1594/PANGAEA.745209 https://doi.org/10.1594/PANGAEA.745209 |
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.745209 https://doi.org/10.2973/odp.proc.sr.105.157.1989 |
_version_ |
1766061253193629696 |