MAGNETIZATION AND GEOCHEMISTRY OF GREIGITE-BEARING CRETACEOUS STRATA, NORTH-SLOPE BASIN, ALASKA
Postdepositional greigite (Fe3S4; ferrimagnetic thiospinel) is of interest to sedimentary geochemists, because it reflects important reactions during diagenesis and to paleomagnetists because it can obscure a detrital paleomagnetic record. The presence, distribution, and origin of greigite are best...
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1994
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ftubristolcris:oai:research-information.bris.ac.uk:publications/2d888250-e9a7-4716-b3c5-ba689f2e9df5 2024-01-28T10:07:59+01:00 MAGNETIZATION AND GEOCHEMISTRY OF GREIGITE-BEARING CRETACEOUS STRATA, NORTH-SLOPE BASIN, ALASKA REYNOLDS, RL TUTTLE, ML RICE, CA FISHMAN, NS KARACHEWSKI, JA Sherman, David M 1994-04 https://hdl.handle.net/1983/2d888250-e9a7-4716-b3c5-ba689f2e9df5 https://research-information.bris.ac.uk/en/publications/2d888250-e9a7-4716-b3c5-ba689f2e9df5 eng eng info:eu-repo/semantics/restrictedAccess REYNOLDS , RL , TUTTLE , ML , RICE , CA , FISHMAN , NS , KARACHEWSKI , JA & Sherman , D M 1994 , ' MAGNETIZATION AND GEOCHEMISTRY OF GREIGITE-BEARING CRETACEOUS STRATA, NORTH-SLOPE BASIN, ALASKA ' , American Journal of Science , vol. 294 , no. 4 , pp. 485-528 . CALIFORNIA CONTINENTAL BORDERLAND ANOXIC MARINE-SEDIMENTS IRON SULFIDE MINERALS CEMENT OIL-FIELD SOUTH TEXAS SULFATE REDUCTION HOLOCENE SEDIMENTS WESTERN INTERIOR PYRITE FORMATION SULFUR-ISOTOPE article 1994 ftubristolcris 2024-01-04T23:42:56Z Postdepositional greigite (Fe3S4; ferrimagnetic thiospinel) is of interest to sedimentary geochemists, because it reflects important reactions during diagenesis and to paleomagnetists because it can obscure a detrital paleomagnetic record. The presence, distribution, and origin of greigite are best understood through combined magnetic and geochemical studies. Such studies of greigite-bearing Upper Cretaceous siliciclastic beds from the Simpson Peninsula, North Slope, Alaska, reveal relations among sulfur species and magnetic properties, and they illustrate the use of geochemical analysis to constrain the age of secondary magnetization carried by greigite. Greigite is ubiquitous in marine mudstone of the Seabee Formation, and it dominates the magnetic properties of the Seabee (magnetic susceptibility [MS]: 5.9 x 10-4 volume SI; magnitude of natural remanent magnetization [NRM]: 6.6 x 10-2 amperes/meter [A/m]; averages of 22 specimens in which greigite is the only magnetic mineral). The Seabee rocks fill an ancient submarine canyon cut into marine, transitional, and nonmarine sandstone, siltstone, and mudstone beds of the undifferentiated Ninuluk and Seabee Formations. In these sandstone and siltstone beds, some of which contain biodegraded oil, greigite occurs sporadically but is locally concentrated to yield high values of MS (5 x 10(-3) vol. SI) and NRM magnitude (0.5 A/m). Samples that contain detrital iron-titanium oxides, principally titanohematite, as the only magnetic minerals have lower values of MS and NRM magnitude. Different geochemical signatures in the Seabee Formation and undifferentiated Ninuluk and Seabee rocks indicate different origins of their greigite and associated iron disulfide minerals. In the Seabee, greigite and pyrite formed during early diagenesis via bacterial sulfate reduction utilizing indigenous sulfate and organic carbon. Evidence for early diagenetic iron sulfide includes (1) negative deltaS-34 values (typically between -22 and -30 permil) of acid-volatile sulfur (sulfur in ... Article in Journal/Newspaper north slope Simpson Peninsula Alaska University of Bristol: Bristol Research Simpson Peninsula ENVELOPE(-88.750,-88.750,68.568,68.568) |
institution |
Open Polar |
collection |
University of Bristol: Bristol Research |
op_collection_id |
ftubristolcris |
language |
English |
topic |
CALIFORNIA CONTINENTAL BORDERLAND ANOXIC MARINE-SEDIMENTS IRON SULFIDE MINERALS CEMENT OIL-FIELD SOUTH TEXAS SULFATE REDUCTION HOLOCENE SEDIMENTS WESTERN INTERIOR PYRITE FORMATION SULFUR-ISOTOPE |
spellingShingle |
CALIFORNIA CONTINENTAL BORDERLAND ANOXIC MARINE-SEDIMENTS IRON SULFIDE MINERALS CEMENT OIL-FIELD SOUTH TEXAS SULFATE REDUCTION HOLOCENE SEDIMENTS WESTERN INTERIOR PYRITE FORMATION SULFUR-ISOTOPE REYNOLDS, RL TUTTLE, ML RICE, CA FISHMAN, NS KARACHEWSKI, JA Sherman, David M MAGNETIZATION AND GEOCHEMISTRY OF GREIGITE-BEARING CRETACEOUS STRATA, NORTH-SLOPE BASIN, ALASKA |
topic_facet |
CALIFORNIA CONTINENTAL BORDERLAND ANOXIC MARINE-SEDIMENTS IRON SULFIDE MINERALS CEMENT OIL-FIELD SOUTH TEXAS SULFATE REDUCTION HOLOCENE SEDIMENTS WESTERN INTERIOR PYRITE FORMATION SULFUR-ISOTOPE |
description |
Postdepositional greigite (Fe3S4; ferrimagnetic thiospinel) is of interest to sedimentary geochemists, because it reflects important reactions during diagenesis and to paleomagnetists because it can obscure a detrital paleomagnetic record. The presence, distribution, and origin of greigite are best understood through combined magnetic and geochemical studies. Such studies of greigite-bearing Upper Cretaceous siliciclastic beds from the Simpson Peninsula, North Slope, Alaska, reveal relations among sulfur species and magnetic properties, and they illustrate the use of geochemical analysis to constrain the age of secondary magnetization carried by greigite. Greigite is ubiquitous in marine mudstone of the Seabee Formation, and it dominates the magnetic properties of the Seabee (magnetic susceptibility [MS]: 5.9 x 10-4 volume SI; magnitude of natural remanent magnetization [NRM]: 6.6 x 10-2 amperes/meter [A/m]; averages of 22 specimens in which greigite is the only magnetic mineral). The Seabee rocks fill an ancient submarine canyon cut into marine, transitional, and nonmarine sandstone, siltstone, and mudstone beds of the undifferentiated Ninuluk and Seabee Formations. In these sandstone and siltstone beds, some of which contain biodegraded oil, greigite occurs sporadically but is locally concentrated to yield high values of MS (5 x 10(-3) vol. SI) and NRM magnitude (0.5 A/m). Samples that contain detrital iron-titanium oxides, principally titanohematite, as the only magnetic minerals have lower values of MS and NRM magnitude. Different geochemical signatures in the Seabee Formation and undifferentiated Ninuluk and Seabee rocks indicate different origins of their greigite and associated iron disulfide minerals. In the Seabee, greigite and pyrite formed during early diagenesis via bacterial sulfate reduction utilizing indigenous sulfate and organic carbon. Evidence for early diagenetic iron sulfide includes (1) negative deltaS-34 values (typically between -22 and -30 permil) of acid-volatile sulfur (sulfur in ... |
format |
Article in Journal/Newspaper |
author |
REYNOLDS, RL TUTTLE, ML RICE, CA FISHMAN, NS KARACHEWSKI, JA Sherman, David M |
author_facet |
REYNOLDS, RL TUTTLE, ML RICE, CA FISHMAN, NS KARACHEWSKI, JA Sherman, David M |
author_sort |
REYNOLDS, RL |
title |
MAGNETIZATION AND GEOCHEMISTRY OF GREIGITE-BEARING CRETACEOUS STRATA, NORTH-SLOPE BASIN, ALASKA |
title_short |
MAGNETIZATION AND GEOCHEMISTRY OF GREIGITE-BEARING CRETACEOUS STRATA, NORTH-SLOPE BASIN, ALASKA |
title_full |
MAGNETIZATION AND GEOCHEMISTRY OF GREIGITE-BEARING CRETACEOUS STRATA, NORTH-SLOPE BASIN, ALASKA |
title_fullStr |
MAGNETIZATION AND GEOCHEMISTRY OF GREIGITE-BEARING CRETACEOUS STRATA, NORTH-SLOPE BASIN, ALASKA |
title_full_unstemmed |
MAGNETIZATION AND GEOCHEMISTRY OF GREIGITE-BEARING CRETACEOUS STRATA, NORTH-SLOPE BASIN, ALASKA |
title_sort |
magnetization and geochemistry of greigite-bearing cretaceous strata, north-slope basin, alaska |
publishDate |
1994 |
url |
https://hdl.handle.net/1983/2d888250-e9a7-4716-b3c5-ba689f2e9df5 https://research-information.bris.ac.uk/en/publications/2d888250-e9a7-4716-b3c5-ba689f2e9df5 |
long_lat |
ENVELOPE(-88.750,-88.750,68.568,68.568) |
geographic |
Simpson Peninsula |
geographic_facet |
Simpson Peninsula |
genre |
north slope Simpson Peninsula Alaska |
genre_facet |
north slope Simpson Peninsula Alaska |
op_source |
REYNOLDS , RL , TUTTLE , ML , RICE , CA , FISHMAN , NS , KARACHEWSKI , JA & Sherman , D M 1994 , ' MAGNETIZATION AND GEOCHEMISTRY OF GREIGITE-BEARING CRETACEOUS STRATA, NORTH-SLOPE BASIN, ALASKA ' , American Journal of Science , vol. 294 , no. 4 , pp. 485-528 . |
op_rights |
info:eu-repo/semantics/restrictedAccess |
_version_ |
1789336280510758912 |