(Table T2) Remanent anomaly and Koenigsberger ratio of ODP holes
Magnetic field strength and magnetic susceptibility were logged with the geological high-resolution magnetic tool (GHMT) at three of the holes drilled during Ocean Drilling Program Leg 178 to the west of the Antarctic Peninsula. Polarity stratigraphies derived from the GHMT logs bear close resemblan...
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ftpangaea:oai:pangaea.de:doi:10.1594/PANGAEA.142421 2024-09-15T17:48:05+00:00 (Table T2) Remanent anomaly and Koenigsberger ratio of ODP holes Williams, Trevor J Louvel, Véronique Lauer-Leredde, C MEDIAN LATITUDE: -1.970240 * MEDIAN LONGITUDE: 20.370108 * SOUTH-BOUND LATITUDE: -67.696160 * WEST-BOUND LONGITUDE: -78.487820 * NORTH-BOUND LATITUDE: 77.340600 * EAST-BOUND LONGITUDE: 168.336900 * DATE/TIME START: 1992-08-16T18:45:00 * DATE/TIME END: 2000-02-21T16:00:00 * MINIMUM DEPTH, sediment/rock: 86.0 m * MAXIMUM DEPTH, sediment/rock: 480.0 m 2002 text/tab-separated-values, 70 data points https://doi.pangaea.de/10.1594/PANGAEA.142421 https://doi.org/10.1594/PANGAEA.142421 en eng PANGAEA https://doi.pangaea.de/10.1594/PANGAEA.142421 https://doi.org/10.1594/PANGAEA.142421 CC-BY-3.0: Creative Commons Attribution 3.0 Unported Access constraints: unrestricted info:eu-repo/semantics/openAccess Supplement to: Williams, Trevor J; Louvel, Véronique; Lauer-Leredde, C (2002): Magnetic polarity stratigraphy from downhole logs, West Antarctic Peninsula, ODP Leg 178. In: Barker, PF; Camerlenghi, A; Acton, GD; Ramsay, ATS (eds.) Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 178, 1-23, https://doi.org/10.2973/odp.proc.sr.178.222.2002 145-883F 145-884E 162-986C 162-987E 178-1095B 178-1096C 178-1103A 188-1166A Depth bottom/max sediment/rock top/min Drake Passage DRILL Drilling/drill rig Event label Iceland Sea Joides Resolution Koenigsberger ratio Leg145 Leg162 Leg178 Leg188 North Greenland Sea North Pacific Ocean Ocean Drilling Program ODP Petrography description Prydz Bay Remanent anomaly standard deviation South Pacific Ocean dataset 2002 ftpangaea https://doi.org/10.1594/PANGAEA.14242110.2973/odp.proc.sr.178.222.2002 2024-07-24T02:31:23Z Magnetic field strength and magnetic susceptibility were logged with the geological high-resolution magnetic tool (GHMT) at three of the holes drilled during Ocean Drilling Program Leg 178 to the west of the Antarctic Peninsula. Polarity stratigraphies derived from the GHMT logs bear close resemblance to the polarities determined from core paleomagnetism at two of the holes and were used for magnetostratigraphic dating, especially in intervals where no core was recovered. Polarity is determined in the following way. First, the susceptibility log is used to determine the induced magnetization of the sediment. Then the background field, the field of the metal drill pipe, and the field anomaly of the sediment's induced magnetization are removed from the measured total field to leave the downhole anomaly of the sediment's remanent magnetization. The sign (positive or negative) of this anomaly gave a good polarity stratigraphy for Holes 1095B and 1096C, which are located in sediment drifts. A further step, correlation analysis, is based on the fact that in an interval of normal polarity sediment the remanent anomaly will correlate with the induced anomaly, whereas in reversed polarity sediment they will anticorrelate. The magnetite-rich, fine-grained sediments found in the two holes drilled into the sediment drift have a ratio of remanent to induced magnetization (the Koenigsberger ratio) of ~1. In contrast, the coarser-grained diamict sediments on the shelf have a Koenigsberger ratio of ~0.2, and extracting the remanent part of the downhole anomaly is much more difficult. By the comparison of core and log results, we can assess the viability of the GHMT polarities in detail, what proportion of the overprint in the cores is imparted by the coring process, and whether any paleointensity information is extractable from the GHMT logs. Dataset Antarc* Antarctic Antarctic Peninsula Drake Passage Greenland Greenland Sea Iceland North Greenland Prydz Bay PANGAEA - Data Publisher for Earth & Environmental Science ENVELOPE(-78.487820,168.336900,77.340600,-67.696160) |
institution |
Open Polar |
collection |
PANGAEA - Data Publisher for Earth & Environmental Science |
op_collection_id |
ftpangaea |
language |
English |
topic |
145-883F 145-884E 162-986C 162-987E 178-1095B 178-1096C 178-1103A 188-1166A Depth bottom/max sediment/rock top/min Drake Passage DRILL Drilling/drill rig Event label Iceland Sea Joides Resolution Koenigsberger ratio Leg145 Leg162 Leg178 Leg188 North Greenland Sea North Pacific Ocean Ocean Drilling Program ODP Petrography description Prydz Bay Remanent anomaly standard deviation South Pacific Ocean |
spellingShingle |
145-883F 145-884E 162-986C 162-987E 178-1095B 178-1096C 178-1103A 188-1166A Depth bottom/max sediment/rock top/min Drake Passage DRILL Drilling/drill rig Event label Iceland Sea Joides Resolution Koenigsberger ratio Leg145 Leg162 Leg178 Leg188 North Greenland Sea North Pacific Ocean Ocean Drilling Program ODP Petrography description Prydz Bay Remanent anomaly standard deviation South Pacific Ocean Williams, Trevor J Louvel, Véronique Lauer-Leredde, C (Table T2) Remanent anomaly and Koenigsberger ratio of ODP holes |
topic_facet |
145-883F 145-884E 162-986C 162-987E 178-1095B 178-1096C 178-1103A 188-1166A Depth bottom/max sediment/rock top/min Drake Passage DRILL Drilling/drill rig Event label Iceland Sea Joides Resolution Koenigsberger ratio Leg145 Leg162 Leg178 Leg188 North Greenland Sea North Pacific Ocean Ocean Drilling Program ODP Petrography description Prydz Bay Remanent anomaly standard deviation South Pacific Ocean |
description |
Magnetic field strength and magnetic susceptibility were logged with the geological high-resolution magnetic tool (GHMT) at three of the holes drilled during Ocean Drilling Program Leg 178 to the west of the Antarctic Peninsula. Polarity stratigraphies derived from the GHMT logs bear close resemblance to the polarities determined from core paleomagnetism at two of the holes and were used for magnetostratigraphic dating, especially in intervals where no core was recovered. Polarity is determined in the following way. First, the susceptibility log is used to determine the induced magnetization of the sediment. Then the background field, the field of the metal drill pipe, and the field anomaly of the sediment's induced magnetization are removed from the measured total field to leave the downhole anomaly of the sediment's remanent magnetization. The sign (positive or negative) of this anomaly gave a good polarity stratigraphy for Holes 1095B and 1096C, which are located in sediment drifts. A further step, correlation analysis, is based on the fact that in an interval of normal polarity sediment the remanent anomaly will correlate with the induced anomaly, whereas in reversed polarity sediment they will anticorrelate. The magnetite-rich, fine-grained sediments found in the two holes drilled into the sediment drift have a ratio of remanent to induced magnetization (the Koenigsberger ratio) of ~1. In contrast, the coarser-grained diamict sediments on the shelf have a Koenigsberger ratio of ~0.2, and extracting the remanent part of the downhole anomaly is much more difficult. By the comparison of core and log results, we can assess the viability of the GHMT polarities in detail, what proportion of the overprint in the cores is imparted by the coring process, and whether any paleointensity information is extractable from the GHMT logs. |
format |
Dataset |
author |
Williams, Trevor J Louvel, Véronique Lauer-Leredde, C |
author_facet |
Williams, Trevor J Louvel, Véronique Lauer-Leredde, C |
author_sort |
Williams, Trevor J |
title |
(Table T2) Remanent anomaly and Koenigsberger ratio of ODP holes |
title_short |
(Table T2) Remanent anomaly and Koenigsberger ratio of ODP holes |
title_full |
(Table T2) Remanent anomaly and Koenigsberger ratio of ODP holes |
title_fullStr |
(Table T2) Remanent anomaly and Koenigsberger ratio of ODP holes |
title_full_unstemmed |
(Table T2) Remanent anomaly and Koenigsberger ratio of ODP holes |
title_sort |
(table t2) remanent anomaly and koenigsberger ratio of odp holes |
publisher |
PANGAEA |
publishDate |
2002 |
url |
https://doi.pangaea.de/10.1594/PANGAEA.142421 https://doi.org/10.1594/PANGAEA.142421 |
op_coverage |
MEDIAN LATITUDE: -1.970240 * MEDIAN LONGITUDE: 20.370108 * SOUTH-BOUND LATITUDE: -67.696160 * WEST-BOUND LONGITUDE: -78.487820 * NORTH-BOUND LATITUDE: 77.340600 * EAST-BOUND LONGITUDE: 168.336900 * DATE/TIME START: 1992-08-16T18:45:00 * DATE/TIME END: 2000-02-21T16:00:00 * MINIMUM DEPTH, sediment/rock: 86.0 m * MAXIMUM DEPTH, sediment/rock: 480.0 m |
long_lat |
ENVELOPE(-78.487820,168.336900,77.340600,-67.696160) |
genre |
Antarc* Antarctic Antarctic Peninsula Drake Passage Greenland Greenland Sea Iceland North Greenland Prydz Bay |
genre_facet |
Antarc* Antarctic Antarctic Peninsula Drake Passage Greenland Greenland Sea Iceland North Greenland Prydz Bay |
op_source |
Supplement to: Williams, Trevor J; Louvel, Véronique; Lauer-Leredde, C (2002): Magnetic polarity stratigraphy from downhole logs, West Antarctic Peninsula, ODP Leg 178. In: Barker, PF; Camerlenghi, A; Acton, GD; Ramsay, ATS (eds.) Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 178, 1-23, https://doi.org/10.2973/odp.proc.sr.178.222.2002 |
op_relation |
https://doi.pangaea.de/10.1594/PANGAEA.142421 https://doi.org/10.1594/PANGAEA.142421 |
op_rights |
CC-BY-3.0: Creative Commons Attribution 3.0 Unported Access constraints: unrestricted info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1594/PANGAEA.14242110.2973/odp.proc.sr.178.222.2002 |
_version_ |
1810289059056058368 |