High-resolution evidence for dynamic transitional geomagnetic field behaviour from a Miocene reversal, McMurdo Sound, Ross Sea, Antarctica
We report a high-resolution record of a Miocene polarity transition (probably the Chron C6r-C6n transition) from glacimarine sediments in McMurdo Sound, Ross Sea, Antarctica, which is the first transition record reported from high southern latitudes. The transition is recorded in two parallel cores...
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2007
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ftunivnebraskali:oai:digitalcommons.unl.edu:geosciencefacpub-1516 2023-11-12T04:04:42+01:00 High-resolution evidence for dynamic transitional geomagnetic field behaviour from a Miocene reversal, McMurdo Sound, Ross Sea, Antarctica Roberts, Andrew P. Bakrania, Anisch Florindo, Fabio Rowan, Christopher J. Fielding, Christopher R. Powell, Ross D. 2007-01-01T08:00:00Z application/pdf https://digitalcommons.unl.edu/geosciencefacpub/506 https://digitalcommons.unl.edu/context/geosciencefacpub/article/1516/viewcontent/Roberts_EPS_2007_High_resolution_evidence.pdf unknown DigitalCommons@University of Nebraska - Lincoln https://digitalcommons.unl.edu/geosciencefacpub/506 https://digitalcommons.unl.edu/context/geosciencefacpub/article/1516/viewcontent/Roberts_EPS_2007_High_resolution_evidence.pdf Papers in the Earth and Atmospheric Sciences Paleomagnetism geomagnetic field behaviour polarity reversal glacial processes Antarctica Earth Sciences Other Earth Sciences text 2007 ftunivnebraskali 2023-10-30T11:38:21Z We report a high-resolution record of a Miocene polarity transition (probably the Chron C6r-C6n transition) from glacimarine sediments in McMurdo Sound, Ross Sea, Antarctica, which is the first transition record reported from high southern latitudes. The transition is recorded in two parallel cores through a 10.7 m stratigraphic thickness. The sediments are interpreted as having been deposited in a marine environment under the influence of floating ice or seaward of a glacier terminus from which a large sediment load was delivered to the drill site. The core was recovered using rotary drilling, which precludes azimuthal orientation of the core and determination of a vector record of the field during the transition. However, constraints on transitional field behaviour are provided by the exceptional resolution of this record. Large-scale paleomagnetic inclination fluctuations in the two cores can be independently correlated with each other using magnetic susceptibility data, which suggests that the sediments are reliable recorders of geomagnetic field variations. Agreement between the two parallel transition records provides evidence for highly dynamic field behaviour, as suggested by numerous large-scale inclination changes (∼90◦) throughout the transition. These large-scale changes occur across stratigraphically narrow intervals, which is consistent with the suggestion of rapid field changes during transitions. In one intact portion of the core, where there is no apparent relative core rotation between samples, declinations and inclinations are consistent with the presence of a stable cluster of virtual geomagnetic poles within the transition (although the possibility that this cluster represents a rapid depositional event cannot be precluded). These observations are consistent with those from other high-resolution records and provide a rare detailed view of transitional field behaviour compared to most sedimentary records, which are not as thick and which appear to have been smoothed by sedimentary remanence ... Text Antarc* Antarctica McMurdo Sound Ross Sea University of Nebraska-Lincoln: DigitalCommons@UNL Ross Sea McMurdo Sound |
institution |
Open Polar |
collection |
University of Nebraska-Lincoln: DigitalCommons@UNL |
op_collection_id |
ftunivnebraskali |
language |
unknown |
topic |
Paleomagnetism geomagnetic field behaviour polarity reversal glacial processes Antarctica Earth Sciences Other Earth Sciences |
spellingShingle |
Paleomagnetism geomagnetic field behaviour polarity reversal glacial processes Antarctica Earth Sciences Other Earth Sciences Roberts, Andrew P. Bakrania, Anisch Florindo, Fabio Rowan, Christopher J. Fielding, Christopher R. Powell, Ross D. High-resolution evidence for dynamic transitional geomagnetic field behaviour from a Miocene reversal, McMurdo Sound, Ross Sea, Antarctica |
topic_facet |
Paleomagnetism geomagnetic field behaviour polarity reversal glacial processes Antarctica Earth Sciences Other Earth Sciences |
description |
We report a high-resolution record of a Miocene polarity transition (probably the Chron C6r-C6n transition) from glacimarine sediments in McMurdo Sound, Ross Sea, Antarctica, which is the first transition record reported from high southern latitudes. The transition is recorded in two parallel cores through a 10.7 m stratigraphic thickness. The sediments are interpreted as having been deposited in a marine environment under the influence of floating ice or seaward of a glacier terminus from which a large sediment load was delivered to the drill site. The core was recovered using rotary drilling, which precludes azimuthal orientation of the core and determination of a vector record of the field during the transition. However, constraints on transitional field behaviour are provided by the exceptional resolution of this record. Large-scale paleomagnetic inclination fluctuations in the two cores can be independently correlated with each other using magnetic susceptibility data, which suggests that the sediments are reliable recorders of geomagnetic field variations. Agreement between the two parallel transition records provides evidence for highly dynamic field behaviour, as suggested by numerous large-scale inclination changes (∼90◦) throughout the transition. These large-scale changes occur across stratigraphically narrow intervals, which is consistent with the suggestion of rapid field changes during transitions. In one intact portion of the core, where there is no apparent relative core rotation between samples, declinations and inclinations are consistent with the presence of a stable cluster of virtual geomagnetic poles within the transition (although the possibility that this cluster represents a rapid depositional event cannot be precluded). These observations are consistent with those from other high-resolution records and provide a rare detailed view of transitional field behaviour compared to most sedimentary records, which are not as thick and which appear to have been smoothed by sedimentary remanence ... |
format |
Text |
author |
Roberts, Andrew P. Bakrania, Anisch Florindo, Fabio Rowan, Christopher J. Fielding, Christopher R. Powell, Ross D. |
author_facet |
Roberts, Andrew P. Bakrania, Anisch Florindo, Fabio Rowan, Christopher J. Fielding, Christopher R. Powell, Ross D. |
author_sort |
Roberts, Andrew P. |
title |
High-resolution evidence for dynamic transitional geomagnetic field behaviour from a Miocene reversal, McMurdo Sound, Ross Sea, Antarctica |
title_short |
High-resolution evidence for dynamic transitional geomagnetic field behaviour from a Miocene reversal, McMurdo Sound, Ross Sea, Antarctica |
title_full |
High-resolution evidence for dynamic transitional geomagnetic field behaviour from a Miocene reversal, McMurdo Sound, Ross Sea, Antarctica |
title_fullStr |
High-resolution evidence for dynamic transitional geomagnetic field behaviour from a Miocene reversal, McMurdo Sound, Ross Sea, Antarctica |
title_full_unstemmed |
High-resolution evidence for dynamic transitional geomagnetic field behaviour from a Miocene reversal, McMurdo Sound, Ross Sea, Antarctica |
title_sort |
high-resolution evidence for dynamic transitional geomagnetic field behaviour from a miocene reversal, mcmurdo sound, ross sea, antarctica |
publisher |
DigitalCommons@University of Nebraska - Lincoln |
publishDate |
2007 |
url |
https://digitalcommons.unl.edu/geosciencefacpub/506 https://digitalcommons.unl.edu/context/geosciencefacpub/article/1516/viewcontent/Roberts_EPS_2007_High_resolution_evidence.pdf |
geographic |
Ross Sea McMurdo Sound |
geographic_facet |
Ross Sea McMurdo Sound |
genre |
Antarc* Antarctica McMurdo Sound Ross Sea |
genre_facet |
Antarc* Antarctica McMurdo Sound Ross Sea |
op_source |
Papers in the Earth and Atmospheric Sciences |
op_relation |
https://digitalcommons.unl.edu/geosciencefacpub/506 https://digitalcommons.unl.edu/context/geosciencefacpub/article/1516/viewcontent/Roberts_EPS_2007_High_resolution_evidence.pdf |
_version_ |
1782341739843944448 |