Glacial isostatic adjustment and the free air gravity anomaly as a constraint on deep mantle viscosity.
A gravitationally self-consistent theory for relative sea-level variations forced by Pleistocene deglaciation events is employed to explore the extent to which RSL and free air gravity observations together constrain the viscosity of the mantle beneath the seismic discontinuity at 670 km depth. A tr...
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ftunivhongkonghu:oai:hub.hku.hk:10722/192112 2023-05-15T16:35:26+02:00 Glacial isostatic adjustment and the free air gravity anomaly as a constraint on deep mantle viscosity. Peltier, WR Wu, P 1983 https://doi.org/10.1111/j.1365-246X.1983.tb01884.x http://hdl.handle.net/10722/192112 eng eng Geophysical Journal - Royal Astronomical Society Geophysical Journal - Royal Astronomical Society, 1983, v. 74 n. 2, p. 377-449 doi:10.1111/j.1365-246X.1983.tb01884.x 449 0956-540X 2 eid_2-s2.0-0021058066 377 http://hdl.handle.net/10722/192112 74 This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License. CC-BY-NC-ND Article 1983 ftunivhongkonghu https://doi.org/10.1111/j.1365-246X.1983.tb01884.x 2023-01-14T15:59:31Z A gravitationally self-consistent theory for relative sea-level variations forced by Pleistocene deglaciation events is employed to explore the extent to which RSL and free air gravity observations together constrain the viscosity of the mantle beneath the seismic discontinuity at 670 km depth. A trade-off is revealed between errors in the assumed deglaciation history and errors in the inferred value of the viscosity of the lower mantle. Taking full account of such uncertainty, plausible values of the viscosity beneath the transition region are bounded above by 1023 poise (cgs units). The preferred value is at least a factor of 2 lower than this and is strongly constrained by the observed free air gravity anomaly over Hudson Bay. The calculations described in detail here show for the first time that the relatively large gravity anomalies observed over sites of Würm- Wisconsin deglaciation do not require any pronounced increase of mantle viscosity with depth in order to explain them. published_or_final_version Article in Journal/Newspaper Hudson Bay University of Hong Kong: HKU Scholars Hub Hudson Hudson Bay Geophysical Journal International 75 1 169 200 |
institution |
Open Polar |
collection |
University of Hong Kong: HKU Scholars Hub |
op_collection_id |
ftunivhongkonghu |
language |
English |
description |
A gravitationally self-consistent theory for relative sea-level variations forced by Pleistocene deglaciation events is employed to explore the extent to which RSL and free air gravity observations together constrain the viscosity of the mantle beneath the seismic discontinuity at 670 km depth. A trade-off is revealed between errors in the assumed deglaciation history and errors in the inferred value of the viscosity of the lower mantle. Taking full account of such uncertainty, plausible values of the viscosity beneath the transition region are bounded above by 1023 poise (cgs units). The preferred value is at least a factor of 2 lower than this and is strongly constrained by the observed free air gravity anomaly over Hudson Bay. The calculations described in detail here show for the first time that the relatively large gravity anomalies observed over sites of Würm- Wisconsin deglaciation do not require any pronounced increase of mantle viscosity with depth in order to explain them. published_or_final_version |
format |
Article in Journal/Newspaper |
author |
Peltier, WR Wu, P |
spellingShingle |
Peltier, WR Wu, P Glacial isostatic adjustment and the free air gravity anomaly as a constraint on deep mantle viscosity. |
author_facet |
Peltier, WR Wu, P |
author_sort |
Peltier, WR |
title |
Glacial isostatic adjustment and the free air gravity anomaly as a constraint on deep mantle viscosity. |
title_short |
Glacial isostatic adjustment and the free air gravity anomaly as a constraint on deep mantle viscosity. |
title_full |
Glacial isostatic adjustment and the free air gravity anomaly as a constraint on deep mantle viscosity. |
title_fullStr |
Glacial isostatic adjustment and the free air gravity anomaly as a constraint on deep mantle viscosity. |
title_full_unstemmed |
Glacial isostatic adjustment and the free air gravity anomaly as a constraint on deep mantle viscosity. |
title_sort |
glacial isostatic adjustment and the free air gravity anomaly as a constraint on deep mantle viscosity. |
publishDate |
1983 |
url |
https://doi.org/10.1111/j.1365-246X.1983.tb01884.x http://hdl.handle.net/10722/192112 |
geographic |
Hudson Hudson Bay |
geographic_facet |
Hudson Hudson Bay |
genre |
Hudson Bay |
genre_facet |
Hudson Bay |
op_relation |
Geophysical Journal - Royal Astronomical Society Geophysical Journal - Royal Astronomical Society, 1983, v. 74 n. 2, p. 377-449 doi:10.1111/j.1365-246X.1983.tb01884.x 449 0956-540X 2 eid_2-s2.0-0021058066 377 http://hdl.handle.net/10722/192112 74 |
op_rights |
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License. |
op_rightsnorm |
CC-BY-NC-ND |
op_doi |
https://doi.org/10.1111/j.1365-246X.1983.tb01884.x |
container_title |
Geophysical Journal International |
container_volume |
75 |
container_issue |
1 |
container_start_page |
169 |
op_container_end_page |
200 |
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1766025663573131264 |