The thermal evolution of an Earth with strong subduction zones
It is commonly supposed that plate tectonic rates are controlled by the temperature-dependent viscosity of Earth's deep interior. If this were so, a small decrease in mantle temperature would lead to a large decrease in global heat transport. This negative feedback mechanism would prevent mantl...
| Main Authors: | , |
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| Other Authors: | |
| Format: | Article |
| Language: | en_US |
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American Geophysical Union (AGU)/Wiley
2017
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| Online Access: | http://hdl.handle.net/1721.1/106535 |
| _version_ | 1811082745970950144 |
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| author | Conrad, Clinton P. Hager, Bradford H |
| author2 | Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences |
| author_facet | Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Conrad, Clinton P. Hager, Bradford H |
| author_sort | Conrad, Clinton P. |
| collection | MIT |
| description | It is commonly supposed that plate tectonic rates are controlled by the temperature-dependent viscosity of Earth's deep interior. If this were so, a small decrease in mantle temperature would lead to a large decrease in global heat transport. This negative feedback mechanism would prevent mantle temperatures from changing rapidly with time. We propose alternatively that convection is primarily resisted by the bending of oceanic lithosphere at subduction zones. Because lithospheric strength should not depend strongly on interior mantle temperature, this relationship decreases the sensitivity of heat flow to changes in interior mantle viscosity, and thus permits more rapid temperature changes there. The bending resistance is large enough to limit heat flow rates for effective viscosities of the lithosphere greater than about 1023 Pa s, and increases with the cube of plate thickness. As a result, processes that affect plate thickness, such as small-scale convection or subduction initiation, could profoundly influence Earth's thermal history. |
| first_indexed | 2024-09-23T12:08:20Z |
| format | Article |
| id | mit-1721.1/106535 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T12:08:20Z |
| publishDate | 2017 |
| publisher | American Geophysical Union (AGU)/Wiley |
| record_format | dspace |
| spelling | mit-1721.1/1065352022-10-01T08:26:48Z The thermal evolution of an Earth with strong subduction zones Conrad, Clinton P. Hager, Bradford H Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Conrad, Clinton P. Hager, Bradford H It is commonly supposed that plate tectonic rates are controlled by the temperature-dependent viscosity of Earth's deep interior. If this were so, a small decrease in mantle temperature would lead to a large decrease in global heat transport. This negative feedback mechanism would prevent mantle temperatures from changing rapidly with time. We propose alternatively that convection is primarily resisted by the bending of oceanic lithosphere at subduction zones. Because lithospheric strength should not depend strongly on interior mantle temperature, this relationship decreases the sensitivity of heat flow to changes in interior mantle viscosity, and thus permits more rapid temperature changes there. The bending resistance is large enough to limit heat flow rates for effective viscosities of the lithosphere greater than about 1023 Pa s, and increases with the cube of plate thickness. As a result, processes that affect plate thickness, such as small-scale convection or subduction initiation, could profoundly influence Earth's thermal history. National Science Foundation (U.S.) (grant 9506427-EAR) National Science Foundation (U.S.) (Graduate Research Fellowship) 2017-01-19T19:19:05Z 2017-01-19T19:19:05Z 1999-10 1999-08 Article http://purl.org/eprint/type/JournalArticle 00948276 http://hdl.handle.net/1721.1/106535 Conrad, Clinton P., and Bradford H. Hager. “The Thermal Evolution of an Earth with Strong Subduction Zones.” Geophysical Research Letters vol. 26, no. 19, 1999, pp. 3041–3044. © 1999 American Geophysical Union (AGU). en_US http://dx.doi.org/10.1029/1999GL005397 Geophysical Research Letters Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf American Geophysical Union (AGU)/Wiley Other univ. web domain |
| spellingShingle | Conrad, Clinton P. Hager, Bradford H The thermal evolution of an Earth with strong subduction zones |
| title | The thermal evolution of an Earth with strong subduction zones |
| title_full | The thermal evolution of an Earth with strong subduction zones |
| title_fullStr | The thermal evolution of an Earth with strong subduction zones |
| title_full_unstemmed | The thermal evolution of an Earth with strong subduction zones |
| title_short | The thermal evolution of an Earth with strong subduction zones |
| title_sort | thermal evolution of an earth with strong subduction zones |
| url | http://hdl.handle.net/1721.1/106535 |
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