Antarctica ice sheet basal melting enhanced by high mantle heat
Antarctica is losing ice mass by basal melting associated with processes in deep Earth and reflected in geothermal heat flux. The latter is poorly known and existing models based on disputed assumptions are controversial. Here I present a new geophysical model for lithospheric thickness and mantle h...
| Published in: | Earth-Science Reviews |
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| Main Author: | |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Elsevier
2022
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| Online Access: | https://oceanrep.geomar.de/id/eprint/55172/ https://oceanrep.geomar.de/id/eprint/55172/2/1-s2.0-S0012825222000381-main.pdf https://oceanrep.geomar.de/id/eprint/55172/8/1-s2.0-S0012825222000381-mmc1.pdf https://doi.org/10.1016/j.earscirev.2022.103954 |
| Summary: | Antarctica is losing ice mass by basal melting associated with processes in deep Earth and reflected in geothermal heat flux. The latter is poorly known and existing models based on disputed assumptions are controversial. Here I present a new geophysical model for lithospheric thickness and mantle heat flux for the entire Antarctica and demonstrate that significant parts of the East Antarctica craton have lost the cratonic lithosphere signature and the entire West Antarctica has a highly extended lithosphere, consistent with its origin as a system of back-arc basins. I conclude that the rate of Antarctica ice basal melting is significantly underestimated: (i) the area with high heat flux is double in size and (ii) the amplitude of the high heat flux anomalies is 20–30% higher than in previous results. Extremely high heat flux (>100 mW/m2) in almost all of West Antarctica, continuing to the South Pole region, and beneath the Lake Vostok region in East Antarctica requires a thin (<70 km) lithosphere and shallow mantle melting, caused by recent geodynamic activity. This high heat flux may promote sliding lubrication and result in dramatic reduction of ice mass, such as in Heinrich events. The results form basis for re-evaluation of the Antarctica ice-sheet dynamics models with consequences for global environmental changes. |
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