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Effects of continents on Earth cooling: Thermal blanketing and depletion in radioactive elements
Author(s) -
Grigné Cécile,
Labrosse Stéphane
Publication year - 2001
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2000gl012475
Subject(s) - earth's internal heat budget , mantle (geology) , geology , blanketing , continental crust , geophysics , mantle convection , earth science , lithosphere , physics , paleontology , stars , tectonics , astronomy
Estimate of mantle heat flow under continental shields are very low, indicating a strong insulating effect of continents on mantle heat loss. This effect is investigated with a simple approach: continents are introduced in an Earth cooling model as perfect thermal insulators. Continental growth rate has then a strong influence on mantle cooling. Various continental growth models are tested and are used to compute the mantle depletion in radioactive elements as a function of continental crust extraction. Results show that the thermal blanketing effect of continents strongly affects mantle cooling, and that mantle depletion must be taken into account in order not to overestimate mantle heat loss. In order to obtain correct oceanic heat flow for present time, continental growth must begin at least 3 Gy ago and steady‐state for continental area must be reached for at least 1.5 Gy in our cooling model.