Strain and retrogression partitioning explain long-term stability of crustal roots in stable continents
| Autor: | Bénédicte Cenki-Tok, Patrice Rey, Diane Arcay |
|---|---|
| Přispěvatelé: | Géosciences Montpellier, Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA), School of Geosciences, The University of Sydney, Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Université des Antilles (UA)-Centre National de la Recherche Scientifique (CNRS) |
| Rok vydání: | 2020 |
| Předmět: |
[SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics
010504 meteorology & atmospheric sciences Strain (chemistry) Continental crust Partial melting Geology 010502 geochemistry & geophysics 01 natural sciences Stability (probability) Term (time) Petrology 0105 earth and related environmental sciences Positive feedback |
| Zdroj: | Geology Geology, Geological Society of America, In press, ⟨10.1130/G47301.1⟩ Geology, Geological Society of America, 2020, 48 (7), pp.658-662. ⟨10.1130/G47301.1⟩ |
| ISSN: | 1943-2682 0091-7613 |
| DOI: | 10.1130/g47301.1 |
| Popis: | Away from tectonically active regions, the continental crust has an average thickness of 40 ± 1 km. Yet, it shows a remarkable variability from 25 to 65 km, comparable to that of the most tectonically active regions. Here, we consider the problem of the formation and preservation of anomalous deep crustal roots in stable intracontinental regions. Using two-dimensional thermomechanical experiments, we show that the interplay between partial melting, the formation of garnet-pyroxene-bearing rocks, and their strain rate–dependent retrogression result in the preservation of thick and strong crustal roots. We argue that it is the partitioning into narrow regions of strain, retrogression, and weakening coupled into a positive feedback loop that explains why strong high-grade crustal roots remain largely immune to gravitational stresses and are able to persist over hundreds of millions of years. |
| Databáze: | OpenAIRE |
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