Long-lived Paleoproterozoic eclogitic lower crust

The nature of the lower crust and the crust-mantle transition is fundamental to Earth sciences. Transformation of lower crustal rocks into eclogite facies is usually expected to result in lower crustal delamination. Here we provide compelling evidence for long-lasting presence of lower crustal eclog...

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Bibliographic Details
Published in:Nature communications 2021-11, Vol.12 (1), p.6553-6553, Article 6553
Main Authors: Buntin, Sebastian, Artemieva, Irina M., Malehmir, Alireza, Thybo, Hans, Malinowski, Michal, Högdahl, Karin, Janik, Tomasz, Buske, Stefan
Format: Article
Language:English
Subjects:
704/2151/210
704/2151/2809
704/2151/508
Delamination
Earth crust
Earth mantle
Earth science
Earth sciences
Eclogite
Humanities and Social Sciences
Isotopes
Lithosphere
multidisciplinary
Orogeny
Science
Science (multidisciplinary)
Seismic stability
Velocity
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Summary:The nature of the lower crust and the crust-mantle transition is fundamental to Earth sciences. Transformation of lower crustal rocks into eclogite facies is usually expected to result in lower crustal delamination. Here we provide compelling evidence for long-lasting presence of lower crustal eclogite below the seismic Moho. Our new wide-angle seismic data from the Paleoproterozoic Fennoscandian Shield identify a 6–8 km thick body with extremely high velocity (Vp ~ 8.5–8.6 km/s) and high density (>3.4 g/cm 3 ) immediately beneath equally thinned high-velocity (Vp ~ 7.3–7.4 km/s) lowermost crust, which extends over >350 km distance. We relate this observed structure to partial (50–70%) transformation of part of the mafic lowermost crustal layer into eclogite facies during Paleoproterozoic orogeny without later delamination. Our findings challenge conventional models for the role of lower crustal eclogitization and delamination in lithosphere evolution and for the long-term stability of cratonic crust. The nature of the lower crust and the crust-mantle transition is fundamental to Earth Sciences. Here, the authors provide evidence for long-lasting presence of lower crustal eclogite below the seismic Moho, challenging conventional models.
ISSN:2041-1723
2041-1723
DOI:10.1038/s41467-021-26878-5