Lesson plan
Metamorphic core complex
Metamorphic core complexes are exposed areas of deep crust brought to the surface by crustal extension (stretching). They form, and are exhumed, through relatively fast transport of middle and lower continental crust to the Earth's surface in the form of uplifting welts of hot rock and magma. The resulting doming causes the overlying rock to gravitationally collapse, sliding down and usually away from the uplift along low-angle detachment faults. Brittle, faulted cover rock above the detachment surface lies in direct contact with the ductile middle-lower crust below. High-grade metamorphic rocks (eclogite-, granulite- to amphibolite- facies) are exposed below the detachment faults (and mylonitic shear zones). Amphibolite- to greenschist-facies, syndeformational metamorphism, and ductile-brittle to brittle deformation are shown on the upper-side (hanging-wall), with tilted geometries. They range from several miles to over 50 miles across, and usually exhibit several miles of vertical uplift. They are common in areas of localized crustal extension in otherwise thickened fold-thrust belts. The origin of the low angles of the detachment faults were a subject of debate as of 2022.
Article summary
Metamorphic core complexes are exposed areas of deep crust brought to the surface by crustal extension (stretching). They form, and are exhumed, through relatively fast transport of middle and lower continental crust to the Earth's surface in the form of uplifting welts of hot rock and magma. The resulting doming causes the overlying rock to gravitationally collapse, sliding down and usually away from the uplift along low-angle detachment faults. Brittle, faulted cover rock above the detachment surface lies in direct contact with the ductile middle-lower crust below. High-grade metamorphic rocks (eclogite-, granulite- to amphibolite- facies) are exposed below the detachment faults (and mylonitic shear zones). Amphibolite- to greenschist-facies, syndeformational metamorphism, and ductile-brittle to brittle deformation are shown on the upper-side (hanging-wall), with tilted geometries. They range from several miles to over 50 miles across, and usually exhibit several miles of vertical uplift. They are common in areas of localized crustal extension in otherwise thickened fold-thrust belts. The origin of the low angles of the detachment faults were a subject of debate as of 2022.
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Discussion questions
- Summarise the article in your own words. Which single claim would you verify first, and why?
- Which claim in this article is most likely to be revised as the sources update? How would you check its current status?
- If two sources disagreed about one of these facts, what would you need in order to trust one over the other?
Bibliography
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Key claims and bibliography are generated from the same tracked claims and sources as the article page.