The nature and geological history of the deep crust under the Eifel, Germany
作者:
H.‐G. Stosch,
A. Schmucker,
Ch. Reys,
期刊:
Terra Nova
(WILEY Available online 1992)
卷期:
Volume 4,
issue 1
页码: 53-62
ISSN:0954-4879
年代: 1992
DOI:10.1111/j.1365-3121.1992.tb00450.x
出版商: Blackwell Publishing Ltd
数据来源: WILEY
摘要:
ABSTRACTThe crust ≈ 10–20 km under the Eifel is composed of amphibolite‐facies metasediments and meta‐igneous rocks of tonalitic to granodioritic composition; mafic granulites occupy the base of the crust down to a Moho depth between about 29 and 34 km. The meta‐granodiorites and meta‐tonalites have I‐type chemical characteristics and appear to have formed approximately 400 Myr ago by partial melting of a lower crustal source. Amphibolite‐facies metamorphism probably followed within the same orogeny. During the Quaternary, many amphibolite‐facies rocks were subjected to contact heating in crustal magma chambers and/or during transport to the earth's surface. Contact heating is also recorded in radiogenic isotope compositions of minerals from one xenolith. A genetic link between meta‐igneous amphibolites and the deeper crustal mafic granulites can neither be proven nor discounted by the isotope data. If there is a genetic relationship, it requires fractionation of a mafic magma in the lower crust and assimilation of metasediments and separation of a
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