K-Ar dating of amphibole-bearing rocks in the Schwarzwald, SW Germany; 1, 40Ar/39Ar age constraints of Hercynian HT-metamorphism

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Authors:Lippolt, Hans J.; Hradetzky, Helmuth; Hautmann, Siegfried
Author Affiliations:Primary:
Ruprechts-Karls-Univ. Heidelberg, Lab. Geochronolog., Heidelberg, Federal Republic of Germany
Volume Title:Neues Jahrbuch für Mineralogie. Monatshefte
Source:Neues Jahrbuch für Mineralogie. Monatshefte, 1994(10), p.433-448. Publisher: E. Schweizerbart'sche Verlagsbuchhandlung, Stuttgart, Federal Republic of Germany. ISSN: 0028-3649
Publication Date:1994
Note:In English. 34 refs.; illus., incl. 2 tables, geol. sketch map
Summary:Separates of hornblende from 25 metamorphosed small bodies of basic rocks gave 40Ar/39Ar ages in the range 350-320 m.y. (early Carboniferous) and show that the K-Ar systems in these amphiboles were closed during the Hercynian high-T metamorphism (≥ 500°C regionally). During this thermal episode only a few metamorphic rocks escaped total 40Ar loss and indicate thermal overprinting in pre-Carboniferous time. Differing ages from neighbouring rocks could be due to small-scale thrusting and imbrication. The amphibole age data show that the Schwarzwald basement experienced a similar evolution to other Moldanubian crystalline units. [R.A.H.]
Subjects:Absolute age; Amphibole group; Amphibolites; Ar-40/Ar-39; Ar/Ar; Argon; Basement; Carboniferous; Chain silicates; Clinoamphibole; Dates; Devonian; Dinantian; High temperature; Hornblende; Isotope ratios; Isotopes; K/Ar; Metabasite; Metaigneous rocks; Metamorphic rocks; Metamorphism; Noble gases; Orogeny; Paleozoic; Radioactive isotopes; Silicates; Stable isotopes; Temperature; Upper Devonian; Variscan Orogeny; Baden-Wurttemberg Germany; Black Forest; Central Europe; Europe; Germany; Southwestern German Massifs
Abstract Numbers:95M/1198
Record ID:1997041120
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom, Reference includes data from Geoline, Bundesanstalt fur Geowissenschaften und Rohstoffe
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