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GEOREF RECORD

(super 40) Ar/ (super 39) Ar laser-probe dating of detrital white micas from Cretaceous sedimentary rocks of the Eastern Alps; evidence for Variscan high-pressure metamorphism and implications for Alpine Orogeny

Hilmar von Eynatten, Reinhard Gaupp and Jan R. Wijbrans
(super 40) Ar/ (super 39) Ar laser-probe dating of detrital white micas from Cretaceous sedimentary rocks of the Eastern Alps; evidence for Variscan high-pressure metamorphism and implications for Alpine Orogeny
Geology (Boulder) (August 1996) 24 (8): 691-694

Abstract

The detritus of Cretaceous synorogenic sandstones of the northern margin of the Austroalpine microplate contains evidence for a high-pressure metamorphic basement and obducted oceanic crust exposed in early Alpine time. (super 40) Ar/ (super 39) Ar laser-probe data of detrital white micas give excellent plateau ages in a narrow range from 320 to 360 Ma. White micas cover the whole range from muscovites up to phengites (3.04 to 3.48 Si per formula unit). Heavy mineral spectra contain chrome spinel, glaucophane, chloritoid, epidote, and garnet, as well as zircon, tourmaline, and rutile. Glaucophane, chloritoid, and phengite correlate in their abundance. These minerals also correlate positively with the stable minerals zircon, tourmaline, and rutile derived from continental rock and negatively with chrome spinel, which represents oceanic crustal provenance. We propose that both glaucophane and phengite come from the same source rock, Variscan high-pressure metamorphic rocks of the Austroalpine basement. The Early Carboniferous age gives constraints for paleogeographic models concerning the collision between Gondwana and Laurussia. Furthermore, detrital glaucophane in the early Alpine sedimentary rocks cannot be used as proof for Cretaceous subduction at the Austroalpine-Penninic plate boundary.


ISSN: 0091-7613
EISSN: 1943-2682
Coden: GLGYBA
Serial Title: Geology (Boulder)
Serial Volume: 24
Serial Issue: 8
Title: (super 40) Ar/ (super 39) Ar laser-probe dating of detrital white micas from Cretaceous sedimentary rocks of the Eastern Alps; evidence for Variscan high-pressure metamorphism and implications for Alpine Orogeny
Affiliation: Johannes Gutenberg Universitaet, Institut fuer Geowissenschaften, Mainz, Federal Republic of Germany
Pages: 691-694
Published: 199608
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 24
Accession Number: 1996-064216
Categories: GeochronologyStructural geology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 1 table, geol. sketch map
N47°15'00" - N47°34'60", E09°45'00" - E10°30'00"
Secondary Affiliation: Vrije Universiteit, Amsterdam, NLD, Netherlands
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 199620
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