Alpine metamorphism in the south-east Tauern Window, Austria; 2, Rates of heating, cooling and uplift

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Authors:Cliff, R. A.; Droop, G. T. R.; Rex, D. C.
Author Affiliations:Primary:
Univ. Leeds, Dep. Earth Sci., Leeds, United Kingdom
Other:
Univ. Manchester, Dep. Geol., United Kingdom
Volume Title:Journal of Metamorphic Geology
Source:Journal of Metamorphic Geology, 3(4), p.403-415. Publisher: Blackwell, Oxford, United Kingdom. ISSN: 0263-4929
Publication Date:1985
Note:In English. 26 refs.; illus. incl. 4 tables
Summary:New Rb/Sr, K/Ar and 39Ar/40Ar ages are presented, including a suite of 33 mica ages for a 20 km N-S tunnel section. These and previous geochronological data are discussed in relation to the thermal history from the overthrusting of the Austro-Alpine nappes approx 65 m.y. ago to the present. The earliest metamorphic phase, involving lawsonite crystallization, was associated with emplacement of these nappes; subsequently, T in rocks beneath rose at a mean rate of 3°-6°C/m.y. until the climax of metamorphism. Published data for the age of this climax at high structural levels indicate >35 m.y., but a new 39Ar/40Ar step-heating age of 23.8 + or - 0.8 m.y. on amphibole from near the base of Peripheral Schieferhulle indicates a later climax at deeper structural levels. Following the climax, near-isothermal uplift and erosion reduced P to approx 1 kbar before white mica closure at 19 m.y.; this implies uplift at >3 mm/yr. Along the tunnel, white mica K/Ar ages vary systematically from 24 to 16.5 m.y. with position relative to a late 4 km amplitude dome, whereas biotite Rb/Sr ages are uniform at 16.5 m.y. across the whole profile; doming is thus dated at 16.5 m.y. with transient uplift rates >5 mm/yr. At other times uplift rates were <1 mm/yr. [R.A.H.]
Subjects:Absolute age; Ar-40/Ar-39; Argon; Blueschist facies; Cenozoic; Crystallization; Dates; Facies; Faults; Geochronology; Isotopes; K/Ar; Metamorphic rocks; Metamorphism; Mica group; Mineral assemblages; Noble gases; P-T conditions; Radioactive isotopes; Rb/Sr; Regional metamorphism; Sheet silicates; Silicates; Stable isotopes; Structural geology; Tectonics; Tertiary; Thrust faults; Uplifts; Alps; Austria; Central Europe; Europe; Penninic Zone; Tauern Window; Alpine-type
Abstract Numbers:86M/3917
Record ID:1987035408
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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008 190110e198512 xxka 0 0 eng d
040 |a ViAlAGI  |c ViAlAGI 
072 7 |a 03  |2 georeft 
072 7 |a 05A  |2 georeft 
072 7 |a 16  |2 georeft 
100 1 |a Cliff, R. A.  |e analytic author  |u Univ. Leeds, Dep. Earth Sci., Leeds 
245 1 0 |a Alpine metamorphism in the south-east Tauern Window, Austria; 2, Rates of heating, cooling and uplift 
300 |a p. 403-415 
500 |a In English. 26 refs. 
500 |a Abstract number: 86M/3917 
500 |a Abstractor: R.A.H. 
500 |a Affiliation: Univ. Leeds, Dep. Earth Sci.; Leeds; GBR; United Kingdom 
500 |a Affiliation: Univ. Manchester, Dep. Geol.; ; GBR; United Kingdom 
500 |a Key title: Journal of Metamorphic Geology 
500 |a Source note: Journal of Metamorphic Geology, 3(4), p.403-415. Publisher: Blackwell, Oxford, United Kingdom. ISSN: 0263-4929 
500 |a Publication type: journal article 
504 |b 26 refs. 
510 3 |a GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom 
520 |a New Rb/Sr, K/Ar and >39`Ar/>40`Ar ages are presented, including a suite of 33 mica ages for a 20 km N-S tunnel section. These and previous geochronological data are discussed in relation to the thermal history from the overthrusting of the Austro-Alpine nappes approx 65 m.y. ago to the present. The earliest metamorphic phase, involving lawsonite crystallization, was associated with emplacement of these nappes; subsequently, T in rocks beneath rose at a mean rate of 3°-6°C/m.y. until the climax of metamorphism. Published data for the age of this climax at high structural levels indicate #GT35 m.y., but a new >39`Ar/>40`Ar step-heating age of 23.8 + or - 0.8 m.y. on amphibole from near the base of Peripheral Schieferhulle indicates a later climax at deeper structural levels. Following the climax, near-isothermal uplift and erosion reduced P to approx 1 kbar before white mica closure at 19 m.y.; this implies uplift at #GT3 mm/yr. Along the tunnel, white mica K/Ar ages vary systematically from 24 to 16.5 m.y. with position relative to a late 4 km amplitude dome, whereas biotite Rb/Sr ages are uniform at 16.5 m.y. across the whole profile; doming is thus dated at 16.5 m.y. with transient uplift rates #GT5 mm/yr. At other times uplift rates were #LT1 mm/yr. 
650 7 |a Absolute age  |2 georeft 
650 7 |a Ar-40/Ar-39  |2 georeft 
650 7 |a Argon  |2 georeft 
650 7 |a Blueschist facies  |2 georeft 
650 7 |a Cenozoic  |2 georeft 
650 7 |a Crystallization  |2 georeft 
650 7 |a Dates  |2 georeft 
650 7 |a Facies  |2 georeft 
650 7 |a Faults  |2 georeft 
650 7 |a Geochronology  |2 georeft 
650 7 |a Isotopes  |2 georeft 
650 7 |a K/Ar  |2 georeft 
650 7 |a Metamorphic rocks  |2 georeft 
650 7 |a Metamorphism  |2 georeft 
650 7 |a Mica group  |2 georeft 
650 7 |a Mineral assemblages  |2 georeft 
650 7 |a Noble gases  |2 georeft 
650 7 |a P-T conditions  |2 georeft 
650 7 |a Radioactive isotopes  |2 georeft 
650 7 |a Rb/Sr  |2 georeft 
650 7 |a Regional metamorphism  |2 georeft 
650 7 |a Sheet silicates  |2 georeft 
650 7 |a Silicates  |2 georeft 
650 7 |a Stable isotopes  |2 georeft 
650 7 |a Structural geology  |2 georeft 
650 7 |a Tectonics  |2 georeft 
650 7 |a Tertiary  |2 georeft 
650 7 |a Thrust faults  |2 georeft 
650 7 |a Uplifts  |2 georeft 
651 7 |a Alps  |2 georeft 
651 7 |a Austria  |2 georeft 
651 7 |a Central Europe  |2 georeft 
651 7 |a Europe  |2 georeft 
651 7 |a Penninic Zone  |2 georeft 
651 7 |a Tauern Window  |2 georeft 
653 |a Alpine-type 
700 1 |a Droop, G. T. R.,  |e analytic author 
700 1 |a Rex, D. C.,  |e analytic author 
773 0 |t Journal of Metamorphic Geology  |d Oxford : Blackwell, Dec. 1985  |x 0263-4929  |n Journal of Metamorphic Geology, 3(4), p.403-415. Publisher: Blackwell, Oxford, United Kingdom. ISSN: 0263-4929 Publication type: journal article  |g Vol. 3, no. 4  |h illus. incl. 4 tables