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Metamorphic envelope of two granitic intrusions in the Wołowiec - Łopata Massif (Western Tatra Mts, Central Western Carpathians)
Journal article   Peer reviewed

Metamorphic envelope of two granitic intrusions in the Wołowiec - Łopata Massif (Western Tatra Mts, Central Western Carpathians)

Aleksandra Gaweda, Artur Deditius and Anna Pawlik
Mineralogia Polonica, Vol.30, pp.63-80
1999
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Abstract

The Wołowiec-Łopata massif in the Polish Western Tatra Mts is a place where the relationships of metamorphic envelope of two granitic bodies: alaskite and Rohače Granite can be observed. The presence of all three Al2SiO5 polymorphs with specific mineral assemblages provided the possibility to calculate the P-T path of metamorphic evolution of the massif. Progressive mineral reactions produced by the syntectonic alaskite intrusion occurred during shearing at 660-669C while the pressure dropped slightly from 8.3-8.8 to 6.9-7.4 kbars. Local heating to 8000C, stimulate by the alaskite intrusion, caused metastable blastesis of fibrolitic sillimanite as the result of biotite decomposition. The retrogressive changes started under late magmatic conditions (T = 680-700C, P = 5-6 kbars) and continued down during cooling of the massif. The retrogressive P-T path was broken by the intrusiun of Rohače Granite. It was emplaced into the complex in the extensional regime (4-6 kbars, 650-700C). The Rohače intrusion was screened by the older alaskite, so the influence of the granodioryte body on the metamorphic host rocks was restricted to the zones of tectonic softening and/or its immediate vicinity. Further cooling continued to the temperatures below 500C and pressure slightly above 2 kbars. The Wołowiec-Łopata massif represents the unusual place where the Rohače granodiorite intrusion caused retrogressive changes when compared with the peak metamorphic conditions.

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