STRUCTURE, GEOCHEMISTRY AND MINERALOGY OF HERCYNIAN GRANITOID ROCKS OF THE VERDIKOUSSA AREA, NORTHERN THESSALY, GREECE AND THEIR REGIONAL SIGNIFICANCE

Citation
G. Pepiper et al., STRUCTURE, GEOCHEMISTRY AND MINERALOGY OF HERCYNIAN GRANITOID ROCKS OF THE VERDIKOUSSA AREA, NORTHERN THESSALY, GREECE AND THEIR REGIONAL SIGNIFICANCE, Neues Jahrbuch fur Mineralogie. Abhandlungen, 165(3), 1993, pp. 267-296
Citations number
56
Categorie Soggetti
Mineralogy
ISSN journal
00777757
Volume
165
Issue
3
Year of publication
1993
Pages
267 - 296
Database
ISI
SICI code
0077-7757(1993)165:3<267:SGAMOH>2.0.ZU;2-W
Abstract
The Verdikoussa granitoid pluton in the Pelagonian zone of northern Th essaly consists principally of granodiorite, with marginal diorite and hornblende gabbro. Radiometric dating of biotite indicates a Hercynia n age near the Carboniferous-Permian boundary. The pluton intrudes a H ercynian paragneiss series with recumbent folding (Do phase) and is cu t by ductile shear zones (D1) with NE-trending stretching lineation, d ated as lower Cretaceous from metamorphic muscovites. This is cut by L ate Eocene brittle deformation (D2). The granodiorite has subduction-r elated trace element signatures, but the diorites most closely resembl e continental flood basalts. Some epidote shows petrographic features indicating a magmatic origin: with its host assemblage it indicates cr ystallization at pressures in excess of 6 kbar; hornblende and biotite are also high-pressure forms. The granodiorite contains K-feldspar me gacrysts that have systematic Ba variations and distinctive zonation o f inclusions that suggest a magmatic origin. The granodiorite was empl aced into an extensional regime as a result of subduction of Paleoteth ys beneath the Pelagonian zone. The rift-related mafic rocks may refle ct the resulting opening of a back-arc basin represented by the deep-w ater Permian rocks of southern Greece and Sicily.