Abstract

GUERESCHI, A.B.  and  MARTINO, R.D.. Textural path of metamorphic rocks from central portion of the eastern side of Sierra de Comechingones, Córdoba, Argentina. Rev. Asoc. Geol. Argent. [online]. 2003, vol.58, n.1, pp.61-77. ISSN 0004-4822.

The metamorphic basement on the eastern side of Sierra de Comechingones (Córdoba), consist mainly of Bt-Grt gneisses, stromatic migmatites and diatexites. Considering textural paths followed by metamorphic rocks a clockwise loop is established. It has been recognized a medium-grade metamorphic event M1-D1 preserved like relictic rocks, mineral paragenesis (Grt + Bt St Rt) and structures (S1 foliation). After overcome St + Bt stability and higher pressure conditions of Grt + Rt, these rocks reached metamorphic peak conditions M2-D2 producing high-grade paragenesis, partial melting of metapelitic rocks (stromatic migmatites with Sil + Kfs) and developing a pervasive metamorphic foliation S2. The dominant pelitic assemblage found in gneisses and migmatites is Qtz + Pl + Bt + Grt + Sil + Kfs. After the metamorphic peak, a dynamic event M3-D3 with high temperature shear deformation is produced. Later, a decompression + cooling event (M4) took place, producing plagioclase coronas around garnet in all rocks and a second anatexis with Crd + Kfs diatexites. A cooling + hydration event (M5) followed decompression is evidenced by biotite coronas around garnet. The path was closed during the M6 hydration event developed at lower temperatures producing mineral alterations. This high-grade metamorphic basement would form the internal zone of a Late Precambrian-Early Cambrian collision of Pampia terrane with the western Gondwana margin.

Keywords : Petrology; Metamorphism; Textural path; Sierra de Comechingones; Córdoba.

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