Baldo, Edgardo G. and Casquet, César and Galindo Francisco, Mª del Carmen (1998) Datos preliminares sobre el metamorfismo de la Sierra de Pie de Palo, Sierras Pampeanas Occidentales (Argentina). Geogaceta, 24 . pp. 39-42. ISSN 0213-683X
The Sierra de Pie de Palo belongs to the Western Sierras Pampeanas. Although still poorly known in detail, the sierra consists of a relatively autochthonous sequence of shelf sediments metamorphosed to low grade (the Caucete Group) and an allochthonous complex of polymetamorphic medium-to-high grade igneous and sedimentary rocks thrust towards the west and northwest. Mylonitization is widespread. Radiometric dating by different methods (U-Pb, 4°Ar/39Ar and K-Ar) suggests that at least two tectonothermal events are present in the allochthonous: Grenville (ca. 1 Ga) and Famatinian (480-312Ma). Metamorphism has been studied in a Ca-rich pelite with a complex mineralogical composition (Qtz, Ms, Pg, Bt, Grt, Ky, Hbl, St, Rt, 111, PI, Ep). This rock is a mylonite. Three metamorphic stages are recognized: the first two correspond to a prograde M, metamorphism under relatively high P/T conditions (peak at 13kb and about 600ºC). The second is related to mylonitization (Mm 1) with T - 575ºC and P < 1 Okb. We suggest that this rock is polymetamorphic, M, metamorphism beirig probably related to the Grenville orogeny and Mmyl to the Famatinian orogeny.
|Uncontrolled Keywords:||High-pressure metamorphism, Ca-rich pelites, Geocronology, Sierra de Pie de Palo, Sierras Pampeanas Occidentales, Argentina|
|Subjects:||Sciences > Geology > Petrology|
|Deposited On:||04 Nov 2010 12:31|
|Last Modified:||16 Nov 2010 12:05|
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