RT Journal Article
T1 The Pampean Orogeny of the southern proto-Andes: Cambrian continental collision in the Sierras de Cordoba
A1 Rapela, C. W.
A1 Pankhurst, R. J.
A1 Casquet Martín, César
A1 Baldo, E.
A1 Saavedra, J.
A1 Galindo Francisco, María Del Carmen
A1 Fanning, C. M.
AB A detailed study of the pre-Silurian geology of the Sierras de Córdoba, Eastern Sierras Pampeanas, is used to define the sequence of magmatic and metamorphic events during the Pampean orogeny. This primarily involved Early to Mid-Cambrian subduction and terrane collision at the western margin of Gondwana during the amalgamation of the super-continent. Evidence for this is based principally on new information concerning (a) regional mapping and field relations, (b) analysis of the structures, deformational history and meta-morphic evolution and (c) geochronology and geochemistry of the igneous and metamorphic rocks. The main events recognized are (1) Late Proterozoic break-up of Rodinia (Nd model ages of 1500 ± 200 Ma, inherited zircons 800–1400 Ma), (2) development of an Early Cambrian passive margin sequence (Puncoviscana Formation and equivalents), (3) emplacement of metaluminous calc-alkaline granitoids (G1a, dated at 530 ± 3 Ma) as a result of NE-directed subduction, (4) crustal thickening, ophiolite obduction, compression and high-grade metamorphism (M2: 8.6±0.8 kbar, 810 ± 50°C, c.525 Ma) related to collision, and culmina-ting in (5) isothermal uplift and widespread low-P anatexis (M3, 4.0±0.5 kbar, 715 ± 15°C, c.520 Ma). The last event is responsible for the linked generation of highly peraluminous granites (G1b) and cordieritites. Subsequent emplacement into the accreted terrane of Ordovician trondhjemite-tonalites (500-470 Ma) and dextral wrench shear are interpreted as inner cordilleran counterparts of the Famatinian arc, which developed to the west along the newly-formed proto-Andean margin.
PB The Geological Society
YR 1998
FD 1998-01
LK https://hdl.handle.net/20.500.14352/118894
UL https://hdl.handle.net/20.500.14352/118894
LA eng
NO Rapela, C. W., Pankhurst, R. J., Casquet, C., Baldo, E., Saavedra, J., Galindo, C., & Fanning, C. M. (1998). The Pampean Orogeny of the southern proto-Andes: Cambrian continental collision in the Sierras de Córdoba. Geological Society, London, Special Publications, 142(1), 181-217. https://doi.org/10.1144/GSL.SP.1998.142.01.10
NO Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina
NO Commission of the European Communities
DS Docta Complutense
RD 6 abr 2025