TY - JOUR
T1 - The Rio Lacteo Formation of Southern Chile. Late Paleozoic orogeny in the Andes of southernmost South America
AU - Bell, C. M.
AU - Suárez, M.
N1 - Funding Information:
Field support was provided by the Chilean Research Council (FONDECYT) projects No. 1930246 and 1960097, the Chilean Servicio Nacional de Geologı́a y Minerı́a, and the Aysén Regional Government. Overseas travel for C. M. Bell was supported by a Royal Society grant. R. De la Cruz and D. Quiroz provided data from adjacent areas. Helpful comments and constructive criticism of earlier drafts of the manuscript were provided by I. W. D. Dalziel, D. Cunningham, B. C. Storey, and H. R. Rollinson. R. J. Pankhurst, and a second reviewer provided helpful advice. Thin section analysis was assisted by K. A. Jones. Diagrams and maps were prepared by K. L. Sharp.
PY - 2000/5/1
Y1 - 2000/5/1
N2 - The late Paleozoic Rio Lacteo Formation forms the metamorphic basement of the Mesozoic and Cenozoic Andean orogenic belt in the Lago General Carrera area (about 45°S) of southern Chile. The rocks were emplaced during a late Paleozoic orogeny on the active continental margin of southernmost South America. They form part of a SW to NE striking fold belt with dominant overthrusting towards the SE. The metamorphic grade and structural style are indicative of deformation in the crystalline core of an orogenic belt, probably resulting from microplate interactions, rather than fore-arc accretion. The Rio Lacteo Formation represents metamorphorphosed marine turbidites, limestones and pyroclastic rocks which accumulated in an intraplate setting. The strata were intensely deformed and subjected to medium grade, greenschist to epidote-amphibolite facies metamorphism in pre-late Carboniferous times. Four phases of deformation have been identified. The first phase produced a strong planar fabric. This was followed by subhorizontal SW to NE stretching and NW to SE compressive shortening. The third phase formed a spaced cleavage related to E-W extension. The fourth episode produced broad shear zones, characterised by chevron folding and intrusive dykes of crush breccia, related to thrusting towards the southeast. (C) 2000 Elsevier Science Ltd. All rights reserved.
AB - The late Paleozoic Rio Lacteo Formation forms the metamorphic basement of the Mesozoic and Cenozoic Andean orogenic belt in the Lago General Carrera area (about 45°S) of southern Chile. The rocks were emplaced during a late Paleozoic orogeny on the active continental margin of southernmost South America. They form part of a SW to NE striking fold belt with dominant overthrusting towards the SE. The metamorphic grade and structural style are indicative of deformation in the crystalline core of an orogenic belt, probably resulting from microplate interactions, rather than fore-arc accretion. The Rio Lacteo Formation represents metamorphorphosed marine turbidites, limestones and pyroclastic rocks which accumulated in an intraplate setting. The strata were intensely deformed and subjected to medium grade, greenschist to epidote-amphibolite facies metamorphism in pre-late Carboniferous times. Four phases of deformation have been identified. The first phase produced a strong planar fabric. This was followed by subhorizontal SW to NE stretching and NW to SE compressive shortening. The third phase formed a spaced cleavage related to E-W extension. The fourth episode produced broad shear zones, characterised by chevron folding and intrusive dykes of crush breccia, related to thrusting towards the southeast. (C) 2000 Elsevier Science Ltd. All rights reserved.
UR - http://www.scopus.com/inward/record.url?scp=0342323867&partnerID=8YFLogxK
U2 - 10.1016/S0895-9811(00)00005-5
DO - 10.1016/S0895-9811(00)00005-5
M3 - Article
AN - SCOPUS:0342323867
SN - 0895-9811
VL - 13
SP - 133
EP - 145
JO - Journal of South American Earth Sciences
JF - Journal of South American Earth Sciences
IS - 1-2
ER -
