02439naa a2200229 a 450000100080000000500110000800800410001910000200006024500600008026000090014052017850014965000110193465000120194565000130195765000130197065300160198370000190199970000250201870000200204370000180206377301280208118057302017-04-11       1981    bl ---       0--  u    #d1 aDEL'ARCO, J. O.  aGeologia do pré - cambriano na folha SE.21 - Corumbá.  c1981  aThis account of the Precambrian geology of the SE.21 Corumba Sheet is based on the results of geological mapping by Projeto RADAMBRASIL  at s scale of 1:1,000,000. The Sheet is bounded by the latitudes of 16 00' and 20 00'S, and the longitude of 54 00' and 60 00'W, including an area of 193,960 km2 within the States of Mato Grosso and Mato Grosso do Sul, limited to the west by the frontier with Bolivia. The basement of this area forms part of the southern extension of the Amazonian Craton, and includes polymetamorphic rocks of Lower (?) to Middle Precambrian age, separated geographically, petrologically and geochronologically in two distinct complexes: Rio Apa and Xingu. The Rio Apa Complex contains granites, granodiorites, granite-gneisses, diorite-gneisses an schists, and radiometric determinations showed a Rb/Sr Isochron age of 1726 +- 38 m.y., considerded to be minimum for this unit. The Xingu Complex comprioses granites, granodioritos, quartz-monozites, granite-gneisses and cataclasites, and yielded a Rb/Sr isochron age of 1433 +- 69m.y. The Upper Precambrian metasediments of the Aguapei Group rest un conformably on the Xingu Complex, and are divided into the Fortuna, Vale da promissao and Morro Cristalino Formations. A possible outcropof basic-ultrabasic rocks, associated with the Rincon del Tigre Intrusives identified in Bolivia, is apparently younger than the Aguapei Group. The upper part of the Precambrian stratigraphy of this area is formed by the rocks belonging to the paraguai-Araguaia Fold Belt witch include the Cuiaba Group, the Corumba Group (Puga, Cerradinho, Bocaina and Tamengo Formations), the Jacadigo Group (Urucum and Santa Cruz Formations), and the Alto Paraguai Group (Moenda, Araras, Raizama and Sepotuba Formations in this area).  aBrazil  ageology  aPantanal  aGeologia  aMato Grosso1 aTARAPANOFF, I.1 aPEREIRA, L. G. da M.1 aSOUZA, S. L. de1 aLUZ, D. S. da  tIn: SIMPOSIO DE GEOLOGIA DO CENTRO-OESTE, 1981, Goiania. Ata... Goiania: Sociedade Brasileira de Geologia, 1981. p.154-176.