ESBOÇO GEOLÓGICO-TECTÔNICO DO CRÁTON DO GUAPORÉ
ESBOÇO GEOLÓGICO-TECTÔNICO DO CRÁTON DO GUAPORÉ
| dc.contributor | en-US | |
| dc.contributor | pt-BR | |
| dc.creator | ISSLER, ROBERTO SILVA | |
| dc.date | 2017-05-16 | |
| dc.date.accessioned | 2022-12-15T20:14:22Z | |
| dc.date.available | 2022-12-15T20:14:22Z | |
| dc.identifier | https://ppegeo.igc.usp.br/index.php/rbg/article/view/11161 | |
| dc.identifier.uri | https://repositorioslatinoamericanos.uchile.cl/handle/2250/5360305 | |
| dc.description | Recent work on the Precambrian of the Guaporé Craton carried out by the geologists of the RADAM Project is presented, and is suggested that both geological evidence and geochronological data indicate a broad subdivision in stratigraphic units, The Xingu Complex defined as a Petrotectonic assemblage composed by granulites, gnaisses, migmatites, granites, granodiorites, diorites, trondhjemites, syenites, amphibolites - quartzites and schists as enclaves. These rocks widely distributed have amphibolite to granulite metamorphic facies and are older than 2 500 m.y. The Grão Pará and Beneficente Groups, overlying the Xingu Complex, have been subdivided into itabirites and mafic rocks in the fìrst group, likewise the second group is composed by orthoquartzites, slates and quartzites. Possibly both groups are homologous and isochronous. The metamorphic isogrades range from amphibolite to green schist in the Grão Pará Group to green schist at Beneficente Group. The age os the Grão Pará Group is 2 000-1 800 m.y. The Uatumã Group is defined as a widespread continental terrigenous - volcanic sequence, with andesites, dacites, rhyolites, rhyodacites as well as ignimbrites, crystal tuffs, lithic tufls, vitric tuffs and flow-breccias. The volcanic rocks are associated with granitic, granodioritic and syenitic, subvolcanic, circular, cratogenic intrusives, emplaced along the meridional border of the Amazonas Syneclise. The elapsed time of the volcanic activity ranges from I 730 m.y. to I 000 m.y., through three well dated paroxisms, while the subvolcanic anorogenic ore bearing intrusives complexes have ages ranging from 1700-980 m.y. A hypothesis is put forward in which the genesis of such volcanism and subvolcanism is connected with the epeirophoresis between the Guianês and Guaporé Cratons. The platform sedimentary covers are represented by Gorotire and Prosperança Formations, that occur over large regions of the Guaporé Craton, particularly in the south of the Amazonas Syneclise. They are generally formed by non-mature lithic sandstones,lithofeldspatic sandstones, arkoses, shales, siltstones and polymictic conglomerates, and may be slightly folded and faulted. They are rich in unstable materials such as feldspars, rock fragments (phyllites, sericite-schists, chlorite-schists, shales, micaschists), and also by ferromagnesians minerals - which suggest a rapid deposition and a provenance from a basement eroded in a rather short span of time. The Prosperança and Gorotire Formatioris are believed to have an Antecarnbrian age. The meso-Cenozoic cover in the south and southeast part of Guaporé Craton, in the region of Parecis and west of Bananal, are the most expressive sedimentary clastics. The tectonic framework seems to be much more complex than was thought at few time ago. Structural features, such orogenic belts, lineaments, folds, faults, domes, etc., have been found through RADAR images and field work. | en-US |
| dc.description | Resumo indisponível. | pt-BR |
| dc.format | application/pdf | |
| dc.language | por | |
| dc.publisher | Sociedade Brasileira de Geologia | pt-BR |
| dc.relation | https://ppegeo.igc.usp.br/index.php/rbg/article/view/11161/10620 | |
| dc.rights | Direitos autorais 2017 Revista Brasileira de Geociências | pt-BR |
| dc.source | Revista Brasileira de Geociências; v. 7, n. 3 (1977); 177-211 | en-US |
| dc.source | Revista Brasileira de Geociências; v. 7, n. 3 (1977); 177-211 | es-ES |
| dc.source | Revista Brasileira de Geociências; v. 7, n. 3 (1977); 177-211 | pt-BR |
| dc.source | 0375-7536 | |
| dc.subject | en-US | |
| dc.subject | pt-BR | |
| dc.title | ESBOÇO GEOLÓGICO-TECTÔNICO DO CRÁTON DO GUAPORÉ | en-US |
| dc.title | ESBOÇO GEOLÓGICO-TECTÔNICO DO CRÁTON DO GUAPORÉ | pt-BR |
| dc.type | info:eu-repo/semantics/article | |
| dc.type | info:eu-repo/semantics/publishedVersion | |
| dc.type | pt-BR |