Uso de imagens ASTER no mapeamento lito- estrutural e de zonas de alteração-estudo de caso do distrito de Chifunde, Província de Tete

Abstract

The use of satellite images (Telesensing) plays an important role in both our work geological cartography and mineral exploration, as well as geotechnical-environmental studies among others, due to its greater area range, quality in terms of spatial resolution and low costs. This scientific project demonstrates the contribution to geological-structural and zones of change in the area under study through the integration of ASTER, ASTER satellite images GDEM, and SRTM, in association with local geology data particularly from the north of Tete Province, central Mozambique region. To this end, the work consists of several levels of digital processing, subdivided into pre-processing (band resampling for the VNIR subsystem, and atmospheric and radiometric measurements) and processing (combination, bandwidth ratio, and application of techniques of relevance shading and SAM, which allowed identifying, delimiting the lithologies and visualizing the lineaments and alteration zones. The study area covers a part of the northern zone of Tete Province (Part of the District of Chifunde) corresponding to sheet 1432 in which it was inserted in the West Gondwana lands and is presented by metamorphosed plutonic and supracrustal rocks, with Mesoprotezoic ages, in the present scientific project based on the spectral response presented by each type of rock, was possible to identify and delimit what made the adjustment of lithological contacts possible, and in more detail in geological information in the study area. In structural terms, three fault domains were distinguished with WSW- ENE,SW-NE,N-S. and four main lineament domains were identified NNE- SSW, WSW-ENE, NW-SE and NE-SW. On the other hand, areas of alteration of which its distribution is controlled by faults/lineaments with the main aforementioned fault orientations, shear zones, and igneous intrusions that are identified as favorable zones for occurrences of gold mineralization associated with sulfides.