These DEMs come with improved ability to perform geospatial analysis 3 using tools such as ArcGIS and QGIS, and to virtually delineate geological features such as lineaments on a local to regional scale 6, 7. The availability of digital elevation models (DEMs) and digital surface models (DSMs) of almost all places on earth through platforms such as Google Earth, USGS earth explorer, and NASA’s world wind, and recent advances in geospatial technologies have enabled remote study of the earth’s geology and terrain properties 1– 5.
Importantly, our method is effective in remote mapping of lineaments and terrain attributes within the study area and has wider applications in other basement complex terrains. The high roughness indices observed have tectonic connotations and are related to the occurrence of lineaments, strain domains, and high degree of rock weathering. Streams in the area exhibit variable flow and partly align with the lineaments. Terrain roughness indices are high at the outcrops and lineament sites. Lineaments are widespread and dense around the batholith, occurring in areas of high elevation, and slope gradient. The case study area, the Idanre Hills in southwestern Nigeria, has a protracted history and is characterized by steep-sided outcrops of a granitic batholith and migmatite-gneiss. Our workflow is based on geographic information system tools and consists of stream network delineation, lineaments mapping, terrain roughness index calculation, and interpretation of structural fabrics from google earth aerial photographs. In this study, we use an integrated geologic mapping technique for remote mapping of lineaments and geologic terrain.
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