Multispectral optical and synthetic aperture radar imaging for geological application: A case study from Southwestern Ecuador- El Oro Province

Abstract

The advancement of geological mapping has become more efficient and effective with the use of remote sensing data.  The synergy between multispectral optical imagery and synthetic aperture radar with medium and high spatial resolution is becoming an interesting solution for Geological Surveys of developing countries. These countries have not yet been able to complete geological mapping at regional scales of 1:250000; 1:100000 (or 1:50000 in priority areas). There are several reasons for this, both in terms geographical location, presence of vegetation and high cloud cover, and the limited allocation of resources.

In this work, we present a methodology involving selecting satellite imagery, geospatial analysing, and interpreting the data to extract preliminary geological information. This approach culminates in the production of an interpreted base map to be used as input prior to the field campaign. 

The result was the identification of geological contacts of the most representative mappable units and observed structural lineaments. The validation of the product consisted in the comparison of the interpreted geological features with the rock units and structures of the published geological map, which showed a percentage similarity of 81 %. 

The methodology employed can be used to produce new geological maps as well as to update existing geological maps. It is particularly useful for remote areas that are difficult to access due to lack of communication routes, where there are social conflicts due to the opposition and resistance to the exploitation of mineral resources.