Geomorphological Overview of the Lowell Mining Concessions, Ecuador

Abstract

This study focuses on determining the geomorphological characteristics of the area within and around the Lowell mining concessions located in the Morona Santiago province, Amazon region of Ecuador, to determine potential use of land applications and territorial planning for local communities in the future.

We outlined the geomorphology units proposed by the SIGTIERRAS project for the Limon Indanza and San Juan Bosco cantons. In total, 31 geoforms were briefly described in order by major to minor surface in the study area on each of the five geomorphological groups based on genesis: slope, tectonic-erosive, fluvial, structural, and polygenic. Then, slope and basin analysis were carried out mainly from digital elevation models (DEM) using QGIS free software. It was identified the Lowell mining concessions lay within two micro basins at official level 5 by Pfafstetter coding system for hydrographic units in Ecuador: basin 49981 for the Santiago River and 49983 for Zamora River, so they were characterized. As a result, multiple morphometric parameters on linear (e.g., stream order), aerial (e.g., circulatory ratio), and relief aspects were obtained for each one. Among other findings, both micro basins are order 4th according with Strahler, elongated form and apparently less susceptible to flooding suggested by values of circulatory ratio (0.36 and 0.52). Moreover, hypsometric curves of the Santiago River (49981) and Zamora River (49983) indicate the two rivers are in a mature to old stage.

In addition, we tested multispectral satellite image analysis, processing two free ASTER L1T images. Several RGB band combinations for clay and iron oxide minerals mapping are presented. However, no significant zone was detected at the study area due to vegetation. Therefore, we propose to use more advanced techniques (e.g., airborne magnetics). Finally, the new insights presented in this study could help to increase the knowledge of the geomorphological characteristics of the zone and hopefully delineate new studies on the region.