Exploring and mapping marine placers in Vigo Estuary Shoreline Using GIS Cartographic Tools

Abstract

Marine placer deposits are accumulations of heavy minerals in coastal areas, both on beaches and in shallow water, usually consisting of ilmenite, rutile and zircon, and less commonly rare earth minerals (REEs) such as monazite and xenotime. This study investigates marine placer deposits in the Vigo Estuary (NW Spain), focusing on integrating diverse on and offshore cartographic data (geology, mineral resources, drainage, bathymetry, tides, Earth observation and others) for exploration. Six hundred two information points of marine placers have been analysed, 379 of them from shallow water, where Thiessen polygons have been spatially calculated. Our results, integrating regional cartographies in a Geographic Information System (GIS), shown great potential of placer minerals on the Santa Marta and Vao beaches (with presence of garnet, ilmenite, zircon, monazite and, locally, xenotime). This work 1) highlights the importance of collecting and analysing different previous information for marine placer exploration in integrated digital cartographies, 2) allows to program new activities to investigate local areas, 3) remark the remote sensing applications (cheap, easy and non-invasive tool), better applied to inaccessible areas, and 4) contribute to allow a sustainable resource exploration and coastal management.