Detection of Ring Structures and Their Surrounding Tectonic Pattern in South-Algeria, North-Mali and North- Niger based on Satellite Data

Abstract

This study is focused on the detection of circular features with different sizes, origins, and state of erosion as well as on their surrounding tectonic pattern based on different satellite images of Southern Algeria, Northern Mali and Northern Niger. Sentinel 2- and Landsat 8/9-images and Sentinel 1- and ALOS L-band Phased Array Synthetic Aperture Radar (PALSAR)-radar data help to identify larger ring structures and smaller circular features, most of them related to magmatic intrusions into the subsurface, but also to cosmic impacts, with varying ages and state of erosion. Some of them seem to be unknown so far as they are partly covered by aeolian sediments and become only visible on radar images. Digital Elevation Model (DEM) data and the DEM derived morphometric maps support these investigations in a GeoInformation System (GIS) embedded environment. Some of the ring structures are only visible on morphometric maps, traced by circular arrangements of slope gradients or concentric drainage patterns. The large, circular structures and the smaller circular features such as volcanic features (cinder cones, calderas, maars, impact craters) were digitized and merged in a GIS with available geologic information.