Morphometric and structural parameters of impact craters in Algeria: Control of sedimentary target rocks and effect of post impact process

Abstract

The Earth Impact Database (EID) currently includes four impact craters located in Algeria. These craters are well-exposed, morphologically visible, partially covered and all situated in a vast, very arid Saharan geological domain devoid of any vegetation cover. Consequently, they can be easily identified using the TanDEM-X digital elevation model and Alsat-1B satellite images. The aim of this work is to identify the characteristics of sedimentary target rocks that control the morphometric and structural parameters of Algerian craters, as well as the effects of post-impact processes. Crater exposure, type, and structure (depth-diameter ratio, rim-to-floor height, central peak and moat diameters), outline (circular, polygonal, elongated) and impactite types are therefore discussed. Relative or stratigraphic dating and erosion/burial rates are estimated for the craters. Results indicate that Amguid and Talemzane are simple, well-preserved young craters, closer to a pristine state. Tin Bider is a complex exposed structure showing an irregular outline with a well-developed central peak and two rings. Ouarkziz is a transitional crater; based on its diameter alone it is classified as a complex crater; however, a topographic central peak is not observed. A deep formation uplift is detected in the central zone, interpreted as a stratigraphic peak where the uplift has not reached significant heights to form a clearly visible peak. This may be due to the reduced diameter of Ouarkziz, which is smaller than what has always been described.