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Description
This study focuses on geological mapping of young (< 20 Ma) Martian craters that are considered to be possible sources of Martian meteorites. The objective is to examine differences and similarities, taking advantage of the fresh morphologies, not affected by a long-history of post-impact processes.
Here we report preliminary results related to the geological mapping of five craters; Mojave, Zunil, Kotka, Canala, and Gasa. The mapping is achieved using ArcGIS software, CTX (5 m/px) and HiRISE (25 cm/px) images. The Mojave and Kotka craters are large, complex craters with diameters of 58 and 39 km respectively. The Zunil and Canala craters are smaller, 10 and 11 km in diameter respectively. The Gasa crater, 7 km in diameter, is a simple crater. All these craters have secondary craters and one or more layers of ejecta deposits. These craters are located at different elevations. They are located on target terrains covering the three epochs of Martian geological history. Geological units are classified into floor material, inner wall material, rim material and ejecta blanket material, smooth surfaces, block wall material, and pitted terrains. All these units occur in the five craters, but in different proportions.
Crater-related pitted materials/terrains are associated with the five craters and are possibly linked to the degassing of volatile materials in the target rock during the modification phase (Tornabene et al., 2012)). A statistical study of these pits (diameter, depth and shape) was conducted using images and CTX DTMs. The detailed mapping of the pits shows that they have a polygonal shape with 5 to 8 sides; their diameter vary from 8 to 150 meters. The pits lack rims, relief, and ejecta. They share similar walls. These pits are well preserved compared to young craters, as they have not yet been eroded or filled by other deposits. So, they can serve as chronological markers and offer insights into subsurface properties before the impact. Further work should focus on more detailed analysis of pit units, which possibly record valuable information about differences between the subsurface properties of young craters. We also plan to extend this study to all craters younger than 20 Ma.
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