User:A. Emraan/Ejecta blanket

Ejecta blanket
A blanket of ejecta is formed during the formation of meteor impact cratering and is composed usually of the materials of that are ejected from the cratering process. Ejecta materials are deposited on the pre-existing layer of target materials and therefore it form a inverted stratigraphy than the underlying bedrock. In some cases, the excavated fragment of ejects materials can from secondary craters. The materials of ejecta blanket come from rock fragments of crater excavation, materials due to impact melting, and outside the crater. Ejecta blankets are found on the terrestrial planets (e.g., Earth, Mars, and Mercury) and satellites (e.g., Moon). However, many of the ejecta blanket of Mars are characterized by fluidized flowing across the surface whereas ejecta of Moon and Mercury are attributed to ballistic sedimentation. Though impact cratering and resulted ejecta blanket are ubiquitous major features in the solid bodies of the solar system, the Earth rarely preserve the signature of impact ejecta blanket due to erosion. Ejecta blankets have a diverse morphology. Variations in ejecta blanket indicates different geological characteristics involved with the impact cratering process such as nature of target materials, kinetic energy involved with the impact process, gives an idea about the planetary environment e.g., gravity and atmospheric effects. Studying impact ejecta is an excellent sampling environment for the future in-situ lunar exploration

Ejecta blanket is a common feature to seen on the martian impact craters specifically around fresh impact crater. One-third of the martian impact craters with ≥ 5 km diameter have discernible impact ejecta around. Ejecta blanket may not always evenly distributed around an impact crater. Based on the structure, ejecta blanket are described as rampart, lobate, butterfly, splosh, sinuous, etc. . Many factors determine the extent of ejecta blanket that ranging from size and mass of impactor (meteorite, asteroid, or comet), surface temperature, gravity and atmospheric pressure of target body, the physical characteristics of target rock. The martian ejecta blankets are categorized broadly into three groups based on the observed morphology identified by spacecraft data :

a. Layer ejecta pattern: the ejecta blanket seems have formed by fluidization process and composed of single or multiple partial or complete layers of sheet of materials surrounding the crater. Sometime eolian modification are also common.

b. Radial ejecta blanket: the ejecta materials are emplaced by the secondary materials ejected along a balletic trajectory. This radial patterns are also found around the lunar and Mercurian craters.

c. Combination of layered and radial ejecta pattern.