Deriving a denudation index for terrestrial meteorite impact craters using drainages as proxies
Department of Civil, Environmental, and Geospatial Engineering
Meteorite impact craters are morphologic features that can develop characteristic radial, centripetal, and concentric drainage patterns. With age, fluvial activity denudes this morphologic feature, thereby erasing the evidence of a prominent geologic event. Apart from morphology and age, the target lithology and climate also influence crater denudation. In this study, we derive an index, called the Denudation Index (DI), which is a measure of rim degradation caused by fluvial activity. DI was derived by summing the average of first order drainages that retains radial and centripetal patterns to the total number of streams. DI was obtained through the extraction of drainages from digital elevation models (DEM) for 71 craters formed since the Phanerozoic eon. The DI was correlated with the morphology, age, lithology and paleoclimate. Paleoclimatic data corresponding to each crater was generated by reconstructing the crater paleo-positions through GPlates and superimposing the same to the Scotese's Global Climate Model with an interval of 1 Ma. The study revealed that denudation is more prominent in a complex crater's formation on a crystalline target rock than in simple crater on a sedimentary target. Craters in the equatorial rainy climate are more denudating than other climates. Thus, this study provides a new, rather novel, method of expressing the denudation of a crater. Furthermore, this study shows that the drainage network is a unique signature that can be used for depicting the denudation of morphologic features, especially a prominent one like the meteorite impact crater.
Deriving a denudation index for terrestrial meteorite impact craters using drainages as proxies.
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