Resurge gullies and «inverted sombrero» morphology, Flynn Creek impact structure, Tennessee

Adrian, D. R., King, D. T., Ormo, J. 2019. Resurge gullies and «inverted sombrero» morphology, Flynn Creek impact structure, Tennessee. Meteoritics and Planetary Science 54, 11, 2758-2768 DOI: 10.1111/maps.13387

The Flynn Creek impact structure is an approximately 3.8 km diameter, marine-target impact structure, which is located in north central Tennessee, USA. The target stratigraphy consists of several hundreds of meters of Ordovician carbonate strata, specifically Knox Group through Catheys-Leipers Formation. Like other, similarly sized marine-target impact craters, Flynn Creek’s crater moat-filling deposits include, in stratigraphic order, gravity-driven slump material, aqueous resurge deposits, and secular (postimpact) aqueous settling deposits. In the present study, we show that Flynn Creek also possesses previously undescribed erosional resurge gullies and an annular, sloping surface that comprises an outer crater rim surrounding an inner, nested bowl-shaped crater, thus forming a concentric crater structure. Considering this morphology, the Flynn Creek impact structure has a crater shape that has been referred to at other craters as an «inverted sombrero.» In this paper, we describe the annular rim and the inner crater at Flynn Creek using geographic information system technology. We relate these geomorphic features to the marine environment of crater formation, and compare the Flynn Creek impact structure with other marine-target impact structures having similar features.

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