Seismic reflection analysis of the Manson Impact Structure, Iowa

Abstract

Our combined interpretation of new, high‐resolution seismic reflection data and reprocessed, but previously published, industrial Vibroseis data indicates that the Manson Impact Structure, Iowa, has an apparent crater diameter of 35 km, an annular trough diameter of around 21 km, a shallow floor (0.6–0.7 km), and a central uplift that has a minimum diameter of 7.5 km. The two reflection lines are coincidentally located along an east‐west radial transect and are constrained by shallow drill information. Results from the two data sets are correlative; both data sets were instrumental to the final interpretation due to the trade‐off between resolution and depth of energy penetration. Based on the combined interpretation, structural uplift of the central peak is estimated to be around 2.8 km. Onlapping seismic sequences are present at the eastern edge of the central uplift. These seismic packages, observed only in the high‐resolution line, are interpreted to represent impact breccia or debris material that was shed from the central peak or dynamically transported from outside of the crater.