Asymmetric (Dipping) Layered Target Constrained Infilling of the Chesapeake Bay Impact Structure
The top of the crystalline basement is deepest at the eastern margin of the central crater (~1.4 km). This level is about the same as the top of the suevite and base of deepest sediment-dominated breccia and blocks in the moat of the central crater in the ICDP-USGS Eyreville core, which suggests the possibility that spillover constrained the ultimate crater geometry. Elevations of the tops of sediment-dominated breccias in the central crater and preimpact sediments outside the central crater's eastern rim are approximately the same, suggesting equilibrium between erosion and deposition with possible spillover. The variable thickness of the sediment layer and differences in strength between the sediments and the underlying crystalline rocks possibly contributed to a terraced, asymmetrical excavation flow out to various distances from the present rim of the central crater.
High and low velocity intervals that extend down to 3.5-km-depth on a USGS regional seismic survey may record effects of the transient-cavity collapse. The upper crater fill was deposited and (or) reworked by ocean resurge and multi-directional oscillation waves. This fill contains shocked rocks and melt particles that represent late-stage ejecta fallback.