Water resurge into newly excavated impact craters causes both erosion and conspicuous graded deposits in those cases where the water is deep enough to overrun the elevated crater rim. We compare published information on resurge deposits from mainly the Lockne, Tvären, and Chesapeake Bay structures with new results from low-velocity impact experiments and numerical simulations. Notwithstanding the limitations of each of the analytical methods (observation, experiment, and simulation), we can visualize the resurge process for various initial impact-target configurations, for which one single method would have been insufficient. The focus is on the ways in which variations in impact angle and target water depth affect water-cavity collapse, the initiation and continuation of the resurge, its transformation into a central water plume, and subsequent antiresurge, as well as tsunami generation. We show that (1) the resurge at oblique impacts, as well as impacts into a target with a varied water depth, becomes strongly asymmetrical, which greatly influences the development of the central water plume and sediment deposition; (2) the resurge may cause a central peak–like debris cumulate at the location of the collapsing central water plume; (3) at relatively deep target waters, the resurge proper is eventually prevented from reaching the crater center by the force of the antiresurge; (4) the antiresurge is separated into an upper and a lower component; (5) the resurge from the deep-water side at an impact into water of varied depth may overcome the resurge from the shallow-water side and push it back out of the crater; and (6) contrary to rim-wave tsunamis, a collapse-wave tsunami requires deeper relative water depth than that of Lockne, the crater-forming impact event with the currently deepest known target water depth.

Collapse and inward slumping of unconsolidated sedimentary strata expanded the Chesapeake Bay impact structure far beyond its central basement crater. During crater collapse, sediment-loaded water surged back to fill the crater. Here, we analyze clast frequency and granulometry of these resurge deposits in one core hole from the outermost part of the collapsed zone (i.e., Langley) as well as a core hole from the moat of the basement crater (i.e., Eyreville A). Comparisons of clast provenance and flow dynamics show that at both locations, there is a clear change in clast frequency and size between a lower unit, which we interpret to be dominated by slumped material, and an upper, water-transported unit, i.e., resurge deposit. The contribution of material to the resurge deposit was primarily controlled by stripping and erosion. This includes entrainment of fallback ejecta and sediments eroded from the surrounding seafloor, found to be dominant at Langley, and slumped material that covered the annular trough and basement crater, found to be dominant at Eyreville. Eyreville shows a higher content of crystalline clasts than Langley. There is equivocal evidence for an anti-resurge from a collapsing central water plume or, alternatively, a second resurge pulse, as well as a transition into oscillating resurge. The resurge material shows more of a debris-flow–like transport compared to resurge deposits at some other marine target craters, where the ratio of sediment to water has been relatively low. This result is likely a consequence of the combination of easily disaggregated host sediments and a relatively shallow target water depth.

The Ordovician (early Sandbian) Lockne impact crater in central Sweden formed in a sea at least 500 m deep. The structure and impact stratigraphy are sufficiently well preserved to permit detailed analysis of the cratering process. The target seabed consisted of a partly lithified, 75–80-m-thick sediment cover resting on continental crystalline basement. An over 7-km-wide inner crater formed in the basement. The surrounding sediment cover was almost completely removed within about 2 km from the rim of the inner crater. At 2.5–8.5 km from the rim, the thickness of preserved preimpact sediment increases with the distance to the inner crater. The top of the preserved sediment is mostly limestone breccia. Brecciation was probably driven by extremely forceful flow of water that was charged with sediment to the limit of its carrying capacity, and therefore stirred deeper than it would erode. The resulting lithology, for which we suggest the term “water-blow breccia,” is monomictic, with all clasts deriving from the underlying parent rock. Great volumes of crystalline ejecta were emplaced during and immediately after water-blow brecciation. The resurge, connected with the subsequent collapse of the water crater, deposited a mixed breccia of transported clasts that includes eroded limestone of various local provenances, as well as crystalline ejecta. The resurge breccia occurs extensively in the region, even outside the area characterized by occurrences of water-blow breccia. Its thickness and clast sizes decrease away from the crater.