Large Meteorite Impacts and Planetary Evolution IV
Mechanisms of late synimpact to early postimpact crater sedimentation in marine-target impact structures
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Published:September 01, 2010
This study is a first attempt to compile sedimentological features of synimpact to postimpact marine sedimentary successions from marine-target impact craters utilizing six well-studied examples (Chesapeake Bay, Gardnos, Kärdla, Lockne, Mjølnir, and Wetumpka). The sedimentary formations succeed autochthonous breccias and, in some cases, allochthonous suevites. These late synimpact and early postimpact depositional successions (on top of the suevites) appear to be in comparable stratigraphic developments and facies in marine-impact craters. Their composition reflects common mechanisms of sedimentation; they were developed from avalanches/scree, slides, and slumps through sequences of mass-flow–dominated deposition before ending with density currents and fine-grained sedimentation from fluidal flow and suspension. With detailed study, it may be possible to separate the late synimpact and early postimpact successions based on their clast composition relative to target stratigraphy. The process-related comparisons presented here are highly simplified, including characteristics of moat, central peak, and marginal basin sedimentation of both simple and complex craters.
- Alabama
- Arctic Ocean
- Baltic region
- Barents Sea
- breccia
- Chesapeake Bay
- Chesapeake Bay impact structure
- chronology
- cratering
- currents
- debris avalanches
- density currents
- Estonia
- Europe
- impact breccia
- impact craters
- impact features
- impactites
- impacts
- Lockne Crater
- marine environment
- mass movements
- mechanism
- metamorphic rocks
- Norway
- Scandinavia
- sedimentary rocks
- sedimentation
- size
- slumping
- succession
- suevite
- suspended materials
- Sweden
- turbidite
- United States
- Western Europe
- Wetumpka
- Kardla Crater
- Mjolnir Crater
- Gardnos Crater
- complex craters
- simple craters