Shock-wave-induced fracturing of calcareous nannofossils from the Chesapeake Bay impact crater
Geology
By: Self-Trail J.M.
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Abstract
Fractured calcareous nannofossils of the genus Discoaster from synimpact sediments within the Chesapeake Bay impact crater demonstrate that other petrographic shock indicators exist for the cratering process in addition to quartz minerals. Evidence for shock-induced taphonomy includes marginal fracturing of rosette-shaped Discoaster species into pentagonal shapes and pressure- and temperature-induced dissolution of ray tips and edges of discoasters. Rotational deformation of individual crystallites may be the mechanism that produces the fracture pattern. Shock-wave-fractured calcareous nannofossils were recovered from synimpact matrix material representing tsunami or resurge sedimentation that followed impact. Samples taken from cohesive clasts within the crater rubble show no evidence of shock-induced fracturing. The data presented here support growing evidence that microfossils can be used to determine the intensity and timing of wet-impact cratering.
Suggested Citation
Self-Trail J.M., 2003, Shock-wave-induced fracturing of calcareous nannofossils from the Chesapeake Bay impact crater: Geology, v. 31, no. 8, p. 697-700, https://doi.org/10.1130/G19678.1.
| Publication type | Article |
|---|---|
| Publication Subtype | Journal Article |
| Title | Shock-wave-induced fracturing of calcareous nannofossils from the Chesapeake Bay impact crater |
| Series title | Geology |
| DOI | 10.1130/G19678.1 |
| Volume | 31 |
| Issue | 8 |
| Year Published | 2003 |
| Language | English |
| Larger Work Type | Article |
| Larger Work Subtype | Journal Article |
| Larger Work Title | Geology |
| First page | 697 |
| Last page | 700 |