Publication Abstracts

Rampino 1999

Rampino, M.R., 1999: Argument supporting explosive igneous activity for the origin of "cryptoexplosion" structures in the midcontinent, United States: Comments Geology. vol. 27, no. 3, pp. 279-280, doi:10.1130/0091-7613(1999)027<0279:ASEIAF>2.3.CO;2.

In the Rampino and Volk (1996) study of the eight structures in the central U.S. chain, we reviewed all previous work and concluded that the ages of all are very poorly constrained, based as they are on perfunctory geologic mapping and crude radiometric dating (mostly K/Ar and Rb/Sr) of uncertain materials; most were published more than 30 years ago. This early work was done before impact was a respectable alternative to endogenous processes, and thus prior to the many studies that have determined the diagnostic characteristics of impact-induced deformation, impact breccias, impact melts, and pseudotachylites (e.g., French, 1990).

We also noted that shock features unique to hypervelocity impact (shocked quartz and shatter cones) were known from Decaturville and Crooked Creek (e.g., Short and Bunch, 1968; Offield and Pohn, 1977), but careful searches for such features have never been attempted for the other six structures. We did not mean to imply that other features (e.g., shattered quartz grains, breccia dikes) found at these structures were diagnostic evidence of impact, only that they were suggestive. Detailed mapping of the structures and breccia distribution, a search for diagnostic shock features, and reliable radiometric dating would be useful. Luczaj (1998), however, presented no new data, and reviewed the same largely pre-1970s literature that we used in the Rampino and Volk (1996) paper.

Luczaj referenced French (1990) to imply that a controversy still exists with regard to the process that produces "cryptoexplosion" structures. The reality is just the opposite. %EP 285

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BibTeX Citation

@misc{ra09700b,
  author={Rampino, M. R.},
  title={Argument supporting explosive igneous activity for the origin of "cryptoexplosion" structures in the midcontinent, United States: Comments Geology},
  year={1999},
  volume={27},
  number={3},
  pages={279--280},
  doi={10.1130/0091-7613(1999)027%3C0279%3AASEIAF%3E2.3.CO;2},
}

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RIS Citation

TY  - JOUR
ID  - ra09700b
AU  - Rampino, M. R.
PY  - 1999
TI  - Argument supporting explosive igneous activity for the origin of "cryptoexplosion" structures in the midcontinent, United States: Comments Geology
VL  - 27
IS  - 3
SP  - 279
EP  - 280
DO  - 10.1130/0091-7613(1999)027%3C0279%3AASEIAF%3E2.3.CO;2
ER  -

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