| 词条 | Fenambosy Chevron |
| 释义 |
The Fenambosy Chevron is one of four chevron-shaped land features on the southwest coast of Madagascar, near the tip of Madagascar, {{convert|180|m|ft|sp=us}} high and {{convert|5|km|mi}} inland. Chevrons such as Fenambosy have been hypothesized as providing evidence of "megatsunamis" caused by comets or asteroids crashing into Earth.[1] However, the megatsunami origin of the Fernambosy and other chevrons has been challenged by other geologists and oceanographers.[2][3] A feature called the Burckle crater lies about {{convert|1,700|km|mi}} east-southeast of the Madagascar chevrons and in deep ocean. it is hypothesized to be an impact crater by the Holocene Impact Working Group. Although its sediments have not been directly sampled, cores from the area contain high levels of nickel and magnetic components that are argued to be associated with impact ejecta. Abbott estimates the age of this feature to be about 4,500 to 5,000 years old.[1] References1. ^1 Scheffers, A., Kelletat, D., Scheffers, S. R., Abbott, D. H., and Bryant, E. A., 2008, Chevrons – enigmatic sedimentary coastal features, Zeitschrift für Geomorphologie, v. 52, no. 3, pp. 375-402. 2. ^Bourgeois, J. and Weiss, R., 2009, "Chevrons" are not mega-tsunami deposits--A sedimentologic assessment, Geology, v. 37, pp. 403–406. 3. ^Pinter, N., and Ishman, S. E., 2008, Impacts, mega-tsunami, and other extraordinary claims, GSA Today. {{webarchive|url=https://web.archive.org/web/20141017163434/http://www.gsajournals.org/archive/1052-5173/18/1/pdf/i1052-5173-18-1-37.pdf |date=2014-10-17 }} v. 18, no. 1, pp. 37–38. External links
3 : Geography of Madagascar|Geological hazards|Tsunami |
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