Conference proceeding
Triggering of the largest Deccan eruptions and other possible geophysical effects of the M (sub w) nearly equal 11 Chicxulub impact
American Geophysical Union Fall Meeting, Vol.2017
Dec 2017
Abstract
The Chicxulub impact in Yucatan, Mexico, and the onset of the most voluminous phase of Deccan Traps eruptions in the Western Ghats of India both occurred within <50,000 years of the Cretaceous-Paleogene boundary (KPB), at which time nearly equal 70% of all species in the fossil record perished, including the non-avian dinosaurs. A broad range of evidence (geochronological, volcanological, geochemical, and tectonic) suggests that the aerially-extensive Wai Sub-group eruptions of the main Deccan sequence may have been triggered by the impact, probably due to a transient increase in the effective permeability of the existing Reunion plume head's mantle magmatic system. Whether similar effects might be observed in the possibly even larger volume of offshore Deccan-equivalent eruptions is not presently well-constrained by geochronological or stratigraphic data. Several lines of evidence suggest that the Chicxulub impact caused an earthquake of magnitude M (sub w) nearly equal 11, or perhaps nearly equal 1000 times more energetic than any known tectonic earthquake, and therefore well outside of human historical experience. The consequences of such a large geophysical event remain to be fully explored, but are likely to have involved triggering of volcanism globally (including the mid-ocean ridge system), tsunamis in the open oceans, seiches in confined bodies of water, soft-sediment liquefaction, and mass wasting, with some far-field events most likely responding to longer-period seismic waves. A particularly interesting case is a deposit in the Hell Creek Formation of southwestern North Dakota ("Tanis"), where a remarkable "death assemblage" of marine and terrestrial biota were buried at exactly KPB time in a local surge deposit, most likely due to a seiche on an arm or embayment of the Western Interior Seaway due to seismic waves from the Chicxulub impact. Another KPB unit (Hvar, Croatia) previously identified as a tsunami deposit might also be interpreted as having resulted from a seiche. This presentation will explore a range of possibly observable phenomena associated with the Chicxulub impact, including, of course, the possibility that both impact and triggered volcanism contributed to the mass extinction.
Metrics
8 Record Views
Details
- Title
- Triggering of the largest Deccan eruptions and other possible geophysical effects of the M (sub w) nearly equal 11 Chicxulub impact
- Creators
- M. A. Richards - University of California, BerkeleyP. R. RenneW. AlvarezRobert A. DePalmaJ. SmitM. MangaL. KarlstromL. VanderkluysenR. FainsteinS. A. GibsonAnonymous
- Publication Details
- American Geophysical Union Fall Meeting, Vol.2017
- Conference
- American Geophysical Union Fall Meeting (2017)
- Publisher
- American Geophysical Union
- Resource Type
- Conference proceeding
- Language
- English
- Academic Unit
- Biodiversity, Earth, and Environmental Science (BEES)
- Identifiers
- 991021015469004721