[meteorite-list] Article on paleo-Bolide porduced tsunamites/seismites

jonee at epix.net jonee at epix.net
Sun Mar 19 03:52:08 EST 2006


Anyone have access to this Article?

Anyone have a link as to specifically what tsunamites and seismites are defined as?

Regards,
Elton
From:
<http://www.gsajournals.org/gsaonline/?request=get-document&doi=10.1130%2F0091-7613(2003)031%3C0557:UESFTL%3E2.0.CO%3B2>
 
Uniquely extensive seismite from the latest Triassic of the United Kingdom: Evidence for bolide impact?
Issn: 0091-7613 Journal: Geology Volume: 31 Issue: 6 Pages: 557-560
Authors: Simms, Michael J.
Article ID: 10.1130/0091-7613(2003)031<0557:UESFTL>2.0.CO;2

    ABSTRACT

    A 2–4 m thick seismite, in places overlain by a previously unreported tsunamite, can be traced across >250,000 km2 of the outcrop and subcrop of the latest Triassic (Rhaetian) Cotham Member of the Penarth Group, United Kingdom, an extent unique for the British Phanerozoic. Its consistent thickness, intensity of deformation, and preferred orientations of slump-fold axes indicate a seismic event of M > 10 with an epicenter >600 km W or NW of central Britain. The magnitude of the event is incompatible with known terrestrial mechanisms (fault, volcano) but is consistent with a major bolide impact. A short, but unknown, interval separates the top of the Cotham Member seismite from major geochemical and biotic perturbations associated with the end-Triassic extinction, although a direct link between the seismite and these other events remains equivocal. The exceptional extent of “mega-seismites” such as this may prove a useful indicator of previously undocumented bolide impacts.




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