[meteorite-list] AVIRIS image of Meteor Crater
From: Bernd Pauli HD <bernd.pauli_at_meteoritecentral.com>
Date: Thu Apr 22 09:46:22 2004
Matt Morgan schrieb:
> It has been suggested that it could be a cryptovolcanic feature.
> Vulcanism? ... Evidence of shocked quartz?
B.J. Kriens, E.M. Shoemaker, K.E. Herkenhoff (1999) Geology of the
impact structure, southeast Utah (Journal of Geophysical
1999, Vol.104, No.E8, pp. 18867-18887):
Evidence is as follows:
1) sedimentary strata in the center of the structure are pervasively
by top-toward-the-center thrust faulting and are complexly folded as
2) top-toward-the-center normal faults are found at the perimeter of the
3) clastic dikes are widespread;
4) the top of the underlying salt horizon is at least 500 m below the
the center of the dome, and there are no exposures of salt or associated
of the Paradox Formation in the dome to support the possibility that a
diapir has ascended through it; and
5) planar microstructures in quartz grains, fan-tailed fracture surfaces
(shatter surfaces), and rare shatter cones are present near the center
KOEBERL C. et al. (1999) A petrographical and geochemical study of
nodules, country rocks, and dike rocks from the Upheaval Dome structure,
(MAPS 34-6, Nov 1999, 861-868):
Based on our field work and the petrographic and geechemical analyses,
conclude that there is no evidence to support the suggestion that the
nodules found at the Upheaval Dome structure represent impactites.
None of the dike rocks shows any evidence of shock metamorphic
Instead, they represent sedimentary rocks with only low-strain
Iridium analyses of some of the dike rock and lag deposit samples by
coincidence spectrometry show values of 4 to 69 ppt, which is well
normal range displayed by crustal rocks. Thus, the evidence of an impact
for Upheaval Dome is still only confined to structural arguments.
> I'm not going to open the can ...
Nor am I because my two gloves do not fit :-)
Received on Tue 08 May 2001 08:21:56 AM PDT