[meteorite-list] North American Impact Craters

From: Bernd Pauli HD <bernd.pauli_at_meteoritecentral.com>
Date: Thu Apr 22 10:18:28 2004
Message-ID: <3E52729C.A9442308_at_lehrer.uni-karlsruhe.de>

Paul Heinrich inquired:

> What was the most recently discovered
> impact crater for the United States?

Hello Paul and List,

E.M. Shoemaker et al. (1995) Impact crater identified on
the Navaho Nation near Chinle, Arizona (abs. Meteoritics 30,
1995, p. 578):

"A small impact crater has been identified about 8 km north of
Chinle, Arizona, on the Navajo Nation. Preliminary studies show
that the crater is in a north-south dircection, measuring about
23 x 34 m in diameter, with a depth of about 1.3 m. The impact
origin of the crater is identified by its shape, subsurface deform-
ation, and an Fe-Ni oxide fragment. We estimate the age to be
about 150-250 yr."

> It doesn't matter whether the
> structure is buried or deeply eroded.

Maybe this one:

C. Koeberl, W.U. Reimold, R.A. Powell, Shocked Quartz
and Impact Melt Rock at the Ames Structure, Oklahoma
(abs. in Meteoritics 29, 1994, 483):

"The Ames structure in NW Oklahoma (centered at about 3615'N,
9812'W) is evident in the form of a relatively circular, concentric,
structural depression with a minimum diameter of about 15 km, on
top of the Upper Ordovician Sylvan Shale. The feature is covered
by about 3000 m of sediments. It is marked by two concentric rims,
an outer ring ... that is ca. 1.5-3 km wide and an inner ring structure
that seems to be the collapsed remnant of a structural uplift ..."

Best regards,

Received on Tue 18 Feb 2003 12:51:24 PM PST

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