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Re: Glass bombs impactite or tektite
Darryl S. Futrell schrieb:
> I never said the Ries bombs (fladle) are tektites. Of course they are
> classified as impact melts, but impact melts can contain varying
> amounts of the projectile that made the crater. (Wabar & Henbury
> impact melts, for example, can contain millions or more of microscopic
> NiFe spherules, and sometimes even intact fragments of their NiFe
> projectiles.) This is missing at Ries.
Hello Darryl, Michael, and List!
With regard to the above info, I found this:
(1) D.A. Iseri et al. (1989) Paleomagnetic and Rock Magnetic
Examination of the Natural Remanent Magnetization of Suevite Deposits at
Ries Crater, Germany (Meteoritics 24-4, 1989, p. 280, excerpt):
Significant variations in magnetic properties with stratigraphic height
occur at Altmühle. The lower red zone appears to contain more
titaniferous and/or finer grained magnetite than all the other suevite.
This layer appears to be petrographically related to the upper sorted
suevite layer of the Nördlingen (1973) drill hole and may represent very
early ejecta. If this is the case, traces of the impactor may be found
in these deposits.
(2) H.E. Newsom (1990) Deposition of Suevite at the Ries Crater
(Meteoritics 25-4, 1990, p. 391, excerpt):
The only possible siderophile element signature of the impactor, so far
detected at the Ries is in the upper sorted layer ( E. Pernicka, P. Horn
and J. Pohl, 1987, Earth Planet.Sci.Lett. 86, 113-121). A detection of
significant levels of Ir in these basal layers would help confirm a
relationship with the upper graded or sorted layer.
Best regards,
Bernd
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