Sandeep,
I have done lots of SEM work on Triassic tuffs from the Southern Alps
(Austria & Italy). The rhyolitic tuffs contain many zircons. Some of them
show spongy texture and various etching features. The backscattered image of
the SEM could also see Zr- and Y-rich clouds around altered zircons. The
tuffs are altered by burial diagenesis und may be a postdepositional
hydrothermal event.
See also:
Obenholzner, J. H. & Heiken, G.: Textural studies of altered/metamorphosed
tuiffs and secondary REE,-, Zr- and Y-minerals. Annalen des
Naturhistorischen Museums in Wien, 100A, 13-38, Vienna 1999.
There is also an abstract at AGU Spring meeting 2000.
best wishes
Johannes H. Obenholzner
NHM-Mineralogie
Postfach 417
A-1014 Vienna
Austria
Dr Sandeep Singh wrote:
> Dear All
>
> Happy New year.
>
> I am working on SHRIMPING (ion probe mass-spectrometry) the Himalayan
> zircon having metamorphic overgrowth. During this I have come across some
> of the zircons which have spongy texture. Can anybody give me some
> references on that which explains the phenomenon.
>
> Sandeep
>
> ***********************************************************************
> Dr. Sandeep Singh
> (office) (residence)
>
> BOYSCAST Fellow 5/54, Melville Pde,
> Centre for Global Meltallogeny South Perth, WA, 6151
> Department of Geology and Geophysics Australia
> University of Western Australia
> Nedlands, Western Australia 6907 phone: +61 (08) 9368 4035 (res.)
> AUSTRALIA
>
> phone: +61 (08) 9380 2640 (off.)
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> website: www.sandeepsingh.20m.com
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