Dear Santanu,
Is there foliation?
garnet+hornblende+epidote+phengite+rutile+quartz schist
no foliation?
garnet+hornblende+epidote+phengite+rutile+quartz fels
In Winkler's book that would be the probable nomenclature, using strictly present minerals and
orientation or not. I still think Winkler's nomenclature is quite simple and very useful.
best
Renato
On Wed, 17 Dec 2014 17:32:02 +0200, Ioannis Baziotis wrote
> Dear Santanu,
>
> I would prefer a name like "amphibolitized eclogite" for your rock.
>
> Regards,
>
> Baziotis Ioannis
>
> ----------------------------------------------------------------
> Ioannis Baziotis [log in to unmask]
> Lecturer Professor of Mineralogy and Petrology
> Agricultural University of Athens
> Laboratory of Mineralogy and Geology
> Athens, 11855 Greece
> (+30)210-529-4156
> [UTF-8?]-----Αρχικό [UTF-8?]μήνυμα-----
> From: Santanu Kumar Bhowmik
> Sent: Wednesday, December 17, 2014 5:12 PM
> To: [log in to unmask]
> Subject: Rock Nomenclature
>
> Dear Colleagues,
>
> I am seeking your suggestions on the nomenclature of a metamorphic
> rock with the assemblage
> garnet+hornblende+epidote+phengite+rutile+quartz. This assemblage
> which became stable during peak metamorphism yielded P-T estimate of
> ~ 15-16 kbar,~ 590-610 C. If this assemblage is evaluated with
> metamorphic rocks that are related to metamorphism during subduction
> initiation, the closest rock name that comes to my mind is
> garnetiferous amphibolite. However, in the strictest sense, the rock,
> in the absence of plagioclase cannot be an amphibolite, if we use
> amphibolite in facies sense. At the same time, the estimated P-T
> range lies in the eclogite facies, also supported in part by
> complete elimination of plagioclase. However, with omphacitic
> clinopyroxene being absent, the rock is also not an eclogite in the
> strictest sense. One additional information in this regard is that
> Na in the protolith is completely partitioned in Hbl, which shows
> substantial presence of Na in the M4 site, apart from its general
> occurrence in the A site.
>
> Your comments and observations are welcome.
>
> With regards,
>
> Santanu
> -------------------------------------------------------
> Dr. Santanu Kumar Bhowmik
> Professor
> Department of Geology & Geophysics
> Indian Institute of Technology
> Kharagpur-721 302
> India
> Mobile:+919434041791
> Telephone:+91-3222-283390(O), 283391, 279766(R)
==========================================================
Dr Renato Moraes
Instituto de Geocincias Universidade de So Paulo
Departamento de Mineralogia e Geotectnica
Rua do Lago, 562 - Cidade Universitria
CEP 05508-080 - So Paulo SP
Brazil
Telefone: INT + 55 + 11 + 3091-0131
FAX: INT + 55 + 11 + 3091-4258
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