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Dear Colleagues,

Spherulites do occur in fault pseudotachylytes (but they are not always present).

Neoformed / coseismic micas, crystallized from a frictional melt, may display a consistent fabric/SPO, acquired through cosesmic viscous flow [e.g., Ferré, E.C., Geissman, J.W., Chauvet, A., Vauchez, A. and Zechmeister, M.S. (2015). Focal mechanism of prehistoric earthquakes deduced from pseudotachylyte fabric. Geology, doi:10.1130/G36587.1. ].

In contrast, devitrification / postseismic micas, formed through alteration of glass, tend to display random (not necessarily radiating) fabrics/SPO.

Kind regards and Happy New Year to all!

Eric
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Dear Arindam,

the micas produced by devitrification/alteration of the glass commonly

form spherulites while the micas crystallized from the melt do not.

Leonardo

 

Da: Tectonics & structural geology discussion list [mailto:[log in to unmask]] Per conto di ARINDAM SARKAR
Inviato: martedì 12 gennaio 2016 14:20
A: [log in to unmask]
Oggetto: Query regarding research problem

 

Respected group members,

 

I am Arindam Sarkar, doctoral fellow of Delhi University, working under supervision of Prof. Anupam Chattopadhyay. Actually I am working on pseudotachylyte. I am little bit confused to distinguish between micaceous minerals crystallized from the melt and the micaceous minerals altered from the glass. If there is any procedure to distinguish these two kinds of micaceous minerals, kindly intimate me. I'll be highly obliged.

 

Thank You,

Regards,

Arindam Sarkar 

--

Arindam Sarkar

Doctoral Fellow (Ph.D.)

Centre for Advanced Studies in Geology,
University of Delhi, Delhi-7

Delhi,India 
Mob: +91 9717118391


-- 
Dr Eric C. Ferre
Professor
Department of Geology
Southern Illinois University
Carbondale, IL 62901-4324
USA

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