Dear Luiz,
I draw your attention to a third mechanism that could be responsible
for LPO in your mylonite, namely, solution-precipitation creep.
Experimental deformation studies on quartzite have shown that
microstructures typically attributed to dilocation creep or dynamic
recrystallization (deformation lamellae, subgrains, undulose
extinction, grain-size reduction etc.) may form by
solution-precipitation creep, and hence are not unequivocal for a given
deformation mechanism. Have a look at these papers:
EXPERIMENTAL-EVIDENCE FOR WATER WEAKENING OF QUARTZITE BY MICROCRACKING
PLUS SOLUTION PRECIPITATION CREEP
DENBROK SWJ, SPIERS CJ
JOURNAL OF THE GEOLOGICAL SOCIETY 148: 541-548 Part 3, MAY 1991
Reiko Imona, Takamoto Okudairaa,*, Kyuichi Kanagawab
Development of shape- and lattice-preferred orientations of amphibole
grains during initial cataclastic deformation and subsequent deformation
by dissolution–precipitation creep in amphibolites from the Ryoke
metamorphic belt, SW Japan
Journal of Structural Geology 26 (2004) 793–805
Crystallographic preferred orientation development by
dissolution±precipitation creep
Paul D. Bons, Bas den Brok
J Structural Geology, 20, 1713-1722. (2000)
Domingo
On 09/03/2006, at 23:59, luiz fernando wrote:
> Dear all,
>
> Despite all the discussion about academic and industry research
> (which in my modest opinion as a PhD student is a very rich field to
> be questioned in these days of complete economic decaying of almost
> every country on this planet) I have some simple questions (actually,
> not so simple in my opinion) that I would like to aks to anyone
> interested. I've been working on dynamic recrystallized muscovite
> bearing quartz mylonites, which show storng lattice preferred
> orientations of both quartz and muscovite. As we know, LPO can be
> formed by (i) creep and propagation of dislocations and (ii) dynamic
> recrystallization, mainly by subgrain rotation (SRR). However, in my
> opinion (and maybe I am wrong on my theorical concepts) both are
> interconnected and the latter is simply the evolution of the former
> due to deformation progress under relatively high temperatures. My
> questions are: how is the real effect of SRR on the LPO? Some papers,
> like Gleason et al. (1993 - JSG) demonstrates that the LPO will become
> more strong. But if the process of rotation continues, the LPOs should
> not be weaken? And is it possible to separate the effect of LPO due
> dislocation creep and recrystallization?
>
> Maybe my english is not so clear (I'm brazilian) and if you have any
> question I can try to be more precise on my questions!!!!!
>
>
> All the best to all
>
>
> Luiz
>
>
>
> Luiz Fernando Grafulha Morales
> PhD student
> Universidade Federal do Rio Grande do Sul
> Av. Bento Gonçalves 9500 - Porto Alegre - RS
> Brazil
> Phone: 55-51-33166910
> FAX: 55-51-33166320
>
>
>
> Yahoo! Acesso Grátis
> Internet rápida e grátis. Instale o discador agora!
Dr. Domingo Aerden
Profesor Titular
Departamento de Geodinámica
Facultad de Ciencias
C/ Fuentenueva s/n
18002 GRANADA, Spain
Tel. +34 958242825
Fax: +34 958248527
E-mail: [log in to unmask]
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