Malcolm,
I have also no idea, how the brittle-ductile transition could coincide
with the phase change to super-critical water. Let me know what you find
out about it.
Ernie, thank you for the very quick answer for me!
Michael
Malcolm McClure schrieb:
> Ernie
>
> Take a look at Robert O Fournier's paper 'Hydrothermal Processes
> related to Movement of Fluid From Plastic into Brittle Rock in the
> Magmatic Epithermal Environment' in Economic Geology 94 : 8 1193 -
> 1210 December 1999.
>
> I'll get back on how this relates to supercritical water.
>
> Regards
>
> Malcolm.
>
>
>
> On 30 Jul 2010, at 16:23, Ernest Rutter wrote:
>
>> There is absolutely no reason why such a correlation could exist,
>> neither is there an evidence for it.
>> Ernie Rutter
>>
>> -----Original Message-----
>> From: Tectonics & structural geology discussion list
>> [mailto:[log in to unmask]] On Behalf Of Malcolm McClure
>> Sent: 30 July 2010 16:15
>> To: [log in to unmask]
>> Subject: Re: Ductilitis
>>
>> Hi Michael
>>
>> Have you come across any reference that supports the possibility that
>> the brittle-ductile transition coincides with the phase change to
>> super-critical water?
>>
>> Regards
>>
>> Malcolm
>>
>> On 30 Jul 2010, at 14:53, Michael Stipp wrote:
>>
>>> Hi Julian,
>>>
>>> great, many thanks! I thought about making the same comment on the
>>> wrong use of the term "ductile". But one word in favor of Dave
>>> Kohlstedt and co-workers and their great 1995-review paper: They
>>> clearly explain it in their text, brittle-ductile denotes the change
>>> in deformation mode and brittle-plastic the change in dominant
>>> deformation mechanism. And they refer to Ernie's paper from 1986.
>>> So, the use of "plastic" and "ductile" does not seem to be so
>>> difficult. Nevertheless, many people seem to ignore it, even when it
>>> is corrected in a review.
>>>
>>> I always use the term plastic shear zone as synonym for mylonite
>>> zone, but this will probably raise the next discussion round on
>>> terminology.
>>>
>>> Best wishes
>>> Michael
>>>
>>>
>>>
>>> Julian Mecklenburgh schrieb:
>>>> Dear All,
>>>>
>>>> Prompted by the recent emails about Shear Zones. I am always
>>>> surprised about how much incorrect use words such as ductile is
>>>> about in the literature.
>>>>
>>>> <rant>
>>>>
>>>> Ductile is a non-localised distributed deformation it says nothing
>>>> about the deformation mechanism
>>>>
>>>> Brittle to ductile transition is the transition from localised to
>>>> distributed deformation with an increase in pressure.
>>>>
>>>> The transition from Cataclatic deformation to thermally activated
>>>> deformation with depth in the Earth is not the brittle to ductile
>>>> transition. But cataclatic to thermally activated transition is a
>>>> bit of a mouthful so what about other options. The suggestion of
>>>> the seismogenic transition is ok what about brittle-plastic
>>>> transition or brittle-viscous transition. There is no consensus on
>>>> this apart from that most people incorrectly use the brittle-
>>>> ductile transition. Even Kohstedt et al. (1995) get it wrong (see
>>>> fig1).
>>>>
>>>> Ernie published a paper on this in the 80's but everybody seems to
>>>> ignore it. See Rutter (1986).
>>>>
>>>> I do not like the term ductile shear zone as it is an oxymoron
>>>> ductile implies distributed deformation but shear zone implies
>>>> localised. A much better term would be plastic shear zones.
>>>>
>>>> </rant>
>>>>
>>>> All the best
>>>> Julian
>>>>
>>>> KOHLSTEDT, D. L., EVANS, B. & MACKWELL, S. J. 1995. Strength of the
>>>> lithosphere: constraints imposed by laboratory experiments. Journal
>>>> of Geophysical Research 100(B9), 17,587-17,602.
>>>>
>>>> RUTTER, E. H. 1986. On the Nomenclature of Mode of Failure
>>>> Transitions in Rocks. Tectonophysics 122(3-4), 381-387.
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