Hi Dave et al.,
I think that parts of the Proterozoic of the Colorado Front Range/Rockies fit this bill. Big Thomson Canyon in north-central Colorado contains a metamorphic gradient from biotite zone to sillimanite zone, with a well defined staurolite zone. To my knowledge kyanite and andalusite are not reported in the area. See Condie and Martell, 1983, GSAB, vol. 94, no 10 for an early reference. I believe Jane Silverstone has done some work on these rocks more recently. I think many of the sillimanite grade rocks of the Rockies may record similar field gradients, but I can’t prove it in most cases as the low grade parts of the field gradients are not well preserved in most places.
Cheers,
Chris Andronicos
> On Oct 26, 2015, at 5:50 PM, Emmanuel Baltatzis <[log in to unmask]> wrote:
>
> Hi Ben,
> You are right concerning the Stonehaven coast (Barrow's zones)where
> staurolite zone passing to sillimanite zone.I think also that Dave
> Pattison
> could find some examples concerning chloritoid and staurolite minerals in
> my Ph.D thesis, University of Manchester under the supervision of Benrie
> Wood (1977).Also,my work on staurolite forming reaction in the eastern
> Dalradian rocks of Scotland. Contrib.Mineral.Petrology.,69,193-200,(1979).
>
>
>
>
>
>
>
>> Hi Dave,
>> I'm puzzled why you haven't included the Stonehaven coast section
>> (adjacent Barrow's Zones, Eastern Scottish Highlands)in your examples
>> of staurolite zone passing directly to sillimanite zone.
>>
>> Ben
>>
>>
>> Quoting Dave Pattison <[log in to unmask]> on Mon, 26 Oct 2015
>> 12:57:25 -0600:
>>
>>> Hi all. Does anyone know of examples of prograde metamorphic sequences,
>>> contact or regional, in which (1) staurolite gives way upgrade to
>>> sillimanite and (2) there is no andalusite or kyanite in the prograde
>>> sequence? Potential regional examples of which I am aware include the
>>> Mooselookmeguntic area in Maine, Snow Lake area in Manitoba, and
>>> Connemara,
>>> Ireland, although each is not entirely straightforward.. Many thanks,
>>> Dave
>>>
>>>
>>>
>>> David R.M. Pattison
>>>
>>> Department of Geoscience
>>>
>>> University of Calgary
>>>
>>> ES 154 | 2500 University Drive NW, Calgary, Alberta, CANADA T2N 1N4
>>>
>>> T: 403.220.3263 | <mailto:[log in to unmask]> [log in to unmask] |
>>> <http://www.ucalgary.ca/pattison/> www.ucalgary.ca/pattison
>>>
>>>
>>>
>>>
>>
>>
>>
>> Ben Harte (Prof)
>> Grant Institute of Earth Sciences,
>> School of GeoSciences, University of Edinburgh,
>> Edinburgh EH9 3JW.
>> Tel: [44] (0)131 651 7220; Fax: [44] (0)131 668 3184
>>
>> --
>> The University of Edinburgh is a charitable body, registered in
>> Scotland, with registration number SC005336.
>>
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