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I also have an aluminum silicate pseudomorph article. I described kyanite psuedomorphs after andalusite, sillimanite psuedomorphs after kyanite, and sillimanite psuedomorphs after andalusite, from a contact metamorphic sequence in the Kwoiek area of British Columbia. This locality is also where I described Mn depletion zoning in garnet (Science, 1966) and sector zoning of staurolite (Science, 1967): Hollister, L.S., 1969, Metastable paragenetic sequence of andalusite, kyanite, and sillimanite, Kwoiek area, British Columbia. American J. Science 267, 352-370. Lincoln On Jul 30, 2009, at 8:03 PM, John Rosenfeld wrote: > Supplementing Nigel's citations, quoting from: > > "J. L. Rosenfeld and G. P. Eaton, 1958, Trip A: Stratigraphy, > Structure, and the Metamorphism in the Middle Haddam Quadrangle and > Vicinity, 50th Annual Meeting of the New England Intercollegiate > Geological Conference, Wesleyan University, Middletown, > Connecticut." [photocopy on request] > > we said: > > "In many cases, fine grained clots of sillimanite show by their > approximately-equivalent size and shape that they are pseudomorphs > after the kyanite porphyroblasts with which they coexist." In the > guidebook we also described the field stop and discussed at length > the P-T path indicated in relation to the P-T boundary between the > two minerals then recently determined by S. P. Clark and others > (1957). > > Also in: > > "H. G. Adams, L. H. Cohen and J. L. Rosenfeld, 1975, > Solid Inclusion Piezothermometry II: Geometric Basis, Calibration > for the Association Quartz-Garnet, and Application to Some Pelitic > Schists, > V. 60, pp. 584-598." > > on p. 596-597 we show a photomicrograph of a selvage of bent > sillimanite needles on a bent kyanite porphyroblast near Bronich in > the Lukmanier Pass region, Switzerland, far north of the mapped > sillimanite isograd. The sillimanite needles show less bending than > the kyanite porphyroblast and are therefore later. We considered > the occurrence as evidence of a P-T path from the kyanite field of > stability into the sillimanite field of stability as a result of > unloading that took place late in the Alpine orogeny, possibly > facilitated by the strain energy of bending. The description is > related to the work on solid inclusion piezothermometry (a.k.a. > "thermobarometry"). > > John > > >> Hi all, >> >> If the discussion is widening, kyanite pseudomorphing andalusite >> is reported in: >> >> Ahmed-Said and Tanner, P-T conditions during emplacement, and D2 >> regional metamorphism, of the Ben Vuirich Granite, Perthshire, >> Scotland. Mineralogical Magazine, 2000; v. 64, p. 737-753. >> >> and back in 1968 Graham Chinner (Min Mag 36, 1052-1068) recorded >> (for the first time ?) sillimanite replacing kyanite in the >> Limpopo belt. >> >> ? >> >> Nigel Harris >> >> >> On Thursday30 Jul 2009, at 16:35, [log in to unmask] wrote: >>> Hi all, >>> we studied a similar occurrence in: >>> >>> Cesare B., Gomez-Pugnaire M.T., Sanchez-Navas A. & Grobety B. (2002) >>> Andalusite - sillimanite replacement (Mazarrón - SE Spain): >>> microstructural and TEM study.American Mineralogist, 87. 433-444. >>> >>> >>> Another partial pseudomorph of Sil on And, with the involvement of >>> staurolite inclusions, is in: >>> Cesare B. (1994) Hercynite as the product of staurolite >>> decomposition in >>> the contact aureole of Vedrette di Ries, eastern Alps, Italy. >>> Contributions to Mineralogy and Petrology, 116, 239-246 >>> >>> For more on epitaxy among Al2SiO5 polymorphs see also: >>> Cesare B. and Grobety B. (1995) Epitaxial replacement of kyanite by >>> staurolite: a TEM study of the microstructures. American >>> Mineralogist., >>> 95, 78-86 >>> >>> Regards, >>> Bernardo >>> -- >>> Bernardo Cesare >>> Dipartimento di Geoscienze >>> Via Giotto, 1, I-35137 PADOVA ITALY >>> Tel: ++39-049-8272019 Fax: ++39-049-8272010 >>> email: [log in to unmask] >>> web site: http://www.dmp.unipd.it/bernardo/bernardo.html >>>> Hi, >>>> >>>> >>>> >>>> Following on Bob Tracy's comment, I attach two images of >>>> sillimanite after >>>> andalusite from the LPHT metamorphic rocks of the Peninsular Ranges >>>> batholith, Baja California, Mexico. As a side note, Ron Vernon was >>>> actually >>>> in the field with me the year (1997 or 1998?) that I collected this >>>> sample. >>>> We could actually see the large chiastolitic grain shapes in the >>>> samples, >>>> so >>>> assumed that it was andalusite. We also noted some blue >>>> coloration and I >>>> was >>>> excited about the possibility of finding kyanite. Turns out it >>>> is all >>>> sillimanite - barely a trace of remnant andalusite in the samples >>>> collected. >>>> >>>> >>>> >>>> The EBSD data show that sillimanite with three different c-axis >>>> orientations >>>> replaced the chiastolite grains. Note that the sillimanite >>>> crosses grew >>>> between the chiastolitic sector zone boundaries. Note also that the >>>> sillimanite replacing the main body of the andalusite has >>>> recrystallized. >>>> >>>> >>>> >>>> I would be interested to know if anyone has seen this type of >>>> microstructure >>>> before. We are considering possibly working this up for a short >>>> publication. >>>> >>>> >>>> >>>> Cheers - Scott >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> ******************************************************************* >>>> ****** >>>> Scott E. Johnson >>>> Department of Earth Sciences >>>> 5790 Bryand Global Sciences Center >>>> University of Maine >>>> Orono, ME 04469-5790 >>>> USA >>>> email: [log in to unmask] >>>> phone: (207) 581-2142 >>>> Fax: (207) 581 2202 >>>> <blocked::http://www.geology.um.maine.edu/user/scott_johnson/ >>>> HM.html> >>>> http://www.geology.um.maine.edu/user/scott_johnson/HM.html >>>> <blocked::http://www.geology.um.maine.edu/geodynamics/> >>>> http://www.geology.um.maine.edu/geodynamics/ >>>> ******************************************************************* >>>> ****** >>>> >>>> >>>> >>>> From: Metamorphic Studies Group [mailto:GEO- >>>> [log in to unmask]] >>>> On >>>> Behalf Of Robert Tracy >>>> Sent: Sunday, July 26, 2009 7:29 AM >>>> To: [log in to unmask] >>>> Subject: Re: oriented sillimanite after ?andalusite >>>> >>>> >>>> >>>> Hanan Kisch's comments are very interesting. When I first saw the >>>> photomicrographs, I immediately thought of sillimanite >>>> replacements of >>>> andalusite (sometimes quite large original andalusite crystals >>>> up to cm in >>>> scale) that occurs in rocks of southern New Hampshire and central >>>> Massachusetts USA. In many cases the replacement (a >>>> pseudomorphing of a >>>> kind) is complete, but the single large original chiastolite >>>> grain shapes >>>> (commonly even with carbonaceous crosses) are perfectly >>>> preserved by finer >>>> grained aggregates of sillimanites in multiple orientations, but >>>> all >>>> apparently sharing a common c-axis orientation. In thin sections >>>> cut >>>> across >>>> the foliation and lineation of the rock, the classic diamond >>>> shapes of the >>>> individual sillimanite grains can be seen in the replacements. >>>> John >>>> Rosenfeld wrote an admirable description of this phenomenon in a >>>> paper in >>>> American Journal of Science in 1969 (the Al-silicate issue), and >>>> several >>>> papers or field guides by Peter Robinson and his students in the >>>> late >>>> 1970s >>>> and early 1980s also describe these composite replacement textures. >>>> >>>> The replacement occurs at sillimanite + K-feldspar grade and >>>> commonly with >>>> migmatization, probably at T of ca. 750C at roughly 0.6 GPa. Our >>>> interpretation was of an early low-P contact metamorphic phase >>>> related to >>>> magmatism in a Taconic back-arc setting, succeeded by an >>>> increase in P as >>>> well as T in a more regional event , although still dominated by >>>> magmatic >>>> heating (so-called "anti-clockwise P-T trajectory" similar to that >>>> described >>>> in the New England terrane of Australia by Ron Vernon and Bill >>>> Collins). >>>> My >>>> impression is that whereas Hanan's case from Norway represents two >>>> distinct >>>> events separated in time, the New England USA occurrence is more >>>> likely a >>>> continuum that starts in the ca, 440-445 Ma time frame with contact >>>> metamorphism and the regional phase is likely at 430-435. >>>> Looking back >>>> again >>>> at his message, however, there is a striking similarity of >>>> timing and >>>> overall character (not uncommon for Caledonian phenomena in Norway, >>>> northern >>>> UK and in the northern Appalachians). >>>> >>>> Bob Tracy >>>> >>>> Hanan Kisch wrote: >>>> >>>> Dear Dr Homam, >>>> >>>> A belated comment. >>>> >>>> Coarse sillimanite porphyroblasts (Kisch 1962, Plate VII, fig. 2 >>>> and Plate >>>> VII, fig. 1) along the western contact of the Fongen-Hyllingen >>>> gabbro >>>> complex in the Tydal area, central Caledonides of the eastern >>>> Trondheim >>>> region, contain sillimanite in two orientations (ibid., Plate >>>> VII, fig. >>>> 2). >>>> This silimanite was probably formed as replacement of >>>> andalusite, which >>>> occurs further south in the contact aureole of the southern >>>> termination of >>>> the gabbro (Vogt 1941; Birkeland & Nilsen 1972). The gabbro was >>>> dated as >>>> late Silurian; together with its contact aureole, it was >>>> overprinted by >>>> late-Caledonian staurolite-kyanite grade regional metamorphism. >>>> >>>> References : >>>> Kisch, H.J. (1962) Petrographical and geological investigations >>>> in the >>>> southwestern Tydal region, Sör-Tröndelag, Norway. Acad. >>>> Proefschr., Univ. >>>> of Amsterdam, 136 pp. >>>> Vogt, Th. (1941). Geological notes on the Dictyonema locality >>>> and the >>>> upper >>>> Gauldal district in the Trondheim area. Norsk Geol. Tidsskr. >>>> 20, 171-192. >>>> Birkeland, T. & Nilsen, O. (1972) Contact metamorphism >>>> associated with >>>> gabbros in the Trondheim region. Norges Geol. Unders. 273, 13-22. >>>> >>>> I hope that this is some help. >>>> >>>> Regards, >>>> >>>> Hanan Kisch >>>> >>>> Dear All >>>> >>>> As Freshte (Ranjbar) supervisor I would like to express my honest >>>> acknowledgement for your valuable comments regarding andalusite >>>> query. >>>> What >>>> we have in region seems to be a very complex metamorphic case >>>> but most >>>> probably a contact metamorphism followed by a regional deformation. >>>> Andaluasit as medium to large fully oriented grain, garnet, >>>> fibrolite and >>>> cordierite (?) can be seen in thin sections. No staurolite has >>>> been found. >>>> Using different direction sectioning from the sample helped us >>>> to find >>>> what >>>> was the mineral. As a matter of fact it was noting but an >>>> oriented growth >>>> of >>>> sillimanite in andalusite, very similar with that reported by >>>> Prof. Vernon >>>> (1987) from Juan Tabo area, USA. >>>> >>>> Best Regards >>>> Dr. S. M. Homam >>>> >>>> >>>> >>>> _____ >>>> >>>> >>>> >>>> _____ >>>> >>>> Share your memories online with anyone you want. Learn more. >>>> <http://clk.atdmt.com/UKM/go/134665338/direct/01/> >>>> <http://clk.atdmt.com/UKM/go/134665338/direct/01/> >>>> >>>> >>>> >>>> Prof. Hanan J. Kisch >>>> Department of Geological and Environmental Sciences >>>> Ben-Gurion University of the Negev >>>> P.O.B. 653, Beer-Sheva 84105, Israel >>>> Tel.: +972 8 646 1290 >>>> Fax (Dept office): +972 8 647 2997 and +972 8 647 7655 >>>> E-mail: [log in to unmask] >>>> >>>> >>>> >>>> >>>> >>>> -- >>>> >>>> >>>> >>>> Dr. Robert J. Tracy >>>> >>>> Department of Geosciences >>>> >>>> 5064 Derring Hall >>>> >>>> Virginia Tech >>>> >>>> Blacksburg VA 24061-0420 >>>> >>>> Office Phone: 540-231-5980 >>>> >>>> Fax: 540-231-3386 >>>> >>>> e-mail: [log in to unmask] >> >> >> -- >> This message has been scanned for viruses and >> dangerous content by MailScanner, and is >> believed to be clean. >> >> Hi all, >> >> If the discussion is widening, kyanite pseudomorphing andalusite >> is reported in: >> >> Ahmed-Said and Tanner, P-T conditions during emplacement, and D2 >> regional metamorphism, of the Ben Vuirich Granite, Perthshire, >> Scotland. Mineralogical Magazine, 2000; v. 64, p. 737-753. >> >> and back in 1968 Graham Chinner (Min Mag 36, 1052-1068) recorded >> (for the first time ?) sillimanite replacing kyanite in the >> Limpopo belt. >> >> <p06210201c697da2a1d1c> >> >> Nigel Harris >> >> >> On Thursday30 Jul 2009, at 16:35, [log in to unmask] wrote: >> >>> Hi all, >>> we studied a similar occurrence in: >>> >>> Cesare B., Gomez-Pugnaire M.T., Sanchez-Navas A. & Grobety B. (2002) >>> Andalusite - sillimanite replacement (Mazarrón - SE Spain): >>> microstructural and TEM study.American Mineralogist, 87. 433-444. >>> >>> >>> Another partial pseudomorph of Sil on And, with the involvement of >>> staurolite inclusions, is in: >>> Cesare B. (1994) Hercynite as the product of staurolite >>> decomposition in >>> the contact aureole of Vedrette di Ries, eastern Alps, Italy. >>> Contributions to Mineralogy and Petrology, 116, 239-246 >>> >>> For more on epitaxy among Al2SiO5 polymorphs see also: >>> Cesare B. and Grobety B. (1995) Epitaxial replacement of kyanite by >>> staurolite: a TEM study of the microstructures. American >>> Mineralogist., >>> 95, 78-86 >>> >>> Regards, >>> Bernardo >>> -- >>> Bernardo Cesare >>> Dipartimento di Geoscienze >>> Via Giotto, 1, I-35137 PADOVA ITALY >>> Tel: ++39-049-8272019 Fax: ++39-049-8272010 >>> email: [log in to unmask] >>> web site: http://www.dmp.unipd.it/bernardo/bernardo.html >>> >>>> Hi, >>>> >>>> >>>> >>>> Following on Bob Tracy's comment, I attach two images of >>>> sillimanite after >>>> andalusite from the LPHT metamorphic rocks of the Peninsular Ranges >>>> batholith, Baja California, Mexico. As a side note, Ron Vernon was >>>> actually >>>> in the field with me the year (1997 or 1998?) that I collected this >>>> sample. >>>> We could actually see the large chiastolitic grain shapes in the >>>> samples, >>>> so >>>> assumed that it was andalusite. We also noted some blue >>>> coloration and I >>>> was >>>> excited about the possibility of finding kyanite. Turns out it >>>> is all >>>> sillimanite - barely a trace of remnant andalusite in the samples >>>> collected. >>>> >>>> >>>> >>>> The EBSD data show that sillimanite with three different c-axis >>>> orientations >>>> replaced the chiastolite grains. Note that the sillimanite >>>> crosses grew >>>> between the chiastolitic sector zone boundaries. Note also that the >>>> sillimanite replacing the main body of the andalusite has >>>> recrystallized. >>>> >>>> >>>> >>>> I would be interested to know if anyone has seen this type of >>>> microstructure >>>> before. We are considering possibly working this up for a short >>>> publication. >>>> >>>> >>>> >>>> Cheers - Scott >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> ******************************************************************* >>>> ****** >>>> Scott E. Johnson >>>> Department of Earth Sciences >>>> 5790 Bryand Global Sciences Center >>>> University of Maine >>>> Orono, ME 04469-5790 >>>> USA >>>> email: [log in to unmask] >>>> phone: (207) 581-2142 >>>> Fax: (207) 581 2202 >>>> <blocked::http://www.geology.um.maine.edu/user/scott_johnson/ >>>> HM.html> >>>> http://www.geology.um.maine.edu/user/scott_johnson/HM.html >>>> <blocked::http://www.geology.um.maine.edu/geodynamics/> >>>> http://www.geology.um.maine.edu/geodynamics/ >>>> ******************************************************************* >>>> ****** >>>> >>>> >>>> >>>> From: Metamorphic Studies Group [mailto:GEO- >>>> [log in to unmask]] >>>> On >>>> Behalf Of Robert Tracy >>>> Sent: Sunday, July 26, 2009 7:29 AM >>>> To: [log in to unmask] >>>> Subject: Re: oriented sillimanite after ?andalusite >>>> >>>> >>>> >>>> Hanan Kisch's comments are very interesting. When I first saw the >>>> photomicrographs, I immediately thought of sillimanite >>>> replacements of >>>> andalusite (sometimes quite large original andalusite crystals >>>> up to cm in >>>> scale) that occurs in rocks of southern New Hampshire and central >>>> Massachusetts USA. In many cases the replacement (a >>>> pseudomorphing of a >>>> kind) is complete, but the single large original chiastolite >>>> grain shapes >>>> (commonly even with carbonaceous crosses) are perfectly >>>> preserved by finer >>>> grained aggregates of sillimanites in multiple orientations, but >>>> all >>>> apparently sharing a common c-axis orientation. In thin sections >>>> cut >>>> across >>>> the foliation and lineation of the rock, the classic diamond >>>> shapes of the >>>> individual sillimanite grains can be seen in the replacements. >>>> John >>>> Rosenfeld wrote an admirable description of this phenomenon in a >>>> paper in >>>> American Journal of Science in 1969 (the Al-silicate issue), and >>>> several >>>> papers or field guides by Peter Robinson and his students in the >>>> late >>>> 1970s >>>> and early 1980s also describe these composite replacement textures. >>>> >>>> The replacement occurs at sillimanite + K-feldspar grade and >>>> commonly with >>>> migmatization, probably at T of ca. 750C at roughly 0.6 GPa. Our >>>> interpretation was of an early low-P contact metamorphic phase >>>> related to >>>> magmatism in a Taconic back-arc setting, succeeded by an >>>> increase in P as >>>> well as T in a more regional event , although still dominated by >>>> magmatic >>>> heating (so-called "anti-clockwise P-T trajectory" similar to that >>>> described >>>> in the New England terrane of Australia by Ron Vernon and Bill >>>> Collins). >>>> My >>>> impression is that whereas Hanan's case from Norway represents two >>>> distinct >>>> events separated in time, the New England USA occurrence is more >>>> likely a >>>> continuum that starts in the ca, 440-445 Ma time frame with contact >>>> metamorphism and the regional phase is likely at 430-435. >>>> Looking back >>>> again >>>> at his message, however, there is a striking similarity of >>>> timing and >>>> overall character (not uncommon for Caledonian phenomena in Norway, >>>> northern >>>> UK and in the northern Appalachians). >>>> >>>> Bob Tracy >>>> >>>> Hanan Kisch wrote: >>>> >>>> Dear Dr Homam, >>>> >>>> A belated comment. >>>> >>>> Coarse sillimanite porphyroblasts (Kisch 1962, Plate VII, fig. 2 >>>> and Plate >>>> VII, fig. 1) along the western contact of the Fongen-Hyllingen >>>> gabbro >>>> complex in the Tydal area, central Caledonides of the eastern >>>> Trondheim >>>> region, contain sillimanite in two orientations (ibid., Plate >>>> VII, fig. >>>> 2). >>>> This silimanite was probably formed as replacement of >>>> andalusite, which >>>> occurs further south in the contact aureole of the southern >>>> termination of >>>> the gabbro (Vogt 1941; Birkeland & Nilsen 1972). The gabbro was >>>> dated as >>>> late Silurian; together with its contact aureole, it was >>>> overprinted by >>>> late-Caledonian staurolite-kyanite grade regional metamorphism. >>>> >>>> References : >>>> Kisch, H.J. (1962) Petrographical and geological investigations >>>> in the >>>> southwestern Tydal region, Sör-Tröndelag, Norway. Acad. >>>> Proefschr., Univ. >>>> of Amsterdam, 136 pp. >>>> Vogt, Th. (1941). Geological notes on the Dictyonema locality >>>> and the >>>> upper >>>> Gauldal district in the Trondheim area. Norsk Geol. Tidsskr. >>>> 20, 171-192. >>>> Birkeland, T. & Nilsen, O. (1972) Contact metamorphism >>>> associated with >>>> gabbros in the Trondheim region. Norges Geol. Unders. 273, 13-22. >>>> >>>> I hope that this is some help. >>>> >>>> Regards, >>>> >>>> Hanan Kisch >>>> >>>> Dear All >>>> >>>> As Freshte (Ranjbar) supervisor I would like to express my honest >>>> acknowledgement for your valuable comments regarding andalusite >>>> query. >>>> What >>>> we have in region seems to be a very complex metamorphic case >>>> but most >>>> probably a contact metamorphism followed by a regional deformation. >>>> Andaluasit as medium to large fully oriented grain, garnet, >>>> fibrolite and >>>> cordierite (?) can be seen in thin sections. No staurolite has >>>> been found. >>>> Using different direction sectioning from the sample helped us >>>> to find >>>> what >>>> was the mineral. As a matter of fact it was noting but an >>>> oriented growth >>>> of >>>> sillimanite in andalusite, very similar with that reported by >>>> Prof. Vernon >>>> (1987) from Juan Tabo area, USA. >>>> >>>> Best Regards >>>> Dr. S. M. Homam >>>> >>>> >>>> >>>> _____ >>>> >>>> >>>> >>>> _____ >>>> >>>> Share your memories online with anyone you want. Learn more. >>>> <http://clk.atdmt.com/UKM/go/134665338/direct/01/> >>>> <http://clk.atdmt.com/UKM/go/134665338/direct/01/> >>>> >>>> >>>> >>>> Prof. Hanan J. Kisch >>>> Department of Geological and Environmental Sciences >>>> Ben-Gurion University of the Negev >>>> P.O.B. 653, Beer-Sheva 84105, Israel >>>> Tel.: +972 8 646 1290 >>>> Fax (Dept office): +972 8 647 2997 and +972 8 647 7655 >>>> E-mail: [log in to unmask] >>>> >>>> >>>> >>>> >>>> >>>> -- >>>> >>>> >>>> >>>> Dr. Robert J. Tracy >>>> >>>> Department of Geosciences >>>> >>>> 5064 Derring Hall >>>> >>>> Virginia Tech >>>> >>>> Blacksburg VA 24061-0420 >>>> >>>> Office Phone: 540-231-5980 >>>> >>>> Fax: 540-231-3386 >>>> >>>> e-mail: [log in to unmask] >>>> >>>> >> >> >> -- >> This message has been scanned for viruses and >> dangerous content by MailScanner, and is >> believed to be clean. > >