| Abstract: | Monoclinic calcium-poor shear-transformation lamellae and calcium-rich exsolution lamellae occur parallel to (100) in orthopyroxene. The formation of both structures from an orthopyroxene host involves a shear on (100) parallel to [001], with additional cation exchange in the exsolution case. The shear transformation involves a macroscopic simple shear angle of 13.3?? (shear strain of 0.236) and produces a specific a-axis orientation with respect to the sense of shear; we have found that this orientation dominates in exsolution lamellae in kinked orthopyroxene, where the sense of shear is known. In undeformed orthopyroxene, there is generally no preferred sense of orientation of the monoclinic a axes. We advance a specific model for exsolution involving nucleation and growth by shear transformation combined with cation exchange, thus circumventing the classical nucleation barrier and permitting exsolution at lower solute supersaturations. ?? 1981 Springer-Verlag. |
| Genre: | Article |
| ProdID: | 70012078 |
| Citation Author: | Kirby, S. H.; Etheridge, M. A. |
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| Citation End Page: | 109 |
| Citation Issue: | 3 |
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| Citation Language: | English |
| Citation Larger Work Title: | Physics and Chemistry of Minerals |
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| Citation Number Of Pages: | 5 |
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| Citation Search Results Text: | Exsolution of Ca-clinopyroxene from orthopyroxene aided by deformation; 1981; Article; Journal; Physics and Chemistry of Minerals; Kirby, S. H.; Etheridge, M. A. |
| Citation Start Page: | 105 |
| Citation Volume: | 7 |
| Citation Year: | 1981 |
| Type: | citation/reference |
| Text: | Exsolution of Ca-clinopyroxene from orthopyroxene aided by deformation; 1981; Article; Journal; Physics and Chemistry of Minerals; Kirby, S. H.; Etheridge, M. A. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| URL (DIGITAL OBJECT IDENTIFIER): | http://dx.doi.org/10.1007/BF00308225 |
| Date Other: | Thu, 1 Jan 1981 00:00 -0600 |
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