Alternative processes for developing fabric and mineral compositional zoning in intrusive rocks
| Autor: | Stephen Marshak, J. Mabon, J. Defrates, Craig C. Lundstrom |
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| Rok vydání: | 2010 |
| Předmět: | |
| Zdroj: | International Geology Review. 53:377-405 |
| ISSN: | 1938-2839 0020-6814 |
| DOI: | 10.1080/00206814.2010.496183 |
| Popis: | We present textural and mineral compositional analyses of samples from previously published experiments examining the behaviour of partially molten silicates in a thermal gradient and/or at a compositional interface. Textural and electron backscatter diffraction (EBSD) analyses demonstrate that, when new minerals grow within a temperature gradient, they develop elongation and in some cases a preferred orientation parallel to the gradient; however, reaction of existing randomly oriented crystals in a thermal gradient does not produce a preferred orientation. For example, amphibole and magnetite crystals growing within the melt-rich hotter end of a thermal migration experiment develop elongate habits. Similarly, when basaltic andesite is juxtaposed with gabbro in a thermal gradient, newly formed crystals of olivine have a preferred crystallographic orientation, whereas the minerals that existed before the reaction remain in their original, random orientation. Compositional analyses and imaging show that oli... |
| Databáze: | OpenAIRE |
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