Reference Type | Journal (article/letter/editorial) |
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Title | The Minastira peraluminous granite, Puno, southeastern Peru: a quenched, hypabyssal intrusion recording magma commingling and mixing |
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Journal | Mineralogical Magazine | ISSN | 0026-461X |
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Authors | Kontak, Daniel J. | Author |
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Clark, Alan H. | Author |
Year | 1997 (December) | Volume | 61 |
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Issue | 409 |
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Publisher | Mineralogical Society |
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Download URL | https://rruff.info/doclib/MinMag/Volume_61/61-409-743.pdf+ |
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DOI | doi:10.1180/minmag.1997.061.409.01Search in ResearchGate |
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| Generate Citation Formats |
Mindat Ref. ID | 224 | Long-form Identifier | mindat:1:5:224:2 |
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GUID | 0 |
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Full Reference | Kontak, Daniel J., Clark, Alan H. (1997) The Minastira peraluminous granite, Puno, southeastern Peru: a quenched, hypabyssal intrusion recording magma commingling and mixing. Mineralogical Magazine, 61 (409) 743-764 doi:10.1180/minmag.1997.061.409.01 |
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Plain Text | Kontak, Daniel J., Clark, Alan H. (1997) The Minastira peraluminous granite, Puno, southeastern Peru: a quenched, hypabyssal intrusion recording magma commingling and mixing. Mineralogical Magazine, 61 (409) 743-764 doi:10.1180/minmag.1997.061.409.01 |
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In | (1997, December) Mineralogical Magazine Vol. 61 (409) Mineralogical Society |
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Abstract/Notes | AbstractThe Minastira granite, a c. 25 Ma subvolcanic plug of fine-grained granitic rock in the Cordillera Oriental of SE Peru, has preserved textures indicative of a history involving mixing of at least two magmas, a volumetrically dominant felsic component and a less voluminous mafic one. The felsic component is represented by variably fractured, altered and embayed crystals of quartz, feldspar, biotite with minor coarsegrained melt- and fluid-inclusion rich apatite, and possible cordierite (now a pseudomorphous Fe-Mg phase), whereas the mafic component is represented by calcic plagioclase. The process of magma mixing is reflected by: (1) ubiquitous sieved-textured plagioclase with complex textural relationships; (2) a large range in plagioclase compositions with reversals and spike patterns in profiles; (3) embayed and internally fractured (thermal shock?) quartz; (4) the rare occurrence of pyroxene coronas on quartz; and (5) textures within biotite suggestive of its incipient breakdown. The lack of mafic enclaves indicates that physico-chemical conditions of the mixing were conducive to homogenization (i.e. chemical diffusion) and a superficially homogeneous rock is now observed. The association of glomeroclasts of crystals originating from both the mafic and felsic end members and a quenched quartz-feldspar matrix indicate that the mixing occurred in an underlying magma chamber. |
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