Chapter 18: Granitoid Rocks - Faculty web pages

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$Math 361 Problem Set #5 Due 5 October 2012 - Faculty web pages$

$Math 362 Problem Set #9 â€“ Solution 27 April 2012 - Faculty web ...$

<strong>Granitoid</strong> Petrography• Medium to coarse-grained, slow cooling and presence ofvolatiles, especially H 2 O• Plagioclase, qtz, , alkali feldspar – dominant felsic phases• Hornblende and biotite – dominant mafic phases• Muscovite – common in Al-rich granites• Cpx – subordinate• Accessory minerals – apatite, zircon, magnetite, ilmenite,monazite, sphene, allanite, , tourmaline, pyrite, and fluorite
Zircon Xenocrysts – Hard, refractoryand commonly survive both chemicaland mechanical weathering.Can be eroded from an igneous source,transported, deposited and buried andmetamorphosed.Pure metamorphic zircons are unzoned.Used in U-PbUdating because of highconcentration of U.If zircons remain after melting (restite(restite),they may contain inherited Pb from theirformer lives and yield an erroneous age.Figure <strong>18</strong>-1. Backscattered electron image of a zircon from the StrontianGranite, Scotland. The grain has a rounded, un-zoned core (dark) that is aninherited high-temperature non-melted crystal from the pre-granite source.The core is surrounded by a zoned epitaxial igneous overgrowth rim,crystallized from the cooling granite. From Paterson et al. (1992), Trans.Royal. Soc. Edinburgh. 83, 459-471. Also Geol. Soc. Amer. Spec. Paper, 272,459-471.
Page 1 and 2: Chapter 18: Granitoid Rocks“Grani
Page 3: 2) Because the crust is solid in it
Page 7 and 8: Alumina saturation: Peraluminous -
Page 9 and 10: Granitoid classification: S-I-A-M S
Page 11 and 12: Table 18-3. The S-I-A-M Classificat
Page 13 and 14: Anorogenic - magmatism within a pla
Page 15: Himalayas - Continent - continent c

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