CaltechAUTHORS
  A Caltech Library Service

Phase relationships of S-type granite with H2_O to 35 kbar: Muscovite granite from Harney Peak, South Dakota

Huang, W. L. and Wyllie, P. J. (1981) Phase relationships of S-type granite with H2_O to 35 kbar: Muscovite granite from Harney Peak, South Dakota. Journal of Geophysical Research B, 86 (B11). pp. 10515-10529. ISSN 0148-0227. doi:10.1029/JB086iB11p10515. https://resolver.caltech.edu/CaltechAUTHORS:20141105-141147490

[img]
Preview
PDF - Published Version
See Usage Policy.

1MB

Use this Persistent URL to link to this item: https://resolver.caltech.edu/CaltechAUTHORS:20141105-141147490

Abstract

Muscovite granite (13.8% muscovite, 4.8% normative corundum) was reacted, with varying percentages of H_2O, in cold-seal vessels at 2 kbar and in piston-cylinder apparatus between 10 and 35 kbar. The diagrams illustrating melting/crystallization relationships are: P-T sections with both excess H_2O and with no H_2O added (0.66% H_2O in rock); T-X_(H_2O) sections at 15 kbar and 25 kbar showing H_2O-undersaturated conditions; the H_2O-undersaturated surface for the crystallization of quartz/coesite (small amounts of aluminosilicate minerals persist to higher temperatures). Glass compositions measured by electron microprobe from samples with 5% H_2O at 15 kbar confirm that liquids are syenitic through at least 100°C above the solidus, as predicted from the effect of pressure on the Residua System. Results are explained successfully by phase relationships involving muscovite, quartz, and orthoclase in K_2O-Al_2O_3-SiO_2-H_2O, with reactions depicted in a P_(total)-P_(e_(H_2O))-T model, with special reference to the divariant surfaces in the region P_(e_(H_2O)) < P_(total). With reduced P_(e_(H_2O)) (or a_(H_2O)), produced either by small amounts of H_2O (and H_2O-undersaturation) or by CO_2 + H_2O mixtures, subsolidus dehydration reaction temperatures decrease, vapor-present solidus temperatures increase, and muscovite stability in presence of liquid increases. In general, muscovite, biotite, and amphibole can be precipitated from magmas containing only a few tenths per cent H_2O (although the H_2O-undersaturated liquids coexisting with crystals may contain 3% or more dissolved H_2O). This particular granite cannot be a primary magma from mantle or subducted oceanic crust. It is a possible product of partial fusion of pelitic rocks between about 20 km and 40 km depth given sufficient H2O, and xenocrystal muscovite or sillimanite from the source rocks. The phase relationships are consistent with the idea of S-type granites, but not sufficient to prove the origin of this rock. Additional tests require phase relationships of other associated granitic rocks, and details of geochemistry, geophysics, and field relationships.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1029/JB086iB11p10515DOIArticle
http://onlinelibrary.wiley.com/doi/10.1029/JB086iB11p10515/abstractPublisherArticle
Alternate Title:Phase relationships of S-type granite with H2O to 35 kbar: Muscovite granite from Harney Peak, South Dakota
Additional Information:Copyright 1981 by the American Geophysical Union. (Received October 8, 1980; revised March 19, 1981; accepted March 20, 1981.) Paper number 1B0494. This research was supported by the Earth Sciences Section of the National Science Foundation, NSF grant EAR 76-20413. For review of earlier versions of parts of the manuscript we thank V. C. Juan, D. M. Kerrick, R. C. Newton, and Y. Wang.
Funders:
Funding AgencyGrant Number
NSFEAR 76-20413
Issue or Number:B11
DOI:10.1029/JB086iB11p10515
Record Number:CaltechAUTHORS:20141105-141147490
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20141105-141147490
Official Citation:Huang, W. L., and P. J. Wyllie (1981), Phase relationships of S-type granite with H2O to 35 kbar: Muscovite granite from Harney Peak, South Dakota, J. Geophys. Res., 86(B11), 10515–10529, doi:10.1029/JB086iB11p10515.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:51327
Collection:CaltechAUTHORS
Deposited By: George Porter
Deposited On:05 Nov 2014 23:03
Last Modified:10 Nov 2021 19:09

Repository Staff Only: item control page