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The significance of tridymite in igneous and metamorphic petrogenesis

Published online by Cambridge University Press:  14 March 2018

George P. Black*
Affiliation:
Grant Institute of Geology, University of Edinburgh

Extract

Physico-Chemical data clearly show that the presence of tridymite in a rock indicates the prevalence not only of high temperatures, but also of relatively low pressures during the formation of that rock. Whereas many authors (e.g. Shand, 1927; Larsen, 1936) have used tridymite as an indicator of temperature, the importance of tridymite as an indicator of pressure has been largely overlooked.

Although the presence of tridymite is by itself sufficient to enable the pressure, and hence the depth, at which a rock formed to be estimated within certain limits, the presence of tridymite in association with some other pressure-or temperature-indicating mineral allows much closer limits to be set.

Type
Research Article
Copyright
Copyright © 1954, The Mineralogical Society

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References

Black, (G. H.), 1953. Some aspects of the petrology of the Isle of Rhum. Thesis submitted to the University of Edinburgh for the degree of Ph.D.Google Scholar
Bowen, (N.L.), 1913.The melting phenomena of the plagioclase feldspars. Amer. Journ. Sci., ser.., vol. 35, pp. 577.599.Google Scholar
Blcidgman, (H. W.), 1949. The physics of high pressure. London.Google Scholar
Goranson, (R.W.), 1938. Silicatewater systems: phase equilibria in the NaA1SiaO8- H20 and KA1SiaOs-I-I20 systems at high temperatures and pressures. Amer. Journ. Sci., ser.., vol. 35A, pp. 71.91. [M.A. 7-88.]Google Scholar
Harker, (A.), 1950. Metamorphism. A study in the transformations of rock masses. London. pp. 68.69.Google Scholar
Larsen, (E.S.), and others, 1936. Petrologic results of a study of the minerals from the Tertiary volcanic rocks of the San Juan region, Colorado. Amer. Min., vol. 21, pp. 691.694. [M.A. 7-31.]Google Scholar
Mosesman, (M.A.) and Puzer, (K.S.), 1941. Thermodynamic properties of the crystalline forms of silica. Journ. Amer. Chem. Soc., vol. 63, pp. 2348.2356.Google Scholar
Shand, (S.J.), 1927. Eruptive rocks. London. pp. 51.52. [M.A. 3-316.]Google Scholar
Wager, (L.R.), 1953a. Layered intrusions. Meddel. Dansk Geol. Forening, vol. 12, pp. 335349.Google Scholar
Wager, (L.R.), and others, 1953b. A granophyre from Coire Uaigneich, Isle of Skye, containing quartz paramorphs after tridymite. Min. Mag., vol. 30, pp. 263.275.Google Scholar
Wells, (M.K.), 1951.Sedimentary inclusions in the hypersthene-gabbro, Ardnamurchan, Argyllshire. Min. Mag., vol. 29, pp. 715736.Google Scholar