The Nature and Significance of Exsolved Phases in Some Chrome Spinels from the Rhum Layered Intrusion

A. Putnis and G. D. Price
Mineral Sciences Group, Department of Mineralogy and Petrology, Downing Place, Cambridge CB2 3EW

Summary: Chrome spinels from seams in the Rhum layered intrusion, Inner Hebrides, generally contain very fine platelets of exsolved phases. Despite the low bulk Ti content (< 1%) of the spinel grains, analytical electron microscopy shows these platelets to be highly enriched in titanium. Electron diffraction indicates the presence of platelets of two different phases, one a magnesian ilmenite, the other a defect spinel intermediate phase. The platelets are the result of oxidation of the spinel at moderate (c. 600 °C) temperatures and their distribution suggests that oxygen fugacity gradients existed across some of the seams.

Mineralogical Magazine; December 1979 v. 43; no. 328; p. 519-526; DOI: 10.1180/minmag.1979.043.328.12
© 1979, The Mineralogical Society
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