A Differentiated Ultrabasic Sheet on Sgurr Dearg, Isle of Skye

Fergus G. F. Gibb
Department of Geology, University of Manchester

Summary: The field relations, mineralogy, and petrography of a small Tertiary ultrabasic sheet are briefly described. Chemical analyses show that compositional variations exist within the intrusion and electron-probe analyses demonstrate that optically undetectable zoning is present in the olivine. Throughout the intrusion, which is composed primarily of forsteritic olivine, calcic plagioclase, and clinopyroxene, there is a differential distribution of olivine. This distribution is attributed to flow differentiation during intrusion followed by gravitative sinking of olivine crystals.

Mineralogical Magazine; September 1972 v. 38; no. 299; p. 811-818; DOI: 10.1180/minmag.1972.038.299.05
© 1972, The Mineralogical Society
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