Crystallization History of a Zoned Plagioclase

G. J. Pringle1, L. T. Trembath and G. E. Pajari Jr.
University of New Brunswick, Fredericton, New Brunswick, Canada
1Present address-Geological Survey of Canada.

Summary: Electron microprobe and textural data are used to deduce a crystallization history for plagioclase in the Grand Manan Island (Canada) diabase sheet. The plagioclase crystals consist of a prominent core (An79-67) surrounded by a distinctly more calcic zone (An82-76), which grades into a normally zoned mantle (An73-40). This zoning pattern is interpreted as reflecting the elevation of a dry diabase magma from at least 10 to 20 km to near surface conditions.

Mineralogical Magazine; December 1974 v. 39; no. 308; p. 867-877; DOI: 10.1180/minmag.1974.039.308.06
© 1974, The Mineralogical Society
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