Compositional variation in the chevkinite group: new data from igneous and metamorphic rocks
Electron microprobe analyses are presented of chevkinite-group minerals from Canada, USA, Guatemala, Norway, Scotland, Italy and India. The host rocks are metacarbonates, alkaline and subalkaline granitoids, quartz-bearing pegmatites, carbonatite and an inferred K-rich tuff. The analyses extend slightly the range of compositions in the chevkinite group, e.g. the most MgO-rich phases yet recorded, and we report two further examples where La is the dominant cation in the A site. Patchily- zoned crystals from Virginia and Guatemala contain both perrierite and chevkinite compositions. The new and published analyses are used to review compositional variation in minerals of the perrierite subgroup, which can form in a wide range of host rock compositions and over a substantial pressure- temperature range. The dominant substitutions in the various cation sites and a generalized substitution scheme are described.
Citation Information
Publication Year | 2009 |
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Title | Compositional variation in the chevkinite group: new data from igneous and metamorphic rocks |
DOI | 10.1180/minmag.2009.073.5.777 |
Authors | Harvey E. Belkin, R. MacDonald, F. Wall, B. Baginski |
Publication Type | Article |
Publication Subtype | Journal Article |
Series Title | Mineralogical Magazine |
Index ID | 70193855 |
Record Source | USGS Publications Warehouse |
USGS Organization | Eastern Energy Resources Science Center |