The Emmons Pegmatite, Greenwood, Oxford County, Maine.

The Emmons pegmatite, noted for its many phosphates, is Maine's most species-rich pegmatite. The Emmons pegmatite (fig. 1) is an example of a highly evolved boron-lithium-cesium-tantalum-enriched pegmatite. The Emmons pegmatite, one of Maine's major micromineral locations, is not the only pegmatite on Uncle Tom Mountain: the highly evolved Dumper Dew pegmatite ([29]) and the larger but less evolved Tiger Bill pegmatite are two of the other pegmatites. In the Emmons pegmatite, "biotite" occurs only in the wall zone as platy to elongated crystals to 8 cm. This mode of occurrence is typical for more evolved pegmatites worldwide. The Emmons pegmatite is a highly evolved boron-lithium-cesium-tantalum-enriched pegmatite formed by anatexis of migmatites ([27]; [31]) as a result of postorogenic, prerifting extension and decompressional melting about 250 Ma. [Extracted from the article]