This is the introduction from "Pegamites and Associated Rocks in the Newry Hill Area, Oxford County, Maine." A report published by Vincent E. Shainin and Louis F. Dellwig, concerning work done partly on behalf of the U. S. Atomic Energy Commission and was published with the permission of the Commission.
The Newry Hill area, Maine, includes in approximately four square miles 37 exposed pegmatites which have been emplaced in Devonian metamorphic and igneous rocks. Numerous investigations in the past have been prompted by the presence of strategic, gem, and rare pegmatite minerals in this area. The present report describes the occurrence, distribution, and quantities of beryl and other strategic minerals in these pegmatites.
The oldest known sedimentary rocks in this area were metamorphosed to form a quartz-muscovite schist that grades into a quartz-biotite schist adjacent to intruded gabbro. Partial alteration of gabbro to actinolite schist was brought about by the intrusion of the pegmatites; the pegmatites were associated with a granodiorite intrusive to the north.
The Main, Dunton, Red Crossbill, Crooker, Kinglet, and Spodumene Brook pegmatites were mapped in detail and their mineralogy and internal structure are described. Important data concerning the smaller pegmatites are tabulated.
Forty-five minerals, series, and varieties have been found in these pegmatites and are described. Outer zones consist primarily of quartz, perthite, plagioclase and muscovite with accessory black tourmaline and garnet. For the most part, the rare constituents are confined to the inner units. Mineralogy varies from one pegmatite to another.
Of economic importance are perthite, beryl, spodumene and amblygonite. Although pollucite and gem tourmaline have been mined in this area, no new deposits were found.
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