Lithium-Boron-Beryllium Gem Pegmatites, Oxford Co., Maine: Havey and Mount Mica Pegmatites

Abstract

INTRODUCTIONThis fieldtrip will visit two world renowned gem-producing pegmatites, in the Oxford County pegmatite field of western Maine: Havey and Mount Mica pegmatites. This is intended to be primarily an instructional fieldtrip lead by pegmatite experts from the Maine Mineral and Gem Museum (MMGM) MP 2 (Mineralogy, Pegmatology, Petrology) research group. This is an opportunity to learn about the latest research and advances in the field of pegmatology in Maine. Mt. Mica and the Havey pegmatites are enriched in Be, B, and Li and over the last ten years have produced significant finds of gem tourmaline. The Havey produces a very consistent mint green elbaite with lesser amounts of pink and some rare blue gem elbaite. Mt. Mica has produced a huge quantity of gem elbaite in a wide range of colors. Some of the elbaite crystals recently mined from Mt. Mica are exceptionally large and many are fine museum-quality mineral specimens.This field trip guide is divided into the following four sections:1. Field trip summary with the leaders identified (A1- Maine (357595.99 m E, 4918691.40 m N). The field trip will begin with a brief discussion in the parking lot. We encourage carpooling to limit the number of vehicles entering the mines. A convoy of vehicles will travel approximately one hour to the Havey Quarry located off of Levine Road in Poland (395997.39 m E, 4880613.82 m N). Plan to spend approximately 2hrs at this location, starting with a discussion and later an opportunity to collect. Departing the Havey Quarry, the convoy will travel north approximately 40 minutes to the Mt. Mica Quarry located off of Mt. Mica road in Paris (382422.66 m E, 4902813.15 m N). Plan to spend approximately 2 hrs. at this site, which will begin with a discussion and end with an opportunity to collect on the dumps afterwards. There will not be an opportunity to go underground. At 4:00 pm, participants will leave the mine and travel north approximately 40 minutes back to Bethel. We encourage all participants to attend the Friday night reception at the Maine Mineral and Gem Museum. For this field trip, be prepared with a lunch as we will not be stopping along the way. There will be bathroom facilities available at each of the mine sites. Enrollment will be limited to 25 participants. Expect cold and unpredictable weather and dress accordingly. Please note: both quarries we are visiting are not open to the public except via previous arrangement. 1 A1-2 SIMMONS, FALSTER, WEBBER, FELCH, BRADLEY GENERAL GEOLOGY OF THE OXFORD COUNTY PEGMATITE FIELD IN MAINE REGIONAL GEOLOGYThe New England Appalachians formed during a prolonged Wilson Cycle between the breakup of the supercontinent Rodinia in the Neoproterozoic and the staged assembly of the supercontinent Pangea in the Phanerozoic. The pre-Silurian rocks mainly fall into two groups: those of Laurentian or peri-Laurentian affinity, toward the west, and those of peri-Gondwanan affinity, toward the east . These rocks were juxtaposed via mainly convergent plate motions, deformed, metamorphosed, a...

Apatite as an archive of pegmatite-forming processes: an example from the Berry-Havey pegmatite (Maine, USA)

“…Pegmatites from the Oxford field present different degrees of evolution, from barren bodies to highly evolved ones that show well-developed internal zoning (Roda-Robles et al 2015b). They may intrude in migmatites, amphibolites and mica schists, either concordant to the host rock foliation or as irregular and discordant bodies (Simmons et al 2017). There is not a general consensus on the origin of these pegmatites.…”

Tantalowodginite, (Mn0.5□0.5)TaTa2O8, a New Mineral Species from the Emmons Pegmatite, Uncle Tom Mountain, Maine, U.S.A.

“…Tantalowodginite was found by one of the authors (RS) during mining activities in the Emmons pegmatite. The Emmons pegmatite is exposed on Uncle Tom Mountain near the town of Greenwood in Oxford Co., Maine, U.S.A (44819 0 24.37 00 N, 70841 0 45.02 00 W) and is part of the Oxford Pegmatite Field (Simmons et al 2017). The pegmatite intruded a high-grade metasedimentary migmatitic sequence that shows plastic deformation.…”