Oxford County pegmatite field

Region East, Northeast
Mineral systems
Deposit types
Critical minerals
Other minerals

Information leading to the delineation of this focus area

Basis for focus area Lithium-bearing pegmatites in Oxford County are well known. A new spodumene-bearing pegmatite was recently exposed on the north side of Plumbago Mountain, Oxford County, Maine. The pegmatite is spodumene-rich and potentially a significant new Li resource. The site is in a remote area on the north side of Plumbago Mountain that was originally known as Spodumene Brook (Shainin and Dellwig, 1955; Barton and Goldsmith, 1968). A number of pegmatite sites in the district are being remined for gem (principally tourmaline) and specimen material: Black Mountain, Brimstone Mountain, Emmons Quarry, Havey Quarry, Mount Mica Quarry, Rose Quartz Crystal Locality. Many historically mined sites in the district are on private property and have been closed to collecting (Cameron and others, 1954). Also see Bradley and others (2016) and Wise and Brown (2010). Other areas of interest include the Rumford Series, Paris/Greenwood Series, and Franklin County Series (Bemis Stream, Harden/Keith, Brimstone Mountain) (Wise and Francis, 1992).
Identified resources Historical production of feldspar and lithium (spodumene).
Production Unknown.
Status Past mining. Some locations are actively being quarried as specimens and gem-grade minerals (tourmaline). Feldspar mining was primary commodity for many quarries until 1960s. In some instances Li-, Cs-, Nb/Ta-, and Be-bearing accessory phases were stockpiled. Gem-grade minerals and mineral specimens.
Estimated resources Freeman Resources, LLC has conducted preliminary exploration at the Plumbago North Quarry, Newry, Oxford County. The pegmatite is projected to contain about 10 million metric tons of spodumene ore; an average content from two tests of bulk ore was 4.68% Li2O (Simmons and others, 2019).
Geologic maps Eusden and others (2018), scale 1:24,000; Guidotti (1965), scale 1:62,500; Pankiwskyj (1978c, 1981), scale 1:62,500; Creasy (1979), scale 1:62,500; Moench (1971), scale 1:62,500; Moench and Hildreth (1976), scale 1:62,500; Osberg and others (1985), scale 1:500,000; Moench and Pankiwskyj (1988), scale 1:250,000; Eusden and others (2020), scale 1:24,000; Greenwood quadrangle (Koteas, in press), North Waterford quadrangle (Koteas, in press).
Geophysical data Inadequate Rank 4 and 5 aeromagnetic and aeroradiometric coverage.
Favorable rocks and structures Pegmatite.
Deposits Rumford Series: Black Mountain Quarry, Plumbago North, Dunton Quarry, Twin Tunnels, Rose Quartz Crystal Locality. Franklin County Series: Brimstone Mountain, Bemis Stream, Harden-Keith. Paris/Greenwood Series: Emmons, Dumper Dew, BB#7, Mount Mica, Mount Marie, General Electric. Auburn Series: Havey, Western Mount Apatite.
Evidence from mineral occurrences MRDS.
Geochemical evidence Favorable mineralogy and rock type. Lithium-bearing phases include spodumene, montebrasite, and lepidolite.
Geophysical evidence Henderson and Smith (1964): Boynton and Gilbert (1964a, b); Boynton and Gilbert (1964c); Bond (1993).
Evidence from other sources Unknown.
Comments Newry area pegmatites of the Rumford series have been quarried for feldspar in the first half of the 1900s, accessory phases included spodumene, montebrasite, pollucite, and columbite. Plumbago North Quarry currently being investigated for lithium reserves (spodumene). Havey Quarry, Poland, Androscoggin County mining gem materials (tourmaline). Small-scale mining operations (<10 localities) are seasonally mining for mineral specimens. Although past producers, likelihood of future extraction is unknown. Regional geophysical anomalies are present, but the possibility at deposit scale and the amount or resource is unknown. An Earth MRI geologic mapping project was completed in May 2022.
Cover thickness and description Cover less than 2-50 m.
Authors Myles Felch, Amber Whittaker, Fred M. Beck, Nora K. Foley, Dwight C. Bradley, Anjana K. Shah, Gregory J. Walsh, Bernard E. Hubbard.
New data needs Additional mapping, geophysics, geochemical analyses of newly identified mineralization occurrences.
Geologic mapping and modeling needs Some 1:24,000 scale mapping in progress, but incomplete.
Geophysical survey and modeling needs High-resolution airborne magnetic and radiometric survey needed.
Digital elevation data needs Lidar complete.