Cardigan Pluton

The Cardigan Pluton is the most voluminous pluton in the state of New Hampshire, USA. It was formed during onset of magamatism during the Acadian Orogeny and is part of the Kinsman suite of the New Hampshire Plutonic Series [ Allen, T., (2001) Nappes, Gneiss Domes and Plutonic Sheets of West-Central New Hampshire in Timothy W. Grover, Helen N. Mango, and Edward J. Hasenohr, editors, Guidebook to Field Trips in Vermont and Adjacent New Hampshire and New York, New England Intercollegiate Geologic Conference, 89th Annual Meeting. pp. A2.1 - A2.19.] . The pluton is approximately 20 x 90 km wide and on average about 2.5 km thick. The pluton ranges in composition from granite to tonolite (s-type) and is likely derived from crustal melting of pelitic rocks. The rocks show foliation indicating they were implaced early in the Acadian Orogeny and subsequently overprinted by later metamorphic events. Minerals in the Cardigan Pluton include large K-feldspar megacrysts and quartz, plagioclase, muscovite, garnet, biotite, and less abundant minerals including sillimanite, cordierite, ilmenite, graphite, apatite, monazite, zircon, and allanite [Plank, T. (1987). Magmatic garnets from the cardigan pluton and the acadian thermal event in southwest new hampshire. American Mineralogist, 72(7-8), 681-688.] . The pluton is dated at 411 +/- 19 Ma by the Rb/Sr method [ Lyons, J.B., Bothner, W., Moench, R., Thompson, J.B., (1997), Bedrock Geology of New Hampshire. Map Sheet. ] .

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