Alkaline Rocks and Carbonatites of the World

Setup during HiTech AlkCarb: an online database of alkaline rock and carbonatite occurrences

Rattlesnake Pluton

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Occurrence number: 
174-00-137
Country: 
United States
Region: 
Massachusetts
Location: 
Longitude: -71.15, Latitude: 42.1
Carbonatite: 
No

The Rattlesnake intrusion is an elliptical, multiple stock of 22 km2, composed principally of a biotite granite and a number of types of riebeckite granite, intruded into the Dedham quartz monzonite, which is probably Precambrian. The biotite granite grades into fine grained riebeckite granite over some 30 m. The riebeckite granite consists of microcline microperthite, quartz, 1-6% of euhedral spongy riebeckite and accessories, while in its western part riebeckite granite pegmatites with up to 24% riebeckite occur as dykes and pods. An arcuate marginal zone on the northern side of the pluton consists of a coarse grained riebeckite granite, and riebeckite-biotite granite occurs in the transition zone with the biotite granite and in a small area of the eastern part of the intrusion. Analyses of rocks and riebeckite are available (Lyons and Krueger, 1976).

Age: 
K-Ar analyses of five riebeckite samples averaged 366 ±9 Ma (Lyons and Krueger, 1976, p. 91).
References: 

LYONS, P.C. and KRUEGER, H.W. 1976. Petrology, chemistry, and age of the Rattlesnake pluton and implications for other alkalic granite plutons of southern New England. Memoir, Geological Society of America, 146: 71-102

Map: 
Fig. 1_185 Rattlesnake pluton (after Lyons and Krueger, 1976, Fig. 2).
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith