|Name||Esmond Igneous Suite - granodiorite|
|Geologic age||Late Proterozoic|
Igneous > Plutonic > Granitic > Granodioritegranodiorite - Gray, tan, greenish, or pale-pink, medium- to coarse-grained, mainly porphyritic rock (phenocrysts of microcline). Contains microcline, perthite, plagioclase, quartz, and accessory biotite, epidote, zircon, allanite, monazite, apatite, sphene, and opaque minerals; secondary muscovite, chlorite, and calcite. Mainly massive.
|Comments||Part of Esmond-Dedham Subterrane (West Bay Area). Per printed map: age of rock based on radiometric data from RI005 (U-Th-Pb (zircon) dating by Hermes and Zartman (1985) who record a 621+/-8 Ma emplacement date) and RI009.|
Hermes, O.D. (comp.), Gromet, L.P. (comp.), Murray, D.P. (comp.), Hamidzada, N.A., Skehan, J.W., and Mosher, S., 1994, Bedrock geologic map of Rhode Island: Rhode Island Map Series No. 1, Kingston, Rhode Island, scale 1:100,000.
Hermes, O.D., and Zartman, R.E., 1985, Late Precambrian and Devonian plutonic terrane within the Avalon Zone of Rhode Island: Geological Society of America Bulletin, v. 96, p. 272-282.
Hermes, O.D., Gromet, L.P., and Zartman, R.E., 1981, Zircon geochronology and petrology of plutonic rocks in Rhode Island, p. 315-338: in Boothroyd, J.C., and Hermes, O.D., editors, Guidebook to Field Studies in Rhode Island and Adjacent Areas: 73rd New England Intercollegiate Geological Conference, University of Rhode Island, Kingston, 383p.