Diabase, metagabbro, and diorite and related rocks (MTpCAd;0)

State	Montana
Name	Diabase, metagabbro, and diorite and related rocks
Geologic age	Proterozoic
Original map label	pCd
Primary rock type	diorite
Secondary rock type	gabbro
Other rock types
Lithologic constituents	Major Igneous > Plutonic > Gabbroic (Dike or sill) Igneous > Plutonic > Dioritic (Dike or sill)
Map references	Ross, P.R., Andrews, D.A., and Witkind, I.J., 1955, Geologic map of Montana: U.S. Geological Survey, 2 sheets, scale 1:500,000.
Unit references	Lewis, R.S., 1998, Preliminary geologic map of the Butte 1° x 2° quadrangle: Montana Bureau of Mines and Geology Open File Report 363, 16 p, scale 1:250,000. Thom, W.T., Jr. and Dobbin, C.E., 1924, Stratigraphy of Cretaceous-Eocene transition beds in eastern Montana and the Dakotas: Geological Society of America Bulletin, v. 35, no. 9, p. 481-505. Harrison, J.E., Whipple, J.W., and Lidke, D.J., 1998, Geologic map of the western part of the Cut Bank 1° x 2° quadrangle, northwestern Montana: U.S. Geological Survey Miscellaneous Geologic Investigations Series Map I-2593, scale 1:250,000. [http://pubs.er.usgs.gov/publication/i2593] Lonn, J.D., and McFadden, M.D., 1999, Geologic map of the Wallace 30' x 60' quadrangle: Montana Bureau of Mines and Geology Open File Report 388, 15 p., scale 1;100,000. Harrison, J.E., Griggs, A.B., and Wells, J.D., 1986, Geologic and structure maps of the Wallace 1° x 2° quadrangle, Montana and Idaho: Montana Bureau of Mines and Geology Montana Atlas Series 4-A, scale 1:250,000. Harrison, J.E., 1972, Precambrian Belt basin of northwestern United States--Its geometry, sedimentation and copper occurrences: Geological Society of America Bulletin, v. 83, no. 5, p. 1215-1240.
Geographic coverage	Flathead - Mineral - Missoula - Sanders