Halifax Pluton

Field trip to the Halifax Pluton, South Mountain Batholith, Nova Scotia

The ~375 Ma South Mountain Batholith is the largest batholith in the Appalachian orogen. Essentially the entire body is peraluminous, containing biotite, muscovite, and more rarely cordierite, garnet, and other aluminous minerals. On this trip, we saw remarkable xenoliths, layered granitoid rocks, and amazing schlieren structures.

Stop 1Pluton margin and small xenoliths
Stop 3Large fragmenting xenolith
Stop 4Layered granodiorite
Stop 5“Arocknid” schlieren and autoliths
Stop 8Fluorite veins and cordierite in the pluton interior
Thin sectionsThin sections from Stops 1, 3, and 8

Geologic map of Nova Scotia (adapted from the former Arocknid web page).

References (guidebook in bold)

Abbott, R.N., 1989, Internal structures in the South Mountain Batholith, Nova Scotia, Canada. Geological Society of America Bulletin, v. 101, p. 1493-1506.

Clarke, D.B., 2003, Exploded xenoliths, layered granodiorites, and chaotic schlieren associated with the eastern contact of the South Mountain Batholith: Field Trip Guidebook, Field Trip 403, Geological Society of America, Northeastern Section Meeting, Halifax, Nova Scotia, 26 p.

Clarke, D.B. and Clarke, G,K,C., 1998, Layered granodiorites at Chebucto Head, South Mountain Batholith, Nova Scotia. Journal of Structural Geology, v. 20, p. 1305-1324.

Clarke, D.B., Henry, A.S., and White, M.A., 1998, Exploding xenoliths and the absence of elephants’ graveyards in granite batholiths. Journal of Structural Geology, v. 20, p. 1325-1343.

MacDonald, M.A. and Horne, R., 1988, Petrology of the zoned, peraluminous Halifax Pluton, south-central Nova Scotia. Maritime Sediments and Atlantic Geology, v. 24, p. 33-46.