An overview of recent bedrock mapping and follow-up petrological studies of the South Mountain Batholith, southwestern Nova Scotia, Canada

Abstract

Describes the evolution of the South Mountain Batholith. Mapping has resulted in the delineation of 49 map units consisting of granodiorite, monzogranite, leucomonzogranite and leucogranites. The units are assigned to 13 plutons which are grouped into two stages. Petrographic and geochemical studies indicate a continuous sequence from least evolved biotite granodiorite to most evolved leucogranite. Published geochronological data indicates that all plutons were intruded and crystallized during a very short time interval (<5 Ma) at ca. 370 Ma. Structural characteristics indicate that the batholith was subjected to regional stresses associated with the waning stages of the Acadian Orogeny during intrusion. Differences in the composition of the various rock types are explained by variations in protolith composition. The style of mineralization in the plutons is interpreted as reflecting protolith composition and the physio-chemical conditions that prevailed during crystallization. Accordingly, the economic potential of the thirteen plutons must be evaluated individually. -from Authors