A Comparative Petrological Study of Three Nova Scotian Intrusions: the Jeddore Dyke, the Sober Island Dyke, and the Marshdale Intrusive

Abstract

A thorough investigation of three igneous bodies found in Nova Scotia (Jeddore dyke, Sober Island dyke, and Marshdale plug) has brought out a number of important results. The two dykes, located along the Eastern Shore, are calc-alkaline lamprophyres with ages of 370+/-5 Ma., approximately contemporaneous with the Musquodoboit and South Mountain batholiths. Their similar mineralogy, age, orientation, and chemistry suggest they are genetically related. The Marshdale plug, on the other hand, is a gabbroic body having few if any similarities to the two dykes. It does, however, share several features with the Shelburne dyke or "Great Dyke" suggesting that it formed during Triassic rifting associated with the opening of the North Atlantic Ocean.

Keywords: Pages: 94 Supervisor: D. Barrie Clarke