Abstract
A body of hornblendite composed of crystals of extraordinary size is described. It is suggested that the giant crystals of hornblende imply a large proportion of volatile or aqueous matter in the hornblendic magma and that the body may be better considered as a hornblendite pegmatite and the product of a pegmatitic magma. As late solutions continued to move through the body they caused additional changes in the hornblendite itself, partly replacing the hornblende by biotite, chlorite, magnetite, and pyrite, changes especially characteristic of hydrothermal alteration of the hypothermal kind. Relation to other rocks in the region is discussed, and the large body of hornblendite is seen to fit well into the setting of prevailingly hornblendic rocks and to represent one of the end-products of differentiation of a quartz dioritic magma.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
