The Lamprophyre Problem

Abstract

Judd was one of the early workers to recognize that changes in the mineral constitution of an intrusive igneous rock, changes affecting the earlier minerals, may take place prior to the completion of crystallization. He points out that minerals, since their first crystallization, may have undergone several series of changes, totally dissimilar in kind, and resulting from causes altogether different, and that the dissolved material may be carried away from a crystal and deposited within the cavities of neighbouring crystals of different species. This process must result in the blending together in the most inextricable manner of material derived from different crystallized minerals, and the whole characters of the rock may be completely altered.