Physical Sciences and Mathematics Commons^™

The Development Of Foliations In Low, Medium And High Grade Metamorphic Tectonites, William J. Gregg

Geology Theses and Dissertations

Studies of foliation and associated microstructures are presented from a variety of rock types and localities in the metamorphic terrains of the northeastern United States.
At Islesboro, Maine cleavage is well developed in lower greenschist grade siltstones and interbedded pelites of lower Paleozoic age. Cleavage in the siltstone units consists of two types of discrete mica films: short film segments and lengthened mica film. Thick secondary mica-rich layers are also exhibited in some siltstones. The short film segments appear to be basic elements through which cleavage development progresses by a linkage process that is poorly understood. The linkage of these …