Author: H R Gault

Publisher: Forgotten Books

Published: 2018-03-21

Total Pages: 24

ISBN-13: 9780365186854

Excerpt from Zinc-Copper Deposit at Tracy Arm Petersburg District Alaska The area in the vicinity of Tracy Arm is underlain mainly byk'a group of northwest-trending metamorphic rocks that flank the west edge of the Coast Range batholith. (see pl. These rocks are here subdivided into three zones: an eastern zone of light-brown schists; a central zone of dark-green schists, black phyllites and gray-green schists and a western zone of light-green chlorite schists. The bound aries, based in part on lithology and in part on degree of metamorphism, are not sharply defined. The metamorphic rocks are bordered on the east by quartz diorite gneiss of the Coast Range batholith. Silicic dikes and Sills that seem to be genetically associated with the batholith also have intruded the metamorphic rocks. Lamprophyre dikes are' the youngest igneous rocks in the area and intrude both the quartz diorite gneiss and the schists. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.