A report about analyzing the age of igneous rock using its lead-alpha activity.

Abstract: "Lead-alpha activity age determinations were made on zircon from seven granitic rocks of central and southeastern Alaska. The results of the age determinations indicate two periods of igneous intrusion, one about 95 million years ago, during the Cretaceous period, and another about 53 million years ago, during the early part of the Tertiary. The individual ages determined on zircon from 2 rocks from southeastern Alaska and 1 from east-central Alaska gave results of 90, 100, and 96 million years; those determined on 4 rocks from central Alaska gave results of 47, 56, 58, and 51 million years."

From abstract: To help the mining industry of Alaska and to assist in the development of the mineral resources of the Territory have been the prime motives of the Geological Survey's investigations in Alaska during the past 35 years, in which nearly one half of the Territory has been covered by its reconnaissance and exploratory surveys. It was natural, therefore, that the Alaska Railroad, when it undertook intensive consideration of the problem of finding tonnage that would increase its revenues, should look to the Geological Survey to supply technical information as to the known mineral deposits along its route and to indicate what might be done to stimulate a larger production of minerals and induce further mining developments and prospecting that would utilize its service.

Report discussing the geology of the pegmatites in the Crystal Mountain district in Larimer County, Colorado.

A bibliography which consists of references to published literature, press releases, speeches, and both open-file and other unclassified reports dealing with uranium, thorium, and radioactive occurrences in several United States states.

From introduction: The study of the Crystal Mountain district, Larimer County, Colo., is but one phase of this post-World War II pegmatite program, in part carried out by the Geological Survey on behalf of the Division of Raw Materials of the Atomic Energy Commission.

From letter of transmittal: It is believed that this report will stimulate the mining industry by making available, in compact form, the accumulated results of the experience of mining men in this field and by directing attention to those mining methods developed in older districts which appear to be adapted to the conditions prevailing in Alaska.

Report summarizing results of research conducted by the U.S. Geological Survey during fiscal year 1965. It provides an overview of the economic and scientific work of the organization.

From introduction: For several years the Division of Topography of the United States Geological Survey has been engaged in compiling positions determined within the United States which are believed to be of sufficient accuracy for use in the preparation of its maps. This compilation has been found extremely useful in the office, and it is believed that its usefulness will be greatly extended by placing it before the public. This list comprises between 9,000 and 10,000 positions. To publish it in extenso, with descriptions of the stations, their latitudes and longitudes, the distances and azimuths to neighboring stations, and the methods of determination, would extend this bulletin beyond all reasonable limits. To avoid making too bulky a volume, it has been decided to publish merely the latitudes and longitudes, with abbreviations indicating the authority, and references to the publications in which other data relating to the positions may be found.

Introduction: This work is an alphabetical list of the geographic names that are now applied and have been applied to to places and features of the Alaska Landscape.