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G.C. Kennedy

Publications and source records attributed to G.C. Kennedy.

6 recordsLinked to original sources
USGS1945

The preparation of polished thin sections

The relations in ores between opaque and translucent minerals can not be determined satisfactorily by independent examination of either polished surfaces or thin sections. Previous attempts to prepare polished thin sections by Tolman and Rogers, and thinned polished sections by Donnay, appear not to have been entirely successful. Canada balsam, the cementing medium used, is not sufficiently tenacious to overcome the stresses imparted to the surface of the polished grain by the polishing process, which cause the grains to crackle and curl away from the glass slide. This paper describes two mounting media which largely overcome these stresses. These media are the thermoplastics glycol phthalate and Gelva V 7. Glycol phthalate is best suited to the polishing of thin sections on a cloth lap. Gelva V 7 is preferable if sections are to be polished on a Graton-Vanderwilt polishing machine. Photomicrographs of the results are appended.

Economic Geology↗
USGS1944

Chromite occurrences and a nickel prospect, Baranof Island, southeastern Alaska

This report presents the results of a brief geologic reconnaissance of some of the chromite-bearing sills between Red Bluff Bay and Silver Bay in central Baranof Island, southeastern Alaska (see figs. 1 and 2), and the results of a magnetic study of a chromite body in the ultrabasic rocks at Red Bluff Bay. Also included are the results of a brief examination of a nickel prospect near Sitka. The field work, upon which this report is largely based, was done by the authors in the early part of August 1943 as a part of a Geological Survey project to investigate some of the ultrabasic rocks of southeastern Alaska to determine the presence or absence in them of significant nickel-copper or chromium deposits. Previous studies of some of the chromite-bearing ultrabasic rocks of Baranof Island were made by Guild and Balsley during the summer of 1941.

Alaska↗