Rare earths, thorium, and other minor elements in sphene from some plutonic rocks in west-central Alaska

Journal of Research of the U.S. Geological Survey
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Abstract

Sphene is an abundant accessory mineral in some abnormally radioactive plutonic rocks in west-central Alaska. Seven samples of sphene from four different areas in west-central Alaska contained from 20350 to 39180 parts per million total rare earths and 390 to 2000 ppm thorium. The lanthanide content in six of the seven sphenes is chiefly the light rare earths and is similar to that of crustal abundance; a seventh sphene from the Darby Mountains, however, contains above average amounts of the heavy rare earths. A comparison of the lanthanide distribution in sphene from several areas indicates that the structure of sphene will accommodate whatever lanthanides are available when the mineral crystallizes. The amount of thorium and rare earths in sphene is also affected by the presence of other accessory minerals. Sphene in rocks containing either allanite or zircon has a lower thorium content than in rocks that do not contain allanite or zircon. Sphene, because of its abundance, may contain the greater part of the rare earths and thorium in some of the plutonic rocks of west-central Alaska.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Rare earths, thorium, and other minor elements in sphene from some plutonic rocks in west-central Alaska
Series title Journal of Research of the U.S. Geological Survey
Volume 5
Issue 5
Year Published 1977
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Description 6 p.
First page 623
Last page 628
Country United States
State Alaska
Other Geospatial Darby Mountains, Granite Mountain, Selawik Hills, Zane Hills
Online Only (Y/N) N
Additional Online Files (Y/N) N
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