Lead-alpha age determinations of granitic rocks from Alaska
Trace Elements Investigations
618
This report concerns work done on behalf of the Division of Raw Materials of the U.S. Atomic Energy Commission
By: John J. Matzko, H.W. Jaffe, and C. L. Waring
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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.
Study Area
| Publication type | Report |
|---|---|
| Publication Subtype | USGS Numbered Series |
| Title | Lead-alpha age determinations of granitic rocks from Alaska |
| Series title | Trace Elements Investigations |
| Series number | 618 |
| DOI | 10.3133/tei618 |
| Year Published | 1957 |
| Language | English |
| Publisher | U.S. Geological Survey |
| Description | 27 p. |
| Country | United States |
| State | Alaska |
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