Accession Number:

AD0619835

Title:

LANTHANUM, EUROPIUM AND DYSPROSIUM DISTRIBUTIONS IN IGNEOUS ROCKS AND MINERALS,

Descriptive Note:

Corporate Author:

MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF GEOLOGY AND GEOPHYSICS

Report Date:

1962-08-09

Pagination or Media Count:

9.0

Abstract:

Whole-rock samples of three oceanic basalts, one diabase, and four granites from northeastern North America, and feldspar and mica mineral concentrates from three of the granites have been analyzed for La, Eu, and Dy by means of neutron activation. By plotting on a logarithmic scale the concentration versus atomic number of each rare-earth element relative to its chondritic abundance, it is shown that the crustal rocks all show an enrichment of La over Dy relative to chondrites. The basalts are quite uniform, but the granites are variable in the degree of enrichment of La. In basalts Eu lies close to the straight line joining La and Dy and thus appears to be normal, but in the granites Eu lies below this line by a factor of 1.6 to 3.4. Analysis of feldspar and mica mineral concentrates from the granites shows Eu to be preferentially included in the feldspar fraction. The abnormal behavior of Eu is attributed to its being in the 2 oxidation state at some point during magmatic crystallization. Author

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Distribution Statement:

APPROVED FOR PUBLIC RELEASE