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Rare earths in the Leadville Limestone and its marble derivates

Chemical Geology

By:
, ,
DOI: 10.1016/0009-2541(75)90088-1

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Abstract

Samples of unaltered and metamorphosed Leadville Limestone (Mississippian, Colorado) were analyzed by neutron activation for ten rare-earth elements (REE). The total abundance of the REE in the least-altered limestone is 4-12 ppm, and their distribution patterns are believed to be dominated by the carbonate minerals. The abundances of the REE in the marbles and their sedimentary precursors are comparable, but the distribution patterns are not. Eu is enriched over the other REE in the marbles, and stratigraphically upward in the formation (samples located progressively further from the heat source), the light REE become less enriched relative to the heavy REE. The Eu anomaly is attributed to its ability, unique among the REE, to change from the 3+ to 2+ oxidation state. Whether this results in preferential mobilization of the other REE or whether this reflects the composition of the pore fluid during metamorphism is unknown. Stratigraphically selective depletion of the heavy REE may be attributed to more competition for the REE between fluid and carbonate minerals in the lower strata relative to the upper strata. This competition could have been caused by changes in the temperature of the pore fluid or to the greater resistance to solution of the dolomite in the lower parts of the formation than the calcite in the upper parts. ?? 1975.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Rare earths in the Leadville Limestone and its marble derivates
Series title:
Chemical Geology
DOI:
10.1016/0009-2541(75)90088-1
Volume
16
Issue:
1
Year Published:
1975
Language:
English
Publisher:
Elsevier
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Chemical Geology
First page:
27
Last page:
37
Number of Pages:
11