Masters Theses


"The Eldor carbonatite complex, located in the Labrador Trough region of Quebec, Canada, is a relatively unstudied deposit. The complex has a ubiquitos distribution of pyrochlore throughout the units, contains REE mineralization in the form of monazite and contains several minerals which would be economically viable as a by-product of pyrochlore mining.

The units identified in this study, at the Eldor complex, consist of early stage 2 calcite and dolomitized carbonatites and late-stage VeInIng calcite carbonatite. Fenitization is apparent in many of the units.

Cathodoluminescence mIcroscopy was used extensively to identify the extent of fenitization, characterize the type and stage of carbonate and apatite present as well as identifiy other constituents.

Pyrochlore mineralization is concentrated in the glimmerite units of the complex. Several types, alterations and generations of pyrochlore exist in the units at Eldor. Pyrochlore composition is highly variable within each specimen as well as each unit. Pyrochlore in the Ankeritic-Carbonatitic Unit is characterized by notable enrichment of uranium.

Hydrothermal fluids deposited the pyrochlore in the Glimmerite unit at Eldor. A Ta/Nb versus Fe/Nb ratio plot indicates fenitizing fluids did not produce the Glimmerite pyrochlore. An elevated Ce/Ce* ratio for the Glimmerites indicates high fluid flow, complexting and oxidation during formation.

Monazite is the independent REE mineral identified the complex. It is present as discrete grains in several types of units and it is especially concentrated in the Ankeritic-Carbonatitic Unit. This monazite formed during secondary alteration of the unit when the LREE's were released from apatite and formed in the presence of abundant phosphorus.

The Ta/Nb ratio in the carbonatite-related Eldor units IS elevated to values as high as six which is unusual for most carbonatite complexes. A compilation of data indicates there are several are complexes (Nachendaz, Mt Weld, Jacupirangi and Kola) with similar values. Ta/Nb values greater than unity indicates a possible geochemical link between dissimilar carbonatite complexes"--Abstract, pages iii-iv.


Hagni, Richard D.

Committee Member(s)

Grant, S. Kerry
Miller, F. Scott, 1956-


Geosciences and Geological and Petroleum Engineering

Degree Name

M.S. in Geology and Geophysics


University of Missouri--Rolla

Publication Date

Spring 1997


xxvi, 200 pages

Note about bibliography

Includes bibliographical references (pages 194-198).

Geographic Coverage

Labrador Trough (N.L. and Québec)


© 1997 Wayne Russell Wright, All rights reserved.

Document Type

Thesis - Restricted Access

File Type




Subject Headings

Carbonatites -- Labrador Trough (N.L. and Québec)
Geology -- Labrador Trough (N.L. and Québec)
Mineralogy -- Labrador Trough (N.L. and Québec)

Thesis Number

T 7305

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