Abstract
dc:description.abstractMetamictization and complex chemistry are major obstacles to the crystal chemical characterization of natural allanites. To overcome these problems, allanites, Ca(REE)Fe²+Al₂Si₃O₁₂(OH), where REE = La, La-Ce, Ce, Nd, Sm, Eu, Gd, Er, Dy, Yb and Y have been synthesized hydrothermally from unbuffered and buffered oxide mixes at 500 to 650°C, 5.5 kbar (550 MPa), and 700 to 725°C, 4 kbar (400 MPa). Although allanite is readily synthesized, high yields are obtained only for allanite-(LREE) compositions, and end"member composition is obtained only for allanite-(La). Er and Yb ions are too small to substitute at the A(2) site in allanite, but a small amount can substitute at the VI~coordinated M(3) site. Fe²+ in the M(3) site favors LREE substitution, which supports the contention that allanite is Ce'selective.
Degree
thesis:*- Name thesis:degree_name
- Ph. D.
- Level thesis:degree_level
- doctoral
- Discipline thesis:degree_discipline
- Geological Sciences
- Department dc:contributor.department
- Geological Sciences
- Grantor dc:publisher
- Virginia Tech
- Year dc:date.issued
- 1987
Author and committee
dc:creator, dc:contributor.*- Author dc:creator
-
- Affholter, Kathleen
- Chair dc:contributor.committeechair
-
- Hewitt, David A.
- Committee members dc:contributor.committeemember
-
- Bloss, F. Donald
- Gibbs, Gerald V.
- Ribbe, Paul H.
- Speer, J. Alexander
Rights
dc:rights- Statement dc:rights
-
- In Copyright
- Licence dc:rights.uri
- Language dc:language.iso
- en
Identifiers
dc:identifier.*- Dc Identifier Other
- etd-02062013-040123
- OAI identifier oai:identifier
- oai:vtechworks.lib.vt.edu:10919/37332