Metasomatism in a subduction complex: Constraints from microanalysis of trace elements in minerals from garnet amphibolite from the Catalina Schist
- Los Alamos National Lab., NM (United States)
- Smithsonian Institution, Washington, DC (United States)
Trace element abundances and zoning were measured in minerals from a metasomatized garnet-amphibolite block from the Catalina Schist, using both ion and proton microprobes. Zoisite strongly concentrates light rare earth elements (REEs), Sr, Y, and Pb; amphibole concentrates Ni and Zn; garnet concentrates Y and heavy REEs; and titanite concentrates Nb. Major and trace elements in the garnets are zoned. Garnets in the core of the block display an overgrowth enriched in Mn, Y, and heavy REE, on a Y- and heavy-REE-pore core. Zirconium values remain relatively constant. The element enrichments in the garnet overgrowth suggest mobility of REEs at either a hand-sample or regional scale at subduction-zone pressure-temperature conditions. Metamorphic fluids may selectively transport heavy REEs relative to some high field strength elements in some convergent-margin settings. The distribution of Sr and Pb within subduction zones may reflect the dehydration and melting behavior of epidote-group minerals.
- OSTI ID:
- 7202193
- Journal Information:
- Geology; (United States), Vol. 20:4; ISSN 0091-7613
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
AMPHIBOLITES
CHEMICAL COMPOSITION
PETROGENESIS
CALIFORNIA
SEDIMENTARY BASINS
GARNETS
GEOCHEMISTRY
METAMORPHISM
MICROANALYSIS
RARE EARTHS
SCHISTS
SUBDUCTION ZONES
CHEMISTRY
DEVELOPED COUNTRIES
ELEMENTS
GEOLOGIC STRUCTURES
METALS
METAMORPHIC ROCKS
MINERALS
NORTH AMERICA
OXYGEN COMPOUNDS
ROCKS
SILICATE MINERALS
SILICATES
SILICON COMPOUNDS
USA
580000* - Geosciences