Metasomatism in a subduction complex: Constraints from microanalysis of trace elements in minerals from garnet amphibolite from the Catalina Schist

Journal Article · Wed Apr 01 04:00:00 EST 1992 · Geology; (United States)

DOI:https://doi.org/10.1130/0091-7613(1992)020<0347:MIASCC>2.3.CO;2· OSTI ID:7202193

Hickmott, D D; Rogers, P S.Z. ^[1]; Sorensen, S S ^[2]

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1. Los Alamos National Lab., NM (United States)
2. 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), Journal Name: Geology; (United States) Vol. 20:4; ISSN GLGYB; ISSN 0091-7613
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
AMPHIBOLITES
CALIFORNIA
CHEMICAL COMPOSITION
CHEMISTRY
DEVELOPED COUNTRIES
ELEMENTS
GARNETS
GEOCHEMISTRY
GEOLOGIC STRUCTURES
METALS
METAMORPHIC ROCKS
METAMORPHISM
MICROANALYSIS
MINERALS
NORTH AMERICA
OXYGEN COMPOUNDS
PETROGENESIS
RARE EARTHS
ROCKS
SCHISTS
SEDIMENTARY BASINS
SILICATE MINERALS
SILICATES
SILICON COMPOUNDS
SUBDUCTION ZONES
USA