The origin of manganese-rich metasediments and their relationship to iron formation and base metal deposits, western Georgia piedmont
Manganiferous metasediments (coticules), banded iron-formation, and tourmaline-quartz rocks (tourmalinites) are found in close spatial association to each other and to volcanogenic base metal sulfide and gold deposits in the Northern Piedmont of western Georgia. Coticules, which consist of up to 90% garnet and contain from 1 to 15 weight % MnO and 14 to 37 % Fe/sub 2/O/sub 3/, are often hosted by metabasalt. Tourmalinites occur as poorly-bedded aggregates or disseminations and are also found locally associated with metabasalt. Trace element analyses of coticules yield conflicting results. Cu + Co + Ni values and Zr/Cr ratios are low and indicate a hydrothermal origin. Alumina concentrations, Y/P/sub 2/O/sub 5/% ratios, and Th values indicate the probable presence of pelagic sediments in the protolith. Rare earth element patterns are enriched in the light elements and have slight negative Eu anomalies, resembling the patterns of pelagic clays most closely. The protolith of coticules was apparently a hydrothermal sediment with pelagic and/or terrigenous input. Tourmaline in tourmalinites is chemically similar to stratabound sulfide-related examples. Both coticules and tourmalinites are interpreted as metamorphosed seafloor exhalative sediments and thus indicate the potential for the presence of genetically related ore mineralization.
- Research Organization:
- Ames Lab., IA (USA)
- OSTI ID:
- 6211371
- Report Number(s):
- IS-T-1334; ON: DE87013597
- Resource Relation:
- Other Information: Thesis. Portions of this document are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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GEORGIA
GEOLOGIC DEPOSITS
METAMORPHIC ROCKS
ORIGIN
PETROGENESIS
CHEMICAL COMPOSITION
GARNETS
MAGNETITE
MINERALOGY
PETROLOGY
TOURMALINE
ALUMINIUM COMPOUNDS
ALUMINIUM SILICATES
BORON COMPOUNDS
BORON SILICATES
CHALCOGENIDES
FEDERAL REGION IV
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IRON ORES
IRON OXIDES
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ORES
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
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SILICATE MINERALS
SILICATES
SILICON COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
USA
580100* - Geology & Hydrology- (-1989)
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Petrology
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