Isotopic and chemical studies of the Viburnum Trend lead ores of southeast Missouri
Lead isotope analyses of galena determine on the ion microprobe were combined with sulfur isotope analyses done by conventional mass spectrometry and fluid inclusion leachate analyses in an effort to determine the origin of the Viburnum Trend lead ores. Fluid inclusion leachate analyses indicate that the composition of the ore forming fluids of the Viburnum Trend is similar to that of typical oil field brines. The relatively elevated K/sup +//Na/sup +/ ratio of the ore forming brines may be due to interaction with the granitic basement or with arkosic sediments. The Br/sup -//Cl/sup -/ ratio of the fluid inclusions suggests that the brines from which the octahedral galena was deposited originated as evaporated seawater, and that the brines from which the cubic galena was deposited derived much of their salinity from the dissolution of halite. A rough correlation between the isotopic composition of lead and sulfur in galena persists throughout the Viburnum Trend. The isotopic data can be explained mostly in terms of the mixing of two end members. The age of the mineralizing event, the physical requirements for the source basin, and the chemical similarities of the ore forming fluids to present day Arkoma Basin brines indicate that the source of the ore forming brines was the Ouachita-Arkoma Basin during the later Carboniferous to Early Permian. The correlation of the isotopic composition of lead and sulfur in the galenas strongly suggests that both elements were transported together in solution. It is proposed that the sulfur was transported in the oxidized state and that sulfate reduction via the oxidation of organic carbon was the mechanism of ore precipitation.
- Research Organization:
- Harvard Univ., Boston, MA (USA)
- OSTI ID:
- 6955808
- Country of Publication:
- United States
- Language:
- English
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580400* -- Geochemistry-- (-1989)
ALKALI METALS
BASEMENT ROCK
BRINES
BROMIDES
BROMINE COMPOUNDS
CHALCOGENIDES
CHEMICAL ANALYSIS
CHEMISTRY
CHLORIDES
CHLORINE COMPOUNDS
CORRELATIONS
DISPERSIONS
ELEMENTS
FEDERAL REGION VII
GALENA
GEOCHEMISTRY
GEOLOGIC DEPOSITS
GEOLOGIC HISTORY
HALIDES
HALOGEN COMPOUNDS
HYDROGEN COMPOUNDS
ION MICROPROBE ANALYSIS
ISOTOPE RATIO
LEACHATES
LEAD
LEAD COMPOUNDS
LEAD ORES
LEAD SULFIDES
MASS SPECTROSCOPY
METALS
MICROANALYSIS
MINERALS
MISSOURI
MIXTURES
NONDESTRUCTIVE ANALYSIS
NONMETALS
NORTH AMERICA
ORES
ORIGIN
OXYGEN COMPOUNDS
POTASSIUM
SEAWATER
SODIUM
SOLUTIONS
SPECTROSCOPY
SULFIDE MINERALS
SULFIDES
SULFUR
SULFUR COMPOUNDS
USA
WATER