Title

Fluid-Inclusion Studies of Regionally Extensive Epigenetic Dolomites, Bonneterre Dolomite (Cambrian), Southeast Missouri: Evidence of Multiple Fluids during Dolomitization and Lead-Zinc Mineralization

Abstract

Presents microthermometric data for fluid inclusions in the regionally extensive epigenetic dolomite at the base of the ore-hosting Bonneterre Dolomite and in gangue dolomite of the Viburnum Trend Pb-Zn district. Samples of epigenetic dolomite cover an area of more than 25 000 km2 west of the St. Francois Mountains and permit determination of regional variations of temperature and composition of the mineralizing fluids and possible fluid interactions. Homogenization temperature-ice-melting relationships (temperature-salinity) among these inclusions document at least two end-member fluid components: a warmer, less saline fluid (120 to 187°C; wt% equiv. NaCl) and a cooler, more saline fluid (60 to 80°C; >30 wt% equiv. NaCl). Intermediate temperatures and fluid compositions indicate that the end-member fluids likely mixed as they flowed through the region. The data are interpreted to indicate multiple basinal-fluid interactions coeval with dolomitization and associated Pb-Zn ore formation.

Department(s)

Geosciences and Geological and Petroleum Engineering

Keywords and Phrases

Cambrian; dolomitization; fluid inclusion study; lead/zinc; mineralization; ore formation; temperature; USA, Missouri, Bonneterre Dolomite

Geographic Coverage

Southeastern Missouri

Time Period

Cambrian

International Standard Serial Number (ISSN)

167606

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 1992 Geological Society of America (GSA), All rights reserved.

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