Dolomitization and fluid interaction in the Reelfoot rift, southeastern Missouri: Geochemical and petrologic studies

Conference · Wed Jan 01 04:00:00 EST 1992 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:5931995

Shelton, K L; Haeussler, G T; Burstein, I B ^[1]; Gregg, J M ^[2]; Palmer, J R ^[3]

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1. Univ. of Missouri, Columbia, MO (United States)
2. Univ. of Missouri, Rolla, MO (United States). Dept. of Geology and Geophysics
3. Missouri Dept. of Natural Resources, Rolla, MO (United States). Div. of Geology and Land Survey

Platform carbonates of the Bonneterre Dolomite (Cambrian) from 2--3 km deep within the Reelfoot Rift of SE Missouri record a diagenetic environment dominated by primitive basinal fluids emanating from a continental rift. The rifted area has been suggested as a possible source region for metals and sulfur for major Mississippi Valley-type (MVT) mineral deposits of the Viburnum Trend, hosted in shallower (< 1 km), stratigraphically equivalent rocks. Rift-related carbonates are replaced extensively by coarse crystalline, nonplanar dolomite; vug and fracture porosity is filled by dolomite and calcite cement, and less commonly by quartz, anhydrite and sulfide minerals. CL and microprobe analysis reveal a simple dolomite cement stratigraphy with an inner Fe-rich and an outer Fe-free zone. These cement zones and their chemistry are in marked contrast to those of more complexly zoned, MVT-related dolomite cements in shallower carbonates throughout SE MO and N Arkansas. Sr-87/Sr-86 values for rift-related, replacement (0.714--0.715) and cement (0.720--0.727) dolomites are highly radiogenic. [delta]C-13 and [delta]O-18 values become progressively more negative with paragenetic time. Fluid inclusion homogenization temperatures (250--180 C) indicate a diagenetic environment nearly 100 C hotter than that preserved in shallower MVT-related carbonates. If the rift environment is a source region for fluids and ore constituents for shallower MVT mineralization, it is only one of several sources or its fluids must have undergone extensive chemical interaction with rocks along their flow paths to have evolved into the more complex chemistry indicated for the shallower site of ore deposition.

• OSTI ID: 5931995
• Report Number(s): CONF-921058--
• Conference Information: Journal Name: Geological Society of America, Abstracts with Programs; (United States) Journal Volume: 24:7
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
CALCITE
CARBONATE MINERALS
CARBONATE ROCKS
CATHODOLUMINESCENCE
CHEMICAL ANALYSIS
CHEMISTRY
DEVELOPED COUNTRIES
DIAGENESIS
DOLOMITE
ELECTRON MICROPROBE ANALYSIS
GEOCHEMISTRY
GEOLOGIC STRUCTURES
GEOLOGY
ISOTOPE RATIO
LUMINESCENCE
MICROANALYSIS
MINERALIZATION
MINERALS
MISSOURI
NONDESTRUCTIVE ANALYSIS
NORTH AMERICA
PETROLOGY
POROSITY
RIFT ZONES
ROCKS
SEDIMENTARY ROCKS
SOURCE ROCKS
USA