Geochemical study of authigenic minerals in the Salt Wash Member of the Morrison Formation, Slick Rock District, San Miguel County, Colorado

Book · Wed Jan 01 04:00:00 EST 1986

OSTI ID:6278322

Breit, G N

Authigenic minerals were examined to evaluate the diagenetic history of this fluvial unit. The minerals were characterized petrographically, chemically, mineralogically and isotopically to define their geochemical environment of deposition. Minerals examined include albite, barite, calcite, chalcedony, chlorite, dolomite, illite-smectite, hematite, kaolinite, pyrite, quartz, and smectite. The minerals formed during three distinct episodes of diagenetic alteration: early diagenesis, late diagenesis and recent alterations. Early diagenetic minerals formed soon after deposition of the host rocks. The composition of the pore waters was largely a product of evaporation and interaction with felsic volcanic ash. These solutions were alkaline, and generally oxidizing; however, near detrital plant fragments, they were chemically reducing. During deep burial, two tectonically driven solutions entered the Morrison Formation through faults. These solutions precipitated calcite, barite, dolomite, and copper minerals and resulted in ferric oxide dissolution. The first of the solutions was a brine that originated in the evaporites of the Pennsylvanian Hermosa Formation. The second solution was a dilute, meteoric water. During Late Tertiary time into the Recent, units overlying the Morrison Formation were eroded. As the Morrison Formation was exposed, meteoric water flowed through structurally favored portions of the Salt Wash Member dissolving plagioclase and chlorite, and precipitating kaolinite.

• Research Organization: Colorado School of Mines, Golden (USA)
• OSTI ID: 6278322
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580400* -- Geochemistry-- (-1989)
ALBITE
ALKALINE EARTH METAL COMPOUNDS
ALUMINIUM COMPOUNDS
ALUMINIUM SILICATES
BARITE
BARIUM COMPOUNDS
BARIUM SULFATES
BRINES
CALCITE
CALCIUM CARBONATES
CALCIUM COMPOUNDS
CARBON COMPOUNDS
CARBONATE MINERALS
CARBONATES
CHALCOGENIDES
CHEMISTRY
CHLORITE MINERALS
CLAYS
COLORADO
DEPOSITION
DIAGENESIS
DISSOLUTION
DOLOMITE
FEDERAL REGION VIII
FELDSPARS
GEOCHEMISTRY
GEOLOGIC DEPOSITS
GEOLOGIC HISTORY
GROUND WATER
HEMATITE
HYDROGEN COMPOUNDS
ILLITE
INTERSTITIAL WATER
IRON COMPOUNDS
IRON ORES
IRON OXIDES
IRON SULFIDES
KAOLINITE
MAGNESIUM CARBONATES
MAGNESIUM COMPOUNDS
METEORIC WATER
MINERALS
NORTH AMERICA
ORES
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PYRITE
QUARTZ
SILICATE MINERALS
SILICATES
SILICON COMPOUNDS
SILICON OXIDES
SMECTITE
SULFATE MINERALS
SULFATES
SULFIDE MINERALS
SULFIDES
SULFUR COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
USA
WATER