Diagenesis of early Permian evaporites and carbonates, Palo Duro Basin, Texas

Conference · Tue Jan 01 00:00:00 EST 1985 · Geol. Soc. Am., Abstr. Programs; (United States)

OSTI ID:6460809

Posey, H H; Fisher, R S; Hovorka, S D; Elliott, L A

Anhydrite nodules within dolomite grainstone constitute a characteristic facies marking the transition from open marine deposits of the Lower Permian Wolfcamp Formation into hypersaline dolomite and evaporite deposits of the overlying Wichita Formation. Accompanying this transition is a shift from nodular to bedded anhydrite, a decrease in faunal diversity, finer carbonate grain size, a greater abundance of algae and a decrease in calcite abundance. Anhydrite nodules in the Upper Wolfcamp probably displaced carbonate muds before Wichita deposition. Other diagenetic features include dolomitization, and anhydrite recrystallization and replacement by silica. Sr, C, O and S isotopes help account for many of the primary and diagenetic features. Values for delta/sup 34/S and /sup 87/Sr//sup 86/Sr from unaltered Wichita anhydrite beds (approx.13.5 per thousands and 0.7078) indicate equilibrium with Early Permian seawater. Unaltered Upper Wolfcamp nodules, most abundant in the northeastern Palo Dura Basin, have lighter delta/sup 34/S (approx.12.7 per thousands) but probably record the seawater delta/sup 34/S composition of Early Permian, pre-Wichita Formation seawater. delta/sup 34/S of altered anhydrite nodules, cements and anhydrite veins are 1 to 4 per thousands heavier, probably due to anhydrite reduction during silicification. Dolomite ranges from -1 to +5.5 (delta/sup 13/C, PDB) and -1 to +3(delta/sup 18/O, PDB) whereas limestone ranges from -1 to +7 (delta/sup 13/C) and -4.5 to -2.5 (delta/sup 18/O). Dolomite delta/sup 13/C and delta/sup 18/O values are 2 to 4 thousands heavier than adjacent limestone, suggesting that dolomite and calcite are locally in equilibrium.

• Research Organization: Univ. of Texas, Austin (USA)
• OSTI ID: 6460809
• Report Number(s): CONF-8510489-
• Journal Information: Geol. Soc. Am., Abstr. Programs; (United States), Vol. 17; Conference: 98. annual meeting of the Geological Society of America, Orlando, FL, USA, 28 Oct 1985
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
CARBONATE ROCKS
DIAGENESIS
MINERALOGY
EVAPORITES
PALO DURO BASIN
ANHYDRITE
CARBON ISOTOPES
CHEMICAL COMPOSITION
DOLOMITE
GEOCHEMISTRY
ISOTOPE RATIO
OXYGEN ISOTOPES
PERMIAN PERIOD
TEXAS
ALKALINE EARTH METAL COMPOUNDS
CALCIUM CARBONATES
CALCIUM COMPOUNDS
CALCIUM SULFATES
CARBON COMPOUNDS
CARBONATE MINERALS
CARBONATES
CHEMISTRY
FEDERAL REGION VI
GEOLOGIC AGES
ISOTOPES
MAGNESIUM CARBONATES
MAGNESIUM COMPOUNDS
MINERALS
NORTH AMERICA
OXYGEN COMPOUNDS
PALEOZOIC ERA
PERMIAN BASIN
ROCKS
SEDIMENTARY ROCKS
SULFATE MINERALS
SULFATES
SULFUR COMPOUNDS
USA
580300* - Mineralogy
Petrology
& Rock Mechanics- (-1989)
580400 - Geochemistry- (-1989)