Environmental significance of evaporitic textures of Mississippian Mission Canyon Formation, Williston Basin, North Dakota

Conference · Fri Feb 01 04:00:00 EST 1985 · Am. Assoc. Pet. Geol., Bull.; (United States)

OSTI ID:5718415

Pol, J C; Mescher, P K

The Mission Canyon evaporite wedge, the Frobisher-Alida interval, has commonly been interpreted as typical nodular or chicken-wire anhydrite from a sabkha depositional setting. Upon examination of over 190 cores from North Dakota and Montana, the authors identified a variety of evaporite textures and interpreted several distinct origins for them. The following evaporite textures were recognized: (A) precipitative or primary, (B) intraclastic, (C) evaporite cement, (D) replacement, and (E) dissolution-stage. Depositional evaporites (A,B) form by direct precipitation in supersaturated solutions (primary texture) or by reworking of primary evaporite (intraclastic texture). Primary texture forms by direct precipitation from a supersaturated brine occurring in shallow lagoons or tidal ponds (subaqueous evaporite) or within the sediment (nodular anhydrite). Three types of subaqueous textures were identified: (1) isolated laths, (2) rosettes or clusters of laths, and (3) large swallowtails. Intraclastic texture results from the reworking of previously precipitated evaporite. It is recognized by angularity of the clasts, size sorting, and association with carbonate intraclasts. Depositional environment of this texture is interpreted as evaporitic shallow-water lagoons, punctuated by occasional storm events. Diagenetic textures include cementation, replacement, and evaporite dissolution. Cementation by evaporite was found primarily in carbonate grainstones and is usually poikilotopic. Replacement textures may develop early or late in the diagenetic history of the rocks. Early replacement was found in primary restricted carbonate facies. Original texture (algal laminations, bioturbation, carbonate grains) were usually preserved after replacement. Late-stage replacement was observed in more marine facies, with the original texture not preserved. Isolated nodules of fibrous anhydrite result.

• Research Organization: ARCO Exploration Co., Denver, CO
• OSTI ID: 5718415
• Report Number(s): CONF-850322-
• Conference Information: Journal Name: Am. Assoc. Pet. Geol., Bull.; (United States) Journal Volume: 69:2
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
CARBONATE ROCKS
DEPOSITION
FEDERAL REGION VIII
GEOLOGIC AGES
GEOLOGIC FORMATIONS
MISSISSIPPIAN PERIOD
NORTH AMERICA
NORTH DAKOTA
PALEOZOIC ERA
RESERVOIR ROCK
ROCKS
SEDIMENTARY ROCKS
USA
WILLISTON BASIN