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The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 69 (1985)

Issue: 2. (February)

First Page: 313

Last Page: 313

Title: Textural Evidence for Origin of Salt Dome Previous HitAnhydriteNext Hit Cap Rocks, Winnfield Dome, Louisiana: ABSTRACT

Author(s): Mark R. Ulrich, J. Richard Kyle, Peter E. Price

Article Type: Meeting abstract


Textures within Previous HitanhydriteNext Hit cap rock are products of repeated cycles of halite dissolution and residual Previous HitanhydriteNext Hit accretion at tops of salt stocks. Quarrying operations at Winnfield dome have exposed extensive portions of the Previous HitanhydriteNext Hit cap rock zone. This zone is composed primarily of unoriented, xenoblastic Previous HitanhydriteNext Hit crystals in laminae less than 1 mm to several centimeters thick. Laminations are defined by thin, dark sulfide accumulations and pressure solution of Previous HitanhydriteNext Hit. Deformed, banded Previous HitanhydriteNext Hit clasts are contained locally within laminae. Multiple-laminated, concave downward Previous HitanhydriteNext Hit mounds occur along some horizons. They may contain Previous HitanhydriteNext Hit breccia fragments or sulfides. Coarsely crystalline salt mounds, containing disseminated idioblastic Previous HitanhydriteNext Hit also occur a ong horizons. Mound morphologies vary from tall and thin to broad and squat; maximum dimensions range from less than 0.5 m to about 2.0 m. These moundlike structures are related spatially and genetically.

Moundlike structures are believed to form from salt spines along the salt-Previous HitanhydriteNext Hit contact. As the spine dissolves through several cycles of dissolution and accretion, a laminated Previous HitanhydriteNext Hit mound is preserved; if the spine becomes isolated from dissolution, then a salt inclusion is preserved. Previous HitAnhydriteNext Hit beds within the Louann Salt, deformed during diapirism, are preserved as deformed Previous HitanhydriteNext Hit clasts. Steeply dipping, bedded Previous HitanhydriteNext Hit zones within the salt stock may produce brecciated Previous HitanhydriteNext Hit mounds when incorporated into the cap rock. Sulfides record the movement of metalliferous fluids through the salt-Previous HitanhydriteTop contact. Cores from other Gulf Coast domes indicate that these textures and interpreted processes are common.

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