Evidence for episodic basin dewatering in salt-dome cap rocks

Journal Article · Wed Aug 01 04:00:00 EDT 1990 · Geology; (USA)

DOI:https://doi.org/10.1130/0091-7613(1990)018<0716:EFEBDI>2.3.CO;2· OSTI ID:6212882

Hallager, W S ^[1]; Ulrich, M R ^[2]; Kyle, J R; Gose, W A ^[3]; Price, P E ^[4]

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1. Chevron Oil Field Research, La Habra, CA (USA)
2. Mobil Exploration and Production, Houston, TX (USA)
3. Univ. of Texas, Austin (USA)
4. Marathon Oil Company, Houston, TX (USA)

A detailed record of episodic basin-dewatering events is preserved in the anhydrite cap rocks to two Gulf Coast salt domes. Metal rich brines were intermittently expelled geopressured zones deep in the stratigraphic section and were channeled upward along escape structures bounding the salt diapirs. Overhanging anhydrite cap rock helped to focus some escaping fluid into the zone of dissolution between the top of salt and overlying residual anhydrite cap rock. Iron, lead, and zinc sulfide solubilities were exceeded in this zone, possibly in response to dissolution and reduction of cap-rock sulfates. Because the metalliferous brines entered the dissolution zone intermittently, they were recorded as relatively thin horizontal bands of sulfide sandwiched between thicker accumulations of anhydrite. Continued dissolution of salt and underplating of residual anhydrite caused the sulfide bands to be displaced upward relative to the base of the cap, leading to an inverted stratigraphic record of basin-dewatering events. Paleomagnetic data from the Winnfield salt dome suggest the sulfide-producing basin-dewatering events and anhydrite cap-rock accumulation occurred between 157 and 145 Ma.

• OSTI ID: 6212882
• Journal Information: Geology; (USA), Journal Name: Geology; (USA) Vol. 18:8; ISSN GLGYB; ISSN 0091-7613
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
AGE ESTIMATION
ALKALINE EARTH METAL COMPOUNDS
ANHYDRITE
BRINES
CALCIUM COMPOUNDS
CALCIUM SULFATES
CAP ROCK
CHALCOGENIDES
DIMENSIONS
DISSOLUTION
ELEMENTS
ENERGY SYSTEMS
GEOLOGIC DEPOSITS
GEOLOGIC HISTORY
GEOLOGIC STRATA
GEOLOGIC STRUCTURES
GEOLOGY
GEOPRESSURED SYSTEMS
GULF COAST
INORGANIC PHOSPHORS
IRON COMPOUNDS
IRON SULFIDES
LEAD COMPOUNDS
LEAD SULFIDES
MAGNETISM
METALS
MINERALS
NORTH AMERICA
OXYGEN COMPOUNDS
PALEOMAGNETISM
PHOSPHORS
REMOVAL
SALT DEPOSITS
SOLUBILITY
STRATIGRAPHY
SULFATE MINERALS
SULFATES
SULFIDES
SULFUR COMPOUNDS
THICKNESS
TRANSITION ELEMENT COMPOUNDS
USA
WATER REMOVAL
ZINC COMPOUNDS
ZINC SULFIDES