A gravity study of the thermopolis anticline, southern Bighorn Basin, Wyoming

Conference · · Mountain Geologist; (United States)

OSTI ID:5676361

Grannell, R B; Showalter, P K ^[1]

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1. California State Univ., Long Beach (United States)

Approximately three hundred gravity stations were measured in the area of the Thermopolis anticline along the southern margin of the Bighorn Basin, Wyoming. Three broad anomaly patterns dominate the isostatic residual gravity map: a 10 mgal negative anomaly associated with sedimentary fill in the Bighorn Basin, a 20 mgal positive anomaly associated with the uplift of Precambrian basement in the Owl Creek Mountains, and a 2-3 mgal positive anomaly associated with the Thermopolis anticline. The anticline anomaly dominates a complex anomaly pattern located between the Owl Creek uplift and Bighorn Basin. Three poorly controlled patterns characterize the Owl Creek Mountains positive anomaly: a positive anomaly (eastern part) centered 6 miles (10km) from Precambrian basement exposures suggests thin basement overlying thick Wind River Basin sediments in thrust contact, a positive anomaly (western part) associated with Precambrian exposures suggests the presence of thick basement, and a smaller positive anomaly (central part of the range) is uninterpretable due to lack of gravity control. Gravity models suggest basement involvement in parts of the Thermopolis anticline besides Rose Dome and Warm Springs where wells have penetrated basement; the basement surface parallels the orientation of overlying units. Several other anticlines or domes show positive gravity anomalies on the isostatic residual map (Red Spring, Corley, Grass Creek-Golden Eagle, Little Sand Draw, Lucerne, and Gebo); the authors modeled the latter two with basement uplifts. Positive gravity signatures at Thermopolis Hot Springs suggest chemical precipitation in addition to basement involvement and negative signatures suggest geothermally-induced leaching.

• OSTI ID: 5676361
• Report Number(s): CONF-8905393--
• Conference Information: Journal Name: Mountain Geologist; (United States) Journal Volume: 28:2-3
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
ANTICLINES
BASEMENT ROCK
DATA ANALYSIS
DEVELOPED COUNTRIES
FEDERAL REGION VIII
GEOLOGIC MODELS
GEOLOGIC STRUCTURES
GEOPHYSICAL SURVEYS
GRAVITY SURVEYS
GROUND UPLIFT
HOT SPRINGS
MOUNTAINS
NORTH AMERICA
SEDIMENTARY BASINS
SURVEYS
THERMAL SPRINGS
TWO-DIMENSIONAL CALCULATIONS
USA
WATER SPRINGS
WYOMING