Structure of the Rio Grande rift in southern New Mexico and West Texas based on gravity interpretation
The Rio Grande rift, which is marked by a positive heat-flow anomaly in southern New Mexico, has been the subject of a gravity study based on 4,500 stations which cover a strip across New Mexico. The area consists of a series of basins and intervening ranges formed during Miocene time. This basin-and-range structure is strongly reflected in the Bouguer gravity anomalies, which range from -125 mgal over unlifts to -190 mgal over basins. Lineaments in trends of gravity anomalies are oblique to the predominant north-south trend of the rift and suggest that, in detail, the crust broke upon fractures oblique to the large-scale north-south trend. Thicknesses of Cenozoic sediments, determined from gravity measurements, range from 2 to 3 km in basins. The gravity effect of sediments is removed by stripping, and a broad +30-mgal gravity anomaly is located over the rift. Regional and residual Bouguer gravity anomaly maps were constructed. The source of the 30-mgal gravity high is interpreted to ba a shallow slab of basalt or a deep upwarp of the mantle that results in crustal attenuation. The low-velocity zone may project up toward the base of the crust under the Basin and Range province. Experiments and the observed fault pattern suggest an extensional origin for the Rio Grande rift fracture system.
- Research Organization:
- Univ. of Wyoming, Laramie
- OSTI ID:
- 5075795
- Journal Information:
- Geol. Soc. Am., Bull.; (United States), Vol. 89:1
- Country of Publication:
- United States
- Language:
- English
Similar Records
Definition of the Rio Grande rift in northern New Mexico by residual Bouguer gravity anomaly analysis (Abstract)
The decompensative gravity anomaly and deep structure of the region of the Rio Grande rift
Related Subjects
RIO GRANDE RIFT
GEOLOGIC STRUCTURES
GRAVITY SURVEYS
DATA ANALYSIS
FRACTURES
GEOLOGIC FAULTS
GEOLOGIC MODELS
HEAT FLOW
MAPS
NEW MEXICO
SEDIMENTS
TECTONICS
TEXAS
THICKNESS
DIMENSIONS
FAILURES
GEOPHYSICAL SURVEYS
NORTH AMERICA
SOUTHWEST REGION
USA
150301* - Geothermal Exploration & Exploration Technology- Geophysical Techniques & Surveys
150201 - Geology & Hydrology of Geothermal Systems- USA- (-1989)