A geophysical investigation of possible southern extensions of the Midcontinent rift system
- Univ. of Texas, El Paso, TX (United States). Dept. of Geological Sciences
The Midcontinent rift system (MCR) is a 2,000 km long arc-shaped feature extending from Kansas to Michigan via Lake Superior. The MCR is responsible for the most prominent gravity feature in North America and is 1.11--1.09 Ga in age. The purpose of this paper is to discuss possible southern extensions of the MCR. These extensions include the East Continent Gravity High (ECGH) which extends southeastward from the Great Lakes through Ohio, Kentucky, and Tennessee and several mafic intrusions which extend southwestward through Texas and New Mexico. The ECGH area recently has been the target of researchers who appear to have discovered a Proterozoic basin which is associated with a gravity low which flanks the ECGH. The intrusions in Texas and New Mexico are associated with northeast and northwest trending gravity and magnetic highs. These anomalies appear to be parallel and perpendicular to the pre-existing structural trends. The sources of these anomalies are associated with portions of the Debaca Basement Terrain and Pajarito Mountain in New Mexico, the Franklin Mountains and Crosbyton geophysical anomaly in Texas, and the Central Basin Platform in Texas and New Mexico. Wells drilled into the Precambrian are the primary source of information on these bodies. Dates on these bodies are between 1.07--1.22 Ga. The mafic bodies are present on both sides of the postulated Grenville age suture zone in Texas. This postulated suture may be marked by east-west trending high-low gravity anomaly pair. There are at least three possible hypothesis for the cause of rifting in the region: (1) hot spot track, (2) transform faulting and/or rifting directly related to the MCR, and (3) collision events of Grenville age in Texas.
- OSTI ID:
- 5505051
- Report Number(s):
- CONF-921058-; CODEN: GAAPBC
- Journal Information:
- Geological Society of America, Abstracts with Programs; (United States), Vol. 24:7; Conference: 1992 annual meeting of the Geological Society of America (GSA), Cincinnati, OH (United States), 26-29 Oct 1992; ISSN 0016-7592
- Country of Publication:
- United States
- Language:
- English
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