Rison anomaly

Region Central, South Central
Mineral systems
Deposit types
Other minerals

Information leading to the delineation of this focus area

Basis for focus area Magnetic anomaly high similar in amplitude and size to the magnetic anomaly over Magnet Cove. Deposit type is unknown but shares geophysical similarity to the Magnet Cove carbonatite/peralkaline complex.
Identified resources None.
Production None.
Status Unknown.
Estimated resources Unknown.
Geologic maps Haley and others (1993), scale 1:500,000.
Geophysical data Inadequate aeromagnetic and aeroradiometric coverage.
Favorable rocks and structures Serpentinized peridotite was encountered at a depth of 1,085 m within this focus area.
Deposits None.
Evidence from mineral occurrences None.
Geochemical evidence Arkansas Geological Survey drill hole noted the presence of 10 foot section of calcite with highly altered ferro-magnesian minerals and abundant magnetite, ilmenite, and other Ti-rich minerals, indicating chemical similarity to carbonatites found in Magnet Cove.
Geophysical evidence Gravity and magnetic anomalies associated with the Rison peridotite have approximately the same amplitude as that at Magnet Cove.
Evidence from other sources Hendricks (1988) reports of the anomaly and the mineralogy of the peridotite encountered in the deep drill hole.
Cover thickness and description Arkansas Geological Survey maintains core from the Arkansas Natural Gas Corp Tate No. 1 well, located 5 km west of Rison, AR. Igneous rock was encountered at 1,085 m.
Authors Corbin Cannon, Anne E. McCafferty.
New data needs New aeromagnetic and aeroradiometric survey with additional ground gravity, new geologic mapping.
Geologic mapping and modeling needs No recent geologic maps at 1:24,000 scale; new geologic mapping needed.
Geophysical survey and modeling needs High resolution geophysical aeromagnetic and aeroradiometric coverage.
Digital elevation data needs Lidar adequate.