GEOLOGIC MAP OF THE NORTHEAST DISTRICT IN THE NORTH ARKANSAS LEAD AND ZINC REGION, SHARP AND LAWRENCE COUNTIES, ARKANSAS

This map is the first, in a series of three, that depicts the surface geology of the North Arkansas Lead and Zinc Region. The Region is divided into two major focus areas: the Northcentral District and the Northeast District. The Northeast District comprises portions of five 7.5-minute series topographic quadrangles including Poughkeepsie, Smithville, Eaton, Black Rock, and Imboden. The larger Northcentral District is split into two major focus areas: West Half and East Half. The Northeast District is within the Salem Plateau of the Ozark Plateaus Province. Approximately 350 feet of Early to Middle Ordovician carbonate and clastic rocks, and Cretaceous clastic rocks are exposed in this area. The lower part of the Everton Formation on this map includes rocks that were divided into the Smithville limestone and the overlying Black Rock limestone on the Geologic Map of Arkansas (1929) and included in the upper part of the Powell on the Geologic Map of Arkansas (1976). Lead mining started in 1851 and the earliest zinc mining in Arkansas began around 1858. The oldest zinc mines are in Sharp and Lawrence Counties. A smelter built during 1857 in Calamine of Sharp County is thought to be one of the first zinc smelters in the country. Total production in the district is estimated to be 4,000 tons of mostly zinc. Mining activity had ceased by 1930 leaving 33 abandoned lead and zinc mines in the Northeast District. E.E. Glick (1972-1974) mapped the area in preparation for the 1:500,000-scale Geologic Map of Arkansas. Field work for the current project was conducted for Earth Mapping Resources Initiative (EMRI) investigating zinc as a critical mineral resource. New field data was recorded on a portable GPS data collector and uploaded to a geodatabase. Approximately 100 samples were collected for petrographic analysis and 87 samples were collected and submitted to the U.S. Geological Survey for geochemical analysis.

This map was produced for the Earth Mapping Resources Initiative (EMRI) grant program administered by the U.S. Geological Survey under Cooperative Agreement Award G23AC00460.