X-RAY DIFFRACTION AND PETROGRAPHIC ANALYSIS OF MAGNET COVE CARBONATITE CORE, ARKANSAS

Geothermal activity such as hot springs are known to precipitate calcium carbonate (CaCO3) minerals, producing rocks such as tufa, travertine, and carbonatite. The precipitation of CaCO3 is caused by the reduction of CO2, which is less soluble in warmer waters. Geothermal heating of water in natural springs drives this precipitation of CaCO3 in areas of Arkansas including Magnet Cove. Several geologic reports of Magnet Cove claim the presence of carbonates stemming from the geothermal processes of the region; however, the identification of the carbonate material varies among the reports, including tufa, travertine, and carbonatite. After examining a Magnet Cove core sample from a calcite deposit, the petrographic analysis and X-ray diffraction revealed that between the depth of 33 feet to 43 feet, it contained natrolite and epidote. These minerals are not usually associated with carbonatite nor tufa. Utilizing existing information on the formation of natrolite and epidote may reveal how these minerals formed in Arkansas hot springs.