Magnet Cove District

Location: Arkansas, United States (34.469, -92.863 approx.)

Commodities: barite; titanium; vanadium; niobium; rare earth elements

Geology

“The last mining in the West Pit (Figure 2) was in 1944, while the East Pit was abandoned some time before. The abundant clays of hydrothermal and weathering origin present in the pits have been reworked by rainwash, resulting in poor pit exposures. Some of the clay areas are partially covered with grass and small willows. The best exposures in the pits are "knobs" of relatively unaltered igneous rock that project from the pit floor as a result of selective mining operations. Several of the lower sections of the West Pit are under water the year round.” (Fryklund and Holbrook (1950)) “Carbonatite dikes and partly altered clay-rich dikes have a range of REE concentrations and chondrite-normalized REE patterns (Table 7; Fig. 6A and B). Apatite-rich carbonatite (sample K5(47.4)) contains the highest concentration of REE and is particularly enriched in Nd, Sm, Eu, Tb, and Ho compared to other carbonatite dikes and to calcite-rich carbonatite (sample MC-Car-1). Ankerite-rich carbonatite (sample F1(54.5)) has an unusual, somewhat flat pattern with a maximum at Tb, like some specimens from the Christy prospect (Fig. 5A-C). The other carbonatites and clay-rich dikes are enriched in the light REE relative to the heavy RFV, as is typical of carbonatite and alkaline rocks (Cullers and Graf, 1984) and most primary Magnet Cove lithologies (Flohr and Ross, 1989, 1990, unpub. data). The REE signature of the Potash Sulphur Springs dike (sample MH-D2- 90, Fig. 5F) bears a greater similarity to the partly altered Rutile deposit veins than to the clay-rich Christy dikes. Differences among the REE distribution of different carbonatite types (Fig. 6A) may be explained by fractional crystallization processes (Le Bas, 1989), by crystal chemical considerations (Morgan and Wandless, 1980), or by preferential transport of some REE during late-stage veining events…” (Flohr (1994))

Record imported from USGS USMIN ver. 4.0 (June 2019). Developments after that date appear on facility records, not here; see the methodology.