Comparison of the chemical characteristics of the uranium deposits of the Morrison Formation in the Grants uranium region, New Mexico

Abstract

Statistical treatment of the chemical data of samples from the northeast Church Rock area, Ruby deposit, Mariano Lake deposit, and the Ambrosia Lake district indicates that primary ore-forming processes concentrated copper, iron, magnesium, manganese, molybdenum, selenium, vanadium, yttrium, arsenic, organic carbon, and sulfur, along with uranium. A barium halo that is associated with all of these deposits formed from secondary processes. Calcium and strontium were also enriched in the ores by secondary processes. Comparison of the chemical characteristics of the redistributed deposits in the Church Rock district to the primary deposits in the Grants uranium region indicates that calcium, manganese, strontium, yttrium, copper, iron, magnesium, molybdenum, lead, selenium, and vanadium are separated from uranium during redistribution of the deposits in the Church Rock area. Comparisons of the chemical characteristics of the Church Rock deposits and the secondary deposits at Ambrosia Lake suggest some differences in the processes that were involved in the genesis of the redistributed deposits in these two areas.

Comparison of the chemical composition of mineralized and unmineralized sandstone and conglomerate samples from the uranium-bearing Chinle Formation of the Colorado Plateau

“…Table 2 compares the results of the present study with conclusions reached by Spirakis and others (1984) and Spirakis and Pierson (1983) for tabular uranium-vanadium deposits in the Upper Jurassic Morrison Formation of the Henry Mountains, Utah and the Grants uranium region, New Mexico. Although there is some variation in the chemistry of the deposits, many of the elements enriched in the Chinle deposits are also enriched in most of the other tabular deposits.…”

“…The enrichment of Pb in tabular-type deposits in the Morrison Formation of the Henry Mountains and Grants areas was thought to be the product of radioactive decay of U (Spirakis and others, 1984;Spirakis and Pierson, 1983). For the Chinle deposits, however, the average amount of Pb now present in the G100 group is in excess by about 50 ppm of the amount that would be expected from the radioactive decay of U, assuming that mineralization took place about 200 million years ago.…”