Rare Earth Elements (REE) Deposits Associated with Great Plain Margin Deposits (Alkaline-Related), Southwestern United States and Eastern Mexico

Abstract

W.G. Lindgren in 1933 first noted that a belt of alkaline-igneous rocks extends along the eastern edge of the Rocky Mountains and Basin and Range provinces from Alaska and British Columbia southward into New Mexico, Trans-Pecos Texas, and eastern Mexico and that these rocks contain relatively large quantities of important commodities such as, gold, fluorine, zirconium, rare earth elements (REE), tellurium, gallium, and other critical elements. In New Mexico, these deposits were called Great Plain Margin (GPM) deposits, because this north-south belt of alkaline-igneous rocks roughly coincides with crustal thickening along the margin between the Great Plains physiographic province with the Basin and Range (including the Rio Grande rift) and Rocky Mountains physiographic provinces, which extends into Trans-Pecos Texas and eastern Mexico. Since 1996, only minor exploration and development of these deposits in New Mexico, Texas, and eastern Mexico has occurred because of low commodity prices, permitting issues, and environmental concerns. However, as the current demand for gold and critical elements, such as REE and tellurium has increased, new exploration programs have encouraged additional research on the geology of these deposits. The lack of abundant quartz in these systems results in these deposits being less resistant to erosion, being covered, and not as well exposed as other types of quartz-rich deposits, therefore additional undiscovered alkaline-related gold and REE deposits are likely in these areas. Deposits of Th-REE-fluorite (±U, Nb) epithermal veins and breccias are found in the several GPM districts, but typically do not contain significant gold, although trace amounts of gold are found in most GPM districts. Gold-rich deposits in these districts tend to have moderate to low REE and anomalously high tungsten and sporadic amounts of tellurium. Carbonatites are only found in New Mexico and Mexico. The diversity of igneous rocks, including alkaline-igneous rocks, and associated mineral deposits along this boundary suggests that this region is characterized by highly fractionated and differentiated, multiple pulses of mantle-derived magmas evolving to lower crustal magmas related to the subduction of the Farallon plate. The differences in incompatible trace elements, including REE and beryllium, between the different granitic to rhyolite rocks are likely related to either differences in the crustal rocks that were assimilated during magmatic differentiation or by potential minor contamination from crustal sources and/or magma mixing. Deep-seated fracture systems or crustal lineaments apparently channeled the magmas and hydrothermal fluids. Once magmas and metal-rich fluids reached shallow levels, the distribution and style of these intrusions, as well as the resulting associated mineral deposits were controlled by local structures and associated igneous rock compositions.

Neural Network Modeling for the Extraction of Rare Earth Elements from Eudialyte Concentrate by Dry Digestion and Leaching

“…This implies the need to describe the process with additional models of class (6). However, the potential number of such models is over 16,000, so the computational costs for modeling via the brute force method would be too high.…”

“…The initial set of regressors included variables: cHCl, cH 2 O, T, t, cHCl·cH 2 O, cHCl·T, cHCl·t, cH 2 O·T, cH 2 O·t, T·t, cHCl·cH 2 O·T, cHCl·cH 2 O·t, cHCl·T·t, and cH 2 O·T·t. These regressors correspond to linear first order models in the form of Equation (6).…”

“…Other ore deposits tend to be distributed unevenly globally [6,7]. Nowadays, above 90% of the REE in the world market is supplied by China, which has abundant rare earth mines.…”

Introduction to a Resources Special Issue on Criticality of the Rare Earth Elements: Current and Future Sources and Recycling

“…This N-S trending belt of alkaline magmatism is associated with crustal thickening between the Basin and Range and the Rocky Mountains and hosts Th-REE-fluorite (±U, Nb) epithermal mineralization. The gold-rich deposits in this region have moderate to low REE concentrations, although the presence of carbonatites in this region and in associated parts of Mexico suggest that there may be potential for carbonatite-hosted REE mineralization in this area [11].…”

“…McLemore provides an outline of REE potential of mineralizing systems associated with the alkaline igneous rocks along the edge of the Basin and Range province, specifically focusing on the alkaline rocks of the Great Plain Margin, New Mexico, USA [11]. This N-S trending belt of alkaline magmatism is associated with crustal thickening between the Basin and Range and the Rocky Mountains and hosts Th-REE-fluorite (±U, Nb) epithermal mineralization.…”