Description
The California Geological Survey (CGS) has entered into a two-year cooperative agreement with the United States Geological Survey (USGS) to conduct geologic
mapping of the New York Mountains in the Mojave Desert of southeastern California
(Figure 1). This project is part of the USGS’ Earth Mapping Resources Initiative
(Earth-MRI) to gather information on potential domestic sources of critical minerals.
Critical minerals are defined as being essential for manufacturing products significantly important to the economy and national security and as having supply chains
vulnerable to outside disruption. The Federal Fiscal Year 2019 Earth-MRI effort focuses on potential rare earth element (REE) bearing deposits in the United States.
In the west, the USGS identified the Mountain Pass Focus Area carbonatites and
Proterozoic basement rocks as a deposit type likely to be of interest for future exploration and development. The Mountain Pass mine, located approximately 20 miles
northwest of the study area, is the only active producer of REEs in the United States
and one of only five active carbonatite-hosted REE mines globally. The Mountain
Pass mine produces light REEs that occur in bastnaesite, which is hosted within a
1375 ± 5 Ma carbonatite intrusive complex. REE mineralization and thorium anomalies have previously been identified within the New York Mountains. Heavy REE mineralization has been described as hosted within mineralized shear zones and allanite
pegmatites and dikes within the northern New York Mountains.
During the winters of 2019 and 2020, the California Geological Survey is conducting 1:24,000-scale geologic mapping of the Castle Peaks, Crescent Peak, Ivanpah,
and Pinto Valley 7.5-minute quadrangles along the New York Mountains in San Bernardino County, California. The new geologic mapping will be compiled with existing smaller-scale geologic mapping to create four preliminary 1:24,000-scale geologic
maps. Mapping activities will be coordinated with the Nevada Bureau of Mines and
Geology and the USGS’ geologic mapping and geophysical investigation team. The final products for the project will include a geologic data model with an accompanying
geologic map for each of the four quadrangles. Funding for this project is provided by
the USGS’ Earth-MRI and the State of California.
