The project objective is to determine the processes responsible for critical element enrichment in carbonatites and to enhance our ability to identify and assess economic deposits. This project will work at various scales to meet this objective and will primarily focus on deposits within the US or our Critical Minerals Mapping Initiative collaborative Nations Canada and Australia.
Science Issue and Relevance
Identification and assessment of critical elements is a USGS and Department of the Interior priority because dependency on foreign sources creates a strategic vulnerability. Critical elements are essential to the economy and have potential supply chain disruptions, but compared to most base and precious metals, little work has been undertaken to 1) determine favorable environments for exploration, and 2) identify where these elements reside when enriched.
Carbonatites are complex, poorly understood alkaline igneous rock defined by containing greater than 50 modal % primary carbonate minerals. Carbonatite-related ore deposits are the primary supplier of light rare earth elements (LREEs) and niobium (Nb) and the only current significant source of LREEs and Nb outside of China. Critical element enrichment is carbonatites is extremely complex and poorly understood. Determining why some carbonatites are enriched and why certain zones of these deposits are enriched is essential in the delineation and assessment of critical elements.
Methods to Address Issue
The project objective is to determine the processes responsible for critical element enrichment in carbonatites and to enhance our ability to identify and assess economic deposits. Work involves the integration of field, mineralogical, and chemical studies of key locations, deposits, and minerals and is conducted through four tasks.
Formation of giant, carbonatite-related ore deposits: objective is to conduct a petrogenetic study to understand how these giant deposits are formed to guide future exploration – focus study area is Mount Weld in Australia because it is the largest light rare earth element producer outside of China.
Evaluation of processes controlling critical element enrichment in alkaline complexes in Montana and Wyoming: objective is to investigate the source of critical elements and the processes responsible for the observed enrichments in alkaline igneous complexes in this region.
Fate and transport of REEs in carbonatite systems through fluid inclusion studies: objective is to characterize the chemistry of fluids that transport and concentrate rare earth elements (REE) in high-grade and high-tonnage carbonatite complexes.
Evaluation of compositional variations in barite as an exploration tool: objective is to investigate barite as a potential proxy for rare earth element mineralization and its use as a sensitive tool for identifying rare earth element deposits. Barite is a common mineral that forms during multiple stages of carbonatite emplacement and is an important gangue mineral in rare earth element mineralized zones.
Here are related science projects.
Research Chemistry
Critical Elements in Carbonatites: From Exploration Targets to Element Distribution
Argon Geochronology
Systems Approach to Critical Minerals Inventory, Research, and Assessment
Denver Microbeam Laboratory
- Overview
The project objective is to determine the processes responsible for critical element enrichment in carbonatites and to enhance our ability to identify and assess economic deposits. This project will work at various scales to meet this objective and will primarily focus on deposits within the US or our Critical Minerals Mapping Initiative collaborative Nations Canada and Australia.
Science Issue and Relevance
Identification and assessment of critical elements is a USGS and Department of the Interior priority because dependency on foreign sources creates a strategic vulnerability. Critical elements are essential to the economy and have potential supply chain disruptions, but compared to most base and precious metals, little work has been undertaken to 1) determine favorable environments for exploration, and 2) identify where these elements reside when enriched.
Carbonatites are complex, poorly understood alkaline igneous rock defined by containing greater than 50 modal % primary carbonate minerals. Carbonatite-related ore deposits are the primary supplier of light rare earth elements (LREEs) and niobium (Nb) and the only current significant source of LREEs and Nb outside of China. Critical element enrichment is carbonatites is extremely complex and poorly understood. Determining why some carbonatites are enriched and why certain zones of these deposits are enriched is essential in the delineation and assessment of critical elements.
Methods to Address Issue
The project objective is to determine the processes responsible for critical element enrichment in carbonatites and to enhance our ability to identify and assess economic deposits. Work involves the integration of field, mineralogical, and chemical studies of key locations, deposits, and minerals and is conducted through four tasks.
Formation of giant, carbonatite-related ore deposits: objective is to conduct a petrogenetic study to understand how these giant deposits are formed to guide future exploration – focus study area is Mount Weld in Australia because it is the largest light rare earth element producer outside of China.
Evaluation of processes controlling critical element enrichment in alkaline complexes in Montana and Wyoming: objective is to investigate the source of critical elements and the processes responsible for the observed enrichments in alkaline igneous complexes in this region.
Fate and transport of REEs in carbonatite systems through fluid inclusion studies: objective is to characterize the chemistry of fluids that transport and concentrate rare earth elements (REE) in high-grade and high-tonnage carbonatite complexes.
Evaluation of compositional variations in barite as an exploration tool: objective is to investigate barite as a potential proxy for rare earth element mineralization and its use as a sensitive tool for identifying rare earth element deposits. Barite is a common mineral that forms during multiple stages of carbonatite emplacement and is an important gangue mineral in rare earth element mineralized zones.
- Science
Here are related science projects.
Research Chemistry
This project develops and maintains state-of-the-art analytical laboratories, expertise, and methods for a broad range of elemental and mineralogical analyses in support of the research priorities of the Mineral Resources Program, USGS, and DOI.Critical Elements in Carbonatites: From Exploration Targets to Element Distribution
Critical elements are essential to the modern economy and have potential supply chain disruptions, but compared to most base and precious metals, little work has been done in understanding ore-grade enrichments. Carbonatites are the primary source of the worlds light rare earth elements and niobium, and a potential source for heavy rare earths, scandium, tantalum, and thorium. Project objectives...Argon Geochronology
This project supports the USGS argon geochronology laboratory in Denver. The USGS 40Ar/39Ar geochronology laboratory is a state-of-the-art research facility for determining absolute ages of minerals and rocks. The 40Ar/39Ar laboratory contributes critical geochronology to individual USGS research projects and to partners in academia and other Federal agencies. This laboratory develops methodology...Systems Approach to Critical Minerals Inventory, Research, and Assessment
This project supports the Earth Mapping Resources Initiative (EarthMRI) by developing a mineral systems approach for defining focus areas. This project is investigating domestic sources of critical minerals in three sequential stages: inventory, research, and assessment. 1) Inventory the abundance of critical minerals in ore, minerals, and processed materials from major deposits in each system...Denver Microbeam Laboratory
TThe USGS Denver Microbeam Laboratory provides critical analytical and characterization support for a wide variety of internal USGS projects and external collaborators. In addition, the lab continually works to develop new methods or improve existing methods to analyze a variety of sample matrices. - Data
- Publications