Craig Johnson is a Research Geologist with the Geology, Geophysics, and Geochemistry Science Center.
Craig attended Dartmouth (AB), Michigan (MS), and Yale (PhD). He held a NASA postdoc and a staff position at the American Museum of Natural History in New York prior to joining the USGS in 1992. Craig is responsible for a stable isotope laboratory in which isotopes of carbon, hydrogen, nitrogen, oxygen, and sulfur are measured in rocks, waters, gases, and biological materials. Craig studies ore genesis, environmental impacts of mining, the source and fate of solutes in natural waters and crustal fluids, the isotopic record of marine sulfate, and isotopic records of paleoenvironments.
Science and Products
Isotope and Chemical Methods for Mineral and Geoenvironmental Assessments and Support of USGS Science Strategy
This Project integrates several geochemical tools—stable isotope geochemistry, noble gas geochemistry, active gas geochemistry, single fluid inclusion chemistry, and fluid inclusion solute chemistry—in studies of the processes that form mineral deposits and the processes that disrupt them during mining or natural weathering. Research is directed toward fundamental scientific questions or, in...
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...
Science and Products
- Science
Isotope and Chemical Methods for Mineral and Geoenvironmental Assessments and Support of USGS Science Strategy
This Project integrates several geochemical tools—stable isotope geochemistry, noble gas geochemistry, active gas geochemistry, single fluid inclusion chemistry, and fluid inclusion solute chemistry—in studies of the processes that form mineral deposits and the processes that disrupt them during mining or natural weathering. Research is directed toward fundamental scientific questions or, in...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... - Data
- Multimedia
- Publications