Our work focuses on collaborating with high-priority U.S. Geological Survey projects and other Federal and international agencies, and on providing radiogenic and stable isotope analyses to support mineral- and environmentally-related geologic investigations.
Radiogenic Isotope Techniques
Radiogenic isotope techniques are used for analysis of materials, fluids, and fluid and solid inclusions from ancient and modern environments. Analytical procedures are improved and developed using thermal ionization mass spectrometry and inductively coupled plasma mass spectrometry for studies directed at: regional and site-specific metal mobilization, metal transport, redistribution processes, and sources of fluids for regional geologic, ore genesis, life-cycles, and environmental applications.
Stable Isotope Work
Stable isotope work includes developing new and refining existing analytical techniques for the following applications:
- oxygen isotope analysis of dissolved sulfate for studies of mine drainage, acid deposition and ecosystems;
- hydrogen isotope analysis of silicate and other hydrated minerals for studies of ore genesis; and
- sulfur isotope analysis of submilligram samples of sulfide and sulfate minerals using continuous-flow technology for environmental, ore genesis and ecosystem studies.
Return to Mineral Resources Program
Below are data or web applications associated with this project.
GIS and Data Tables for Focus Areas for Potential Domestic Nonfuel Sources of Rare Earth Elements
Geochemical and Modal Data for Mesoproterozoic Igneous Rocks of the St. Francois Mountains, Southeast Missouri
Geochemical Database for Iron Oxide-Copper-Cobalt-Gold-Rare Earth Element Deposits of Southeast Missouri
Below are publications associated with this project.
The Mystic subterrane (partly) demystified: New data from the Farewell terrane and adjacent rocks, interior Alaska
Lead and strontium isotopes as monitors of anthropogenic contaminants in the surficial environment
Geochemical and Pb isotopic characterization of soil, groundwater, human hair, and corn samples from the Domizio Flegreo and Agro Aversano area (Campania region, Italy)
Regional geologic and petrologic framework for iron oxide ± apatite ± rare earth element and iron oxide copper-gold deposits of the Mesoproterozoic St. Francois Mountains terrane, southeast Missouri, USA
Geochemistry, Nd-Pb Isotopes, and Pb-Pb Ages of the Mesoproterozoic Pea Ridge Iron Oxide-Apatite–Rare Earth Element Deposit, Southeast Missouri
Beryllium—A critical mineral commodity—Resources, production, and supply chain
Pb-Sr isotopic and geochemical constraints on sources and processes of lead contamination in well waters and soil from former fruit orchards, Pennsylvania, USA: A legacy of anthropogenic activities
Soil geochemical survey of abandoned mining sites in the Eastern-Central Peloritani Mountains, Sicily, Italy
REE enrichment in granite-derived regolith deposits of the southeast United States: Prospective source rocks and accumulation processes
Reconstruction of an early Paleozoic continental margin based on the nature of protoliths in the Nome Complex, Seward Peninsula, Alaska
Pb-Sr-Nd isotopes in surficial materials at the Pebble Porphyry Cu-Au-Mo Deposit, Southwestern Alaska: can the mineralizing fingerprint be detected through cover?
Gold deposits of the Carolina Slate Belt, southeastern United States--Age and origin of the major gold producers
- Overview
Our work focuses on collaborating with high-priority U.S. Geological Survey projects and other Federal and international agencies, and on providing radiogenic and stable isotope analyses to support mineral- and environmentally-related geologic investigations.
Radiogenic and stable isotope clean laboratory in Reston, VA. Cleanliness is defined based on the number of particles of a defined diameter per unit volume. According to U.S. Federal Standard, a Class 100 clean room must have no more than 100 particles of diameter 0.5 mm per cubic foot of air. Photo by USGS. (Public domain.) Radiogenic Isotope Techniques
Radiogenic isotope techniques are used for analysis of materials, fluids, and fluid and solid inclusions from ancient and modern environments. Analytical procedures are improved and developed using thermal ionization mass spectrometry and inductively coupled plasma mass spectrometry for studies directed at: regional and site-specific metal mobilization, metal transport, redistribution processes, and sources of fluids for regional geologic, ore genesis, life-cycles, and environmental applications.
Stable Isotope Work
Stable isotope work includes developing new and refining existing analytical techniques for the following applications:
- oxygen isotope analysis of dissolved sulfate for studies of mine drainage, acid deposition and ecosystems;
- hydrogen isotope analysis of silicate and other hydrated minerals for studies of ore genesis; and
- sulfur isotope analysis of submilligram samples of sulfide and sulfate minerals using continuous-flow technology for environmental, ore genesis and ecosystem studies.
Return to Mineral Resources Program
- Data
Below are data or web applications associated with this project.
GIS and Data Tables for Focus Areas for Potential Domestic Nonfuel Sources of Rare Earth Elements
In response to Executive Order 13817 of December 20, 2017, the U.S. Geological Survey (USGS) coordinated with the Bureau of Land Management (BLM) to identify 35 nonfuel minerals or mineral materials considered critical to the economic and national security of the United States (U.S.). Acquiring information on possible domestic sources of these critical minerals is the basis of the USGS Earth MappiGeochemical and Modal Data for Mesoproterozoic Igneous Rocks of the St. Francois Mountains, Southeast Missouri
This data release accompanies the Data Series report 'Compilation of new and previously published geochemical and modal data for Mesoproterozoic igneous rocks of the St. Francois Mountains, southeast Missouri (https://doi.org/10.3133/ds1080). The compilation includes recently acquired as well as previously published geochemical and modal petrographic data for igneous rocks in the St. Francois MounGeochemical Database for Iron Oxide-Copper-Cobalt-Gold-Rare Earth Element Deposits of Southeast Missouri
The Geochemical Database for Iron Oxide-Copper-Cobalt-Gold-Rare Earth Element Deposits of Southeast Missouri (IOCG-REE_GX) contains new geochemical data compilations for samples from IOCG-REE type deposits in which each rock sample has one "best value" determination for each analyzed species, greatly improving speed and efficiency of use. IOCG-REE_GX was created and designed to compile whole-rock - Publications
Below are publications associated with this project.
Filter Total Items: 35The Mystic subterrane (partly) demystified: New data from the Farewell terrane and adjacent rocks, interior Alaska
The youngest part of the Farewell terrane in interior Alaska (USA) is the enigmatic Devonian–Cretaceous Mystic subterrane. New U-Pb detrital zircon, fossil, geochemical, neodymium isotopic, and petrographic data illuminate the origin of the rocks of this subterrane. The Devonian–Permian Sheep Creek Formation yielded youngest detrital zircons of Devonian age, major detrital zircon age probability pAuthorsJulie A. Dumoulin, James V. Jones, Stephen E. Box, Dwight C. Bradley, Robert A. Ayuso, Paul B. O'SullivanLead and strontium isotopes as monitors of anthropogenic contaminants in the surficial environment
Isotopic discrimination can be an effective tool in establishing a direct link between sources of Pb contamination and the presence of anomalously high concentrations of Pb in waters, soils, and organisms. Residential wells supplying water containing up to 1600 ppb Pb to houses built on the former Mohr orchards commercial site, near Allentown, Pennsylvania, United States, were evaluated to discernAuthorsRobert A. Ayuso, Nora K. FoleyGeochemical and Pb isotopic characterization of soil, groundwater, human hair, and corn samples from the Domizio Flegreo and Agro Aversano area (Campania region, Italy)
A geochemical survey was carried out to investigate metal contamination in the Domizio Littoral and Agro Aversano area (Southern Italy) by means of soil, groundwater, human hair and corn samples. Pb isotope ratios were also determined to identify the sources of metals. Specifically, the investigation focused on topsoils (n = 1064), groundwater (n = 26), 25 human hair (n = 24) and corn samples (n =AuthorsCarmela Rezza, Stefano Albanese, Robert A. Ayuso, Annamaria Lima, Jaana Sorvari, Benedetto De VivoRegional geologic and petrologic framework for iron oxide ± apatite ± rare earth element and iron oxide copper-gold deposits of the Mesoproterozoic St. Francois Mountains terrane, southeast Missouri, USA
This paper provides an overview on the genesis of Mesoproterozoic igneous rocks and associated iron oxide ± apatite (IOA) ± rare earth element, iron oxide-copper-gold (IOCG), and iron-rich sedimentary deposits in the St. Francois Mountains terrane of southeast Missouri, USA. The St. Francois Mountains terrane lies along the southeastern margin of Laurentia as part of the eastern granite-rhyolite pAuthorsWarren C. Day, John F. Slack, Robert A. Ayuso, Cheryl M. SeegerGeochemistry, Nd-Pb Isotopes, and Pb-Pb Ages of the Mesoproterozoic Pea Ridge Iron Oxide-Apatite–Rare Earth Element Deposit, Southeast Missouri
Iron oxide-apatite and iron oxide-copper-gold deposits occur within ~1.48 to 1.47 Ga volcanic rocks of the St. Francois Mountains terrane near a regional boundary separating crustal blocks having contrasting depleted-mantle Sm-Nd model ages (TDM). Major and trace element analyses and Nd and Pb isotope data were obtained to characterize the Pea Ridge deposit, improve identification of exploration tAuthorsRobert A. Ayuso, John F. Slack, Warren C. Day, Anne E. McCaffertyBeryllium—A critical mineral commodity—Resources, production, and supply chain
Beryllium is a lightweight metallic element used in a wide variety of specialty and industrial applications. As a function of its unique chemical and physical properties, such as a high stiffness-to-weight ratio, resistance to temperature extremes, and high thermal conductivity, beryllium cannot be easily replaced by substitute materials in applications where combinations of these properties makeAuthorsGraham W. Lederer, Nora K. Foley, Brian W. Jaskula, Robert A. AyusoPb-Sr isotopic and geochemical constraints on sources and processes of lead contamination in well waters and soil from former fruit orchards, Pennsylvania, USA: A legacy of anthropogenic activities
Isotopic discrimination can be an effective tool in establishing a direct link between sources of Pb contamination and the presence of anomalously high concentrations of Pb in waters, soils, and organisms. Residential wells supplying water containing up to 1600 ppb Pb to houses built on the former Mohr orchards commercial site, near Allentown, PA, were evaluated to discern anthropogenic from geogeAuthorsRobert A. Ayuso, Nora K. FoleySoil geochemical survey of abandoned mining sites in the Eastern-Central Peloritani Mountains, Sicily, Italy
This investigation focused on topsoils (n = 122) and vertical profiles (n = 6) distributed over an area of 250 km2 in the eastern-central Peloritani Mountains, northeastern Sicily. Georeferenced concentration of 53 elements (including potentially harmful ones), determined by ICP-MS after an aqua regia leach, were used to produce geochemical maps by means of a GIS-aided spatial interpolation procesAuthorsA. Consenza, A. Lima, Robert A. Ayuso, Nora K. Foley, S. Albanese, A. Messina, B. De VivoREE enrichment in granite-derived regolith deposits of the southeast United States: Prospective source rocks and accumulation processes
The Southeastern United States contains numerous anorogenic, or A-type, granites, which constitute promising source rocks for REE-enriched ion adsorption clay deposits due to their inherently high concentrations of REE. These granites have undergone a long history of chemical weathering, resulting in thick granite-derived regoliths, akin to those of South China, which supply virtually all heavy REAuthorsNora K. Foley, Robert A. AyusoReconstruction of an early Paleozoic continental margin based on the nature of protoliths in the Nome Complex, Seward Peninsula, Alaska
The Nome Complex is a large metamorphic unit that sits along the southern boundary of the Arctic Alaska–Chukotka terrane, the largest of several micro continental fragments of uncertain origin located between the Siberian and Laurentian cratons. The Arctic Alaska–Chukotka terrane moved into its present position during the Mesozoic; its Mesozoic and older movements are central to reconstruction ofAuthorsAlison B. Till, Julie A. Dumoulin, Robert A. Ayuso, John N. Aleinikoff, Jeffrey M. Amato, John F. Slack, W.C. Pat ShanksPb-Sr-Nd isotopes in surficial materials at the Pebble Porphyry Cu-Au-Mo Deposit, Southwestern Alaska: can the mineralizing fingerprint be detected through cover?
The Cretaceous Pebble porphyry Cu-Au-Mo deposit is covered by tundra and glacigenic sediments. Pb-Sr-Nd measurements were done on sediments and soils to establish baseline conditions prior to the onset of mining operations and contribute to the development of exploration methods for concealed base metal deposits of this type. Pebble rocks have a moderate range for 206Pb/204Pb = 18.574 to 18.874, 2AuthorsRobert A. Ayuso, Karen D. Kelley, Robert G. Eppinger, Francesca ForniGold deposits of the Carolina Slate Belt, southeastern United States--Age and origin of the major gold producers
Gold- and iron sulfide-bearing deposits of the southeastern United States have distinctive mineralogical and geochemical features that provide a basis for constructing models of ore genesis for exploration and assessment of gold resources. The largest (historic) deposits, in approximate million ounces of gold (Moz Au), include those in the Haile (~ 4.2 Moz Au), Ridgeway (~1.5 Moz Au), Brewer (~0.2AuthorsNora K. Foley, Robert A. Ayuso