Instrument measures elemental abundance and isotopic ratios in samples as small as a few nanograms. Uses include geochronology, geological thermometry, and trace element geochemistry of geological and biological materials.
Manual of chemical sediment analysis using Coulometer and CHN Analyzers to measure carbon content, spectrometric analysis for biogenic silica, and radiochemistry to measure isotopes. Includes techniques,sample preparation, and safety procedures.
Report of research on the Carolina slate belt and gold deposits in Virginia, North Carolina, South Carolina, and Georgia with geologic mapping, mineralogic, geochemical, and fluid evolution studies, radiogenic dating, and stable isotope studies.
Explains the important paleoclimatic information we have obtained from this subaqueous cavern. The time-series data show important contrasts with what would be predicted from orbital theory, provoking extensive scientific discussion.
Direct measurement of an important indicator of interannual variability is extended, using geological proxy measures, farther back in time to well before modern measurements were made. This tells us about the history of climate variability.
Overview of chemical analyses, tracer studies, gas geochemistry, stable isotopes analyses, organic chemistry, and thermometry capabilities at major USGS laboratories with links to technique, equipment, and contacts for each procedure.
Services available at the Geological Survey TRIGA Reactor (GSTR) site in Denver with information on irradiation, neutron activation analysis, fission track radiography, and geochronology and tours of the facility.
Explanation of how geologists date rocks (to determine the ages of the Earth, fossils, mineral deposits, and other geologic events) and processes using radiometric dating techniques based on radioactive isotopes of carbon and potassium/argon.
The area contributing recharge to this aquifer is undergoing rapid growth, generating more wastewater. We found that nitrate, a major component of wastewater and a nutrient that can degrade water quality, has increased in the creeks in this area.
Site on the Chlorofluorocarbon Laboratory and its analytical services for CFCs, sulfur hexafluoride, dissolved gases including nitrogen, argon, methane, carbon dioxide, oxygen, and helium, and tritium/helium-3 dating.