Partially or completely molten magma samples are created at controlled high temperatures and pressures (as high as 1,400°C and 3 GPa) using specially fabricated furnaces and pressure vessels. Depending on the study, the samples may be held at fixed conditions, or can be decompressed or cooled at precisely controlled rates. They are then rapidly quenched to preserve magmatic compositions and assemblages of minerals, melt (glass), and gases or gas bubbles. Experiments are designed to simulate the creation, storage, ascent, and degassing of magma in order to develop a quantitative understanding of the physical and chemical processes leading to hazardous volcanic behavior. The facility also produces a wide range of high-quality interlaboratory glass and mineral standards.
Geochronology laboratories in Menlo Park provide absolute age control for a wide variety of USGS projects. The laboratories are world renowned for high-quality results on difficult samples and for careful work to develop new techniques and interlaboratory standards. Geochronologists use high-precision 40Ar/39Ar, conventional K/Ar, and Rb/Sr techniques to date rocks ranging in age from 10,000 years to billions of years old. Recent results have placed precise and reliable time constraints on tectonic events, volcanic systems, and ore deposits. In recent years, the emphasis has been on dating young (10,000 to 200,000 years) volcanic deposits from active centers to understand rates of volcanic growth and geochemical evolution and to constrain volcanic hazards. The laboratory has recently purchased a new multicollector noble-gas mass spectrometer and is developing a custom argon extraction line to date younger rocks with higher precision.
The gas chromatography and stable isotopes laboratory is optimized for chemical and isotopic analysis of volcanic and geothermal fluids (gas and liquid phases).
The infrared spectroscopy laboratory is designed to measure the amount and speciation of water and carbon species dissolved in naturally and experimentally produced silicate glass and rock-forming crystals. The data are used in magmatic degassing studies and to determine the molecular structure of silicate melts and solid crystals.
The U.S. Geological Survey's Rock- and Paleo-magnetics Laboratory is a facility dedicated to the study of past variations of the Earth's magnetic field and the magnetic properties of rocks. Scientists affiliated with the laboratory analyze the magnetic record contained in rocks and apply the data toward solving various geologic problems, including mapping active volcanoes. For the full suite of information about this lab, visit the USGS Rock- and Paleo-magnetics Laboratory website.
The mineralogy and petrology laboratory is a shared facility for preparation and identification of mineralogical and petrologic samples. It houses automated X-ray powder diffractometer, heavy-liquid and magnetic mineral separation equipment, fine grinding and sieving equipment, wafering saw, petrographic and binocular microscopes, and fume hoods for caustic chemical treatments.
The rock preparation laboratory is a shared facility for rock cutting, grinding, and sieving of bulk samples. It includes a separate rock/core layout room.
The machine shop is a shared facility for machining and repair of equipment. It includes lath, drill press, vertical mill, band saw, and standard hand tools, chemicals, and lab accessories.
In partnership with the Stanford University School of Earth Sciences, the USGS operates a large-format Sensitive High-Resolution Ion MicroProbe (SHRIMP) that provides a unique capability for the Western Region and the Bureau (http://shrimprg.stanford.edu). Ion microprobe analysis (secondary ion mass spectrometry, SIMS) is used for precise determination of isotope ratios and trace element concentrations in solid materials with high spatial resolution. The SHRIMP RG (Reverse Geometry) typically extracts atoms for analysis in its doubly focusing mass spectrometer from a volume 30 micrometers in diameter and a few micrometers deep. USGS scientists from all regions use the SHRIMP RG, most in geology, some in hydrology, and a few in biology. Recent research topics include U–Pb and U–Th (U series) geochronology; trace element concentrations in minerals, volcanic glass, and biogenic carbonates; and Sr isotope ratios in biogenic and hydrothermal calcium carbonate.
The CalVO GIS group works with geologists to build spatial databases that describe the distributions of geologic products, especially volcanic products, and structures that are visible at the earth's surface. These spatial databases reconstruct a volcano's eruption history to determine the types, spatial extent, and occurrence intervals of hazardous phenomena that the volcano is capable of producing. This in turn spurs geospatial analysis and targeted research into the physical processes that occur before, during, and after volcanic eruptions to better understand where the effects of the volcano will be felt and how these eruptions start, proceed, and end. These data and understanding become the basis for hazard mapping and risk management, which then can guide the location of monitoring instrumentation. The geologic map, hazard, and monitoring instrumentation data are stored in spatially aware databases for analysis, distribution, and visualization. These data are provided on-line through live maps, map services, and data downloads.