Stable Isotope Lab

John W. Valley
Charles R. Van Hise Professor
Stable Isotope Geochemistry and Metamorphic Petrology
(608) 263-5659

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  New Techniques for Stable Isotope Analysis

The UW-Madison Stable Isotope Laboratory is active in many areas of the Earth Sciences including studies of: the evolution of the crust and mantle, magma genesis, volcanology, migration of fluids in the crust, formation of base-metal ore deposits, diagenesis in sedimentary basins, carbon (re)cyling, diffusion rates in minerals, and reconstruction of paleoenvironments, climate change, and paleodiet.  Recent projects have included the study of: zircons from the earliest Earth (Western Australia) to present, martian and lunar samples, mantle xenoliths, caldera volcanism at Yellowstone, the evolution of the Sierra Nevada batholith, and quartz overgrowths in the Saint Peter sandstone.The Stable Isotope Laboratory includes two dual-inlet five-collector Finnigan/MAT 251 mass-spectrometerstwo laser probe systems (Nd-YAG and CO2 lasers) for silicate, oxide, phosphate, and sulfide analysis; and conventional lines for analysis of silicates, oxides, sulfides, hydrous minerals (D/H), carbonates, graphite, and water.The laser fluorination lines yield high-precision oxygen isotope data for silicates and oxides which are used in studies focusing on topics which include: magma genesis, ancient hydrothermal alteration, isotope thermometry and speedometry, diffusion rates of oxygen in minerals, oxygen isotope heterogeneity in the mantle and the solar system. Click on thumbnails below for full images.

Laser fluorination system. Laser probe system Laser fluorination system
Laser fluorination system and Finnigan MAT 251 mass spectrometer used for the rapid high-precision analysis of oxygen isotope ratios in silicates and oxides.
Close up of laser fluorination extraction line. Laser and sample chamber at far left. Cryogenic purification line center and right.
Laser fluorination system for the high-precision analysis of three isotopes of oxygen (16O,17O,18O), especially useful for identification of different classes of meteorites.

WiscSIMS- Silicates, oxides, sulfides, and carbonates can also be analyzed by ion microprobe for O, C, H or S isotope ratios at the 1-20 micro-meter scale through WISC-SIMS, the Wisconsin Secondary Ion Mass Spectrometer Facility.

Zircons are Forever

Personnel and Stable Isotope Researchers:

  • Contact: John Valley, Professor of Geology, Director of the Stable Isotope Laboratory
  • Contact: Mike Spicuzza, Instrumentation Technologist, Stable Isotope Laboratory