Stable Isotope Laboratory

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-spectrometers; two 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.


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.	Conventional externally heated nickel rod-bomb fluorination line for the extraction of oxygen from silicates and oxides.	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.

New Techniques for Stable Isotope Analysis

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
Brian Beard, Associate Scientist, Radiogenic Isotope Laboratory
Phil Brown, Professor of Geology
Alan Carroll, Professor of Geology
Dana Geary, Professor of Geology
Philipp Heck, Research Associate
Brian Jicha, Assistant Scientist
Clark Johnson, Professor of Geology, Director of Radiogenic Isotope Laboratory
Clay Kelly, Assistant Professor of Geology
Noriko Kita, Director, WISC-SIMS, the Wisconsin Secondary Ion-Mass-Spectrometer Facility
Reinhard Kozdon, Research Associate
Gordon Medaris, Professor of Geology, emeritus
Ian Orland, Graduate Student
Dayanidi Ortiz, Graduate Student
Brad Singer, Associate Professor of Geology
Taka Ushikubo, Research Associate

Department of Geology & Geophysics, UW-Madison

Page modified March 2008 by web staff.