U.S.G.S.-Stanford Ion Probe (SHRIMP-RG) Laboratory

operated jointly by the U.S.G.S. and Stanford University
http://shrimprg.stanford.edu

Contact Information

Joe Wooden

650-725-9237

jwooden@usgs.gov

Stanford

CALIFORNIA

Instrument Type

MASS SPECTROMETERS - Ion Probe (e.g., SHRIMP or equivalent)

Australian Scientific Instruments; SHRIMP-RG

Application:

Age determination U-Pb

Typical Use:

-For middle Proterozoic and younger samples, U-Pb ages of zircon, monazite, titanite (ages of crystallization and/or metamorphic growth, provenance studies of detrital minerals)
-For early Proterozoic to Archean samples, Pb-Pb ages of zircon, monazite, titanite, xenotime (including diagenetic overgrowths on zircon), other minerals (ages of crystallization and/or metamorphic growth, provenance studies of detrital minerals)
-various trace element measurements in a variety of minerals
-under special operating conditions, some limited stable isotope measurements are possible

Conditions for Use:

Visitors are invited to work in the lab to work with lab personnel.
Visitors are invited to work in the lab to design and do the work yourself.

User Fees:

Costs are based on instrument use only and are calculated on a "per day" basis. There is generally no extra charge for use of sample preparation and characterization facilities, except in unusual circumstances. Visitors with special needs should contact the lab.

Instrument Priorities:

Remote Use:

No

Sample Preparation:

Prospective visitors should contact the lab for detailed sample preparation instructions. In summary, clean mineral separates are mounted in rows within the central 60% area of a 1" round epoxy mount. A standard is included. The sample is cut to 4mm thick and polished. Samples are characterized by cathodoluminescence (zircon) and/or back-scattered electron (BSE) imaging (monazite, xenotime, titanite, some zircon) prior to SHRIMP analysis. For in-situ (1" round thin section or rock mount) analyses or sample preparation for trace element analyses, please contact the lab.

Standard Collections/Lab Blanks:

We have age standards for zircon (Phanerozoic and Proterozoic), monazite, titanite and xenotime. We have a variety of trace element and stable isotope standards.

Software:

Data reduction for age determinations is done with SQUID (an Excel add-in), in conjunction with Isoplot. Trace element data reduction is done with Excel.

Educational Use:

Class demonstrations are available for undergraduates.
Undergraduate student research projects are invited.
Graduate student research projects are invited.