At the Colorado TRaIL, we are equipped to perform all stages of (U-Th)/He analysis including He extraction and measurement, U-Th-Sm analysis, mineral separation, and sample preparation.
He Extraction and Analysis Lab
At CU we use an ASI Alphachron for He extraction and measurement. Individual samples are heated using a diode laser. Sample gas is spiked with 3He, purified with SAES getters, and analyzed on a Pfeiffer Balzers QMS quadrupole mass spectrometer. Heating and measurement are automated using Alphachron software. Currently the machine can hold 25 samples at a time. Our facility can degas all minerals, including apatite, zircon, monazite, sphene, and garnet, and can easily measure the He content of single crystals.
After dissolution, samples are analyzed for U, Th, and Sm contents using an Agilent 7900 Quadrupole ICP-MS (pictured below). This machine was installed in 2017 thanks to an NSF Instrumentation and Facilities Grant to Flowers and Metcalf (NSF #1559306). Below is an image of dissolved apatites in the Agilent SPS4 autosampler attached to the ICP-MS. The Teflon sampler takes up a few hundred microliters of the solution for each analysis.
After the grains have been degassed, we prepare them for ICP-MS analysis in our clean lab wet chemistry facility, located on the 4th floor of Benson Earth Sciences. This lab is equipped with a metal-free acid hood, laboratory oven, and Parr bombs for acid-vapor dissolution. We routinely dissolve both apatite and zircon in this facility.
Mineral Separation Facilities
The CU Thermochronology lab is equipped for all stages of mineral separation. The lab has a Bico rock crusher and pulverizer, Wilfley water table, Franz magnetic separator, and heavy liquid (LMT and MEI) lab. These facilities allow us to go from rock to pure apatite or zircon separate relatively quickly.
For a more complete discussion of mineral separation as applied to thermochronology, please check out this write up on the world’s leading thermochronology blog.
Our sample preparation facilities include two Leica binocular picking scopes with digital cameras for measuring grain dimensions. We have all of the equipment necessary for selecting, characterizing, and packing grains (into either Pt or Nb metal packets).
If you’d like to know more about sample preparation, please check out this write-up on the world’s leading thermochronology blog.