USGS-GD-Scientific Capabilities - GAS GEOCHEMISTRY Equipment




  • Balzers QMG 112 and 511, purchased and constructed over several years beginning in 1980, is a dual quadrapole mass spectrometer for complete chemical analysis (at an accuracy of 3-5 percent) of extremely small samples of gas, typically from an aqueous fluid inclusion as small as several microns in diameter. The quadrapole system can routinely analyze the chemical composition of gas mixtures containing picomole quantities of N2, O2, Ar, H2, He, Ne, CH4, HF, HC1, H2S, SO2, HCN, CO, CO2, SO2, Kr, Xe, and HnCn and chemical reaction products dissolved in minerals and in fluid inclusions. Provisions for bulk gas analysis from crushing or thermal decrepitation via a calibrated leak valve, real-time monitoring of released gases from thermal ramp heating of samples, and for GC-MS and direct flow injection of crushed or thermally decrepitated samples. The instrument includes a Nd-Yag laser and Nikon microscope system for releasing volatiles in fluid inclusions or minerals. Gases from this system can also be transferred to a GC-IRMS via capillaries to the open-split interface on the MAT 252 for isotopic analysis of released gas (CO2). Located in Denver.
  • Balzers QMG 421, purchased in 1993, is a quadrapole mass spectrometer. It is coupled to a microscope-mounted sample chamber within a walk-in freezer. It includes a CO2 laser and delivery system for ablating the ice and liberating gases contained in a single gas bubble. It also includes the necessary valving for separating gases by chromatography and splitting gas for admission to the GC-IRMS open-split capillary interface on the MAT 252. High precision analysis of CO2 in an individual 0.5mm diameter gas bubble in polar ice can be determined to ±/-0.7ppm by volume with quantitative detection below 10-15 moles in the "air" mixture. Located in Denver.

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| Geochronology, Geochemistry, and Tracer Studies  |
| Geochemistry, and Tracer Studies  |