Acquisition of a Laser Furnace System to Develop U-Th-He Dating in the UCLA Noble Gas Laboratory

University Of California-Los Angeles, Los Angeles CA

Investigators

Abstract

EAR-0132997 Grove Laser heating of metal-encapsulated accessory minerals has emerged as the most viable technique for accomplishing high-throughput, low-blank, and readily-tracked helium analysis for (U-Th)/He dating. This award will provide funds for a CW TEMoo mode, Nd-YAG laser and optomechanical equipment for automated beam attenuation to develop a temperature controlled, laser-heated furnace system for helium analysis in the UCLA noble gas laboratory. The laser system will become an essential component of the newly refurbished VG3600 extraction line that is now set up to perform 3He isotope dilution measurements. The newly developed (U-Th)/He dating capabilities will support a number of NSF-sponsored projects that require efficient (U-Th)/He analysis of apatite and sphene. The majority of these investigations are structural studies that rely upon low-temperature thermochronology to detect and characterize the magnitude and timing of Late Cenozoic crustal deformation. The itinerary of planned activities is broad and ranges from studies of the timing of the transition from water to steam-dominated conditions at The Geysers hydrothermal systems to detrital thermochronology in basins that border tectonically active areas. An overarching consideration in all this activity is our desire to develop self-consistent interpretive models that incorporate both 40Ar/39Ar K-feldspar and (U-Th)/He apatite and sphene thermochronometers to derive nearly continuous thermal histories from middle crustal to surface conditions.