Acquisition of a Noble Gas Thermochronometry Laboratory at Berkeley Geochronology Center

这项主要研究仪器（MRI）计划拨款支持在伯克利地质年代学中心建立一个惰性气体热测时实验室（NGTL）。NGTL将侧重于附件相的(U-Th)/He和4He/3He定年，以建立它们的低温（200℃）热历史。拟购买的设备包括双目显微镜、构建气体提取系统组件（包括二极管激光器和超高真空激光提取室）、构建超高真空气体净化系统组件和四极杆质谱仪。激光加热气体萃取净化系统将从样品中释放出He，然后在四极杆质谱仪上进行分析。在气体分析之后，回收的样品将被溶解，溶液将被加标，通过ICP-MS分析在校外设施进行U和Th浓度的同位素稀释测量。NGTL对200摄氏度以下岩石的热历史进行定量评估的能力将用于建立在类地行星最上面几公里处发生的过程的时间尺度和速率。将促进一系列PI和合作研究，包括：(i)量化山区景观中挖掘、侵蚀和构造运动的速率和时间尺度，并测试气候变化对地形的可能影响；（ii）限制近地表行星撞击的温度和时间尺度以及火星陨石在火星上的长期停留温度；（iii）量化地球表面化学风化的时间尺度和速度；（iv）限制样品在地球表面附近的长期停留时间尺度；(v)研究稀有气体在不同材料中的扩散动力学，以推进对固态扩散的基本理解，并有可能确定稀有气体在地球和行星科学中的新应用。对研究生和博士后进行低温测温研究方法的培训，PI计划有针对性地招聘女性和少数民族的研究生和博士后

0618219ShusterThis Major Research Instrumentation (MRI) Program grant supports establishment of a noble gas thermochronometry laboratory (NGTL) at the Berkeley Geochronology Center. The NGTL would focus on (U-Th)/He and 4He/3He dating of accessory phases to establish their low temperature ( 200 degrees C) thermal histories. Equipment to be purchased includes a binocular microscope, components to a build gas extraction system including diode laser and ultrahigh vacuum laser extraction chamber, components to build an ultra high vacuum gas purification system and a quadrupole mass spectrometer. The laser heated gas extraction and purification system would be used to liberate He from samples which would subsequently be analyzed on the quadrupole mass spectrometer. Following gas analysis, recovered samples would be dissolved and solutions would be spiked for isotope dilution measurements of U and Th concentrations via ICP-MS analysis at available off campus facilities. NGTL capabilities for quantitative evaluation of the thermal histories of rocks below 200 degrees C will be used to establish timescales and rates of processes taking place in the uppermost few kilometers of terrestrial planets. A range of PI and collaborative research will be facilitated including: (i) quantifying the rates and timescales of exhumation, erosion and tectonism in mountainous landscapes and testing possible influences that climate variability has on relief, (ii) constraining the temperatures and timescales of near-surface planetary impacts and long-duration residence temperatures of the Martian meteorites while on Mars, (iii) quantifying the timescales and rates of chemical weathering at Earth's surface, (iv) constraining long-term residence timescales of samples near Earth's surface, and (v) studying noble gas diffusion kinetics in different materials to advance basic understanding of solid-state diffusion and potentially identify novel applications of the noble gases to the Earth and planetary science. Graduate and postdoctoral researchers will be trained in low-temperature thermochronometry research methods and the PI's plan targeted recruitments of women and minorities for graduate and postdoctoral fellowships.***