Acquisition of (U-Th)/He Thermochronology Laboratory

9902988米勒这笔拨款为建造一个新的(U-Th)/He热年代学实验室的费用提供部分支持，以补充斯坦福大学现有的40Ar/39Ar和裂变径迹（FT）热年代学实验室。热年代学是指使用天然放射性衰变“时钟”来重建岩石经历的时间-温度历史。因为温度通常可以作为埋藏深度的代表，这些方法可以用来帮助重建挖掘、造山和变形历史。不同的温度表在不同的温度区间内敏感，因此在不同的深度。在磷灰石矿物中，He和FT系统高度互补，它们的灵敏度区间分别约为40至85摄氏度（约1.5至3公里深度）和80至125摄氏度（约3至5公里深度）。新设施的初步工作将针对一系列研究，包括：调查旧金山湾区圣安德烈亚斯断层系统的晚新生代挤压和山地建设，以促进对该系统的运动学理解和地震危险性评估；重建内华达州和犹他州北部盆地和山脉省第三系伸展史；重建中亚中、新生代造山和变形史；采用裂变径迹外探测器铀微测法和SHRIMP-RG离子微探针元素微测法评估U和Th分带对(U-Th)/He年龄精度的影响

9902988MillerThis grant provides partial support for the costs of constructing a new (U-Th)/He thermochronology laboratory to compliment existing 40Ar/39Ar and fission track (FT) thermochronology laboratories at Stanford University. The term thermochronology refers to the use of natural radioactive decay "clocks" to reconstruct the time-temperature histories experienced by rocks. Because temperature can commonly be used as a proxy for burial depth, these methods may be used to help reconstruct exhumation, mountain building, and deformational histories. Different thermochronometers are sensitive within different temperature intervals and thus at different depths. In the mineral apatite, the He and FT system are highly complementary in that their sensitivity intervals are about 40 to 85 degrees C (about 1.5 to 3 km depth) and 80-125 degrees C (about 3 to 5 km depth), respectively.Initial work in the new facility will be directed toward a range of studies including: investigating late Cenozoic transpression and mountain building along the San Andreas fault system in the San Francisco Bay Area to contribute toward kinematic understanding of the system and to seismic hazard assessment; reconstructing the history of Tertiary extension in the northern Basin and Range Province in Nevada and Utah; reconstructing Mesozoic and Cenozoic mountain building and deformational histories in central Asia; and using fission track external detector uranium micromapping methods and SHRIMP-RG ion microprobe element micromapping methods to assess the effects of U and Th zoning on the accuracy of (U-Th)/He ages.***