Low-Frequency Attenuation in Polycrystalline Silicates and Microstructurally Equilibrated Silicate Partial Melts

多晶硅酸盐和微观结构平衡硅酸盐部分熔体的低频衰减

• 批准号: 9706213
• 负责人: Reid Cooper
• 金额: $ 20.59万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-07-01 至 2001-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9706213&HistoricalAwards=false
• 关键词: Low; Frequency; Attenuation; Polycrystalline; Silicates

9706213 Cooper The dynamic and quasistatic mechanical responses of carefully engineered aggregates of ferromagnesian olivine and of microstructurally equilibrated olivine + synthetic basalt partial melts will be evaluated as functions of temperature, frequency, grain size and loading morphology (Young's-modulus mode in compression and flexure, shear-modulus mode in torsion). The experiments emphasize (i) the use of drained conditions for the partial melts, (ii) the use of specific differential-stress and temperature potentials combined with a fine grain size such that a Newtonian rheology describes the crystalline phase in both partial melt and melt-free states, and (iii) a low-viscosity liquid phase in the partial melt experiments such that the compaction length exceeds the specimen size. The immediate goal of the research is to discriminate the effect(s) of partial melting on the dynamic signature of the aggregate from the intrinsic behavior associated with the dissipation of energy by solid-state grain-boundary processes. Given the experimental parameters to be explored, extrapolation of the results to upper-mantle conditions is possible. The longer-range goal of the research is to initiate evaluation of melt-segregation microstructures ("mesostructures") on the dynamic response. ***

小行星9706213库珀 动态和准静态力学响应的精心设计的铁镁橄榄石和微观结构平衡的橄榄石+合成玄武岩部分熔体的聚集体将作为温度，频率，粒度和加载形态（杨氏模量模式在压缩和弯曲，剪切模量模式在扭转）的函数进行评估。 实验强调（i）使用排水条件的部分 熔体，（ii）使用特定的差应力和温度势结合细粒度，使牛顿流变学描述的结晶相在部分熔融和熔体自由状态，和（iii）低粘度的液相在部分熔融实验，使压实长度超过试样尺寸。 该研究的直接目标是区分部分熔化对聚集体的动态特征的影响与固态晶界过程的能量耗散相关的内在行为。 考虑到有待探索的实验参数，外推法 上地幔条件下的结果是可能的。 该研究的长期目标是开始评估动态响应的熔体偏析微观结构（“介观结构”）。 ***