Footwall refrigeration along a detachment fault: implications for the thermal evolution of core complexes
Footwall refrigeration along a detachment fault: implications for the thermal evolution of core complexes
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DOI：
10.1126/science.279.5347.63
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发表时间：
1998-01
期刊：
影响因子：
56.9
通讯作者：
Jean Morrison;J. L. Anderson
中科院分区：
文献类型：
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作者：
Jean Morrison;J. L. Anderson
维普莱山变质核杂岩拆离断层下绿泥质角砾岩中绿帘石和石英的氧同位素组成产生了石英-绿帘石分馏，范围为每密耳4.1至6.4，并向断层系统性增加。这些分馏给出的平均温度从断层下方50米处的约432摄氏度降至断层下方12米处的约350摄氏度。这种在38米范围内高达82摄氏度（每公里2160摄氏度）的极端热梯度最好用循环表面衍生流体的对流热提取来解释。岩石圈伸展模型只考虑构造剥蚀引起的传导冷却，因此需要修正以包括流体引起的断层带冷却。
Oxygen isotope compositions of epidote and quartz from chloritic breccias that underlie the detachment fault in the metamorphic core complex of the Whipple Mountains yielded quartz-epidote fractionations that range from 4.1 to 6.4 per mil and increase systematically toward the fault. These fractionations give mean temperatures that decrease from approximately 432 degrees C at 50 meters below the fault to approximately 350 degrees C at 12 meters below the fault. This extreme thermal gradient of 82 degrees C over 38 meters (2160 degrees C per kilometer) is best explained by advective heat extraction by means of circulating surface-derived fluids. Models of lithospheric extension consider only conductive cooling resulting from tectonic denudation and thus require revision to include fluid-induced fault-zone refrigeration.