攀西古裂谷区地表热流分布特征及其力学含义

HEAT FLOW PATTERN IN PANXI PALEORIFT ZONE, SW CHINA AND ITS MECHANIAL IMPLICATIONS

  • 摘要: 攀西古裂谷区11个地表热流数据变化于40——90 mW/m2,平均值为63 mW/m2。 其分布不仅与测点周围的岩石放射性生热率有关,而且与测点到裂谷轴部主干断裂的距离有关。经过分析对比,作者认为这是区内主干断裂自古新世以来持续挤压运动的结果。断裂的压性活动必然伴随着摩擦热的产生,从而引起断裂两侧局部热异常。 摩擦热的大小取决于断裂所处的力学状态,根据盐边-米易-渡口地区的热流资料推测,攀西昔格达断裂昕处的摩擦应力与运动速率v的状态不会超出v=697.4mW/m2和v=396.3mW/m2所限定的范围。

     

    Abstract: To date, reliable heat flow values at 11 sites have been obtained in Panxi paleorift zone varying from 40 to 90 mW/m2 with the mean of 6315 mW/m2. Heat flow pattern in Panxi paleorift zone depends not only on the radio-heat generation of the rock strata, but also on the distance between heat flow test sites and the main faults in the central part of the zone. This has been recognized as a result of the compressional movement of the related faults since Paleocene. Compressional slip of a fault must result in the occurence. of frictional heat, leading to the appearence of local thermal anonaly on both sides of the fault. Based on heat flow data at Yanbian-Miyi-Dukou area in the central part of the zone, the relationship between frictional stress () and the slip rate (v) of Xigeda fault (one of the dominant faults in the zone) may be considered to lie betweenv = 697.4mW/m2 andv = 396.3mW/m2

     

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