黑水─泉州地学断面东段深部温度与岩石层厚度

DEEP TEMPERATURE AND LITHOSPHERIC THICKNESS LONG THE EASTERN SEGMENT OF THE HEISHUI─QUANZHOU GEOTRAVERSE

应用地震波速度与岩石放射性生热率之间的实验关系，结合地表岩石生热率的测试，对黑水─泉州地学断面东段１８条一维地震剖面上的热源垂向分布进行了评估．在此基础上，建立了一维和二维稳态热传导模型．根据干玄武岩固相线公式，估算了上地幔介质部分熔融开始的深度（＂热＂岩石层厚度）．模型显示出深部温度场沿断面方向侧向变化显著．莫霍界面温度在４００－７００℃间变化，相应的＂热＂岩石层厚度为７５－２０５ｋｍ．一维和二维温度模型的差异主要表现在侧向热传递显著的下地壳和上地幔中．温度场的变化与造山带的形成年代或后期叠加构造热事件的年龄有关．

The experimental relationship between seismic velocity and radiogenic heat generation,in combination with the determined heat production for surface samples,was applied to evaluate the vertical distribution of heat sources for 18 seismic velocity depth profiles located along the Eastern segment of the Heishui-Quanzhou geotraverse. On this basis, the one-dimensional and two-dimensional steady-state heat conduction models along the geotraverse were constructed, and further more,the depth at which partial meltingbegin, i.'thermal' lithospheric thickness, was estimated from the dry basalt solidus. The temperature field shows significant lateral variation, the temperatures at Moho range from 390 to 700℃, the corresponding'thermal' lithospheric thicknesses vary from 75 to 205 km, which is in good accordance with the results obtained from MTS. The differences between 1-D and 2-D models are most pronounced in the lower crust and upper mantle,where lateral heat transfer is remarkable. The temperature distribution along the peotraverse is related to the ages of the orogenses or of the superimposed thermalevents.