摘要
系统研究了中国大陆科学钻探工程主孔100-2000米岩石的热导率和生热率特征。初步研究了岩石热导率随矿物组成的变化关系、岩石热导率的各向异性及其影响因素。主孔2000米的岩心热导率介于1.873-4.062 Wm-1K-1之间,平均热导率2.967 Wm-1K-1。整体上热导率出现的频率主峰分布在2.8-3.0 Wm-1K-1。榴辉岩热导率随着其退变质程度的增加而降低,新鲜榴辉岩热导率集中分布于3.6-3.7 Wm-1K-1,角闪石化榴辉岩的热导率分布在3.1-3.2 Wm-1K-1,强退变的榴辉岩热导率分布于2.4-2.5Wm-1K-1。片麻岩热导率主要分布于2.8-3.0Wm-1K-1。从垂向上看,主孔100-735米主要由榴辉岩组成,热导率整体比较大,平均3.265 Wm-1K-1;1200-1600米主要以花岗质片麻岩为主,热导率比其它层位偏低,平均2.755 Wm-1K-1。通过对面理发育的样品进行测试,东海地区各类岩石的热导率具有较明显的各向异性。榴辉岩和片麻岩热导率的各向异性平均值分别为4.66%和22.99%,超基性岩的热导率平均值为3.322Wm-1K-1,各向异性 16.08%。岩石热导率在垂直于面理的方向上具有最小值,在平行于面理的方向上具有最大值。上述资料对超高压地体热结 构特征的研究提供了重要数据基础。
Thermal conductivity of the cores from CCSD 2000m-mainhole of different rocks are systematically investigated. Basically research on the relationship between the thermal conductivity and the components of minerals in rocks are studied. The anisotropy of thermal conductivity and its possible influencing factors are discussed for the rocks in Donghai area. The thermal conductivity of the cores from 2000m-mainhole varies from 1. 873 to 4.062 Wm -1 K -1 with the average value of 2. 967 Wm -1 K -1 for about 300 samples. The main peak of frequency distribution for total samples occurred between 2.8 -3.0 Wm -1 K -1. The thermal conductivity distribution of eclogite located in 3. 6-3.7 Wm -1K-1 for fresh eclogite, 3. 1 -3.2 Wm -1K-1 for retrograde samples and 2. 4-2. 5 Wm -1K-1 for intensively retrograde eclogite, which show the clear correlation with the degree of retrogression. The thermal conductivity of gneiss is distributed at 2. 8 - 3. 0 Wm -1K-1. In vertical profile from 100 to 735m of mainhole has the higher thermal conductivity in average 3.265 Wm -1K-1 because of the eclogite in the layer. On the contrary, the layer from 1200 to 1600m mainly made up of orthogneiss and has the lower thermal conductivity in average 2. 755 Wm K . Measurements on the foliation-developed core samples indicate that the anisotropy of thermal conductivity occurs in different rocks. The value of thermal anisotropy varies from 4. 66% for eclogite to 22. 99% for gneiss, and the ultra-mafic rocks have the average value of 3. 322 Wm -1K-1 in thermal conductivity and the anisotropy of 16. 08%. The anisotropy of thermal conductivity depends on the azimuth of the measurement relative to the foliation and the maximum and minimum values are occurred when the measurements are parallel and perpendicular to the foliation, respectively.