| 磁化率各向异性与花岗岩形成的构造背景──以广东两类不同成因类型花岗岩为例 |
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| 引用本文： | 杨树锋,陈汉林,陈芙蓉,竺国强,张伯友,石满全.磁化率各向异性与花岗岩形成的构造背景──以广东两类不同成因类型花岗岩为例[J].地球物理学报,1996,39(Z1):158-165. |
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| 作者姓名： | 杨树锋 陈汉林 陈芙蓉 竺国强 张伯友 石满全 |
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| 作者单位： | 1. 浙江大学地球科学系, 杭州 310027,;
2. 中国科学院广州地球化学研究所, 广州 510640 |
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| 基金项目： | 国家自然科学基金;优秀中青年人才专项基金;国家教委博士点基金 |
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| 摘 要： | 广东省两类不同成因类型花岗岩磁化率各向异性研究表明：Ⅰ型花岗岩的磁化率的数值较大，一致性较好；各向异性度比较小，磁化率椭球为纯压扁型．Ｓ型花岗岩的磁化率数值普遍较小，一致性较差；各向异性度比较大，磁化率椭球以兼具压扁型和拉长型为特征；岩体内部两种磁化率椭球（压扁型和拉长型）的３个主轴的方向具有较好的一致性．结合花岗岩的野外地质特征，作者认为，Ｓ型花岗岩在形成过程中受到了板块内部强烈的挤压和剪切作用，不同类型的源岩在强烈的挤压作用下局部地带发生破裂，发育了大规模的剪切推覆作用，在剪切热的作用下源岩物质被改造形成Ｓ型花岗岩；Ⅰ型花岗岩则是原始岩浆侵入到地壳上部形成，其形成的构造背景与当时板块的Ｂ型俯冲有关。
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| 关 键 词： | Ⅰ型花岗岩 S型花岗岩 磁化率各向异性 构造背景 |
| 收稿时间： | 1995-01-03 |
THE RELATIONSHIP BETWEEN ANISOTROPY OF MAGNETIC SUSCEPTIBILITY AND THE TECTONIC SETTING FOR GRANITOID──AS EXEMPLIFIED BY TWO KINDS OF GENETIC GRANITOIDS IN GUANGDONG PROVINCE,CHINA |
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| YANG SHU-FENG,CHEN HAN-LIN,CHEN FU-RONG,ZHOU GUO-QIANG,ZHANG BO-YOU,SHI MAN-QUAN.THE RELATIONSHIP BETWEEN ANISOTROPY OF MAGNETIC SUSCEPTIBILITY AND THE TECTONIC SETTING FOR GRANITOID──AS EXEMPLIFIED BY TWO KINDS OF GENETIC GRANITOIDS IN GUANGDONG PROVINCE,CHINA[J].Chinese Journal of Geophysics,1996,39(Z1):158-165. |
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| Authors: | YANG SHU-FENG CHEN HAN-LIN CHEN FU-RONG ZHOU GUO-QIANG ZHANG BO-YOU SHI MAN-QUAN |
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| Institution: | 1. Dept. of Earth Sciences. Zhejiang University, Hangzhou 310027, China;
2. Institute of Geochemistry, Academia Sinica, Guangzhou 510641, China |
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| Abstract: | The study of anisotropy of magnetic susceptibility for two types of granitoids was carried in Guangdong province, China. For Ⅰ-type granitoid, the anisotropy of magnetic susceptibility is smaller（1.04 on average） and the magnitude ellipsoid of susceptibility commonly shows oblate, the direction of magnetic foliation is very stable with the average direction of 275∠°35°The direction of foliation is consistent with the compressive direction by geological study during early Palaeozoic. For S-type granitoid, the anisotropy of magnetic susceptibility （1.14 on average） is greater than that of Ⅰ-type, but its uniformity is worse on regional distribution. The magnitude ellipsoid of susceptibility appears oblate （E>1） mainly companying with prolate （E<1）,and this reflects the variation of interior texture and structure of S-type granitiod. The direction of magnetic foliation is the same as the direction of schistosity that is observed in field. The occurrence of magnetic foliation is 20.0°∠34.0°and shows the compressive direction while the magnetic foliation and the schistosity were formed is NNE-SSE.Combining the results of geological study, the authors conclude that the S-type grantoid was compressed and sheared intensively during the process of the formation, the different protolithes tolithes were transformed into S-type granitoid. for Ⅰ-type granitoid, it was related to the function of B-type subduction in the continental margin. |
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| Keywords: | ?type granitoid S-type granitoid Anisotropy of magnetic susceptibility Tectonic setting |
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