胶东金矿集中区岩石圈结构与深部成矿作用
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摘要
利用胶东及其邻区 1∶2 0万重力异常和 1∶10万航磁异常探测资料 ,结合地震各向异性研究成果 ,解析其三维岩石圈结构 .在此基础上 ,综合深部结构和矿床地质特征 ,探讨深部作用与成矿动力学 ,深化矿床成因认识 ,为科学找矿提供决策依据 .研究表明 ,壳幔结构的不均一性制约着成矿系统物质和能量的交换 ,反映在其结构、构造和演化等多个方面 .矿集区为地幔隆起带的坳陷区 ,幔坳与幔隆接触部位成矿强度大 ,幔隆区的局部隆起部位成矿强度小 ;金矿床主要分布于花岗岩变薄部位与变质岩的接触带上 ;印支中晚期郯庐断裂带深切上地幔 ,通过壳 -幔相互作用 ,将含矿流体系统输运到更高的层位 ,发生蚀变、矿化作用 .艾山岩体所处构造部位的特殊性 ,反映了它可能是壳幔岩浆对流侵位中心 .
The information of geophysical field was, based on the results of 1∶1 000 00 aeromagnetic anomaly and 1∶2 000 00 Bouguer gravity anomaly in Jiaodong and its neighboring regions, Shandong, China, divided into two parts: deep and shallow focus field. The information of the two different fields was then combined with these of wave velocity anisotropy and deep seated geology. The integrated result was adapted to the analysis of the three dimension structure, the probe into deep seated mineralization and the dynamics of ore forming system. This research indicated that the interaction and conversion of materials and energy in the ore forming system were restricted by the heterogeneity of lithospheric structure, resulting in effects in different aspects, such as texture, tectonics and evolution. The occurrences and processes of deposit concentration region in Jiaodong were basically controlled by the transformation of tectonic regimes. The deposit concentration region is located in the down warping area of the mantle upwelling zone, but gold deposits are located in gradient variation and deformation places of Mohole. The major mineralization intensity is located at the junction between down warping and upward region, while the minor one is located in the upward district of the upward region. The down warping area of the mantle is related to the tectonic regime of compression, but the local deformation following the down warping is connected with the tectonic regime of extension. The gold deposits, controlled by large deep seated faults and shear belts, are mainly distributed near the gradient belts of gravity anomaly and the brink of sub aeromagnetic anomaly regions, the junction between thinning positions of granites and metamorphic rocks. The Tancheng Lujiang fault is a mature lithosphere fault of deep mantle cut, and also a fluid bearing mantle shear zone. Because of long term reduction of lithospheric thickness, the asthenosphere enriched with fluid components and metallogenic elements, occurred under the Tancheng Lujiang fault where occurred the coupling of fluid heat chemistry physics. The shear anatexis of the fault was responsible for the lithogenesis and mineralization, and also for the ore forming reactivation and migration. The mantle ore fluid system was migrated to the upper horizon through this solution divergence and migration along the Tancheng Lujiang fault in the middle late Indo Chinese epoch when the alteration and mineralization took place. The uniqueness of the tectonic position of the Aishan pluton shows that the Aishan pluton might be the center of the convection and intrusion displacement of the crustal mantle magma.
The information of geophysical field was, based on the results of 1∶1 000 00 aeromagnetic anomaly and 1∶2 000 00 Bouguer gravity anomaly in Jiaodong and its neighboring regions, Shandong, China, divided into two parts: deep and shallow focus field. The information of the two different fields was then combined with these of wave velocity anisotropy and deep seated geology. The integrated result was adapted to the analysis of the three dimension structure, the probe into deep seated mineralization and the dynamics of ore forming system. This research indicated that the interaction and conversion of materials and energy in the ore forming system were restricted by the heterogeneity of lithospheric structure, resulting in effects in different aspects, such as texture, tectonics and evolution. The occurrences and processes of deposit concentration region in Jiaodong were basically controlled by the transformation of tectonic regimes. The deposit concentration region is located in the down warping area of the mantle upwelling zone, but gold deposits are located in gradient variation and deformation places of Mohole. The major mineralization intensity is located at the junction between down warping and upward region, while the minor one is located in the upward district of the upward region. The down warping area of the mantle is related to the tectonic regime of compression, but the local deformation following the down warping is connected with the tectonic regime of extension. The gold deposits, controlled by large deep seated faults and shear belts, are mainly distributed near the gradient belts of gravity anomaly and the brink of sub aeromagnetic anomaly regions, the junction between thinning positions of granites and metamorphic rocks. The Tancheng Lujiang fault is a mature lithosphere fault of deep mantle cut, and also a fluid bearing mantle shear zone. Because of long term reduction of lithospheric thickness, the asthenosphere enriched with fluid components and metallogenic elements, occurred under the Tancheng Lujiang fault where occurred the coupling of fluid heat chemistry physics. The shear anatexis of the fault was responsible for the lithogenesis and mineralization, and also for the ore forming reactivation and migration. The mantle ore fluid system was migrated to the upper horizon through this solution divergence and migration along the Tancheng Lujiang fault in the middle late Indo Chinese epoch when the alteration and mineralization took place. The uniqueness of the tectonic position of the Aishan pluton shows that the Aishan pluton might be the center of the convection and intrusion displacement of the crustal mantle magma.
引文
③翟裕生 ,邓军 ,杨立强 ,等 .山东省招远市夏甸金矿构造成矿模式及隐伏矿体预测研究 .中国地质大学 (北京 )科研报告 .1998.[1]陈毓川 .中国主要成矿区带矿产资源远景评价 [M ].北京 :地质出版社 ,1999.10 1～ 30 3.
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[11]孙继源 .华北地区板内构造及深部过程初探 [J].地质科技情报 ,1992 ,11(1) :4～ 13.
[12 ]邓军 ,杨立强 ,方云 ,等 .胶东地区壳 -幔作用与金成矿效应 [J].地质科学 ,2 0 0 0 ,35 (1) :6 0～ 70 .
[2 ]刘光鼎 ,郝天姚 .应用地球物理方法寻找隐伏矿床 [J].地球物理学报 ,1995 ,38(6 ) :85 0～ 85 4.
[3]梁德超 ,杨立强 ,邓军 .地面高精度磁法测量找金应用[J].地球学报 ,1999,2 0 (3) :2 94～ 30 1.
[4 ]顾留成 ,万国普 ,段林祥 ,等 .胶东破碎带蚀变岩型金矿床的地质 -地球物理 -地球化学模型及评价指标研究[A].见 :山东省地质矿产局编 .山东地质矿产研究文集[C].济南 :山东科学技术出版社 ,1996 .178～ 193.
[5 ]李冶华 .华北地台地球物理场、深部构造和金矿床 [J].物探与化探 ,1987,11(6 ) :40 8～ 415 .
[6 ]曾华霖 ,万天丰 ,TeyssierC ,等 .山东玲珑花岗杂岩体三维形态的重力模拟 [J].地球科学———中国地质大学学报 ,1999,2 4(6 ) :6 0 7～ 6 12 .
[7]曲晓明 ,王鹤年 .郭家岭岩体壳幔岩浆混合作用与侵位机制的动力学研究 [J].地质科学 ,1997,32 (4) :44 5～45 4.
[8]彭聪 .山东招平断裂带南段金矿成矿地质背景的地球物理研究 [J].中国地质科学院矿床地质研究所所刊 ,1994,1:139～ 145 .
[9]王良书 ,李成 ,薛革 ,等 .山东及邻区上地幔波速各向异性及动力学意义 [J].地质科学 ,2 0 0 0 ,35 (1) :40～ 46 .
[10 ]魏斯禹 ,滕吉文 ,王谦身 ,等 .中国东部大陆边缘地带的岩石圈结构与动力学 [M ].北京 :科学出版社 ,1990 .1～ 188.
[11]孙继源 .华北地区板内构造及深部过程初探 [J].地质科技情报 ,1992 ,11(1) :4～ 13.
[12 ]邓军 ,杨立强 ,方云 ,等 .胶东地区壳 -幔作用与金成矿效应 [J].地质科学 ,2 0 0 0 ,35 (1) :6 0～ 70 .
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