| 金属矿地震绕射波分离与成像——以庐枞矿集区和钦杭成矿带为例 |
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| 引用本文：王志辉,吕庆田.2017.金属矿地震绕射波分离与成像——以庐枞矿集区和钦杭成矿带为例[J].地球学报,38(s1):79-82. |
| DOI：10.3975/cagsb.2017.s1.21 |
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| 基金项目:国家自然科学基金重点基金项目“长江中下游成矿带深部结构、过程及对成矿的制约—集成研究”(编号: 41630320); 中国地质调查局地质调查项目“钦杭结合带及邻区深部地质调查”(编号: DD20160082); “国家危机矿山接替资源勘查专项新技术方法”项目(编号: 200699065) |
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| 中文摘要:不同于油气藏能源大多产于沉积地层之中, 金属矿成矿部位的地质条件要更为复杂多变。通常情况下矿体表现为不规则形状, 且连续性较差, 难以满足现有地震反射波法所以依据的镜面反射条件(徐明才等, 2009)。不同的围岩地震地质条件差异很大, 甚至同一种岩性受到蚀变、构造作用的影响, 表现出不同的阻抗特征, 当围岩与矿体间的波阻抗差异较小, 难以形成有效的反射波。在控矿构造方面, 通常大规模的构造对成矿具有控矿、控岩作用, 而与成矿部位密切相关的一般是小规模的断裂, 反射波较难识别。根据菲涅耳带理论, 当地质体的尺度小于地震波的一个波长时, 反射地震成像精度会骤降, 而来自这些小尺度、非均匀地质体产生的绕射波和散射波成像较反射波成像具有明显的高分辨率、甚至超高分辨率。利用绕射波成像能够探测和识别地下重要的构造信息, 如破碎带、断层、尖灭点、礁体边界、次火山岩、小尺度的侵入体、不规则盐丘体, 以及其他不连续的地质体(Karimpoul et al., 2015)。考虑金属矿围岩及控矿构造复杂, 矿体几何尺寸较小、形状不规则, 容易产生绕射波, 理论上利用地震绕射波识别这些地质体较反射波更具优势。 |
| 中文关键词:金属矿 地震绕射波 偏移成像 庐枞矿集区 钦杭成矿带 小包庄矿体 |
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| Separation and Imaging of Seismic Diffractions on Metal Deposit: Two Cases in Luzong Deposit Concentration Area and Qinhang Metallogenic Belt |
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| Abstract:Different from oil and gas reservoirs mostly burried in sedimentary strata, the geological condi-tions of metallogenic sites are more complex and changeable. Generally, the ore bodies have irregular shapes and are discontinuous, so it is difficult to meet specular reflection (Xu et al., 2009). Moreover, seis-mogeology characteristics from different lithological rocks are of diversity, and even the same lithological rocks influenced by alteration and tectonic show dif-ferent impedance characteristics. When the wave im-pedance difference between the rock and the ore body is small, it is difficult to originate seismic reflection wave. In terms of ore-controlling structures, large faults control intrusive mass and mineralization, and small faults which are difficult to be detect by seismic reflection exploration are closely related to the met-allogenic sites. Based on the Fresnel theory, if the geological body scale is less than the wavelength, the accuracy of seismic reflection imaging will drop dras-tically. However diffraction wave and scattered wave imaging from these small scale and heterogeneous geological bodies have a high or ultra-high resolution. Diffractions imaging can detect and identify under-ground important structural information, such as fracture zone, faults, pinchout, reef boundary, small scale volcano rocks, intrusive bodies, rough surfaces of salt domes, as well as other geological discontinui-ties (Karimpoul et al., 2015). So it is available to de-tect these geological bodies like complex structures and small scale and irregular shape ore bodies by seismic diffractions in theory. |
| keywords:Base metal deposit Seismic diffractions Migration Luzong deposit concentration area Qinhang metallogenic belt Xiaobaozhuang ore bodies |
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