基于地震数据的黔西南烂泥沟金矿区冲断-褶皱构造控矿模型研究

The Lannigou deposit in East Southwestern Guizhou is a famous of Carlin-style gold deposit in the world, although being with a complicated geological structure and a great disputation on ore genesis. The seismic prospecting is an accurate geophysical exploration method which can clearly reveal inside story of sedimentary basin. Some researchers in Australia and China began to use seismic reflection data to study on metal deposit and got more new understandings...East Southwestern Guizhou is also a key area for oil and gas expecting in South China and total 1010km length of 2D seismic profiles were carried out in past ten years.Two methane-bearing CO2 gas reservoirs were found by two drills with total 9950.55m depth. About total 180km length of six seismic profiles cut through Lannigou gold district.These seismic lines have good reflection quality. The initial interpretation suggests that there is no seismic reflection of intrusive rock.There is an obviously deformation difference in sedimentary cover of Devonian-Triassic. In the depth of Lannigou gold deposit, Devonian-Permian sequences are characteristic of wide and gentle fold and west-dipping reverse fault which connect basin basement and Triassic. But Triassic system of flysch where Lannigou gold deposit occurs is characteristic of east-dipping thrusts and fault related folds. These phenomena would indicate that ore forming of Lannigou gold deposit is associated with the activity of thrust fold in Nanpanjiang-Youjiang basin...The study will use these seismic profiles to ascertain basin-scale architecture, detailed structures, and then to study the geometry and kinematics of ore-controlled structures in Lannigou gold district .A series of tectonic geochemical samples will be selected in thrusts and these test data would be useful to explain the migration pathway of ore fluid and hydrocarbon fluid.Finally,combing with previous studies of Lannigou gold deposit,a structural constraining model of mineralization of Lannigou gold deposit would be built and some preferable ore-finding area would be suggested...This application is different and interesting and its results would enrich and develop metallogeny in sedimentary basin.

黔西南东部烂泥沟是世界著名的卡林型金矿床，但地质构造极为复杂，矿床成因争议较大。地震勘探是沉积盆地最为精准的地球物理探测方法，能清晰揭露盆地内幕,是沉积岩石地区金属矿床勘探和研究的新手段。黔西南东部是我国南方海相油气勘探的重点地区之一，积累了大量地震勘探资料，申请者拟利用横穿烂泥沟金矿区的地震剖面，查明其盆地尺(深)度构造格架和构造细节，研究控矿构造几何学和运动学特征；开展断裂地球化学研究，结合地质和地震研究成果，查明成矿、成藏流体运移聚集轨迹；构建烂泥沟金矿床构造控矿模型，提出深部及外围新的找矿靶区。该申请在矿床学研究方法上具有一定的开拓性和新颖性，研究成果将丰富和发展沉积盆地金属矿床成矿理论。

烂泥沟金矿是南盘江盆地浊积岩中规模最大，地质现象典型的金矿床。本项目查明了烂泥沟金矿区深部构造格架，分析了断裂构造的演化；厘定了不同期次的成藏事件；研究了构造、成藏和成矿间关系，建立了实体成矿模型；已将研究成矿进行推广。.地震解释揭示，烂泥沟金矿区存在伸展、反转和挤压三类构造样式。伸展构造，一为巧洛半地堑，二为烂泥沟-尾怀断层南段，均为基底卷入构造。挤压构造，一部分由先存的伸展构造反转而成（即反转构造样式），但大部分是新生的。地震解释和地质地质调查表明，伸展和挤压之间的转换事件为中三叠世安尼期早-中期交界，即248Ma或246Ma稍后。 .烂泥沟金矿区存在两次成藏事件，其一是泥盆系（生油）-二叠系生物礁（储集），其二是上二叠统（生油）-三叠系中断层（储集）。两类古油藏在地质和地球化学方面（如碳同位素和稀土微量元素等）存在较大的差异。癞子山、石头寨和板街等古油藏均属生物礁型古油藏。地震解释还发现，研究区深部存在两个较为典型的二叠系生物礁，为潜在油气藏，可能与癞子山古油藏类似。生物礁型古油藏测得沥青Re-Os年龄为225Ma，代表了该类古油藏的油气转换时代。本次在F3断层中厘定的断层型古油藏，其中的沥青呈脉状，穿插了金矿石，其形成要晚于成矿，本次测得沥青Re-Os年龄为175Ma,代表了断层型古油藏生油和成藏时代。.早、中三叠世形成的断层，在晚三叠世（晚期前陆盆地阶段）又重新活动。巧洛半地堑的主要断层（如巧洛断层和边界断层），烂泥沟-尾怀断层和不整合面是变质流体和有机流体运移的重要通道。下泥盆统源岩生成的原油运移至二叠系生物礁中聚集成古油藏，在演化为气藏后，向烂泥沟金矿提供了大量的有机气体，通过TSR反应，向成矿提供了大量的硫离子。.基底卷入断层因为延深和延长较大，沟通了盆地基底和沉积盖层，不仅是不同流体运移的重要通道，也是金矿和油藏聚集的重要场所，控制了卡林型金矿和古油藏的分布。通过综合分析认为，烂泥沟金矿深部隐伏的巧洛断层和烂泥沟-尾怀断层南端成矿条件较好。在目前可采矿深度范围内，为矿业企业设计了两个探矿孔，有助于矿业企业的可持续发展。