| 范庆凯.北祁连塞浦路斯型硫化物成矿构造环境研究──与现代劳海盆对比[J].地质与勘探,2018,54(1):9-19 |
| 北祁连塞浦路斯型硫化物成矿构造环境研究──与现代劳海盆对比 |
| A study on the tectonic setting of Cyprus-type sulfide deposits in the North Qilian mountains: Comparison with the modern Lau basin |
| 投稿时间：2017-07-12 修订日期：2017-10-28 |
| DOI：10.12134/j.dzykt.2018.01.002 |
| 中文关键词: 北祁连 劳海盆 塞浦路斯型硫化物矿床 海底热液 |
| 英文关键词: North Qilian orogenic belt, Lau Basin, “Cyprus-type” sulfide deposit, submarine hydrothermal fluid |
| 基金项目:大型油气田及煤层开发国家科技重专项（编号：2016ZX05033002-007）和国家重点研发计划课题（编号：2016YFC0503301）联合资助 |
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| 摘要点击次数: 1932 |
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| 中文摘要: |
| 北祁连塞浦路斯型硫化物矿床形成于中-晚奥陶世弧后蛇绿岩的上部，成矿作用与区内火山活动、张性断裂活动和构造运动相关，热液循环通道主要有火山裂隙系统，熔岩冷却裂隙等，成矿位置与循环通道一致。区域性大断裂是深部高温热液的主要通道，且东段矿化剂S的来源较西段更深，指示更大的断裂延展深度。北祁连塞浦路斯型硫化物矿床的成矿作用可分为两个阶段，分别由火山活动和构造运动主导成矿，并对应北祁连弧后区东段和西段的塞浦路斯型矿床。劳海盆中南部的扩张历史表现为由北向南逐渐开裂，北祁连弧后区蛇绿岩的年龄变化则指示自西向东的开裂过程。劳海盆南部热液区仍处于裂谷环境，具黑矿型矿床的特点，向北逐渐向塞浦路斯型过渡；北祁连弧后区虽以发育塞浦路斯型矿床为特征，但其东段邻近弧后区仍发育大量同时期的黑矿型矿床，表明了东段奥陶纪裂谷的发育。另外，Ba/Nb等比值指示劳海盆由南向北受俯冲消减的影响逐渐减小，北祁连弧后区则同现代劳海盆一样，且东段受俯冲消减作用的影响较西段更为明显，表明开裂时间越早，受俯冲消减的影响越小，反之则受俯冲消减的影响越大。这些都证明了劳海盆与北祁连弧后区的相似性。 |
| 英文摘要: |
| The “Cyprus-type” sulfide deposits in the North Qilian mountains formed in the upper part of Middle-Late Ordovician back-arc ophiolites, which are characterized by a lot of pyroclastic and terrigenous clastic rocks. Their metallogenesis is related with the volcanic activities, regional faulting and tectonic movements there, and the hydrothermal circulation channels mainly consist of volcanically tensional fractures, lava cooling cracks and so on, in keeping with the locations of ore-forming. The regional faults are dominating channels of the high-temperature hydrotherm from the deep usbsurface, and the source of mineralizer S in the east part is deeper than the west, indicating a larger extending depth of faults. The metallogenesis can be divided into two stages, which are mainly controlled by volcanic activities and regional tectonic movements, corresponding to the “Cyprus-type” deposits in the east and west part, respectively. The spreading history of the mid-south Lau Basin shows a pattern of crac king from north to south, while the dating data of North Qilian ophiolites implies a spreading history of cracking from west to east. Hydrothermal fields in the south of Lau Basin (VFR) are still in a rifting setting, with some “Kuroko-type” deposits, which transit into “Cyprus-type” to the north. While the back-arc area of North Qilian is characterized by the “Cyprus type” deposits, where there are still many contemporaneous “Kuroko-type” deposits near the back-arc area in the east, manifesting the rifting in Ordovician. In addition, Ba/Nb and other trace element ratios indicate decreasing influence of subduction on Lau Basin from south to north. While the back-arc area of North Qilian is similar to modern Lau Basin in this aspect, where the influence of subduction on the east part is more obvious than the west, demonstrating that the earlier start of rifting could lead to less impact of subduction and vice versa. These lines of comparison are all similarities between Lau Basin and the back-arc area of the North Qilian mountains. |
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