| 白银厂铜多金属矿床——壳幔交代中的地幔流体成矿探讨 |
| |
| 引用本文： | 任秉琛.白银厂铜多金属矿床——壳幔交代中的地幔流体成矿探讨[J].地球学报,1996,17(Z1):57-63. |
| |
| 作者姓名： | 任秉琛 |
| |
| 作者单位： | 西安地质矿产研究所 |
| |
| 摘 要： | 依据深部构造、火山岩建造与基性和钙碱性、中酸性、酸性火山岩的双峰式火山作用，确定白银厂矿田、矿床形成于切割硅铝层的古裂谷构造环境。其中小铁山、铜厂沟等矿床和折腰山、火焰山矿床两次成矿事件与双峰式火山活动同时发生，成矿作用与酸性火山岩具有时空上的一致性。矿石中CO2流体包裹体除H2O含量高外，与上地幔CO2流体包裹体成分一致；矿石富含大离子亲石元素和具富Mg、K的成矿蚀变元素组合，硫和铅来自下地壳或上地幔。喷气硅质岩锶同位素初始值表明，矿质来源于不均一地幔，S/Se、Co/Ni、Se/Te值亦指示矿质来源于深部。
本文提出矿床形成于强烈扩张的裂谷期，断裂的延深生长使地幔深部产生去挥发作用，释放大量CO2和含金属元素的地幔流体与上地幔基性岩浆向地壳侵入，导致下地壳熔融，形成酸性岩浆。与酸性岩浆喷发的同时，富含挥发份和金属元素的高盐度热卤水，沿断裂上升流入海底沉积成矿。
|
| 关 键 词： | 大陆裂谷 双峰式火山岩 地幔流体成矿 白银厂 |
Discussion on the Mantle Fluid Mineralization in Metasomatism of Crust and Mantle: A Baiyinchang Cu-polymetallic Deposit |
| |
| Ren Bingchen.Discussion on the Mantle Fluid Mineralization in Metasomatism of Crust and Mantle: A Baiyinchang Cu-polymetallic Deposit[J].Acta Geoscientia Sinica,1996,17(Z1):57-63. |
| |
| Authors: | Ren Bingchen |
| |
| Institution: | Xi'an Institute of Geology and Mineral Resources,CAGS |
| |
| Abstract: | In this paper, it is considered that the Baiyinchang ore field is formed in a struc-tural setting of paleorifting that cuts the sial on the basis of deep-seated structure, vol-canic foration and bimodal volcanism with basic and cala-alkalic, intermediate as well as acidic volcanic rocks, among them, two times of mineralization events in Xiaotieshan, Tongchanggou and so on ore deposits, togehter with Zheyaoshan, Hoyanshan ore de-posits are contemporaneous with the bimodal volcanic activity, that is to say, ore-forming process is spatiotemporally consitent with acidic volcanic rocks. Composition of CO2 fluid inclusion in ore consists with those of upper mantle, except that H2O is hight in con-tent. Ore is characterized by riched in large ion lithophile element and by bearng the assem-blage of mineralization alteration riched in Mg and K, S and Pb derives from lower crust or from upper antle. Sr isotope initial values of exhalation silicalite show that ore-forming meterals origined from an imhomogeneity mantle.S/Se, Co/Ni and Se/Te implay that ore-forming meterals come from deep-seated as well.
In this paper, it is set out that the ore deposit is formed in a strong extensional rifting, which made away with the volatite component, from deep-seated mantle to extending of rift. Mantle releaseda plenty of CO2, containing metallic element, togehter with basic magma of upper mantle, was intruded upwards crust, thus resulted in melting of lower crust to form acidic magma. In the meanwhile, hot brine riched in volatite component and metallic element, being hight in salinity, upswings along the rift, and then flows into sea floor to from ore deposit. |
| |
| Keywords: | continental rifting bimodal volcanic rocks mantle fluid mineralization Baiy-inchang |
|
| 点击此处可从《地球学报》浏览原始摘要信息 |
| 点击此处可从《地球学报》下载免费的PDF全文 |
|
