摘要
火山成因块状硫化物(VolcanogenicMassiveSulfide,简称VMS)矿床可见于前寒武纪至现代的各个地质时代。现代海底热液成矿作用为研究VMS矿床提供了一种新的途径,DSDP/ODP钻探资料揭示:①VMS矿床虽然可产生于不同环境,但均与张裂断陷有关。②成矿物质可能来源有2种:一种是含矿火山岩系及下伏基底物质的淋滤;另一种是深部岩浆房挥发份的直接释放。③洋中脊海底热液循环呈双扩散对流模式。在有沉积物覆盖的洋中脊,热液循环更多地考虑流体与沉积物相互作用产生的效果。④从矿物组合的空间分布来看,热液硫化物堆积体上部以烟囱体为主,下部以块状硫化物为主,深部以网脉状硫化物为主,这在不同热液活动区似乎具有普遍性。VMS矿床的矿化模式反映的是一种热液成因,这种热液是深部(1～3km)岩浆侵入所引起并通过海水在热穹隆之上循环产生的。VMS矿床的深入研究要求我们致力于发现新的矿产地,提高样品采集、分析技术,加强海底热液活动与构造、岩浆作用和环境演变的一体化研究。
Volcanogenic Massive Sulfide (VMS) deposits exist from preCambrian to Quaternary. Modern seafloor hydrothermal mineralization process provides a new way to study the VMS deposits. Studies of DSDP/ODP drilling data showed that: ①VMS deposits are related to rifting and subsidence. ②Oreforming metals come from two sources, one is host volcanosedimentary rocks and underlying basement, the other is liberated volatile components from deep magma chamber. ③Midocean ridge seafloor hydrothermal circulation display doublediffusive convection pattern. In areas covered with sedimentary, more attention is paid to the effects produced by the reaction between the hydrothermal fluid and the sedimentary. ④From the point of spatial distribution of mineral assemblage of a hydrothermal sulfide congeries, the upper part is dominated with chimney, and the lower part with massive sulfides followed by stockwork sulfides in the deep part. This seems to be a common feature of various hydrothermal active areas. Mineralization pattern reflected the hydrothermal genesis of VMS deposits, in which the thermal fluid is generated by the circulation of seawater through heat dome, which in turn is a result of the intrusion of the deep (1～3 km) magma. Further studies of VMS deposits requires the discovery of new mineral occurrence, the improvement of sample collection, analyzing techniques, and the integration conception of seafloor hydrothermal activation, tectonic setting, magma processes and environment evolution.
出处
《地球科学进展》
CAS
CSCD
2003年第5期773-782,共10页
Advances in Earth Science
基金
国家重点基础研究发展规划项目"地球圈层相互作用的深海过程和深海记录"(编号:G2000078500)
国家高技术研究发展计划(863)课题"大洋固体矿产资源成矿环境及海底异常条件探测关键技术"(编号:2001AA6010202)资助.
