南大西洋14.0°S热液区热液硫化物矿物学特征及地质意义  

Mineralogy and geological significance of hydrothermal deposits from the 14.0°S hydrothermal field,South Mid-Atlantic Ridge

作　　者：李兵[1,2,3] 石学法[2] 杨耀民 叶俊[2] 方习生[2] 

机构地区：[1]中国科学院海洋研究所,山东青岛266071 [2]国家海洋局第一海洋研究所海洋沉积与环境地质国家海洋局重点实验室,山东青岛266061 [3]中国科学院大学,北京100049 [4]国家深海基地管理中心,山东青岛266061

出　　处：《矿物学报》2015年第1期35-43,共9页Acta Mineralogica Sinica

基　　金：中国大洋协会"十二五"课题"大西洋多金属硫化物成矿潜力与资源环境评价"(批准号:DY125-12-R-01)

摘　　要：南大西洋14.0°S热液区是由我国在大西洋中脊首次发现的热液区,该热液区位于南大西洋中脊与卡蒂诺(Cardno)转换断层相交的离轴内角位置。本文利用透反显微镜和X射线衍射(XRD)方法,对14.0°S热液区的热液硫化物进行了矿物学研究。结果显示,热液硫化物按照矿石构造可分为块状硫化物和烟囱残片两类,块状硫化物包括富铁和富铜硫化物,烟囱残片为富铁硫化物。块状硫化物矿石根据孔隙发育程度的差异,又可分为致密型和多孔硫化物矿石,这种致密程度的差异取决于硅质物质的含量。块状硫化物矿相学特征表明,本区热液活动至少存在3个期次,表层堆积矿石中硅质物质的大量产出很可能与侵入型网脉矿的发育有关。表层堆积矿石贫Zn的特征,指示虽然该区热液具有多期次性,但热液系统内Zn再活化作用不显著,这种特征很可能是由于本区洋壳较好的渗透性导致。The 14.0°S hydrothermal field in the southern mid-Atlantic ridge was first discovered by Chinese scientists and is located on the inside corner at the intersection of the southern mid-Atlantic ridge and the Cardno transform fault.In this paper,we conducted mineralogical studies on hydrothermal sulphides using transmission-reflection microscopy and X-ray diffraction(XRD).Hydrothermal sulphides occurring in this field can be divided into two categories according to their ore structures:massive sulphide ores and black chimney fragments.Massive sulphide ores can further be divided into iron sulphide ores and copper sulphide ores,while chimney fragments consist only of iron sulphide ores.However,according to the porosities which depend on the siliceous content,massive sulphide ores can also be divided into dense ores and porous ones.Microscopic studies of these sulphides suggest that hydrothermal activities in this field are characterized by multi-stages.Three stages were identified for these massive sulphide ores.These multi-stages are characterized by alternative development of sulphide and chert.Occurrence of a large amount of silica in surface stacking ores is probably related to development of a stock-work ore body within the crust.However,the general lack of Zn in surface stacking ores suggests that even though the hydrothermal system is consists of multiple stages,the remobilization of Zn within the hydrothermal system is not significant and probably resulted from the preferable crust permeability.

关 键 词：14.0°S热液区 热液硫化物 金属再活化作用 洋壳渗透性 网脉矿 南大西洋中脊 

分 类 号：P736.3[天文地球—海洋地质] P578[天文地球—海洋科学]