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.
出处
《矿物学报》
CAS
CSCD
北大核心
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)
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
14.0°S hydrothermal field
hydrothermal sulfide
mental remobilization
crust permeability
stock-work ore body
the southern mid-Atlantic ridge
