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Diffusion in sulfide minerals and its application to ore deposits

硫化物矿物的扩散及其在矿床中的应用

基本信息

批准号：
61540596
负责人：
OZAKI Masaharu
金额：
$ 1.15万
依托单位：
Kumamoto University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1986
资助国家：
日本
起止时间：
1986 至 1987
项目状态：
已结题

项目摘要

DIFFUSION IN SULFIDE MINERALS AND ITS APPLICATION TO ONEDEPOSITSDiffusion coefficients for transition elements in natural sphalerite were determined experimentally as a function of temperature and aS_2 using radioacive ^<54>Mn, ^<59>Fe, ^<60>Co, ^<63>Ni and ^<65>Zn. The tracer was deposited on a polished surface of natural sphalerite as a 1 1 drop of aqueous chloride solution. The doped sphalerite was then heated in sealed silica tubes together with an iron and/or synthesized pyrrhotite and/or pyrite aS2 buller, The tracer distribution was determined by measuring and emissions of powder sampled from successive 4 - 8 m thick layers of the sphalerite chip. Results of diffusivity measurements are as follows.1.Logarithms of diffusion rates for ^<59>Fe(D_<Fe> cm^2s^<-1>) normal to the cleavage (110) under Fe-FeS aS_2 buffer are -11.0 0.3 at 800゜C and -11.7 0.2 at 700゜C. Log(D_<Co>) are -10.7 0.2 and -11.5 0.3, respecively. Log(D_Zn_< cm^2s^<-1>) normal to the cleavage (110) under Fe-FeS aS_<2> buffer are -10.9 0.2 at 800゜C and -11.8 0.3 at 700゜C. Log(D<_Ni>) are -10.9 0.3 and -12.0 0.3, respectively.2. The dependence of ^<59>Fe diffusivity on aS_2 is clearly observed in the 800゜C and 700゜C experiments. ^<59>Fe diffusion rates are lower at higher aS_2 conditions (aS_2=10^<-2.9>, Fe_<1-x^S-S_<liq>. buffer; D_<Fe>=10^<-11.0 0.3> at 800゜C) and higher at lower aS_<2>(aS_<2> = 10^<-9.0>, Fe-FeS buffer; D<_Fe> = 10^<-11.3 0.2> at 800゜C).3. Diffusion rates for ^<60>Co parallel to the (110) plane of sphalerite at 800゜C approximately twice that normal to (110). Sphalerites from metamorphosed Besshi-type deposits in Japan have different element abundances but are characterized by a distinct lack of compositional zoning. It is suggested that sphalerites were homogenized by diffusion processes during regional metamorphism. Calculated annealing times are 16 m.y. at 350゜C and 240 m.y. at 300゜C, assuming 1 millimeter mean displacement of zinc atoms in sphalerite.

实验测定了天然闪锌矿中过渡元素在硫化物矿物中的扩散系数随温度和As_2的变化。示踪剂以11滴氯化水溶液的形式沉积在天然闪锌矿的抛光表面上。然后，将掺杂的闪锌矿与铁和/或合成的磁黄铁矿和/或黄铁矿AS2Buller一起在密封的硅胶管中加热，通过测量和从连续4-8m厚的闪锌矿芯片层中取样的粉末的发射来确定示踪剂的分布。扩散系数测量结果如下：1.Fe-FeS As_2缓冲液中，Fe(D&lt；Fe&gt；Cm^2s；-1&gt；)沿解理方向的扩散速率对数在800゜C时分别为-11.0 0.3和-11.7 0.2，在700゜C时分别为-10.7 0.2和-11.5 0.3。在Fe-FeS As_2&gt；缓冲液中，垂直于解理(110)的对数在800゜C时为-10.9 0.2，在700゜C时为-11.8 0.3。在800゜C和700゜C实验中，可以清楚地观察到^&lt；59&gt；Fe扩散系数对As_2的依赖关系。高As_2条件下(As_2=10^&lt；-2.9&gt；，Fe_&lt；1-x^S-S；Liq&gt；)，Fe的扩散速率较低。在800゜C时，D&lt；Fe&>；=10^&lt；-11.0 0.3；；在较低的As_&lt；2&>；(As_&lt；2&>；=10^&lt；-9.0&>；，Fe-FeS Buffer；D&lt；_Fe&>；=10^&lt；-11.3 0.2；；在800゜C时)。当温度为800゜C时，沿闪锌矿(110)晶面平行的扩散速率约为(110)晶面的两倍。日本别石型变质矿床中的闪锌矿具有不同的元素丰度，但具有明显缺乏成分分带的特点。研究表明，闪锌矿在区域变质过程中经历了扩散作用，形成了均一化作用。计算的退火时间为16m.y。在350゜C和240英里。年。在300゜C时，假设闪锌矿中锌原子的平均位移为1毫米。