石英的电子—空穴心在金矿评价中的意义

石英的电子-空穴心在金矿找矿勘探中具有重要意义。阳离子不等价类质同象造成的晶体缺陷,是使其具有电子-空穴心的内在因素。石英中常见的空穴心有Al-O~-、Ti-O~-、Fe-O~-,电子心有Al~(3+)+M、Fe~(3+)+M、Ti~(3+)+M等。电子顺磁共振波谱和热发光是检测石英中电子-空穴心的有效方法。在金矿床中,石英Al-O~-顺磁空穴心浓度较大者,其含金量也比较高。石英热发光曲线的发光峰的数量和强度与金成矿阶段有着明显的关系:早期成矿阶段结晶的基本不含金石英,热发光曲线常为近对称的单峰型,发光强度较大;主成矿阶段形成的含金石英,热发光曲线为多峰型,常具最大的发光强度;晚期成矿阶段生成的含金性较差的右英,热发光曲线呈单峰-双峰型,发光强度亦较大。石英热发光性与金矿体的空间展布表现出一定的联系;在矿体横向上,矿体中石英热发光曲线多为双峰-多峰型,围岩中石英热发光曲线多呈单峰型;在矿体垂向上,随矿体埋深的增加,石英热发光强度有逐渐增大的趋势。含金石英通常具有多个热发光温度,曲线形态为多峰型,且主热发光峰多位于相对较低的温度区间;不含金石英常仅有一个热发光温度,曲线形态为不对称的较平缓的单峰型,或为一平缓的曲线,发光强度较弱。

The Significance of Electron and Hole Centers in the Assessment of Gold Deposits

The electron and hole centers in qttartz are of great significance in goldprospecting. The existence of such centers. is attributed to defects in crystalsresulting from isomorphism between cations of different valences. The common hole centers in quartz include Al--O~-, Ti--O~- and Fe-O~-, while electron centerscomprise Al~(3+) + M, Fe~(3+) + M, Ti~(3+) + M etc. Electron paramagnetic tesonance andthermoluminescence are effective methods for detecting electron and hole cen-ters. In quartz from gold deposits, the Al--O~- hole center shows positive cortela-tion with gold concentration. The number and intensity of peaks of the ther-moluminescent cutves are obviously related to stages of gold mineralization:the curve of the early barren quartz shows nearly Symmetric pattern; that ofthe major stage auriferous quartz is of multimodal type; the curve of the latequartz, low in gold, is marked by unimodal--bimodal type with rather intenseluminescence. The thermoluminescence of quartz is connected to certain extent with dis--tribution of orebodies: the bimodal or multimodal curve commonly indicatesorebodies, whereas the unimodal curve usually marks country rocks. Vertically,the intensity of thermoluminescence tends to increase with the buried depthof the orebody. The thermoluminescence curve of auriferous quartz is usually of multimo--dal type, with. the principal peaks generally negatively skewed. The barrenquartz usually has an asymmetric, gentle and unimodal type curve with weakintensity of luminescence.)