闪锌矿交代黄铜矿形成的”黄铜矿病毒”结构

STUDY OF “CHALCOPYRITE DISEASE” TEXTURE RESULTED FROM REPLA CEMENT OF CHALCOPYRITE BY SPHALERITE

闪锌矿和黄铜矿交生形成的”黄铜矿病毒”结构通常被解释为由富铜热液交代闪锌矿形成。本文通过显微结构研究、电镜观察和电子探针微束分析，都证明了建德铜矿的”黄铜矿病毒”结构系闪锌矿交代黄铜矿形成。闪锌矿中”黄铜矿病毒”群仍保留着原始黄铜矿的轮廓，高倍电镜下具明显的交代残蚀结构，电子探针点、线、面成分分析都表明，无论闪锌矿中”黄铜矿病毒”含量多少，Fe∶Cu原子比始终在1附近，与后期热液交代说不相符。总成分在相图上的投点还否定了固溶体成因的可能。

The “chalcopyrite disease” texture of intimate intergrowths of ch alcopyrite (Cp) and sphalerite (Sp) is commonly considered as the result of repl acement of Sp by Cu-rich hydrothermal solution. In this paper it is proved that the “Cp disease” texture found in the Jiande copper deposit resulted from repl acement of Cp by Sp, based on microstructure investigation, electron microscope observation and electron microprobe analyses. The “Cp disease” group in Sp, in places, shows the outline sketch of a previous Cp, and replacement-palimpsest s tructures have been clearly recognized under electron microscope. According to t he electron microprobe analyses, Fe∶Cu atom ratio of the bulk composition of th e intimate intergrowths of Cp and Sp is always approximate to 1, although the am ount of “Cp disease” in Sp varies largely. It just fits the typical Cp composit ion and does not agree with the theory of late hydrothermal replacement of Sp. F urthermore, the bulk composition points of the intimate intergrowths are beyond the solid solution area on the phase diagram of the Fe-Cu-Zn-S system, ruling out the possibility of exsolution origin of solid solutions.