【摘要】 凤太铅-锌矿田位于华北地块和扬子地块间的秦岭古生代陆间裂谷系南部裂谷之中。通过对古构造的研究得知,该区至少从中泥盆世古道岭组形成时,同生沉积构造就持续不断地活动,受古道岭组顶部古剥蚀面控制的铁白云石硅质岩及铅-锌矿体,就是沿同生构造发生的海底火山喷流沉积的产物。除了大量的地质证据之外,文中还应用了微量元素、稀土元素、稳定同位素及矿物、元素分带性的研究成果,为矿床成因提供进一步的佐证。最后,笔者提出该类型铅-锌矿床的成因模式。更多还原

【Abstract】 The Fengtai Fengtai Pb-Zn ore field is located within the south rift valley of the Pa-leozoic Qinling intercontinental rift system between the North China and Yangtzeplatforms. The strata in the ore field are composed of the Middle Devonian Gudao-ling and Xinghongpu Formations. After sedimentation, the Gudaoling Formation hademerged from the sea, forming a very irregular fossil erosion surface which providean accumulative site for succesive ore deposition. Afterwarde, because of repeatedmovements of the syndepositional northeast-trending fault system, this area was cutinto a series of troughs. The deep-seated fluids in the faults was driven up by thesyndepositional structural movements, thus giving rise to volcanic exhalation on thesea floor. The mineralizing volcanic-exhalative solutions rich,in Zn, Si, Fe, Pb andCu ascended along the syndepositional northeast-trending faults and overflowed;then the solutions were mixed with the oxygen-deficient saline solutions in the sub-marine depressions. Within the environments large amounts of metallic sulfides,silica and ferroan carbonate were deposited with changes of physico-chemical con-ditions, and formed stratiform, stratoid and lenticular Pb-Zn ore bodies and ore-bear-ing rocks. At the same time the volcanic-exhalation produced syndepositional brec-cias and brecciated ores near the syndepositional structure. The petrological and petrochemical characteristics of the ore-bearing rocks,Pb/Zn ratios of the Pb-Zn bodies and trace-element sulfur isotope characteristics haveprovided convincing evidence for the volcanic-exhalative sedimentary ore deposition.更多还原