摘要
The relationship between mineralogical characteristics and isotopic compo-sition of suffides has not received its proper share of attention from geologists, althoughmany references are available concerning the application of sulfur isotopes to geologicalproblems.Located in the vicinity of the contact region between the Yangtze Platform and theSouth China Caledonian Folding Zone, the Huxu deposit is hosted in a structural zone inquartz-diorite-porphyrite emplaced in Jurassic volcanic rocks. Sphalerite and galena arethe principal ore minerals in the deposit. (1) Sphalerite is highiy variable in color and thisvariation can be related to its chemical composition and sulfur isotopic characters. Darkcolored sphalerites are poor in Zn and Ni, rich in Pb, Cu, Fe, Ag and Au and have high δ34Svalues, while the opposite is true for light-colored ones. (2) δ34S of sphalerite is negativelycorrelated with the contents of Zn and Ni and positively correlated with the contents of Pb,Cu, Ag and Au, with the absolute values of the correlation coefficients being greater than0.7. The above two characters suggest that the suthe isotopic composition of sphalerite iscontrolled not only by the physicochemical conditions under which the mineral was formed,but also by mineralogical characteristics of the host mineral. (3) Apparent correlationsexist among the constituent elements in the sphalerite. For example, Zn is negativelycorrelated with Cu, Pb, Fe, Ag and Au and positively correlated with Ni. (4) Sphaleritesof the same color in the same hand specimen always show similar characters with respect totrace element and sulfur isotopes. (5) Two distinct trends of evolution can be recognizedbetween Zn and Cu, Zn and Pb, Zn and Ag and between these elements on one handand δ34S on the other, reflecting that the ore-forming solutions may have resulted frommixing of fluids of different origins. (6) Pb is uniformly distributed in sphalerite and showspositive correlations with Cu, Fe, Ag and δ34S, suggesting isomorphic substitution in thesphalerite lattice.
The relationship between mineralogical characteristics and isotopic compo-sition of suffides has not received its proper share of attention from geologists, althoughmany references are available concerning the application of sulfur isotopes to geologicalproblems.Located in the vicinity of the contact region between the Yangtze Platform and theSouth China Caledonian Folding Zone, the Huxu deposit is hosted in a structural zone inquartz-diorite-porphyrite emplaced in Jurassic volcanic rocks. Sphalerite and galena arethe principal ore minerals in the deposit. (1) Sphalerite is highiy variable in color and thisvariation can be related to its chemical composition and sulfur isotopic characters. Darkcolored sphalerites are poor in Zn and Ni, rich in Pb, Cu, Fe, Ag and Au and have high δ34Svalues, while the opposite is true for light-colored ones. (2) δ34S of sphalerite is negativelycorrelated with the contents of Zn and Ni and positively correlated with the contents of Pb,Cu, Ag and Au, with the absolute values of the correlation coefficients being greater than0.7. The above two characters suggest that the suthe isotopic composition of sphalerite iscontrolled not only by the physicochemical conditions under which the mineral was formed,but also by mineralogical characteristics of the host mineral. (3) Apparent correlationsexist among the constituent elements in the sphalerite. For example, Zn is negativelycorrelated with Cu, Pb, Fe, Ag and Au and positively correlated with Ni. (4) Sphaleritesof the same color in the same hand specimen always show similar characters with respect totrace element and sulfur isotopes. (5) Two distinct trends of evolution can be recognizedbetween Zn and Cu, Zn and Pb, Zn and Ag and between these elements on one handand δ34S on the other, reflecting that the ore-forming solutions may have resulted frommixing of fluids of different origins. (6) Pb is uniformly distributed in sphalerite and showspositive correlations with Cu, Fe, Ag and δ34S, suggesting isomorphic substitution in thesphalerite lattice.
关键词
闪锌矿
矿物学特征
硫同位素
金属成矿流体
化学组成
sphalerite
chemical composition
sulfur isotope
correlation
color
mixed ore-forming fluid
