摘要:
陕西华县八里坡似斑状二长花岗岩体位于华北板块南缘,新的钻探工程探明该岩体中钼矿的规模达中型以上。岩体的岩石地球化学研究表明:SiO2=69.87%~73.76%;Al2O3=13.74%~15.74%,MgO =0.25%~0.46%,K2O =3.85%~4.51%,K2O%> Na2O%;δEu=0.70~0.77,呈弱负铕异常;Sr/Y>40,Zr/Sm>20,Sr=256.8×10-6~637.6×10-6,Y=6.63×10-6~13.72×10-6, Yb=0.98×10-6~1.86×10-6;(87Sr/86Sr)i=0.709~0.710,εNd(t)=-22~-20。这些岩石地球化学结果与中国胶东-大别C型埃达克质岩地球化学特征一致,而且是与成矿有关的埃达克质岩特征相似。位于东秦岭西段的八里坡矿床地质与地球化学特征相似于东段的超大型南泥湖钼(钨)矿床,结合钻探验证,岩体西南深部可能具有较好的钼钨成矿潜力。
Abstract:
Balipo porphyritic monzonitic granite in Huaxian, Shaanxi Province is located on the southern edge of North China Block, in which some middle scale Mo orebodies have been discovered by dills. New lithogeochemical data show that the average of SiO2 content varies from 69.87% to 73.76%, Al2O3=13.74%~15.74% and most are over 15%, MgO=0.25%~0.46%, K2O=3.85%~4.51%,K2O%>Na2O%;δEu=0.70~0.77,appearing weak negative anomaly, Sr/Y>40,Zr/Sm>20; the content of Sr varies from 256.8×10-6 to 637.6×10-6 and most are higher than 400×10-6; Y=6.63×10-6~13.72×10-6,Yb=0.98×10-6~1.86×10-6. Sr and Nd isotopes are characterized by (87Sr/86Sr)i =0.709~0.710,εNd(t)=-22~-20, which are similar with that of C-type adakitic rocks related to mineralization in Jiaodong-Dabie eastern part of China. Very similar geological and geochemical features by comparing Balipo Mo deposit in the west part of East Qinling with Nannihu super-large Mo-W deposit in the east part of East Qinling, combining with some drills, indicate a good prospecting potential for Mo and W in the northwest deep part of Balipo Mo deposit.
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