| Abstract:Jiaodong peninsula is the most important gold production district, The vein rocks are widespread and of diverse types, which are intimately paragenetic with gold deposit. On the basis of detailed regioncal geological investigation of Dayingezhuang-Jintingling, mineralogy, Petrology, geochemistry, isotope geochemistry, relevant analytical methods have been applied to discuss the genesis of dyke and granite, to research the relationship between dyke and gold deposits in time and space.The dyke in the given area mainly consists of lamprophyre, diabace, dioritic porphyrite, quartz dioritic porphyrite, pyroxene diorite, syenite, orthophyre, granite porphyry by means of systematic field survey and inside job.The dykes show the feature of calc-alkalic rock series. Lamprophyre could be divided into two types, one of which is sodic calc-alkali lamprophyre, the other is potassic calcalkaline lamprophyre. The dykes and granites are enriched in large ion lithophile elements(LILE) and light rare earth elements(LREE), depleted in high field strength elements(HFSE)and heary rare earch elements(HREE) without Eu negative anomaly and with a high Sr content.The geochemistry features of lamprophyre show that the melt of lamprophyre derive from enriched mantle with contaminationthe continental crust and some oceanic crust components. Linglong granite which has high Sr content and low Y, and Yb content is the granite with the feature of continental crust, which belongs to the typical Eastern china granite with high Sr, low Y.Ziron U-Pb dating by LA-ICP-MS shows that the dykes have two diagenetic age. The age of lamprophyre in Dayingezhuang is163±2.2Ma, which is closed to the age of Linglong rock body, and the age of dioritic porphyrite in Jintingling is128±8.5Ma, which is closed to the age of Guojialing rock body. Regional data show that Linglong granite is the source rock of gold deposit, and the diagenetic epoch of Guojiallin rock is the same as mineralisation age of gold, thus the dyke is an effective indicator of metallogeny of gold.The results of analysis show that the fresh dykes couldn’t provide the material source for gold mineralization, for they don’t have a high gold grade, the same source and tectonic setting with metallogenic substance which lamprophyre has can indicate prospecting in space. Through the research of the relationship in genesis between dyke and granite, the speculation that there are Guojialing rock body in deposit deeply can be made. |
PDF Full Text Request