| Yichun-Yanshou metallogenic belt of Heilongjiang Province is an important centralized deposit area in Heilongjiang Province even in our country, which is the joint of Songnen-Xiaohingganling massif and Jiamusi massif according to geotectonic position, which is one of the orogens that undergoes the longest history of development and possesses frequent tectonic-magmatic activities in northeast China. Qianjin area is lain in the center to west of Yichun-Yanshou metallogenic belt and tectonic-magmatic complex. With the further research to this area, many significant geological subjects left to be resolved, such as the forming time of magmatites, their sources, tectonic attributes and the relation to metallogene. In this paper, the author will systemically research the geochronology, petrologic and geochemical characteristics, tectonic setting of the magmatites and the relation to the metallogene in order to make metallogenic prognosis and to guide prospecting.The magmatites of Qianjin area distribute widely, most of them are intermediate-acid rocks, we also can see a few of basic veins. The main rock types include granite, granite-porphyry, granodiorite, adamellite, alkali-feldspar granite, etc. According to geochemical characteristics, the magmatites of the study area have wide range of SiO2 contents(48.98%~81.12%), Na2O+K2O ranges from 3.89% to 9.87 % ,Al2O3 ranges from 8.67% to 18.32%, MgO ranges from 0.12% to 7.86%,the invariable elements have rich in aluminums and alkali, deplete in Mg and Fe, and low in Na2O compare with K2O. In the discrimination diagrams, the magmatites have characteristics either S-type or I-type granite. During Harker diagrams of oxides both assemblages show obvious evolutionary tendency, which may reflect they belong to comagmatic evolutionary series. Observing from rare earth elements and trace elements components, we can they display similar characteristics of riching in LREE and LILE, depleting in HFSE and HREE, and have obvious Eu anomaly, which draw the same conclusion that the magmatites originate from the same magmatic source in the aim of Xiling east mountain, Qianjin east mountain and Xiling south mountain.On the basis of field geological investigation to Xiling east mountain, Qianjin east mountain and Xiling south mountain three deposits and reliable high precise isotopic dating, we confirmed the existence of tectonic-magmatic activity around Mesozoic epoch: the tuff of Qianjin east mountain granite-porphyry zircon U-Pb isotopic age is 201.7±1.2Ma and rhyolite zircon U-Pb isotopic age is 200.3±1.3Ma, Xiling south mountain granite-porphyry isotopic age is 195±3.0Ma. Combining to regional geology and isotope characteristic, the author consider that the magmatites of study area originate from intermediate-acid magma which through different degree fractional or crystallizayion ,formed by basic magma underplating lead to lower crust partial melting in the extension background, which are formed from extension environment after pale-Asia stured.Tectonic-magmatic activities in Mesozoic period provide wide space and source. Analyzed results of metallogenic element, the author consider that granite-porphyry, alkali-feldspar granite and hybrid granite have important controlling effect to Pb, Zn, Cu polymetallic ore deposits, which are important resources of metallogenic elements. Xiaojingou group and Fengshantun group stratums also provide amount of metallogenic substances. Xiling east mountain and Xiling south mountain lead-zinc polymetallic ore deposits in the study area are belong to magmatic hydrothermal deposit and volcanic hydrothermal deposit, orebodies occurred in stratums or magmatites; Qianjin east mountain ferrum-copper-lead-zinc polymetallic ore deposit is belong to skarn deposit, ore body occurred in the contact zone of stratum and magmatite. Magmatic activity supply necessary metallogenic element and heat source. The deposits are formed in similar redoxmorphic environment. The formative process is that the melting fluid riching in metallogenic element ascending along the fault, then leaching or metasomatic country rock which leading to metallogenic element enrichment, Metallogenic fluid is locating and precipitating in the advantage place, consequently, forming hydrothermal or skarn deposit.Ore bearing rock bodies developed silications and skarnizations intensively, the geochemistry characteristics showed high in silic and potassium, low in magnesium and iron in invariable elements, and rich in LREE, deplete in Tb, Tm, no or weak Eu anomaly in rare earth elements and high in concentration coefficients of As, Sb, rich in Ba, Rb etc LILE, deplete in Nb, Ta, Ti etc HSFE in trace elements. So we can definite prospecting sign, in other means, tectonic convergence of NE and NW; the place developed in Xiaojingou group and Fengshantun group stratums and the place developed in magmatites which have character above mentioned, can regard as prognostic area and promote exploration arrangement for prospecting.
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