| The Dongwuqi-Nenjiang metallogenic belt is located in the northeast of China. Considered with geotectonic, it’s located on the Central Asian Orogenic Belt (CAOB), and the southeast margin of Mongolia-Okhotsk orogenic belt. The the Greater Khingan Range first-order metallogenic belt is divided into five third-order metallogenic belt, which includes Dongwuqi-Nenjiang metallogenic belt, Heilongjiang metallogenic belt, Derbugan metallogenic belt, Linxi-tuquan metallogenic belt and Wenduermiao-Honggeer metallogenic belt. Within the above metallogenic belt, there develops a series of non-ferrous metal deposit, and Honghuaerji tungsten deposit, Da Yana tungsten deposit, Weilianhe tungsten deposit have been found since 2010. In this paper, based on previous research results, author comprehensively clarifies the tectonic evolution history of tectonic unit that contains the Greater Khingan Range first-order metallogenic belt, and deeply discusses some common argument of tectonic evolution history. On this basis, this paper systematically conducts the studies on geology, geochronology and geochemical of the three newly discovered tungsten (molybdenum) ore deposit. contrasting with a series of typical tungsten deposit of South China tungsten ore district in aspect of rock genesis, ore-forming material source, metallogenic geodynamic background, this paper aims to summary tungsten (molybdenum) ore metallogenic regularities, discuss the metallogenic geodynamics background, propose Metallogenic model, and ultimately provide guidance for next step prospecting and exploration of tungsten ore.About Regional tectonic evolution, significant progress has been made in recent years, but there are still two disputes, the completely closed time of the Paleo-Asian Ocean and the time of the Mongolia-Okhotsk tectonic domain converted to the paleo-Pacific tectonic domain. The time of mineralization outbreak of the study area is Mesozoic, but the evolution of the Paleo-Asian Ocean has come to end in Paleozoic. Therefore, this paper attempts to discuss the second controversial point, in order to clarify its relationship with mineralization. Combined with both previous research data and the zircon U-Pb and Lu-Hf isotope analysis of a large number of granites exposed northern Daxinganling metallogenic belt, regional magmatism can be divided into the five period, (1) 840～780Ma; (2) 530～440Ma; (3) 330～280Ma; (4) 240～160Ma; (5) 150-120Ma。Hf isotopic analysis results show that two peak value ages of Hf two-phase model age is respectively 680-840Ma、1160-1360Ma, and its sHf(t)>0 or about 0, suggesting the magma formed a huge amount of granite in the study area is mainly derived from the depleted mantle or lower crust. According to the relationship both U-Pb age and Hf two-phase model age, when U-Pb age is 500-160Ma, the corresponding the Hf two-stage model age mainly distributes in 600-1400Ma; but when U-Pb age is under 160Ma, the corresponding the Hf two-stage model age is less than 1000Ma and tend to be consistent, besides all the sHf(t)>0 and also tend to concentrate. In conclusion, combined with regional tectonic events, author thinks that, since 160Ma, magmatic source in the study had changed and exist some new joined material. In a word, since 160Ma, the paleo-Pacific tectonic domain start to control research area.Honghuaerji hydrothermal type scheelite deposit is a large-scale W-multi-metal deposit, located in the northwest edge of metallogenic belt. Ore forming rock is granite, and the ore body is hosted by the mineralized granite rock. The Molybdenum (Tungsten) ore bodies are mainly sparse large pulse or thin vein, and distribute in the inner contact zone of the granite body in flat layer. Rock alterations have sericitization, greisenization, silicide, etc, and the alteration related with mineralization is mainly greisenization. The useful mental minerals in ore district are scheelite and molybdenite, which are located in the lower and upper of the ore body, respectively. The geologic feature shows that this deposit is a high temperature hydrothermal type tungsten polymetallic deposit. This paper mainly focuses on its rock metallogenic age and its geochemical characteristics. According to the dating of zircon U-Pb age, molybdenite Re-Os age and muscovite Ar-Ar age, the deposit was formed in the early to middle Jurassic. Geochemically, the mineralized rocks belong to shoshonite series and are characterized by HFSE enrichment (Rb, Th, U, Nd, Hf) and LILE depleted (Ba, Sr, P, Ti, Nb). The mineralized rocks have hige Rb value, but low Ba and Sr values, and are characterized by intense LREE/HREE differentiation. According to the geochronology, geochemistry and regional structure evolution, the author suggests that Honghuaerji hydrothermal type scheelite deposit formed in post orogenic extensional collapse environment after the Mongolia-Okhotsk southward subduction collision orogeny, and their source located in the boundary of crust-mantle was mainly the crust.About Dayana and WeiLianHe, quartz-vein type molybdenum (tungsten) deposite, located in central and southwestern metallogenic belt. The characteristics of ore deposit geological and mineralization is very similar. Ore-forming rock is biotite granite and granite, respectively. Rock alterations are weak, and develop within a few meters on both sides of quartz vein, and mainly include silicification and sericitization. Mineralization types are quartz vein-type wolframite, but there also have some molybdenum altogether with wolframite in Dayana ore deposit. This paper mainly focuses on its rock metallogenic age and its geochemical characteristics. Zircon U-Pb dating shows that both the rock-forming ages is the early cretaceous (135Ma-145Ma), and molybdenite Re-Os dating showed the ore-forming age of Dayana deposit is 133Ma. Geochemically, Ore-forming granites are characterized by high SiO2 and rich Al2O3, belonging to high potassium calc-alkaline series series, and are characterized by unobvious LREE and HREE fractionation, HFSE enrichment (Rb, Th, U, Ta, Nd, Hf) but LILE depleted (Ba, Sr, P, Ti, Nb), strong negative Eu anomaly, low Sr, high Yb, and highly enriched Rb. all suggest the granites are mainly derived from crust source, and have characteristics of a high differentiation of magma evolution. Combined with regional tectonic evolution, the author thinks that the Weilianhe quartz-vein type molybdenum (tungsten) formed under stretch slump background in the process of plate back after the subduction-collision of the Paleo-Pacific, and magma source are derived from crust.Besides, this paper collects a large number data on tungsten ore south china, compared with the study area, aims to solve the problem of magma material source-granite genesis, metallogenic material source of W and the geodynamics background that is conducive to form tungsten ore deposit. Through the comprehensive contrast, granites closely related with tungsten ore are characterized by high SiO2 and rich Al2O3, rich ALK, high potassium calc-alkaline. Rich in HFSE, but poor in LILE, strong negative Eu anomaly, low Sr, high Yb, highly enriched Rb, all suggest the granite mainly derived from crust source. The large amount of Re-Os data show metallogenic material of W is also derived from crust, and its geodynamic background is tensile stretch background. In conclusion, we establish on the geodynamic model of regional tectonic evolution, which are associated with mineralization of tungsten, and finally, provide some advices for tungsten ore prospecting and exploration. |
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