| 河北丰宁撒岱沟门钼矿床成岩成矿年代学及成矿岩体地球化学特征 |
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| 关键词:Zircon U-Pb ages 40Ar/39Ar age Sr-Nd-Hf isotopes major elements of apatite Sadaigoumen Mo deposit |
| 基金项目:中国地质科学院基本科研业务费项目(编号: YYWF201715) |
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| Metallogenic and Petrogenic Geochronology and Geochemical Features of the Ore-related Granite in the Sadaigoumen Mo Deposit,Fengning, Hebei Province |
| The large-sized Sadaigoumen porphyry Mo deposit is located on the north margin of the North China Craton. Previous studies show that there is a big gap between the age of ore-related granite and ore-forming ages, which is inconsistent with the current consensus that a porphyry deposit is formed in a short duration. In order to solve this problem, the authors carried out U-Pb dating of the zircons from different granites in the ore district and 40Ar/39Ar dating of the muscovite from the molybdenite-bearing quartz vein. In addition, the study of the whole rock geochemistry and Sr-Nd-Hf isotopes of the granites and analysis of the major elements for the apatite from the ore-related granite were conducted in this paper. The results show that the muscovite yielded an 40Ar/39Ar plateau age of (237±2) Ma, which is consistent with the zircon U-Pb weighted mean age of (240±1) Ma for the white biotite monzogranite. These data are also coeval, within error, with the molybdenite Re-Os age (ca. 237 Ma) in this deposit obtained by previous research. This shows that the white biotite monzogranite is an ore-related granite, while the red biotite monzogranite with the zircon U-Pb age of (248±1) Ma is a pre-mineralisation intrusion. Geochemically, both the white and red biotite monzogranites belong to the metaluminous to slightly peraluminous high-K calc-alkaline to shoshonite I-type granitoids with high SiO2, alkline and K2O content. Sr-Nd-Hf isotope data demonstrate that these granites were formed by partial melting of the pre-existing Paleoproterozoic crust, which was intimately related to the evolution of the North China Craton during ca. 2.5~1.9 Ga. Apatite from the ore-related white monzogranite is characterized by high F and low Cl content, which is indicative of a high F parental magma of the deposit, and this feature possibly played a significant role in the Mo mineralisation at Sadaigoumen. |
| ZHANG Li-li,JIANG Si-hong,LI Hong-mei,WU Di,KANG Huan.2019.Metallogenic and Petrogenic Geochronology and Geochemical Features of the Ore-related Granite in the Sadaigoumen Mo Deposit,Fengning, Hebei Province[J].Acta Geoscientica Sinica,40(5):708-724. |
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