科研之友
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摘要
The Middle-Lower Yangtze River Valley Metallogenic Belt (MLYB) is one of the most important metallogenic belts in eastern China, and contains many important porphyry deposits. These deposits include the Tongshankou Cu-Mo, Jiguanzui Cu-Au, Chengmengshan Cu-Mo, Wushan Cu-Mo, Fengshandong Cu-Au, Dingjiashan Cu, Yangjishan Au, Shaxi Cu-Au, Dongguashan Cu-Au, Shujiadian Cu and Anjishan Cu deposits, etc. In this review, we summarize the geological characteristics (including the stratigraphy, structure, ore-bearing porphyry types, vein characteristics and wall rock alteration), metallogenic ages and petro-geochemistry of representative porphyry deposits in the MLYB. We conclude that porphyritic magmatism and metallogeny have occurred in three stages. The Early (ca. 149-135 Ma) and Late (ca. 123-105 Ma) stages comprise mainly porphyry-skarn mineralization, whereas the Middle (ca. 133-125 Ma) stage comprises porphyry mineralization. Ore-bearing porphyries in the MLYB are the high-K calc-alkaline to calc-alkaline series, with the majority possess adakitic geochemical signature. The ore-bearing porphyries with adakitic signature may have originated from magma mixing, produced by the delamination of enriched lithospheric mantle and partial melting of the thickened lower crust. The enriched mantle-derived mafic melts component are very important for generating fertile magma, and the delta S-34 and delta O-18 values suggest that ore-forming materials were magma-derived. Compared with porphyry deposits in typical magmatic arc settings, porphyry deposits in the MLYB do not contain advanced argillic lithocaps or high- to intermediate-sulfidation systems, and the magmatic- and ore-forming material sources are also very different.
- 出版日期2015-3
- 单位合肥工业大学
