Title: The Relationship between Mantle-derived Fluid and Gold Ore-formation in the Eastern Shandong Peninsula: Evidences from D-O-C-S Isotopes
Abstract: There are three types of gold deposits in the Eastern Shandong peninsula, the largest gold area in China, i.e. quartz vein, fracture altered and breccia types. The former two developed along a group of NE-trending faults and are hosted by Jurassic biotite granite intrusions dated 160~150 Ma, Precambrian metamorphic rocks and Cretaceous granodiorite dated 130~126 Ma on the Precambrian crystalline basement. And the late one occurs around the northern margin of the Jiaojia—Laizhou Crtaceous basin and the mineralization is controlled by both the detachement fractures and NE-trending faults. In this study we chose 89 samples from ten gold deposits comprising the Linglong, Jiaojia, Sanshandao, Cangshang, Wangershan, Dayigezhuang, Denggezhuang, Pengjiakuang, Fayunkuang and Dazhuangzi; the Linglong Jurassic biotite granite, Guojialing Cretacceous granodiorite, and Archaean gneiss for the systematic measurements of S, D, O and C stable isototpes. The analyses results of these isotopes reflect the three types gold deposits occur in different modes but deposition by the same mixtured fluid system derived from mantle fluid reservior incorporated with crust fluids by the strong interaction with the host rocks at 120 Ma. Their ore-forming age is later than both the Jurassic biotite granite and Cretaceous granodiotite, and overlaps with the age of diabase and lamprophyre dikes ranging from 121Ma to 114Ma. The hydrothermal fluids which is responsible to both gold mineralization and the retrograde alteration of the diabase and lamprophyre dikes is quite similar, belonging to CO2 and potash-enriched fluid system, which is possibly the consequence of the Cretaceous lithospheric thinning and asthenosphere upwelling process in Eastern China.
Publication Year: 2005
Publication Date: 2005-01-01
Language: en
Type: article
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Cited By Count: 37
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