| 西秦岭丹凤群变质火山岩的地质地球化学特征及其成矿环境初探 |
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| 引用本文： | 杨根生,陈彦文,胡晓隆.西秦岭丹凤群变质火山岩的地质地球化学特征及其成矿环境初探[J].现代地质,2004,18(4):518-523. |
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| 作者姓名： | 杨根生 陈彦文 胡晓隆 |
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| 作者单位： | 甘肃省地质勘查局,第一地质矿产勘查院,甘肃,天水,741020 |
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| 基金项目： | 中国地质调查局国土资源大调查项目(K4、1、2、6(2))。 |
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| 摘 要： | 位于西秦岭褶断带的甘肃省两当县太阳寺一带金及多金属矿床的规模已达大型。丹凤群是该矿床的重要的含金、银、铅岩系。其火山岩以基性玄武岩为主,另有部分中性安山岩及少量的酸性流纹岩,具有从基性—中性—酸性的岛弧火山岩的演化模式。变玄武岩表现出岛弧拉斑玄武岩特有的富Al2O3、贫TiO2的特征。构造环境图解表明,这些玄武岩多为岛弧拉斑玄武岩,微量元素特征与Condie1982年给出的岛弧拉斑玄武岩相似,微量元素投点也多落入岛弧玄武岩区。稀土含量特征及球粒陨石标准化模式与岛弧拉斑玄武岩的特征相似,w(ΣREE)值高,且富轻稀土,稀土配分模式为右倾型。岩石组合、岩石化学及地球化学特征指示其为早古生代不成熟的岛弧环境。大规模的火山活动形成了太阳寺一带原始地壳和初始矿源层,后经断裂改造,含矿热液活化转移,使成矿物质进一步富集成矿。
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| 关 键 词： | 地质背景 岩石学 地球化学 岛弧 成矿 丹凤群 西秦岭 |
| 文章编号： | 1000-8527(2004)04-0518-06 |
| 修稿时间： | 2004年7月24日 |
GEOCHEMISTRY AND TECTONIC SETTING OF THE META-VOLCANIC ROCKS FROM DANFENG GROUP IN WESTERN QINLING |
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| YANG Gen-sheng,CHEN Yan-wen,HU Xiao-long.GEOCHEMISTRY AND TECTONIC SETTING OF THE META-VOLCANIC ROCKS FROM DANFENG GROUP IN WESTERN QINLING[J].Geoscience——Journal of Graduate School,China University of Geosciences,2004,18(4):518-523. |
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| Authors: | YANG Gen-sheng CHEN Yan-wen HU Xiao-long |
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| Abstract: | Taiyangsi gold polymetal deposit in Liangdang County, western Qinling is a supper large gold deposit. Danfeng Group is a principle ore-bearing rock formation with gold, silver and lead-zinc mineralization. The volcanic rocks of Danfeng Group mainly consist of basalts and a few of andesite and rhyolite. The meta-basalt of Danfeng Group is characterized by high content in Al_2O_3 and low content in TiO_2. The trace elements in the meta-basalt show the same characteristics as the island-arc tholeiite. The REE distribution patterns with high value of ΣREE, enrichment of LREE and incline to the right are similar to the island-arc tholeiite. The rock association, lithochemical and geochemical characteristics of Danfeng Group show its immature island-arc environment at Early Paleozoic . The large volcanic activities formed the primitive earth crust and the initial ore-source bed around the Taiyangsi area. The remobilization of ore-bearing hydrothermal solution formed further mineralization and enrichment in gold, silver,lead and zinc through the fractures and modification. |
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| Keywords: | geotectonic setting lithology geochemistry island-arc environment metallogenic Danfeng Group western Qinling |
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