| 王一伟,罗绍强,凌强,刘增达,徐琳.四川松潘地区上三叠统新都桥组黑色岩系地球化学特征及其风化、物源与构造背景的指示[J].地质找矿论丛,2025,40(3):279-290 |
| 四川松潘地区上三叠统新都桥组黑色岩系地球化学特征及其风化、物源与构造背景的指示 |
| Geochemical Characteristics of the Black Rock Series in the Upper Triassic Xinduqiao Formation, Songpan Area, Sichuan Province: Implications for Weathering, Provenance, and Tectonic Setting |
| 投稿时间：2025-06-10 修订日期：2025-08-29 |
| DOI：10.6053/j.issn.1001-1412.2025.03.001 |
| 中文关键词: 三叠系 新都桥组 黑色岩系 地球化学 风化 物源 构造背景 松潘地区 |
| 英文关键词:Triassic Xinduqiao Formation black rock series geochemistry weathering provenance tectonic setting Songpan area |
| 基金项目:四川省地质矿产勘查开发局地质矿产专项“四川省松潘县东北寨金矿区南调查评价项目”(DZ-DZKC202408)、四川省地质矿产勘查开发局科技专项“四川省松潘县岷江金矿带区域控矿规律与找矿预测研究”(SCDZ-KJXM202515)联合资助。 |
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| 中文摘要: |
| 松潘地区晚三叠系新都桥组黑色岩系是区域金矿的重要赋矿层位，为了研究黑色岩系形成区的古风化、古气候、物源及构造背景，对松潘县十里乡西侧的黑色岩系进行了元素地球化学测试和分析。结果表明黑色岩系主量元素贫SiO2、Al2O3、TiO2、K2O、MnO、Na2O，富MgO、CaO；微量元素显著富集V、Cr、Ni、Cs，相对富集Co、Ga、Rb、Pb、Th，显著亏损Ba、Sr、Zr、Nb、Hf、Ta；稀土元素总量与大陆上地壳相当，属轻稀土元素富集型，具中等负铕异常。地球化学特征综合揭示：新都桥组黑色岩系物源区岩石经历了中等偏高程度的化学风化作用，属盆地东缘初始沉积；形成于半干旱偏湿润气候条件下的缺氧还原环境；物源区岩石为长英质岩石；物源区构造背景具有大陆岛弧、被动大陆边缘的多物源属性，综合分析认为物源主要来自东侧的秦岭造山带及扬子板块西北缘。本研究为深入理解松潘-甘孜盆地东缘晚三叠世构造-沉积环境演化及区域金矿成矿背景提供了重要的地球化学依据。 |
| 英文摘要: |
| The black rock series of the Late Triassic Xinduqiao Formation in the Songpan area constitutes a significant host horizon for regional gold deposits. To investigate the paleo weathering, paleo climate, provenance, and tectonic setting of the formation area of the black rock series, elemental geochemical testing and analysis were conducted on the black rock series located west of Shili Township, Songpan County. The results indicate that the major elements of the black rock series are depleted in SiO2, Al2O3, TiO2, K2O, MnO, and Na2O, while enriched in MgO and CaO. Trace elements show significant enrichment in V, Cr, Ni, and Cs; relative enrichment in Co, Ga, Rb, Pb, and Th; and notable depletion in Ba、Sr, Zr, Nb, Hf, and Ta. The total rare earth element content is comparable to that of the upper continental crust, characterized by light rare earth element enrichment and a moderate negative europium anomaly. Comprehensive geochemical analysis reveals that the source rocks of the black rock series in the Xinduqiao Formation underwent moderate to relatively intense chemical weathering, indicating initial sedimentation at the basin’s eastern margin. The rocks formed in an oxygen-deficient reducing environment under semi-arid to relatively humid climatic conditions. The source rocks are felsic in nature, and the tectonic setting of the source area exhibits multi-provenance characteristics, including continental island arc and passive continental margin attributes. Integrated analysis suggests that the provenance was primarily derived from the eastern Qinling Orogenic Belt and the northwestern margin of the Yangtze Plate. This study provides important geochemical evidence for an in-depth understanding of the Late Triassic tectonic-sedimentary environmental evolution and the regional gold metallogenic background at the eastern margin of the Songpan-Ganzi Basin. |
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