扬子东南缘“南华纪”火山岩与沉积盆地演化
来源期刊：中国有色金属学报2013年第9期
论文作者：马慧英 孙海清 谢 维
文章页码：2631 - 2641
关键词：火山岩；盆地演化；“南华纪”；扬子东南缘
Key words：volcanic rocks; basin evolution; Nanhuaian period; southeastern margin of Yangtze platform
摘 要：对分布在江南造山带中段湘黔桂地区的火山-侵入基性-超基性岩类的地质、地球化学特征进行研究。结果表明：新元古代“南华纪”沉积盆地基底火山岩属于岛弧型，基底沉积建造为活动大陆边缘或大陆型岛弧盆地沉积；成盆早期的区域伸展，在扬子东南缘发育了一个断阶式陆坡盆地环境，接受次稳定型多元性陆缘碎屑沉积，形成的火山岩为钙碱性，属于初始裂谷火山岩。盆地大地构造背景解释为具较强构造活动的被动大陆边缘环境。“南华纪”中期盆地进一步伸展，沿桂北—湘西形成大量的低钙铝质、强碱-碱质的碱性玄武岩类，属于板内裂谷环境。至此，盆地完成由挤压造山—初始裂解—全面伸展的体制转换，盆地进入稳定发展阶段，直至震旦纪初的广泛海侵，淹没碳酸盐台地形成。
Abstract: The geological and geochemical characteristics of the volcanic intrusive basic-ultrabasic complex in the central section of the Jiangnan Orogen in Hunan—Guizhou—Guangxi region were studied. The results indicate that the basement volcanic rocks of sedimentary basin in Nanhuaian period of Proterozoic Era belongs to island arc type. The basement sedimentary formation is active continental margin or continental island arc basin sediments. The initial regional extension built a fault-step continental slope basin in the southeastern margin of Yangtze platform, accepting sub-stable plural clastic deposit from continental margin. This calc-alkaline volcanic rock is initial swifting volcanic rock. The basin’s tectonic setting is passive continental margin. In middle Nanhuaian period, the basin further extended along northern Guangxi—western Hunan to form a large quantity of alkaline basaltic rock with low calcium aluminum, belonging to intraplate rift environment. So far, the basin transformation has finished from compressive orogeny to initial splitting to full expansion, and then the basin began to develop steadily until the wildly transgression in early Sinian Era and submerged carbonate platform formed.
马慧英1，孙海清1，谢 维2
(1. 湖南省地质调查院，长沙 410116；
2. 中南大学 地球科学与信息物理学院，长沙 410083)
摘 要：对分布在江南造山带中段湘黔桂地区的火山-侵入基性-超基性岩类的地质、地球化学特征进行研究。结果表明：新元古代“南华纪”沉积盆地基底火山岩属于岛弧型，基底沉积建造为活动大陆边缘或大陆型岛弧盆地沉积；成盆早期的区域伸展，在扬子东南缘发育了一个断阶式陆坡盆地环境，接受次稳定型多元性陆缘碎屑沉积，形成的火山岩为钙碱性，属于初始裂谷火山岩。盆地大地构造背景解释为具较强构造活动的被动大陆边缘环境。“南华纪”中期盆地进一步伸展，沿桂北—湘西形成大量的低钙铝质、强碱-碱质的碱性玄武岩类，属于板内裂谷环境。至此，盆地完成由挤压造山—初始裂解—全面伸展的体制转换，盆地进入稳定发展阶段，直至震旦纪初的广泛海侵，淹没碳酸盐台地形成。
关键词：火山岩；盆地演化；“南华纪”；扬子东南缘
MA Hui-ying1, SUN Hai-qing1, XIE Wei2
(1. Hunan Institute of Geological Survey, Changsha 410116, China;
2. School of Geosciences and Info-Physics, Central South University, Changsha 410083, China)
Abstract:The geological and geochemical characteristics of the volcanic intrusive basic-ultrabasic complex in the central section of the Jiangnan Orogen in Hunan—Guizhou—Guangxi region were studied. The results indicate that the basement volcanic rocks of sedimentary basin in Nanhuaian period of Proterozoic Era belongs to island arc type. The basement sedimentary formation is active continental margin or continental island arc basin sediments. The initial regional extension built a fault-step continental slope basin in the southeastern margin of Yangtze platform, accepting sub-stable plural clastic deposit from continental margin. This calc-alkaline volcanic rock is initial swifting volcanic rock. The basin’s tectonic setting is passive continental margin. In middle Nanhuaian period, the basin further extended along northern Guangxi—western Hunan to form a large quantity of alkaline basaltic rock with low calcium aluminum, belonging to intraplate rift environment. So far, the basin transformation has finished from compressive orogeny to initial splitting to full expansion, and then the basin began to develop steadily until the wildly transgression in early Sinian Era and submerged carbonate platform formed.
Key words:volcanic rocks; basin evolution; Nanhuaian period; southeastern margin of Yangtze platform
