北山蛇绿岩特征及构造属性
Character and Structural Attribute of the Beishan Ophiolite
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摘要: 概述了北山地区4条蛇绿岩带的岩石类型组合及岩石地球化学特征,并结合区域地质情况分析认为:红柳河-牛圈子-洗肠井蛇绿岩带形成于早古生代洋盆环境,特征最接近现代洋壳蛇绿岩,在该带北侧保存有标志活动陆缘的公婆泉-东七一山岛弧火山岩带,南侧保存有标志南北两个板块开裂前伸展拉张的浅海—次深海形成的寒武纪含磷钒铀锰沉积岩系地层,说明该蛇绿岩带指示南北两个板块间裂解与聚合的位置。芨芨台子-小黄山蛇绿岩带分布于公婆泉-东七一山岛弧与星星峡-旱山地块之间,形成于早古生代弧后盆地环境。红石山-百合山-蓬勃山蛇绿岩带和辉铜山-帐房山蛇绿岩带形成于晚古生代裂谷拉张最大化至初始小洋盆出现的阶段,即类似于"红海型"海槽的环境。Abstract: This paper summarizes the assemblege of rock types and geochemical characteristics of four ophiolite belts in Beishan region, and analyzes the the regional geological background conditions. The result shows that the Hongliuhe-Niujuanzi-Xichangjing ophiolite belt was foamed in Early Palaeozoic and is part of the oceanic basin type and quite similar to the present oceanic ophiolite in characteristic. This ophiolite belt indicates the sutureline of the north-south plates because the Gongpoquan-dongqiyishan volcanic rocks in the north belongs to the inland volcanic rock series with active continental margin environment and the shallow sub-sea P-V-Mn-U-bearing sedinentary strata of the Cambrian in the south representing the extended tectonic before the plate becoming divergent.
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Key words:
- ophiolite /
- oceanic basin /
- back-arc basin /
- rift /
- beishan
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