新疆东天山觉洛塔格地区梧桐窝子岩组构造环境探讨

DISCUSSION ON THE STRUCTURAL ENVIRONMENT OF THE WOTONGWOZI GROUPAT JUE-LUO-TA-GE REGION IN THE EAST TIANSHAN,XINJIANG

梧桐窝子岩组为晚石炭世海底扩张喷发形成的一套中基性火山岩-细碧岩-硅质岩-碳酸盐岩建造.通过对剖面组合特征研究,认为该岩组是由辉长岩-辉绿岩-玄武岩-放射虫硅质岩组成的洋壳残片和岛弧物质的安山岩、凝灰岩、沉凝灰岩及弧前沉积的凝灰质砂岩、钙质砂岩、微晶大理岩、正常碎屑岩(糜棱岩、千糜岩)3部分组成的蛇绿混杂岩带.三者所处构造背景、沉积环境不同,在岩石学、岩石化学及岩石地球化学特征上亦有较大差异.

The Wutongwozi Group consists of basic volcanics, detailed green rock, quartzites and carbonates, which were formed during sea floor spreading in the Late Carboniferous. According to detailed sections, this group of rocks was compounded by three parts of contaminated ophiolite. They are i) ocean shell relicts of gabbro, basalt, and silicate; ii) island arc material such as andesite, tuff and sediment-tuff and iii) sedimentary rocks before the arc formed including sandstone, calcium sandstone, microlitic Dali rock, and the normal fragmental rock (mylonite, phyllite). These three parts have different sources and sedimentary environments, and are also very different in petrology, rock chemistry and geochemistry.