论文部分内容阅读
为华北克拉通缺失晚奥陶世—早石炭世地层的记录,岩相古地理解释为一个古陆,我们研究认为它可能是一个高地。寒武—奥陶纪时华北克拉通为广泛的浅海相碳酸盐岩沉积,指示为海台地势,地壳厚度<30km。志留—泥盆纪时为一高地,地壳厚约>40km。晚石炭世发育海相、海陆交互相沉积,地壳厚度也在30km左右。高地的形成与构造挤压有关,根据区域地质资料和有限的花岗岩资料推测,在志留纪时,水平的挤压力可能来自西部,西部有埃达克型和喜马拉雅型花岗岩出露,指示南祁连与华北发生了碰撞。晚期泥盆纪时的挤压力源于北方,北方有零星埃达克岩出露,推测与古亚洲洋地体之间的弧陆碰撞有关。志留—泥盆纪的华北高地属于冷高地,没有伴随花岗岩的大量活动,因此,高地的垮塌与拆沉无关,可能与晚石炭世时的地壳伸展减薄有关,地壳厚度减薄了大约10km。志留—泥盆纪的华北高地比中国东部高原面积还大,也许是中国地质历史上最大的一个高地,研究这个冷高地形成和破坏的机制及其对全球构造、气候、环境的影响等具有重要的意义。
For the record of missing Late Ordovician-Early Carboniferous stratigraphy in North China Craton, the lithofacies palaeogeography was interpreted as an ancient land, and our research suggests it may be a highland. Cambrian - Ordovician time North China craton for a wide range of shallow marine carbonate deposition, indicating that the topography of the sea, the crust thickness <30km. The Silurian - Devonian period was a highland with a crustal thickness of> 40km. Late Carboniferous developed marine facies, sea and land interaction facies deposition, the crust thickness is about 30km. The formation of the highlands is related to tectonic extrusion. According to the regional geological data and the limited granite data, it is speculated that during the Silurian, horizontal compressional forces may come from the western part, and Adak and Himalayan-type granites show up in the west, Qilian collided with North China. Late Devonian compressions originated in the north and sporadic adakites were exposed in the north, suggesting that they were related to the arc-continent collision between the ancient Asian oceanic terranes. The Silurian-Devonian North China plateau is a cold plateau with no extensive granite activity. Therefore, the collapse of the plateau has nothing to do with detachment, which may be related to the extension and thinning of the crust during the Late Carboniferous. The thickness of the crust is reduced by about 10 km . The Silurian-Devonian North China plateau is larger than the plateau in eastern China. It may be the largest highland in China’s geologic history to study the mechanism of the formation and destruction of the cold plateau and its impact on the global tectonics, climate and environment Significance.