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本文利用裂变径迹方法探讨阿尔金断裂中段吐拉-肃北之间隆升和剥露过程。古生代花岗岩和侏罗系沉积岩的磷灰石裂变径迹年龄介于107.2±9.0Ma到14.1±1.3Ma之间,明显小于其侵位年龄或者沉积年龄。自西部的吐拉到东端的肃北,磷灰石裂变径迹年龄逐渐升高,从14.1±1.3Ma增加到107.2±9.0Ma。花岗岩和侏罗系砂岩的磷灰石裂变径迹模拟结果表明,阿尔金断裂南侧地质体经历了两阶段的快速冷却过程,早期为33Ma左右,晚期为8Ma左右;阿尔金断裂北侧经历了晚白垩世开始的相对缓慢的冷却过程以及8Ma以来快速冷却事件。阿尔金断裂南北两侧的地质体的裂变径迹年龄和热历史略有差异,可能反映阿尔金断裂的影响。33Ma左右的快速冷却事件可能是阿尔金断裂活动引起的快速去顶作用的开始,这一事件对应了印度和欧亚板块碰撞。8Ma左右的冷却事件,与阿尔金山地区盆地内的快速沉积过程相一致,同时可能是青藏高原抬升与侧向生长在本区的响应。
In this paper, the fission track method is used to investigate the process of uplifting and exfoliation between Tula-Subei in the middle of Altyn Tagh fault. The ages of apatite fission track of Paleozoic granites and Jurassic sedimentary rocks are between 107.2 ± 9.0Ma and 14.1 ± 1.3Ma, which are obviously smaller than their emplacement age or sedimentary age. The age of apatite fission track gradually increases from Tula to the east of Su-Bei in western China, from 14.1 ± 1.3Ma to 107.2 ± 9.0Ma. The results of apatite fission track simulation of granite and Jurassic sandstone show that the geological body in the south of Altyn Tagh fault underwent two stages of rapid cooling process, with an early age of about 33Ma and a late age of about 8Ma. The northern side of the Altyn Tagh fault experienced The relatively slow cooling process since Late Cretaceous and the rapid cooling events since 8Ma. The fission track age and thermal history of the geologic bodies on the north and south sides of the Altyn Tagh fault are slightly different and may reflect the influence of the Altun fault. The rapid cooling event of about 33 Ma may be the start of the rapid de-toping effect caused by Altyn Tagh fault activity, which corresponds to the plate collision between India and Eurasia. The cooling event of about 8 Ma coincides with the rapid deposition process in the basin in the Altun Mountains and may also be the response of the Tibetan Plateau uplift and lateral growth in this area.