【摘要】 三江特提斯造山带位于青藏高原东南侧,历经古生代-中生代不同特提斯洋开合、复杂增生造山和强烈成矿作用,倍受学界关注。本文应用锆石裂变径迹年代学研究中咱地块-义敦岛弧的构造活动,取得了新的认识,对特提斯演化扩展了时限制约。计获得12件锆石裂变径迹年龄分析结果,年龄变化于165～76Ma之间,并可划分为多个年龄组,即165Ma、144Ma、135～134Ma、126～108Ma、102～89Ma和76Ma。主要揭示新特提斯构造热事件,这些年龄组分别记录了班公湖-怒江洋形成阶段、班公湖-怒江洋开始闭合、雅鲁藏布江洋盆俯冲、班公湖-怒江洋闭合、陆内碰撞和陆内伸展。此时中咱地块-义敦岛弧均处于陆内演化过程。更多还原

【Abstract】 The Sanjiang Tethys orogenic belt is located in the southeastern side of the Qinghai-Tibet Plateau. It has undergone the opening and closing of different Tethys oceans,complex accretive orogeny and strong mineralization from Paleozoic to Mesozoic. In this paper the zircon fission track thermochronology is applied to research on the tectonic activities of Zhongzan terrane and Yidun island arc. It is shown a new understanding about the time limit to the Tethys evolution. Twelve zircon fission track ages were obtained. The ages range from 165 ～ 76 Ma and could be divided into several age groups,i. e.,165 Ma,144 Ma,135 ～ 134 Ma,126 ～ 108 Ma,102 ～89 Ma and 76 Ma. These age groups well reveal the Tethyan tectonic evolution. The 165 Ma and 144 Ma recorded the Bangonghu-Nujiang Ocean forming and the Bangonghu-Nujiang Ocean coming into closure respectively. The 135 ～ 134 Ma and 126 ～ 108 Ma reflect that the Yarlung-Zangbo Ocean started to subducting and then gradually closed. The ocean basin opening-closing was accompanied with volcanic eruption,magma intrusion and ore mineralization. The 102 ～ 89 Ma indicated the time limit of the intracontinental collisions in both Lhasa-Qiangtang terrane and Songpan-Ganzi terrane after the Yarlung-Zangbo Ocean closure. The 76 Ma corresponded to the intracontinental extension. At this time,the Zhongzan terrane and Yidun island arc are in the intracontinental evolution,resulting in large scale of mineralization.更多还原