新疆构造手风琴式开合演化的基本特点

THE BASIC FEATURES OF THE ACCORDION-STYLE OPENING-CLOSING EVOLUTION OF STRUCTURES IN XINJIANG

摘要: 新疆手风琴式开合的判别标志明显。开合历史分为前震旦纪、古生代和中、新生代三大阶段。开合演化都是在前期陆壳基底上,经开裂而形成再生地槽,由裂谷进一步发展成为有限洋盆,而后又逐步聚合形成新的陆壳。其总的发展过程是古陆壳（古克拉通）→裂谷→有限洋盆→新陆壳（新地台）→拉伸推覆→盆山。

Abstract: There are definite criteria for determining the accordion-style opening and closing of structures in Xinjiang. The opening and closing history may involve three major stages: pre-Sinian, Paleozoic and Meso-Cenozoic. The opening-closing forms and features of the three stages are notably different. The Paleozoic stage （from Sinian to Early Permian） involves six cycles of opening-closing. Generally the opening-closing progressed from north to south. The opening-closing is characterized by polycyclicity, unequilibrium, orientation, migration, duality and limitation. The opening-closing evolution is described as follows: the continental crustal basement was opened to form a regenerated geosyncline; the rift further developed into a restricted ocanic basin, which later converged to form new continental crust. The general process of development was paleo-crust （paleo-craton）→rift→restricted oceanic basin→ new contiental crust （new platform）→extensional nappe→basin-and-mountain.