欢迎访问《高校地质学报》官方网站,今天是
分享到:

J4

• 文章目录 •    下一篇

北美西部与中国东南部盆岭构造对比研究

舒良树,王德滋   

  1. 南京大学地球科学系,南京 210093
  • 收稿日期:2006-03-20 修回日期:2006-03-20 出版日期:2006-03-20 发布日期:2006-03-20

A Comparison Study of Basin and Range Tectonics in the Western North America and Southeastern China

SHU Liang-shu, WANG De-zi   

  1. Department of Earth Sciences, Nanjing University, Nanjing 210093, China
  • Received:2006-03-20 Revised:2006-03-20 Online:2006-03-20 Published:2006-03-20

摘要: 北美西部与中国东南部盆地与山岭构造是太平洋东西两岸独特的地质地貌景观,它们的形成与演化有着其特定的时间、空间、物质条件和深刻的构造背景。分别阐述了这两个地区盆岭构造的地质背景、构造单元划分及其构造岩浆组合、基底与深部构造特征、不同类型盆地与花岗岩山岭的时空演化、成因机制、耦合样式、演化历史,对这两个盆岭地区变质核杂岩的几何学、岩石学、年代学、成因动力学进行了分析。基本地质特征研究表明,太平洋东西两岸盆岭构造存在许多相似处,包括:(1)中、新生代均属太平洋构造域,均受太平洋构造体制制约;(2)受古太平洋板块俯冲影响的开始时间相同,均为中侏罗世,形成的活动大陆边缘宽度相近;(3)板块俯冲角度均在早、晚白垩世之交发生变化,从低角度转为高角度,导致弧后进一步伸展垮塌、岩石圈减薄;(4)均程度不等地发育了科迪勒拉型伸展构造和变质核杂岩;(5)伸展盆地与花岗岩山岭的形成背景相似,盆岭空间相伴,成因相关,时间相近。正是这些相似性,使中国东南部盆岭构造和北美西部盆岭构造的对比成为可能。同时,两岸盆岭构造也存在若干差异,如:(1)岩石组合差异;(2)形成时代差异;(3)地幔柱活动差异;(4)俯冲带位置迁移差异;(5)基底固结程度与变质核杂岩差异。这些差异,构成了太平洋东西两岸盆岭构造的不同地域特色和地质地貌景观。

Abstract: The basin and range tectonics in both western North America and Southeastern China are a distinctive geologic and geomorphologic scene.Their formation and evolution possess profound geologic settings and tempral-spatial-material conditions. This paper studies the geologic setting, tectonic units and tectono-magmatic assemblages, basement and deep-seated structures, temporal-spatial relation, formation mechanism, coupling patterns and evolutional history of basin and granitic ranges in these two regions, analyzes the geometry, petrography, geochronology and petrogenesis of metamorphic core complexes in the two basin and range regions. Our studies suggest that some principal similarities occur in the basin and range zones on both sides of Pacific Ocean, including(1)Two regions belong to Pacific tectonic regime during Mesozoic-Cenozoic and are controlled by Pacific system;(2)The beginning time influenced by Pacific plate subduction is the same, the Middle Jurassic,with close width of active continental margin;(3)The time of subduction angle change from gentle to steep is the same, about 100 Ma, which further caused back-arc extension-collapse tectonics and lithospheric thinning; (4) The Cordilleran-type extensional tectonics and metamorphic core complexes are developed well in both regions; (5) The extensional basins and granitic ranges in both sides of the Pacific share similar forming geotectionic setting,their spatioal coupling and genetic relation. At the same time, some differences exist in these two regions, including (1) difference in magmatic assemblages; (2) difference in forming age of basin and range tectonics; (3) difference in activity of mantle plume; (4) difference in migration of subduction zone; (5) difference in solidification degree of basement and metamorphic core complexes .