【摘要】 对地球物理位场进行处理分析的结果表明 ,在云南三江造山带近南—北向为主的构造框架背景中 ,存在有多处与之相互正交或斜交的近东—西向构造 ,这些近东西方向展布的构造呈现出隐伏或深部构造特点。在布格重力异常影像中表现为大波长、幅值低的深部构造带特征 ;地质上表现为一系列近东—西向出现的断裂、岩体和矿床的成带分布 ;遥感解译结果则表现出在三江造山带内有多条平行展布的浅埋深东西向隐伏构造带。本文结合地质、地球物理地震波速信息等资料 ,对该区近东西向构造特征及分布规律进行探讨后提出三江地区存在的近东西—向展布的近东西向构造可能是青藏高原主碰撞造山后 ,各块体物质向东南挤出的深部物质流变构造的反映 ,也可能是在三江造山带挤压碰撞及走滑拉张环境下的伸展构造或老构造的再活化。它的形成机制可能类似于青藏高原南部南—北向伸展构造 (裂谷 )。近东—西向构造的深入研究和成因再认识对于深入分析云南三江地区复杂的地质构造 ,区域地壳演化历史 ,特别对是重新认识区域成矿规律、指导找矿具有重要意义更多还原

【Abstract】 An analysis of the geophysical field shows that there are several nearly east—west structures in the Sanjiang (i.e. three rivers: the Jinsha, Nujiang and Lancang rivers) orogenic zone. These east—west structures are buried and deep lying, showing characteristics of the long wave-length and low amplitude in the Bouguer gravity anomaly map. They are reflected as a series of nearly east—west faults, plutons and ore deposits on the geological map, and as a number of shallow-buried parallel structure zones on the remote sensing images. Based on data of geology, geophysics and seismic velocity, it is suggested that these east—west structures may be the rheomorphic structures of deep materials squeezed out southeastward from the blocks after the collision orogeny of the Qinghai—Tibet Plateau. Or they may have resulted from the re-activation of the extensional or old structures in the compression—collision and strike-slip settings of the Sanjiang orogenic zone. They may have the same formation mechanism as the north—south extensional structures (rifts) in the southern Qinghai—Tibet Plateau.更多还原