摘要： 作为北天山造山带内的中生代小型山间盆地,后峡盆地的构造属性及成因演化反映了天山造山带的构造演化历史,是认识天山地区陆块拼合、盆山耦合的重要窗口。文中综合利用野外踏勘、地震解释、平衡剖面恢复等研究手段,对北天山后峡盆地地质特征及其成因演化进行了系统研究。结果表明: (1)天山是后峡盆地侏罗纪的重要物源区,该时期石炭系基底仅为1个水下低突起,并未隆升成山而分隔盆地南、北的侏罗系,现今的后峡残留山间盆地是后期构造运动所致;(2)后峡盆地的形成经历了伸展—挤压的复合应力背景,早侏罗世—中侏罗世早期的弱伸展作用形成断陷盆地,晚侏罗世的强烈挤压作用改造了先前的伸展构造并使盆地定型,喜马拉雅构造期的强烈挤压改造主要表现为地层的抬升剥蚀和构造幅度的变化。该研究成果对明确天山造山带的构造演化及指导相邻盆地油气勘探具有重要意义。

关键词: 地层特征, 构造特征, 沉积物源, 成因演化, 后峡盆地, 天山造山带

Abstract: The Houxia Basin,which is a small intermontane basin of the northern Tianshan orogenic belt in the Mesozoic,whose structural characteristics and genetic evolution are critical to understand the tectonic evolution,collision of the landmass,and basin-orogen coupling relationship in the Tianshan region. In this paper,the geological features and genetic evolution of Houxia Basin were systematically studied by means of field survey,seismic interpretation,and balanced section restoration. We found that: (1)the North Tianshan Mountain provided an important provenance to the Houxia Basin during the Jurassic. At that time,the Carboniferous basement was an underwater low bulge,which did not rise into mountains that could have separated the north and south Jurassic strata. The present residual intermountain basin in the Houxia area resulted from the separation of the later tectonics;(2)the Houxia Basin experienced the complex extension-extrusion stresses. Weak extension between early and middle Jurassic resulted in a graben basin. Strong compression in the Late Jurassic and during the Himalayan period resulted in uplift and erosion of strata and structural amplitude changes. The findings are of great significance to clarify the tectonic evolution of the Tianshan orogenic belt and can guide the oil and gas exploration in adjacent sedimentary basins.

Key words: formation features, tectonic features, sedimentary source, genetic evolution, Houxia Basin, Tianshan Orogenic Belt

中图分类号: 

• P542