焉耆中生代原型盆地沉积演化特征

Characteristics of Sedimentary Evolution in Yanqi Mesozoic Prototype Basin.

从中生代沉积古气候、古地势、古沉积边界、湖泊沉积基准面、沉积沉降中心、沉积体系等6个方面的变化,论述了焉耆中生代原型盆地沉积演化特征。湖泊沉积基准面于中-晚三叠世、早侏罗世晚期两次升高,形成了中-晚三叠世、早-中侏罗世早期、中侏罗世晚期—晚侏罗世早期三大旋回。从三叠纪到中侏罗世早期,从盆地边缘到盆地中心沉积体系基本为冲积扇或河流(潮湿扇)—辫状河—曲流河—滨浅湖沉积体系;中侏罗世中期为河流沉积体系。

This paper discussed the characteristics of palaeoclimate variation,paleotopography evolution,pale-odeposit boundary change,rise and fall and deposition of lacustrine deposit datum level,migration of subsiding center and sedimentary system evolution in Yanqi Mesozoic prototype basin.Since the lacustrine deposit datum level occurred twice rising in Middle-Late Triassic and late of Early Jurassic,three sedimentary cycles,i.e.Middle-Late Triassic,early of Early-Middle Jurassic and late of Middle Jurassic-early of Late Jurassic,were formed in the basin.During Triassic to early of Middle Jurassic,a sedimentary system composed of alluvial apron or stream(humid fan)-braided stream-mean-dering stream-shallow shore lake appeared from margin to center of basin;while in the mid epoch of Middle Jurassic stream sedimentary system occurred.