辽西凌源牛营子盆地晚三叠世--中侏罗世地层层序及区域对比

本文根据重新理清的辽西凌源牛营子盆地晚三叠世-中侏罗世地层层序及时代,讨论其区域地层对比.晚三叠世晚期的邓杖子组是一套崩滑流为主的碳酸盐角砾,其为区域印支期构造运动的造山记录,与京西、冀北杏石口组、辽西北票羊草沟组(坤头菠罗组)可以对比;早侏罗世水泉沟组与京西、冀北南大岭组、辽西北票兴隆沟组层位相当,且各组火山岩时代基本相同;中侏罗世早期郭家店组底部含煤段与京西上窑坡组、冀北下花园组中部、辽西北票组中上部植物组合面貌一致;中侏罗世中期郭家店组砾岩段是燕山期构造变形主幕的产物,北京西山龙门组、冀北下板城下花园组上部、辽西北票海房沟组都是该期的记录,层位相当;辽西中侏罗世中晚期蓝旗组底部的时代为158±1Ma,与京西、冀北髫髻山组安山岩的同位素年龄总体一致.这说明差异较大的燕山板内造山带三叠纪-中侏罗世盆地的沉积记录显示了相似的演化规律.

Late Triassic-Middle Jurassic Stratigraphic Succession in the Niuyingzi Basin ,Lingyuan County,Western Liaoning and the Correlation of Regional Stratigraphic Sequences in the Yanliao Region

This paper discusses the correlation of the regional stratigraphic sequences on the basis of renewed Late Triassic-Middle Jurassic stratigraphic sequences and their ages in Niuyingzi basin of Lingyuan County, western Liaoning Province. The late Upper Triassic Dengzhangzi Formation composed of slump carbonate breccia serves as the record of the Indosinian orogeny, and is correla-table with both Xingshikou Formation in western Beijing and northern Hebei and Yangcaogou Formation (Kuntouboluo Formation) in Beipiao of western Liaoning. The Lower Jurassic Shuiquangou Formation is correlatable with both Nandaling Formation in western Beijing and northern Hebei and Xinlonggou Formation in Beipiao of westeren Liaoning. Dating of the volcanic rocks from those formations yields the similar result. The lower coal-bearing Guojiadian Formation of early Middle Jurassic has similar plant assemblages to both Shangyaopo Formation in western Beijing and Middle Xiahuayuan Formation in northern Hebei as well as to Middle-Upper Bei-piao Formation of Beipiao in western Liaoning. The conglomerate member of middle Middle Jurassic Guojiadian Formation, as the product of the major episode of the Yanshanian movement, is correlatable with both Longmen Formation in the Western Hills, Beijing, and Upper Xiahuayuan Formation of Xiabancheng in northern Hebei and Haifanggou Formation of Beipiao in western Liaoning. Dating of the basement of the middle-late Middle Jurassic Lanqi Formation in western Liaoning gives a zircon SHRIMP U-Pb age of 158±1 Ma, which is similar to that of Tiaojishan Formation in both western Beijing and northern Hebei. The remarkably different sedimentary records of Triassic-Middle Jurassic basins in the intraplate Yanshanian orogenic belt have similar evolutionary characteristics.