中文摘要：

在详细观察描述砂岩宏观特征的基础上,对贡觉组碎屑岩骨架组分、常量元素变化规律进行分析,研究了该地区砂岩的岩石学和物源特征,并指出囊谦盆地的沉积序列由下而上（Eg1~Eg5）具砂岩成分成熟度由差变好再变差的趋势。物源演变趋势分析揭示,沉积早期盆地北、西北部的构造运动强烈,为第二段（Eg2）沉积时期提供成熟度很低的碎屑物质,而第一段（Eg1）至第二段（Eg2）沉积时期长石含量降低而岩屑含量递增,构造强度逐渐增强,冲积扇-河流相处于发育阶段;第三段（Eg3）层序发育时,构造运动逐渐减弱,长石含量增高而岩屑含量逐渐降低,但盆地西北、北部继续遭受强烈剥蚀,东部和南部则下降接受沉积,并伴有岩浆活动,湖泊层序发育达到顶峰;第四段（Eg4）和第五段（Eg5）层序沉积时转而接受过渡型再旋回造山带区,长石含量先增加后降低而岩屑含量先降低后增加。

英文摘要：

Nangqen basin is a typical representative of the medium-mini-type Paleogene basins controlled by local NNW-treading faults distributed along Jinsha River-Red River belt on the northeastern margin of Qinghai-Tibet plateau.Gonjo Formation is perfectly developed and dominated by a set of thick-bedded,purplish red,red terrigenous clastic rock formation containing gypsum rock in association with large-scale high potassium rocks in Nangqen basin.Combined with results of field geological investigation and analysis and determination of samples as well as quantitative studies of the sandstone framework detrital composition of the Paleogene strata,the authors systematically analyzed petrologic characteristics of the sandstones of the Gonjo Formation in Nangqen basin in the framework of the basin evolution.According to the analysis of geochemical features of sandstones of the Gonjo Formation,the characteristics of paleoclimate,paleoenvironment and provenance in the study area were revealed.For sandstones in different strata of Gonjo Formation,systemic sampling and determination were conducted,the detrital composition of sandstone was observed under a microscope,and the sandstone framework detrital composition was calculated and analyzed using the line-count method.The quantitative data of the clastic constituents not only constitute the nomenclature foundation of sandstones but also provide an important basis for understanding the nature of the sedimentary basin and estimating the provenance region.Meanwhile,the data processing methods included the genetic classification of the clastic constituents and the triangular graphical analysis.According to the theoretical analysis and the results of Dickinson W.R,the authors analyzed and discussed the relationship between the provenance and the plate tectonics of clastic rocks of Gonjo Formation.The results indicate that the sandstones of Gonjo Formation belong to recycling orogenic belt area,and only the samples of Eg2 came from polycyclic orogenic belt area and cratonic interior.