青海赛多浦岗日地区雀莫错组粒度特征及沉积环境

在羌塘盆地北部赛多浦岗日地区,侏罗纪雁石坪群下部雀莫错组有大面积的出露,岩性主要为一套碎屑岩夹碳酸盐岩。其下、上段的岩石薄片鉴定为砂岩及粉砂岩。雀莫错组上下段的粒度分析均反映岩石组分由跳跃组分和悬浮组分构成,并且跳跃组分总体的含量占主导地位,反映样品的分选较好。最终认为雀莫错组的沉积环境总体是三角洲相,以三角洲前缘相的砂岩、粉砂岩沉积为主,砂岩类型主要为细粒岩屑砂岩、长石砂岩、石英砂岩等;其中下段是三角洲前缘相靠近前三角洲的部分,上段是三角洲前缘相靠近三角洲平原相的部分。

Characteristic of granularity of Quemocuo Formation in Saiduopugangri region of Qinghai and its sedimentary environment

In Saiduopugangri region of northern Qiangtang Basin，the Quemocuo Formation of lower Jurassic Yanshiping Group is widely exposed． The formation mainly consists of a set of clastic rocks intercalated with car- bonate rocks． The clastic recks are sandstone and siltstone． The granularity analysis of Quemocuo Formation reflects that rock components are made up of jumping components and suspending components， and the former is main com- ponents，indicating that the separation of samples is good． Finally， the authors consider that the overall depositional environment of Quemocuo Formation shows delta facies，in which the main facies are the desposit of sandstone and siltstone of delta- front facies，and the main types of sandstone are detritus sandstone，arkose and quartz sandstone． The lower member of the formation shows the delta- front facies which are near the prodelta， while the upper member of the formation shows the delta- front facies which are near the delta plain facies．