准噶尔盆地南缘晚白垩世东沟组沉积充填特征及环境分析

Sedimentary Filling Characteristics and Environmental Analysis of Late Cretaceous Donggou Formation in Southern Margin of Junggar Basin

通过野外实地调查、沉积岩石学、岩相学、粒度分析和C-O同位素等研究手段,查明东沟组沉积特征和沉积环境。准噶尔盆地南缘晚白垩世东沟组为一套陆上碎屑沉积,岩石颜色主要为砖红色,岩性以砾岩、砂岩和粉砂岩为主,沉积环境为辫状河沉积。河床亚相水动力较强,沉积较多粗碎屑物质,泛滥平原亚相水动力较弱,多沉积细碎屑物质,物源来自再旋回造山带和晚古生代岩浆弧。东沟组砾岩多集中分布在东沟组中部,该时期北天山抬升较快,剥蚀搬运较多粗碎屑物,东沟组岩石在温度较高条件下固结成岩。准噶尔盆地南缘晚白垩世东沟组沉积填充特征及环境分析,为研究晚白垩世沉积演化特征提供了依据,并为准噶尔盆地与北天山盆山耦合关系提供了翔实资料。

Through field investigation,sedimentary petrology,lithofacies,grain size analysis and C-O isotope,the sedi-mentary characteristics and sedimentary environment of Donggou Formation are identified.The Late Cretaceous Dong-gou Formation in the southern margin of Junggar Basin is a set of onshore clastic deposits.The rock color is mainly brick red.The lithologies are mainly conglomerate,sandstone and siltstone.The sedimentary environment is braided riv-er deposits.The river bed subfacies has strong hydrodynamic force and more coarse clastic materials.The flood plain subfacies has weak hydrodynamic force and more fine clastic materials.The provenances are recycled orogenic belt and Late Paleozoic magmatic arc.The conglomerates of the Donggou Formation are mostly concentrated in the middle of the Donggou Formation,indicating that the northern Tianshan uplifted rapidly during this period,and eroded and transported more coarse clastic materials.The rocks of Donggou Formation are consolidated under high temperature.Sedimentary filling characteristics and environmental analysis of the Late Cretaceous Donggou Formation in the southern margin of Junggar Basin provide a basis for studying the sedimentary evolution characteristics of Late Cretaceous and detailed data for the coupling relationship between Junggar Basin and North Tianshan Basin.