海拉尔盆地东明凹陷明D2井白垩系沉积特征及沉积环境分析  

Analysis of Cretaceous sedimentary characteristics and environment from Well MD2 in Dongming depression,Hailar Basin

作　　者：侯艳平[1] 任延广[1] 孙丽[1] 张海军[1] 吴海波[1] 彭威[1] 李敬生[1] HOU Yan-ping;REN Yan-guang;SUN Li;ZHANG Hai-jun;WU Hai-bo;PENG Wei;LI Jing-sheng(Exploration and Development Institute,Daqing Oilfield Co.Ltd.,Daqing 163712,Heilongjiang,China)

机构地区：[1]大庆油田有限责任公司勘探开发研究院,黑龙江大庆163712

出　　处：《世界地质》2020年第2期332-343,共12页World Geology

基　　金：国家科技重大专项(2016E-0202)。

摘　　要：为了解白垩系湖相沉积物中蕴含的古气候信息,探明古气候变化和沉积作用耦合关系,笔者对海拉尔盆地东明凹陷明D2井铜钵庙组、南屯组和大磨拐河组岩芯开展了系统观察和沉积相分析。岩芯薄片观察和X-射线衍射全岩矿物鉴定识别出泥岩、粉砂质泥岩、泥质粉砂岩、粉砂岩、砂岩、砾岩、泥砾岩、煤、凝灰岩和菱铁矿层等十多种岩性,以此建立明D2井岩芯地质综合剖面,分析本区环境演化特征。沉积相研究表明,铜钵庙组以多期辫状河沉积为主,多期河道砂砾岩叠置,或河道砂砾岩上覆细粒泛滥平原沉积;南屯组和大磨拐河组以泥岩、粉砂质泥岩、泥质粉砂岩和粉砂岩等细粒沉积岩为主,主要发育深湖-半深湖亚相与扇三角洲前缘亚相-前扇三角洲亚相,细粒沉积岩中普遍含有菱铁矿,含量3%~10%,同时识别出40层共5.9 m厚的菱铁矿层,表明这一时期东明凹陷以潮湿的气候为主。气候湿暖且植被发育,物理风化作用减弱而导致碎屑沉积物输入减少,促进自生矿物的沉淀,从而形成富有机质富菱铁矿的细粒沉积岩。Cores of Tongbomiao Formation,Nantun Formation and Damoguaihe Formation in Well MD2,Dongming depression,Hailar Basin are systematically described and sedimentary facies are analyzed to understand the crucial paleoclimate information from Cretaceous lacustrine deposits and to define the relationship between climate variation and deposition.Thin-section observation and X-ray diffraction of whole rock minerals identify more than ten kinds of lithologies,including mudstone,silty mudstone,muddy siltstone,siltstone,sandstone,conglomerate,muddy conglomerate,coal,tuff and siderite beds.Based on these lithologies,the authors establish a comprehensive geological profile of Well MD2 and analyze the environmental evolution.The sedimentary facies analysis shows that the Tongbomiao Formation is predominated by multistage braided channel deposits.The channel conglomerates are overlapped or overlain by fine-grained flood plain sediments.In contrast,the Nantun and Damoguaihe formations are characterized by fine-grained deposits composed of mudstone,silty mudstone,muddy siltstone and siltstone,indicating semi-deep,deep lacustrine,fan delta front and pro-fan delta environments.The fine-grained deposits commonly contain siderite minerals,with the content ranging between 3%~10%.40 siderite beds with total thickness of 5.9 m are identified among the fine-grained deposits,suggesting a wet-dominated climate during this period in Dongming depression.Humid climate and flourishing vegetation weaken the physical weathering resulting in low amounts of sediment supply and promote the precipitation of authigenic minerals,forming the organic and siderite-rich fine-grained sediments.

关 键 词：海拉尔盆地 东明凹陷 明D2井 白垩系 沉积特征 沉积环境 

分 类 号：P534.53[天文地球—古生物学与地层学] P575[天文地球—地质学]