岌岌湖现代水下加积扇与东坷里三角洲层序地层学意义比较  

Comparison of Sequence Stratigraphic Significance between East Coulee Delta and Jijihu Modern Subaqueous Aggradational Fan(SAF)

作　　者：李绍虎[1,2] 周继兵 贾丽春 王昭辉 李宝庆[1] 马风华[1] 王程[1] 

机构地区：[1]中国地质大学资源学院,武汉430074 [2]中国地质大学构造与油气资源教育部重点实验室,武汉430074 [3]新疆地矿局第九地质大队,乌鲁木齐830000 [4]山西省第三地质工程勘察院,山西榆次030600

出　　处：《沉积学报》2011年第4期613-621,共9页Acta Sedimentologica Sinica

摘　　要：对比研究东坷里三角洲(East Coulee Delta)和岌岌湖现代水下加积扇的层序地层学意义,认为:(1)东坷里三角洲发育LST—TST组合、FSST组合,其分属两个层序;(2)岌岌湖SAF发育FSST—LST—TST组合、FSST组合,亦分属两个层序;(3)两个陆相实例证明最大水泛面之后均未有高位体系域出现,可能代表非海相与海相背景之间的差异。论文对复合层序边界等问题进行了讨论。Jijihu modern subaqueous aggradational fan（SAF） in Jungar Basin,Xinjiang Province,China,is 24m arch length and 10m radii.Jijihu SAF consists of alluvial fan 1,unit A（SAF）,unit B（slop beds,retrogradational beds and flooding mud-sand beds）,unit C（alluvial fan 2） and unit D（alluvial fan 3）,which have been documented by Li by observing and digging during one week in the condition of 40 degree centigrade Junggar Basin after desert flood in 2007 summery time. Field observation directs as followings：（1） Exception of alluvial fan 1,Jijihu SAF has the similar stacking patterns with East Coulee Delta（Posamentier et al.,1992）.Especially,there is a 1cm red mud bed between alluvial fan 1 and SAF,directing that they belong to continuous sedimentation documented by digging.Although SAF covers alluvial fan 1 in the Northern side of pool,another isochronous unit opposite Jijihu SAF about 10m away in the Southern side directs the lowest alluvial fan clearly.Thereby,alluvial fan 1 becomes the lowest unit that may be interpreted as falling stage systems tract（FSST） during forced regression associated with incision,showing that pond water reaches lowest level.（2） Subsequently,pond level begins to rise,sediments supply exceeds the rate of level rise,and SAF（unit A） develops during normal regression,so that SAF may be interpreted as lowstand systems tract（LST） according to present scenario of sequence stratigraphy.（3） Associated with level rise exceeds sediments supply,unit B develops as follows：Firstly,fine mud-sands begin to accumulate in front of SAF forming slope beds（i.e.,healing phase wedge of Posamentiaer and Allen（1993））.Secondly,coarse sediments such as gravels deposits on the top of SAF,directing retrogression stacking patterns landward.Finely,level reaches to maximum,flooding mud-sand beds begin to precipitate under hot wind in the Junggar Desert.Therefore,three parts（unit B） above may record as transgressive systems tract（TST） during transgression.（4） T

关 键 词：岌岌湖现代水下加积扇 东坷里三角洲 层序地层学 下降期体系域 避免高位正常海退 

分 类 号：P539.2[天文地球—古生物学与地层学]