“源-汇”体系主导下的断陷湖盆陡坡带扇三角洲发育 模式探讨：以苏丹Muglad盆地Fula凹陷为例

断陷湖盆陡坡带粗粒三角洲地质研究对于油气勘探至关重要。通过岩心、测井和地震资料综合分析，在苏丹Muglad 盆地Fula凹陷陡坡带识别出两类扇三角洲，分别为Jake区锥状扇三角洲和Keyi区片状扇三角洲。Jake区物源供给充足，早 白垩世持续供源，形成的锥状扇三角洲岩石颗粒较粗，分选-磨圆差，砂体厚度较厚，分布范围较广；Keyi区物源供给不 足，形成的片状扇三角洲岩石颗粒较细，分选-磨圆更好，砂体厚度较薄，分布范围有限。文章将“源-汇”体系理论引入 到陡坡带粗粒三角洲研究中，通过对母岩剥蚀供源、搬运以及汇聚条件分析，对两类扇三角洲进行成因解释，并建立相应 模式，同时指出，“源-汇”体系只有作为一个整体研究，才能较好地预测断陷湖盆陡坡带扇三角洲分布。

DiscussionOnDepositionalModelsofFanDeltasinSteepSlopeBelt oftheRiftBasinundertheGuidanceofSource-to-SinkSystem Theory:ACaseStudyfromtheFulaSub-basin,MugladBasin,Sudan

Thecoarse-graineddelta,developedinsteepslopebeltofariftbasin,usuallyplaysanimportantroleinoilandgas exploration.Basedontheanalysisofcore,loggingandseismicdata,twotypesoffandeltasarerecognizedinsteepslopebeltinthe FulaSub-basin,MugladBasin,Sudan.Thetaper-shapedfandeltainJakeAreaiscomposedofrelativelycoarse-grainedsandstoneand conglomeratewithmorethicknessandwidedistribution.Thesortingandgroundingarepoorinthistypeoffandeltadeposition.Onthe contrary,thegrainismuchfinerintheplatyfandeltainKeyiAreawhilethesortingandgroundingarerelativelygood.Thesandbody isthinandlimitedspread.ThesourceissufficientinJakeAreabutinsufficientinKeyiAreaduringtheEarlyCretaceous.Thispaper bringsthetheoryofsource-to-sinksystemintothefandeltaresearch.Throughthestudyaboutclasticsupplying,transportingand accumulating,theexplanationofthesetwotypesoffandeltasaregiven,andthedepositionalmodelsarebuilt.Onlyberegardedasa whole,thesource-to-sinksystemstudycanbeutilizedtopredictthefandeltadepositioninsteepslopebeltoftheriftbasin.