咸化断陷湖盆混积岩特征及沉积模式——以金湖凹陷阜二段为例

为明确咸化断陷湖盆环境下混积岩的沉积特征，通过岩心观察、薄片鉴定、X射线衍射全岩矿物分析等技术手段，对金湖凹陷古近系阜二段混积岩开展研究。结果表明：①混积岩以长英质矿物、碳酸盐矿物与黏土矿物为主，可划分为长英质混积岩、灰（云）质混积岩、黏土质混积岩和正混积岩等4类；②综合苏北盆地金湖凹陷咸化断陷湖盆的沉积特征，建立了“浅水到深水，多级控制”的混合沉积模式。在咸化断陷湖盆中，混积岩发育主要受控于陆源碎屑供给、断层活动、沉积环境变化等因素。活动断层强度增大，陆源碎屑向湖盆中央供给强度增强，混积岩沉积类型以母源混合沉积、间断混合沉积为主；沉积环境发生变化，断层活动趋于稳定，湖侵作用增强，陆源碎屑供给范围受限，混积岩以相缘混合沉积类型为主。该研究成果对陆相咸化断陷湖盆深水致密储层的油气勘探具有指导意义。

Characteristics and sedimentary models of diamictite in saline faulted lacustrine basin:a case study of Fu 2 member in Jinhu Sag,Subei Basin

In order to clarify the sedimentary characteristics of diamictiteinsaline faulted lacustrine basin,by means of core observation,core slice identification,X-ray diffraction to whole-rock mineral analysis test and other technical means,the diamictite of the second member of Eocene Funing Formation in Jinhu Sag was studied.The results show that:(1)Diamictite is dominated by feldspar quartz minerals,calcite(dolomite)minerals and clay minerals.It can be divided into four types:feldspar-quartz diamictite,calcite(dolomite)diamictite,clayey diamictite and pure-diamictite.(2)According to the sedimentary characteristics of the saline faulted lacustrine basin in the Jinhu Sag,a mixed sedimentary model of"shallow water to deep water and multi-factor control"was established.In the saline faulted lacustrine basin,the deposition of diamictite is mainly controlled by source supply,fault activityand sedimentary environment changes.Under the active fault control,the terrigenous debris is continuously supplied to the interior of the lacustrine basin,and the sedimentary type is dominated by interfacial mixed sedimentation and intermittent mixed sedimentation.As the fault activity tends to stable,sedimentary environment changes,transgression increases,the sediment of terrigenous debris is limited,and the sedimentary type is dominated by maternal mixed sedimentation.The research results have certain enlightenment significance for the exploration of deep-water tight reservoirs in the continental lacustrine basin.