构造活动影响下地质事件沉积序列：以鄂尔多斯盆地延长组长7油层组为例

中晚三叠世，印支运动I幕导致秦岭隆升，同期地震、火山活动频发，在鄂尔多斯湖盆中保存了大量地质事件沉积层。为了认识构造活动影响下地质事件沉积序列，探讨地质历史时期内各类地质事件的耦合关系，从全新的角度认识大型坳陷湖盆的形成和演化过程，笔者等以鄂尔多斯盆地内部及周缘的长7油层组野外露头及钻井岩心中发育的关键事件沉积层为研究对象，对地震事件、浊流事件、火山事件、缺氧事件沉积特征和叠置关系进行研究。研究结果表明：在长7期，湖盆中多种事件沉积类型主要受控于中—晚三叠世秦岭造山运动，构造活动引起湖盆沉降，为事件沉积层的保存提供了条件；火山事件喷发的火山灰降落在湖盆中形成凝灰岩层，同时，也为湖盆缺氧事件创造了条件；沉积层因地震活动形成震积岩，而地震活动又是诱发浊流事件发生的关键因素；这些构造活动影响下的地质事件交替发生，共同构成长7油层组内各类事件沉积层的相互叠置关系。

Sedimentary sequence of geological events under the influence of tectonic activities: A case from Chang 7 oil member of Yanchang Formation in Ordos Basin

In the Middle - Late Triassic, the first episode of Indosinian Orogeny led to the uplift of the Qinling Mountain. In the same period, earthquakes and volcanic activities occurred frequently. A large number of geological event sedimentary layers were preserved in the Ordos Basin. In order to understand the sedimentary sequence of geological events under the influence of tectonic activities, explore the coupling relationship of various geological events in the geological history, and understand the formation and evolution process of large depression lake basin from a new perspective.Methods:Based on the Chang 7 oil member as the research object, and analyzes the sedimentary characteristics of seismites, turbidites, tuffs and organic rich shale corresponding to seismic events, turbidity events, volcanic events and anoxic events and studied their superimposed relationships.Results: In the Chang-7 period, various event sedimentary sequences in the lake basin were controlled by the Qinling orogeny in the Middle - Late Triassic. The subsidence of the lake basin caused by tectonic activities provided conditions for the preservation of event sedimentary layers. Volcanic eruption volcanic ash formed tuffaceous strata, which created conditions for anoxic events in the lake basin. Seismic events formed seismites and led to turbidity current events.Conclusions:The alternation of these geological events constitutes the result of the superposition of various event sedimentary layers in Chang 7 oil member.