徐家围子断陷升平—兴城地区深层火山岩岩性、岩相特征及喷发期次  

Lithology,lithofacies characteristics and eruption stages of deep volcanic rocks in Shengping-Xingcheng area of Xujiaweizi Rift

作　　者：姜冠一 JIANG Guanyi(Exploration and Development Research Institute of Daqing Oilfield Co Ltd, Daqing 163712, 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：《大庆石油地质与开发》2021年第4期9-25,共17页Petroleum Geology & Oilfield Development in Daqing

基　　金：中国石油天然气股份公司重大科技专项“松北深层天然气富集规律、勘探技术研究与规模增储”(2016E-0203)。

摘　　要：徐家围子断陷升平—兴城地区深层火山具多期喷发的特点,造成火山岩岩性、岩相复杂多变,不同期次的火山岩叠置,地震反射特征杂乱等现象,火山喷发旋回期次的识别划分十分困难。通过典型井岩心岩石学和地球化学研究,结合测井曲线和岩心重矿物分析结果,确定了火山岩分类和岩石命名,建立了火山岩岩相类型,揭示了火山岩形成时期的大地构造背景,厘清岩浆活动的热事件序列。研究表明:升平—兴城地区深层火山岩岩石类型主要有酸性的流纹岩、霏细岩、凝灰岩、熔结凝灰岩和火山角砾岩,中性岩类也有发育,都属钙碱性岩类,准铝质的正常岩系列,形成于板内环境;火山岩相划分为溢流相、爆发相、火山沉积相3种相类型8种亚相;火山岩主要有4个喷发旋回,各旋回之间均以沉积夹层、沉火山灰层或风化壳为边界,其中旋回1与旋回2为黏度低、流动性大的中基性岩浆较宁静喷发,小规模分布于兴城鼻状构造西南部,旋回3和旋回4为酸性岩浆喷发,旋回3较旋回1和旋回2规模明显变大,主要分布于兴城鼻状构造的南部,旋回4分布规模最大,广泛分布于升平—兴城地区。The deep-layer volcanoes in Shengping-Xingcheng area of Xujiaweizi Rift are characterized by multi-stage eruption,resulting in complex lithology and lithofacies of volcanic rocks,superimposition of the volcanic rocks in different stages and disorderly seismic reflection characteristics,so it is very difficult to identify and divide the periods of the volcanic eruption cycles.With the help of the studies on core petrology and geochemistry for typical wells,combined with logging curves and analyzed results of core heavy minerals,the classification and nomenclature of the volcanic rocks are determined,the lithofacies types of the volcanic rocks are established,the geotectonic background during the formation period of the volcanic rocks is revealed,and the thermal event sequence of the magmatism is clarified.The results show that the volcanic rocks in this area are mainly classified into acidic rhyolite,felsite,tuff,fused tuff and volcanic breccia,and interrmediate rocks are also developed,all of which belong to the normal rock series of calc-alkali rocks and para-aluminous rocks formed in intrap late environment.Volcanic lithofacies can be divided into 3 facies types namely overflow facies,explosive facies and volcanic sedimentary facies,and 8 subfacies;there are mainly 4 eruption cycles in the volcanic rocks with the sedimentary interbeds,sedimented volcanic ash layer or weathered crust as the boundaries of each cycle;Cycle 1 and Cycle 2 are the medium basic magma with low viscosity and high fluidity,which erupt quietly and are distributed in a small scale in the southwest of Xingcheng nose structure;Cycle 3 and Cycle 4 are acidic magmatic eruption,and the scale of Cycle 3 is obviously larger than those of Cycle 1 and Cycle 2,which is mainly distributed in the south of Xingcheng nose structure;Cycle 4 is the largest and widely distributed in Shengping-Xingcheng area.

关 键 词：徐家围子断陷 升平—兴城地区 火山岩 岩石学 岩性 岩相 喷发期次 

分 类 号：P618.13[天文地球—矿床学]