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准噶尔盆地车排子地区石炭系广泛发育火山岩,多期次构造运动的影响使得火山岩产生大量天然裂缝。通过岩心观察、薄片鉴定和成像测井资料等分析,认为石炭系火山岩主要发育构造裂缝,多期裂缝相互切割及充填现象明显,裂缝走向主要为NE、NW、NNE和NNW向,其中优势方位为NE向和NW向。结合裂缝切割关系及构造演化背景,采用岩石声发射实验和碳氧稳定同位素分析测试手段确定石炭系火山岩裂缝具有4个形成期次,分别对应海西运动期、印支运动期、燕山运动期和喜马拉雅运动期。研究认为,各期次构造运动的性质控制着不同期次裂缝的类型、规模及方位分布,海西—印支期构造活动最为强烈,是研究区构造裂缝形成的主要时期。
Volcanic rocks are widely developed in the Carboniferous of Chepaizi area in the Junggar Basin. Many natural fractures occur in the volcanic rocks due to the multi-stage tectonic movement. Based on the analysis of core observation, thin slice identification and imaging logging data, it is considered that the Carboniferous volcanic rocks mainly develop tectonic fractures, the mutual cleavage and filling of multiple fractures are obvious, and the fracture directions are mainly NE, NW, NNE and NNW. The dominant azimuths are NE and NW directions. Combined with the relationship between the cleavage and the tectonic evolution, rock acoustic emission experiment and carbon-oxygen stable isotope analysis were used to determine the formation of the Carboniferous volcanic fractures. There are four formations, corresponding to the Hercynian period, the Indosinian movement period, the Yanshan movement period and Himalayan exercise period. The study suggests that the nature of the tectonic movements in each phase controls the type, size and azimuth distribution of fractures in different phases. The Hercynian-Indosinian tectonic activity is the most intense, which is the main period for the formation of structural fractures in the study area.