试论吉拉沟的构造成因

从吉拉沟的形态、第四纪沉积物特征、人工地震剖面、电磁场特征及探槽揭露等认为：吉拉沟在深部对应于一基底隆起，该隆起被海西期断裂所限制。这些断裂在印支早期便停止了活动。在区域南北向应力场及差异压实作用下，基底隆起形成潜山型内核。其上覆中－新生界盖层形成披覆型背斜，在背斜顶部产生一系列平行于轴向的纵张裂隙。在内外营力的共同作用下，这些纵张裂隙不断发展贯通，并演变成规模巨大、近东西走向的吉拉沟。

ON THE TECTONIC ORIGIN OF JILA GULLY

From the form of Jila gully,the character of the Quaternary sediment,the profile of artificial earthquakes,the chart of electromagnetic sounding and prospecting trench,wc consider that the gully is corresponding to basement high in depth. The basement high is dominated by Hercynian faults,and these faults stopped moving in the end of India-Chinese epoch.Under the regional south-north stress field and the force of differential compaction,the basement rises and forms buried hill.Above it,the Mesozoic-Cenzoic covering generates draped fold with the inner core of buried hill,and a series of longitudinal tensile fissures which run parallel -to the axial line of the fold were found on the top of the fold. Under the effort of inside and outside agent, these longitudinal tensile fissures gradually developed to penetrate through each other,and finally turned into this large-scale nearly west-east striking gully.