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    塔河地区火山岩类型、分布与主控因素

    Types, distribution and main controlling factors of volcanic rocks in Tahe area

    • 摘要: 提要:通过岩心观察、地球化学方法、测井地震资料综合分析,认为塔河地区火山岩主要发育英安岩和玄武岩两大类。火山喷发主要以裂隙式喷发、侵出和溢流为主,形成塔河地区大面积火山熔岩流。火山岩的分布由西南向东北逐渐减薄,其分布主要受控于以下几个因素:①盐体覆盖区及其周缘附近,晚海西运动盐体的活动明显控制上覆火山岩岩体形态展布和分布特征,受盐体活动影响,火山岩主要残留于盐边凹陷地带和盐体覆盖区南翼,盐间凹陷火山岩厚度相对较大,盐隆地带残缺较大;②北部地区火山岩分布主要受基底喷发裂隙控制;③盐体南部斜坡地带玄武岩可能从塔里木盆地塔中地区溢流而来。

       

      Abstract: Abstract:Based on core observation, geochemical exploration and a comprehensive analysis of logging and seismic data, the authors hold that that two types of volcanic rocks, i.e., dacite and basalt, occur in Tahe area of Tarim basin, that fissure eruption,extrusion and overflow made up the main forms of volcanic eruption,and that lava flow resulted in the formation of extensive volcanic rocks in Tahe area. The distribution of volcanic rocks is characterized by gradual thinning from southwest to northeast,controlled by the following factors: ① in salt body covered area and its vicinity, the activity of salt body during late Hercynian movement significantly controlled the shape and distribution of the overlying volcanic rock, as evidenced by the facts that the residual volcanic rocks are mainly found in salt-edge sags and the south wing of the area covered with salt body and that these rocks are thickest in sags between salt bodies and thinnest in the salt bulge area which experienced uplifting and erosion; ② the distribution of the volcanic rocks in the north of the study area is mainly controlled by the basement fractures; ③ the volcanic rocks in the southern slope area of the salt body might have been derived from lava overflowing at the center of Tarim basin

       

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