云南地区的地幔过渡带结构及其动力学意义

发布时间：2019-05-31 17:36

【摘要】：计算云南及周边地区48个宽频地震台记录的8600个远震P波接收函数,并根据参考地球模型将接收函数从时间域转换到深度域.在转换深度550 km处,将1°×1°面元内的接收函数叠加成一道信号,共获得了沿纬度28°,27°,26°,25°,24°和23°N的6个共转换面元叠加剖面,其叠加深度在0~800 km之间.结果表明:(1)在26°N以北的地区,410和660 km间断面的平均深度分别为407~408和663~667 km,地幔过渡带的平均厚度处于255~259 km之间,过渡带的厚度接近全球平均厚度250 km;(2)在26°N以南的地区,410和660 km间断面的平均深度分别为412~426和675~703 km,地幔过渡带的平均厚度处于262~279 km之间,明显大于全球平均厚度250 km.云南地区410和660km间断面的加深显然与印度板块在缅甸弧下方的俯冲有关,然而,从云南地区地幔过渡带的结构来分析,本文认为印度板块沿缅甸弧向东俯冲主要发生在26°N以南地区.
[Abstract]:The P wave receiving functions of 8600 distant earthquakes recorded by 48 broadband seismic stations in Yunnan and its surrounding areas are calculated, and the receiving functions are converted from time domain to depth domain according to the reference earth model. At the conversion depth of 550 km, the receiving function in 1 掳脳 1 掳plane element is superimposed into a signal, and six common conversion surface element superposition sections along latitude 28 掳, 27 掳, 26 掳, 25 掳, 24 掳and 23 掳N are obtained. The superposition depth is between 0 掳800 km. The results show that: (1) in the area to the north of 26 掳N, the average depth of 4607 km and 6607 km, mantle transition zones is between 405 and 663 km, km, respectively, and the thickness of the transition zone is close to the global average thickness of 250 km;. (2) in the area south of 26 掳N, the average depth of 410 km and 660 km intersections is 412 and 675 脳 703 km, respectively, and the average thickness of the mantle transition zone is between 262 and 279 km, which is significantly higher than that of the global average thickness of 250 km.. The deepening of the cross section between 660km and 410 in Yunnan is obviously related to the subduction of the Indian plate below the Burmese arc. However, the structure of the mantle transition zone in Yunnan is analyzed. In this paper, it is considered that the eastward subduction of the Indian plate along the Burmese arc mainly occurs in the south of 26 掳N.
【作者单位】：云南大学地球物理系;昆明南方地球物理技术开发有限公司;
【基金】：国家自然科学基金(41374106,41304076)资助
【分类号】：P315.2

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