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3D S-velocity model of the lithosphere-asthenosphere system beneath the Bering Sea
International Journal of Earth Sciences ( IF 1.8 ) Pub Date : 2020-05-02 , DOI: 10.1007/s00531-020-01868-y
Víctor Corchete

The 3D S-velocity structure for the Bering Sea region is determined from dispersion analysis (Rayleigh waves), from which the most conspicuous features of the crust and upper mantle (from 0 to 400 km depth) will be revealed. In the depth range from 0 to 5 km, this model shows the distribution of the sedimentary basins present in the study area, in terms of S-velocity. For the Bering Shelf, the S-velocity values decrease southward, indicating the presence of deep sedimentary basins in the southern Bering Shelf. In the depth range from 5 to 30 km, the S-velocity model shows clearly the division of the Bering Sea basin in three sub-basins: the Aleutian Basin, the Bowers Basin and the Komandorsky Basin, produced by the Bowers Ridge and the Shirshov Ridge. In this model, the low S-velocity pattern determined for the Bering Shelf confirms that its crust is similar to a continental-type crust, no an oceanic crust. The Moho map determined in the present study, from the 3D S-velocity model, is the first Moho map calculated for the Bering Sea region. In this map, the crust beneath the Bering Shelf shows thicker thickness than a typical oceanic crust, from which is concluded that this crust must be considered as a transitional crustal structure. In the depth range from 30 to 100 km, the Aleutian Basin shows a pattern of high S-velocity that can be correlated with the origin of this basin, because this basin is considered as formed by the entrapment of a piece of Pacific plate. In the depth range from 45 to 60 km, the low S-velocity pattern shown for the eastern Aleutian arc is associated to the active arc volcanoes present in this region. From the S-velocity model, the asthenosphere beneath the study area is firstly determined from ~ 100 to ~ 180 km depth. For the depth range from 80 to 400 km, the high S-velocity pattern determined for the eastern Aleutian arc, allows the modeling (imaging) of the subducting Pacific slab, in terms of S-velocity. This pattern of high S-velocity is not visible beneath the western Aleutian arc, because the Pacific plate is not subducting beneath the Bering Sea in the western Aleutian arc.



中文翻译:

白令海以下岩石圈-软流圈系统的3D S速度模型

白令海地区的3D S速度结构是通过色散分析(瑞利波)确定的,从中将揭示出地壳和上地幔(从0到400 km的深度)最明显的特征。在从0到5 km的深度范围内,该模型以S速度显示了研究区域中存在的沉积盆地的分布。对于白令架,S速度值向南递减,表明在白令架南部存在深层沉积盆地。在5到30 km的深度范围内,S速度模型清楚地显示了白令海盆地在三个子盆地中的划分:阿留申盆地,鲍尔斯盆地和科曼多尔斯基盆地,由鲍尔斯岭和谢尔绍夫生产岭。在这个模型中 为白令架确定的低S速度模式证实其地壳类似于大陆型地壳,没有洋壳。根据3D S速度模型,本研究确定的Moho图是为白令海地区计算的第一张Moho图。在此地图中,白令架下面的地壳的厚度比典型的洋壳要厚,由此可以得出结论,该地壳必须被视为过渡地壳结构。在30至100 km的深度范围内,阿留申盆地表现出高S速度的模式,可以与该盆地的起源相关,因为该盆地被认为是由一块太平洋板块的包裹形成的。在45至60公里的深度范围内,东阿留申弧线显示的低S速度模式与该地区存在的活动弧火山有关。根据S速度模型,首先确定约100至〜180 km深度的研究区下方的软流圈。对于80至400 km的深度范围,为东阿留申弧线确定的高S速度模式可以用S速度对俯冲太平洋板块进行建模(成像)。在西阿留申弧线下方看不到这种高S速度的模式,因为太平洋板块并未在西阿留申弧线的白令海下方俯冲。为东阿留申弧线确定的高S速度模式,可以根据S速度对俯冲太平洋板块进行建模(成像)。在西阿留申弧线下方看不到这种高S速度的模式,因为太平洋板块并未在西阿留申弧线的白令海下方俯冲。为东阿留申弧线确定的高S速度模式,可以根据S速度对俯冲太平洋板块进行建模(成像)。在西阿留申弧线下方看不到这种高S速度的模式,因为太平洋板块并未在西阿留申弧线的白令海下方俯冲。

更新日期:2020-05-02
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