摘要:
利用布格重力异常资料,经沉积层及岩石圈改正后,对青藏东缘下察隅-共和地球物理剖面的地壳结构进行了重力正演模拟。模拟结果显示,藏东缘上地壳厚度在20km左右,密度为2.78×103kg/m3;中地壳底界从30～40km变化,密度为2.89×103kg/m3,中地壳内存在密度为2.78×103kg/m3的低密度物质,在温泉至塘格木之间的中地壳底部存在3.33×103kg/m3的高密度物质;下地壳密度为3.10×103kg/m3。莫霍界面最浅处深度在56km左右,最深处达到74km左右,界面起伏变化大,在下察隅、察隅、怒江一带及温泉一带,其莫霍面较深。藏东地壳密度比中部密度要大,藏东低速层位于中地壳内及底部,而中部地区低速层位于上地壳底部。
关键词:
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地壳结构
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青藏高原
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重力
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正演模拟
Abstract:
The crustal structure of Xiachayu-Gonghe geophysical profile in eastern Tibetan plateau is simulated with Bouguer anomaly corrected for sediments and lithosphere.The forward simulation shows that the thickness of upper crust in eastern Tibetan plateau is about 20 km,and the density is 2.78×103 kg·m-3.The bottom interface of middle crust changes from 30-40 km,the density of middle crust is 2.89×103 kg·m-3.The materials with low density of 2.78×103 kg·m-3 exist in middle crust,and those with high density of 3.33×103 kg·m-3 exist at the bottom of middle crust between Wenquan and Tanggemu.The density is 3.10×103 kg·m-3 in lower crust.The shallowest depth of Moho interface is about 56 km,and the deepest one is about 74 km,the undulation of interface is large,the deep Moho locates in Xiachayu,Chayu,Nujiang and Wenquan.
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