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本文利用布格重力异常资料经过“剥皮”、“上延”反演计算,得出了宁夏地区十六条剖面的莫霍面及康拉界面的埋藏深度,並绘制出宁夏及其邻近地区的深部重力异常图、莫霍面等深度平面图。此结果与地质构造、测深资料基本相近。由此得出如下认识:宁夏地区的地壳厚度比东部的陕西地区增厚1—5公里,比西部的甘肃地区薄6公里左右。全区有几个莫霍面凹陷区和隆起区,即银川—平罗莫霍面凹陷区、中卫—中宁莫霍面隆起区、吴忠—马家滩莫霍面凹陷区、海原—李俊堡莫霍面凹陷区。另外还清楚地看到,在宁夏南部地区,大致以大、小罗山、预旺、泾原一线为界,往东地壳厚度逐渐变薄,往西地壳厚度逐渐变厚。历史上宁夏地区的强震位置恰巧与上述凹陷区和隆起区之间的变化梯度带相吻合。
In this paper, using the data of Bouguer gravity anomaly after “skinning” and “up-stretching” inversion calculations, the burial depths of the Moho and Conra interfaces at 16 cross sections in Ningxia are obtained, and the maps of Ningxia and its adjacent regions Deep gravity anomaly, Moho, etc. Depth plan. This result is basically similar to geological structure and sounding data. This leads to the following understanding: the thickness of the crust in Ningxia is 1-5 km thicker than that in the eastern part of Shaanxi Province, and about 6 km thinner than the Gansu Province in the west. The region has several Moho depression and uplift area, namely Yinchuan - Ping Luo Moho depression, Zhongwei - Zhongning Moho uplift, Wuzhong - Majiatan Moho depression, Haiyuan - Li Jun Fort Moho depression area. In addition, it is also clear that in the southern part of Ningxia, the thickness of the crust gradually becomes thinner toward the east and the thickness of the crust to the west gradually becomes thicker, roughly on the basis of the big and small Luoshan, prosperous and Jingyuan primary lines. The historical strong earthquake location in Ningxia coincides with the gradient of variation between the above-mentioned depression and uplift.