对西准噶尔及周边地区壳幔结构的研究是揭示准噶尔盆地演化的重要基础。利用最新的卫星重力场模型,通过计算得到西准噶尔及周边地区的布格重力异常,进而采用三维反演技术,对西准噶尔及周边地区的地壳与上地幔顶部进行密度成像,得到...对西准噶尔及周边地区壳幔结构的研究是揭示准噶尔盆地演化的重要基础。利用最新的卫星重力场模型,通过计算得到西准噶尔及周边地区的布格重力异常,进而采用三维反演技术,对西准噶尔及周边地区的地壳与上地幔顶部进行密度成像,得到了0-80 km 深度范围的密度异常结构。地壳密度分布显示古准噶尔洋壳有可能向 NE 和 NW 分别俯冲于西伯利亚板块和西准噶尔地块之下。上地幔顶部密度变化表明:阿尔泰褶皱带具有相对较低的密度,可能为古大陆巨厚的硅铝层所致;哈萨克斯坦-准噶尔盆地具有相对完整的高密度结构;天山褶皱带区域的密度大幅度变化刻画了超岩石圈断裂对岩石圈的切割以及岩石圈形变与构造活动的痕迹。展开更多
In this paper, we analyze lithospheric density distribution of China and surrounding regions on the basis of 30' × 30' gravity data and 1°×1 °P-wave velodty data, Firstly, we used the empirical e...In this paper, we analyze lithospheric density distribution of China and surrounding regions on the basis of 30' × 30' gravity data and 1°×1 °P-wave velodty data, Firstly, we used the empirical equation be- tween the density and the P-wave velocity difference as the base of the initial model of the Asian lithospheric density. Secondly, we calculated the gravity anomaly, caused by the Moho discontinuity and the sedimentary layer discontinuity, by the Parker formula. Thirdly, the gravity anomaly of the spherical harmonics with 2 40 order for the anomalous body below the lithosphere is calculated based on the model of EGM96. Finally, by using Algebra Reconstruction Techniques (ART), the inversion of 30' ~ 30' residual lithospheric Bouguer gravity anomaly caused by the lithosphere yields a rather detailed struc- tural model. The results show that the lithospheric density distribution of China and surrounding regions has a certain connection with the tectonic structure. The density is relatively high in the Philippine Sea plate, Japan Sea, the Indian plate, the Kazakhstan shield and the Western Siberia plain, whereas the Tibetan Plateau has low-density characteristics. The minimum value of density lies in the north of Philippines, in the Taiwan province and in the Ryukyu island arc.展开更多
文摘对西准噶尔及周边地区壳幔结构的研究是揭示准噶尔盆地演化的重要基础。利用最新的卫星重力场模型,通过计算得到西准噶尔及周边地区的布格重力异常,进而采用三维反演技术,对西准噶尔及周边地区的地壳与上地幔顶部进行密度成像,得到了0-80 km 深度范围的密度异常结构。地壳密度分布显示古准噶尔洋壳有可能向 NE 和 NW 分别俯冲于西伯利亚板块和西准噶尔地块之下。上地幔顶部密度变化表明:阿尔泰褶皱带具有相对较低的密度,可能为古大陆巨厚的硅铝层所致;哈萨克斯坦-准噶尔盆地具有相对完整的高密度结构;天山褶皱带区域的密度大幅度变化刻画了超岩石圈断裂对岩石圈的切割以及岩石圈形变与构造活动的痕迹。
基金supported by Project SinoProbe-02: Experiment and Integration of Deep Probe Techniques in ChinaNational Natural Science Foundation of China (NSFC, Grant No. 40874067)the Research Fund for the Doctoral Program of Higher Education (Grant No. 20070491520)
文摘In this paper, we analyze lithospheric density distribution of China and surrounding regions on the basis of 30' × 30' gravity data and 1°×1 °P-wave velodty data, Firstly, we used the empirical equation be- tween the density and the P-wave velocity difference as the base of the initial model of the Asian lithospheric density. Secondly, we calculated the gravity anomaly, caused by the Moho discontinuity and the sedimentary layer discontinuity, by the Parker formula. Thirdly, the gravity anomaly of the spherical harmonics with 2 40 order for the anomalous body below the lithosphere is calculated based on the model of EGM96. Finally, by using Algebra Reconstruction Techniques (ART), the inversion of 30' ~ 30' residual lithospheric Bouguer gravity anomaly caused by the lithosphere yields a rather detailed struc- tural model. The results show that the lithospheric density distribution of China and surrounding regions has a certain connection with the tectonic structure. The density is relatively high in the Philippine Sea plate, Japan Sea, the Indian plate, the Kazakhstan shield and the Western Siberia plain, whereas the Tibetan Plateau has low-density characteristics. The minimum value of density lies in the north of Philippines, in the Taiwan province and in the Ryukyu island arc.