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| 基于融合重力异常的大别造山带东段莫霍面反演研究 |
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黎哲君1,2, 黄显良1,2, 郑海刚1,2, 王俊1,2, 王邁坤1,2, 袁泉1, 谈昕1
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1.安徽省地震局, 合肥 230031;2.安徽蒙城地球物理国家野外科学观测研究站, 安徽蒙城 233500
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| 摘要: |
| 利用实测布格异常和EGM2008重力异常融合结果,采用频率域位场反演方法计算大别造山带东段莫霍面三维空间分布,结合区域地质构造和地震活动等资料讨论大别造山带东段莫霍面分布特征及其构造含义等。研究结果显示:①莫霍面空间分布体现了块体构造差异,大别造山带莫霍面最深,最大深度达42km,显示东大别造山带存在明显山根,扬子地块深度次之,华北地块最浅;郯庐断裂带及其东侧区域存在莫霍面上隆带;②大别造山带北侧和南侧莫霍面陡变带分别位于青山—晓天断裂附近和襄樊—广济断裂以北,体现华北地块和扬子地块向大别造山带之下俯冲的构造特征,指示了深部构造缝合带位置;莫霍面深度特征表明郯庐断裂带区域构造边界带属性明显,其切割深度至少达到壳幔边界,大别造山带商城—麻城断裂两侧经历了差异隆升;③研究区域绝大多数地震发生在莫霍面以上深度,莫霍面深度陡变带、上隆带及不同莫霍面深度特征区的转换带为区域地震活动提供了深部构造条件。 |
| 关键词: 莫霍面 重力异常 重力反演 大别造山带 地质构造 |
| DOI： |
| 分类号:P315 |
| 基金项目:中国地震局地震科技星火计划项目(XH20025Y)、中国地震局震情跟踪项目(2021010208)、安徽蒙城地球物理国家野外科学观测研究站联合开放基金(MENGO-202112)和武汉引力与固体潮国家野外科学观测研究站开放研究基金(WHYWZ202209)共同资助 |
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| Moho beneath the Eastern Dabie Orogen Insight from Inversion of Merged Gravity Anomaly |
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Li Zhejun1,2, Huang Xianliang1,2, Zheng Haigang1,2, Wang Jun1,2, Wang Yikun1,2, Yuan Quan1, Tan Xin1
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1.Anhui Earthquake Agency, Hefei 230031, China;2.Anhui Mengcheng National Geophysical Observation and Research Station, Mengcheng 233500, Anhui, China
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| Abstract: |
| The gravity anomaly used in this study was obtained by merging EGM2008 gravity anomaly and observed gravity anomaly. The Moho depth beneath the eastern Dabie Orogen was obtained by frequency domain inversion of merged gravity anomaly. In combination with regional tectonic and seismic data,the Moho undulation and its tectonic implications were discussed. The results show that:① the depth of the Moho beneath the eastern Dabie Orogen reaches the maximum value of 42km,while the Moho depth of Yangtze block is intermediate,and the Moho of the North China block is the shallowest. This suggests that there exists a crustal root of the eastern Dabie Orogen and the Moho undulation reflects the tectonic features of different tectonic blocks. ② Steep Moho gradients along the north and south margins of the eastern Dabie Orogen locate at Qingshan-Xiaotian fault and north of the Xiangfan-Guangji fault respectively,represent the subductions of the North China block and the Yangtze block beneath the Dabie Orogen,and indicate the locations of deep suture zones. The Moho undulation shows that the Tanlu fault zone is the boundary of different tectonic blocks,and has extended to crust-mantle boundary or more deep. Within the eastern Dabie Orogen,the west side and east side of Shangcheng-Macheng fault were uplifted out of sync. ③ The great majority of earthquakes in this region occurred above the Moho interface. Steep Moho gradient zones,the Moho uplifting zones and transition zones of different Moho undulation areas provide deep structural environments for seismic activities. |
| Key words: Moho interface Gravity anomaly Gravity inversion Dabie orogen Tectonics |
