During Mesozoic to Cenozoic time, the large-scale tectono-magmatism had strongly modified the lithosphere beneath the southeastern continent of China, leaving the present-day lithosphere as a new one evolving from the...During Mesozoic to Cenozoic time, the large-scale tectono-magmatism had strongly modified the lithosphere beneath the southeastern continent of China, leaving the present-day lithosphere as a new one evolving from the ancient lithosphere that was largely removed and replaced. But this model proposed from geochemical and petrological research is urgently in need of support from seismic observational evidence. In this paper, based on the dataset recorded by the dense stations of two NE oriented broadband seismic profiles deployed in the coastal area of southeastern China(SE China), both P-wave(P-RF) and S-wave(S-RF) receiver functions were isolated. We identified Pls phase converted from the Lithosphere-Asthenosphere Boundary(LAB) in P-RFs of individual stations. Migrated Pls phase indicated a depth of 60–70 km for LAB. Inversions/comparisons of P-RF(Pls phase) and S-RF(Slp phase) waveforms together with Ps and Sp imaging for the crust and upper mantle structure further confirmed this result. P-RF and S-RF migrated images exhibit that a flat LAB is positioned at the depth of 60–70 km spreading along the profile, whereas a distinct structural change of lithospheric base appears at the Min River estuary. Both Ps and PpPs migrated images of P-RFs present an abrupt Moho drop across the Min River fault from south to north, which is consistent with previous result obtained from deep seismic sounding. By taking into consideration other geological and geophysical features such as locally high anomalies of crustal Poisson's ratios and heat flow at the Min River estuary, we infer that the Min River fault penetrates down to the Moho and may, furthermore, interfere in the deeper lithospheric structure.展开更多
The Baikal rift is the most seismically active continental rift in the world and is significant for studying the dynamics of continental rifts, although its precise dynamic mechanisms remain controversial. We calculat...The Baikal rift is the most seismically active continental rift in the world and is significant for studying the dynamics of continental rifts, although its precise dynamic mechanisms remain controversial. We calculated receiver functions (1748) from Global Seismographic Network seismic stations TLY and ULN and stacked receiver functions in different bins. Here we present discontinuities at depths of 410km and 660km and thickness of the mantle transition zone (MTZ) beneath the study area. The MTZ structure shows an obvious thickening (292km) in the Baikal rift zone except for an area of limited thinning (230km), whereas it is basically normal (250km) beneath the Mongolian area, to the southeast of the Baikal rift. Combining these results with previous findings, we propose that the large-scale thickening beneath the Baikal rift zone is likely to be caused by the Mesozoic collision between the Siberian Platform and the Mongolia-North China Block or magmatic intrusion into the lower crust, which would result in crust and lithosphere thickening. Thus, the lower crust becomes eclogitized and consequently detached into the deep mantle because of negative buoyancy. The detachment not only induces asthenosphere upwelling but also accelerates mantle convection of water detached from the subducted slab, which would increase mantle melting, while both processes promote the development of the rift. Our preliminary results indicate that the detachment and the consequent hot upwelling have an important influence on the development of the Baikal rift, and a small-scale mantle upwelling indicated by the located thinning may have destroyed the lithosphere and promoted this development.展开更多
基于ASAP(Arbeitskreis zur Standardisierung von Applikationssystemen,应用系统标准化工作小组)标准架构提到的数据库管理方式,应用Excel完成ECU(Electronic Control Unit,电子控制单元)系统的数据管理。利用MATLAB软件完成ASAP数据...基于ASAP(Arbeitskreis zur Standardisierung von Applikationssystemen,应用系统标准化工作小组)标准架构提到的数据库管理方式,应用Excel完成ECU(Electronic Control Unit,电子控制单元)系统的数据管理。利用MATLAB软件完成ASAP数据库自动生成,实现数据导入、用于a2l文件生成模型创建、头文件修改及地址替换。最终生成可执行文件*.a2l,满足对标定系统中的变量进行标定或观测的需求。展开更多
基金supported by Sinoprobe02-03(Grant No.201011042)the National Natural Science Foundation of China(Grant No.41174081)
文摘During Mesozoic to Cenozoic time, the large-scale tectono-magmatism had strongly modified the lithosphere beneath the southeastern continent of China, leaving the present-day lithosphere as a new one evolving from the ancient lithosphere that was largely removed and replaced. But this model proposed from geochemical and petrological research is urgently in need of support from seismic observational evidence. In this paper, based on the dataset recorded by the dense stations of two NE oriented broadband seismic profiles deployed in the coastal area of southeastern China(SE China), both P-wave(P-RF) and S-wave(S-RF) receiver functions were isolated. We identified Pls phase converted from the Lithosphere-Asthenosphere Boundary(LAB) in P-RFs of individual stations. Migrated Pls phase indicated a depth of 60–70 km for LAB. Inversions/comparisons of P-RF(Pls phase) and S-RF(Slp phase) waveforms together with Ps and Sp imaging for the crust and upper mantle structure further confirmed this result. P-RF and S-RF migrated images exhibit that a flat LAB is positioned at the depth of 60–70 km spreading along the profile, whereas a distinct structural change of lithospheric base appears at the Min River estuary. Both Ps and PpPs migrated images of P-RFs present an abrupt Moho drop across the Min River fault from south to north, which is consistent with previous result obtained from deep seismic sounding. By taking into consideration other geological and geophysical features such as locally high anomalies of crustal Poisson's ratios and heat flow at the Min River estuary, we infer that the Min River fault penetrates down to the Moho and may, furthermore, interfere in the deeper lithospheric structure.
基金supported by National Natural Science Foundation of China(Grant Nos. 40974025 and 40721003)Innovative Research Group Science Foundation (Grant No. 41021063)National Key Project (Grant No.2008ZX05008-006)
文摘The Baikal rift is the most seismically active continental rift in the world and is significant for studying the dynamics of continental rifts, although its precise dynamic mechanisms remain controversial. We calculated receiver functions (1748) from Global Seismographic Network seismic stations TLY and ULN and stacked receiver functions in different bins. Here we present discontinuities at depths of 410km and 660km and thickness of the mantle transition zone (MTZ) beneath the study area. The MTZ structure shows an obvious thickening (292km) in the Baikal rift zone except for an area of limited thinning (230km), whereas it is basically normal (250km) beneath the Mongolian area, to the southeast of the Baikal rift. Combining these results with previous findings, we propose that the large-scale thickening beneath the Baikal rift zone is likely to be caused by the Mesozoic collision between the Siberian Platform and the Mongolia-North China Block or magmatic intrusion into the lower crust, which would result in crust and lithosphere thickening. Thus, the lower crust becomes eclogitized and consequently detached into the deep mantle because of negative buoyancy. The detachment not only induces asthenosphere upwelling but also accelerates mantle convection of water detached from the subducted slab, which would increase mantle melting, while both processes promote the development of the rift. Our preliminary results indicate that the detachment and the consequent hot upwelling have an important influence on the development of the Baikal rift, and a small-scale mantle upwelling indicated by the located thinning may have destroyed the lithosphere and promoted this development.
文摘基于ASAP(Arbeitskreis zur Standardisierung von Applikationssystemen,应用系统标准化工作小组)标准架构提到的数据库管理方式,应用Excel完成ECU(Electronic Control Unit,电子控制单元)系统的数据管理。利用MATLAB软件完成ASAP数据库自动生成,实现数据导入、用于a2l文件生成模型创建、头文件修改及地址替换。最终生成可执行文件*.a2l,满足对标定系统中的变量进行标定或观测的需求。
