检索结果-南通市图书馆

Intracontinental lithospheric delamination:Constraints from imaging the Mantle transition zone beneath the southwestern part of the Sichuan Basin

引用

中国科学:地球科学英文版 2023年第10期66卷 2340-2352页

作者： Fan YANG Juan LI Sidan CHEN Yun CHEN Long LI Yinshuang AI Key Laboratory of Earth and Planetary Physics Institute of Geology and GeophysicsChinese Academy of SciencesBeijing100029China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing100049China Heilongjiang Mohe Observatory of Geophysics Institute of Geology and GeophysicsChinese Academy of SciencesBeijing100029China State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing100029China CAS Center for Excellence in Deep Earth Science Guangzhou510640China

The southwestern part of the Sichuan Basin(SW-SCB)is adjacent to the eastern Himalayan syntaxis.Affected by the Indo-Eurasian collision and subsequent intrusion of the Indian plate into the Eurasian plate during the Cenozoic,this region is ideal for the study of the tectonic evolution of the intracontinental lithosphere and the dynamic processes of deep and shallow structures.In this study,we applied the receiver function technique to the data obtained from a recently deployed high-density broadband seismic array across the Sichuan Basin and Sichuan-Yunnan block(SCB-SYB).We conducted a multi-frequency and multi-model correction analysis to image the structure of the Mantle transition zone beneath this region.The results showed the660-km discontinuity gradually increasing in depth by 10-30 km beneath the western side of the Anninghe-Xiaojiang Fault,suggesting the presence of thermal anomalies caused by the subducted Indian plate from west to east.At the junction of the SCBSYB,the 410-km discontinuity exhibited a slight uplift of 5-10 km,while the 660-km discontinuity showed a significant depression of~30 km over a lateral range of~150 km.Based on previous surface GPS observation and dynamic numerical simulation studies,we suggest that the sharp lateral small-scale topography of this 660-km discontinuity beneath the SW-SCB may have resulted from dripping delamination of the lithosphere within the strain localization area.Furthermore,the aggregation of delaminated lithospheric material at the base of the 660-km discontinuity determines the regional topography of Mantle transition zone discontinuities.In this study,we provided seismological evidence for the challenging detection of small-scale intracontinental lithosphere dripping delamination.Moreover,it provides a new view for studying deep and shallow dynamic processes in intracontinental regions with stress concentration resulting from plate/continental subduction and collision.

关键词： Mantle transition zone Receiver function Southwestern part of the Sichuan Basin Dripping lithospheric delamination Sichuan-Yunnan block

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

New hydrous phases in the Al_(2)O_(3)-SiO_(2)-H_(2)O system under the Mantle transition zone conditions

引用

Science China Earth Sciences 2023年第4期66卷 730-737页

作者： Baoyun WANG Jin LIU Suyu FU Pu XIAO Li LI Xing DING Wansheng XIAO College of Material and Chemical Engineering Tongren UniversityTongren 554300China Center for High Pressure Science and Technology Advanced Research(HPSTAR) Beijing 100193China Department of Earth and Planetary Science the University of TokyoTokyo 1130033Japan State Key Laboratory of Isotope Geochemistry Guangzhou Institute of GeochemistryChinese Academy of SciencesGuangzhou 510640China Key Laboratory of Mineralogy and Metallogeny Guangzhou Institute of GeochemistryChinese Academy of SciencesGuangzhou 510640China

Hydrous minerals in the subducting slabs are potential water carriers into the deep mantle,and thus the synthesis of new hydrous phases is significant in our understanding of water circulation throughout the Earth’s interior.In this study,we report the two new hydrous phases,Al_(2)SiO_(6)H_(2)and Al_(5.5)Si_(4)O_(18)H_(3.5)(hereafter referred to simply as phases Psi and Phi,respectively),which are synthesized in the Al_(2)O_(3)-SiO_(2)-H_(2)O system at 15.5 GPa,1400℃and 17.5 GPa,1600℃ by using Sakura2500-ton multi-anvil apparatus.The luminescence spectra of Cr3+show the phase Psi has characteristic peaks at 687,693 and705 nm,while phase Phi has characteristic peaks at 691,696 and 708 nm.Single-crystal X-ray diffraction (SCXRD) refinements yield a monoclinic structure of both phases (space group P2_(1)) with ideal chemical formulae of Al_(2)SiO6H2and Al5.5Si4O18H3.5respectively.The determined lattice parameters for phase Psi are a=9.4168±0.0016Å,b=4.3441±0.0007Å,c=9.4360±0.002Åand β=119.726±0.005°at ambient pressure and 300 K,while the phase Phi has a=7.2549±0.0018Å,b=4.3144±0.001Å,c=8.0520±0.002Å,and β=101.740±0.009°at ambient pressure and 250 K.Electron microprobe analyses (EPMA) show the chemical compositions of phases Psi and Phi to be Al_(1.99)Si_(0.85)O_(6)H_(2.62)and Al_(5.58)Si_(2.81)O_(18)H_(8.03),respectively,which slightly deviate from the ideal formulae inferred from SCXRD measurements.This may result from the disorder or substitution of Al and Si by H in the crystal structures under our synthesis conditions.Our study suggests that phases Psi and Phi are the two potential water carriers at the upper part of the mantle transitions zone,providing new insights into how deep water is stored in this region.

关键词： New hydrous phases Mantle transition zone Al_(2)O_(3)-SiO_(2)-H_(2)O system Al_(2)SiO_(6)H_(2) Al_(5.5)Si_(4)O_(18)H_(3.5)

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

From Mantle transition zone with Microstructures: A New Paradigm in Ophiolite Studies

引用

Acta Geologica Sinica(English Edition) 2020年第S1期94卷 53-54页

作者： Souvik DAS Department of Earth and Environmental Sciences University of Texas at ArlingtonTX 76019USA

The SE Ladakh(India) area displays one of the best-preserved ophiolite sections in this planet, in places up to 10 km thick, along the southern bank of the Indus River. Recently, in situ ultra-high pressure(UHP) microstructural evidences from Mantle transition zone(MTZ ~ 410–660 km) with diamond and reduced fluids were discovered from two peridotite bodies in the basal mantle part of this Indus ophiolite(Das et al., 2015;2017). Ultrahigh-pressure phases were also found by early workers from podiform chromitites of another equivalent Neo–Tethyan ophiolite in southern Tibet(e.g., Yang et al., 2007;Yamamoto et al., 2009). However, the MTZ phases in the Indus ophiolite are found in silicate peridotites not metallic chromitites and the peridotitic UHP phases show systematic and contiguous phase transitions from the MTZ to shallower depth, unlike the discrete ultrahighpressure inclusions, all in Tibetan chromitites. The gradual change in oxygen fugacity(fo2) and fluid composition from(C-H + H2) to(CO2 + H2O) in the upwelling peridotitic mantle causing melting to produce MORB. At shallow depths(mantle processes, and link deep mantle upwelling and MORB genesis(Fig. 1). The tectonic setting of Neo-Tethyan ophiolites has been a difficult problem since the birth of plate tectonics concept. This problem for the origin of ophiolites in mid-ocean ridge versus supra subduction-zone settings clearly confused the Geoscience community. However, Indian Ocean –type isotopic characteristics are present in Neo-Tethyan ophiolites(Zhang et al., 2005). Recently, continental materials(quartz, k-feldspar etc.) bearing old zircons(up to 2700 Ma) are also recovered from UHP chromitite of Tibetan ophiolite(Yamamoto et al., 2013). Eventually, the presence of older continental material can produce non-MORB like basalts in

关键词： Mantle transition zone Neo-Tethyan ophiolites diamond oxygen fugacity historical contingency

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Imaging Mantle transition zone discontinuities in southwest China from dense array ambient noise interferometry

引用

Earthquake Science 2018年第5期31卷 301-310页

作者： Jikun Feng Huajian Yao Weitao Wang Laboratory of Seismology and Physics of Earth's Interior School of Earth and Space SciencesUniversity of Science and Technology of China Mengcheng National Geophysical Observatory University of Science and Technology of China Institute of Geophysics China Earthquake Administration

Body waves retrieved from ambient noise cross-correlation functions（NCFs） have been reported by more and more recent studies in addition to the dominant recovered surface waves. And one of important applications of these recovered body waves is to investigate the structure of discontinuities within the Mantle transition zone（MTZ）. In this study, clear body wave phases reflected from the MTZ discontinuities at 410 km and 660 km have been observed on the NCFs in the frequency band of 0.1–0.2 Hz from a dense regional seismic array in southwest China. The original timedomain reflected signals in the NCFs were first converted to the depth-domain NCFs based on a velocity model before they were further stacked spatially within different bins. Then the depth-domain NCFs were stacked to investigate the lateral variations of the MTZ discontinuities, that is, the 410-km and 660-km discontinuities. Our results exhibit a simple and lateral coherent P;P phase and a much more complicated P;P phase along two profiles, which are in good agreement with mineralogical prediction and recent receiver function studies in the same area. This interferometric method can provide stable reflected body wave phases mainly in the frequency band 0.1–0.2 Hz due to the secondary microseism noise, which can be potentially used for high-resolution mantle interface imaging. This approach is also a good complement to traditional imaging methods, such as receiver function imaging.

关键词： ambient noise interferometry Mantle transition zone 410-km and 660-km discontinuities reflected body waves southwest China

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Prevalent thickening and local thinning of the Mantle transition zone beneath the Baikal rift zone and its dynamic implications

Prevalent thickening and local thinning of the mantle transi...

引用

中国科学院地质与地球物理研究所2013年度（第13届）...

作者： SI ShaoKun TIAN XiaoBo ZHANG HongShuang TENG JiWen Institute of Geology and Geophysics Chinese Academy of Sciences Graduate University of Chinese Academy of Sciences

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 410 km and 660 km and thickness of the Mantle transition zone(MTZ)beneath the study area. The MTZ structure shows an obvious thickening(292 km)in the Baikal rift zone except for an area of limited thinning(230 km),whereas it is basically normal(250 km)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.

关键词： Baikal rift zone Mantle transition zone P wave receiver function

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Hydration Effect on Equations of State for Minerals in the Peridotite System:Implication for Geotherms in the mantle

引用

Journal of Earth Science 2022年第5期33卷 1124-1144页

作者： Yu Ye Joseph R.Smyth Guangchen Chen State Key Laboratory of Geological Processes and Mineral Resources China University of GeosciencesWuhan 430074China Department of Geological Sciences University of ColoradoBoulderCO80309USA

Water in the deep Earth’s interior has important and profound impacts on the geodynamical properties at high-temperature(T)and high-pressure(P)conditions.A series of dense hydrous Mg-silicate(DHMS)phases are generated from dehydration of serpentines in subduction slabs below the lithosphere,including phase A,chondrodite,clinohumite,phase E,superhydrous phase B and phase D.On the other hand,olivine and its high-P polymorphs of wadsleyite and ringwoodite are dominant nominally anhydrous minerals(NAMs)in the upper mantle and transition zone,which could contain significant amount of water in the forms of hydroxyl group(OH-)defects.The water solubilities in wadsleyite and ringwoodite are up to about 3 weight percent(wt.%),making the transition zone a most important layer for water storage in the mantle.Hydration can significantly affect the pressure-volumetemperature equations of state(P-V-T EOSs)for the DHMS and NAM phases,including the thermal expansivities and isothermal bulk moduli.In this work,we collected the reported datasets for the DHMS and NAM phases,and reconstruct internally consistent EOSs.Next,we further evaluated the thermodynamic Grüneisen parameters,which are fundamental for constraining the temperature distribution in an isentropic process,such as mantle convection.The adiabatic temperature profiles are computed for these minerals in the geological settings of normal mantle and subduction zone,and our calculation indicates that temperature is the dominant factor in determining the gradient of a geotherm,rather than the mineralogical composition.

关键词： equation of state DHMS phases nominally anhydrous minerals thermodynamic Grüneisen parameters adiabatic geotherm subduction slab Mantle transition zone mineralogy

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Preliminary Deformation Experiment of Ringwoodite at 20 GPa and 1 700 K Using a D-DIA Apparatus

引用

Journal of Earth Science 2010年第5期21卷 517-522页

作者： Takaaki Kawazoe Tomohiro Ohuchi Norimasa Nishiyama Yu Nishihara Tetsuo Irifune Geodynamics Research Center Ehime University Senior Research Fellow Center Ehime University

A deformation experiment of ringwoodite with a strain of 9% was achieved at 20 GPa and 1 700 K and at a strain rate of 3×10^-5 s^-1 using a deformation-DIA （D-DIA） apparatus and a multi-anvil 6-6 （MA 6-6） assembly. The crystallographic orientations of the deformed sample were successfully analyzed by the electron backscatter diffraction （EBSD） method, although any notable latticepreferred orientation （LPO） was not observed presumably due to the insufficient strain in the present experiment. In this study, the deformation experiment on ringwoodite succeeded at P-T conditions consistent with the lower part of the Mantle transition zone and at a controlled strain rate for the first time. The present study extended the pressure range of deformation experiments in the D-DIA apparatus from 16 GPa in our earlier study to 20 GPa at 1 700 K. The successful extension of the pressure range demonstrates potential importance of the D-DIA apparatus in studying rheological properties of minerals under the P-T conditions of the whole Mantle transition zone.

关键词： ringwoodite Mantle transition zone rheology viscosity mantle dynamics.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Receiver function migration image of the deep structure in the Bohai Bay Basin,eastern China

Receiver function migration image of the deep structure in t...

引用

中国科学院地质与地球物理研究所2006学术年会

作者： Ling Chen~*,Tianyu Zheng,and Weiwei Xu Seismological Laboratory(SKL-LE),Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,PR China

We apply a receiver function poststack migration method to image the crustal and upper mantle structures beneath the Bohai Bay Basin,eastern China.The thick sediments of the basin appear to have a substantial influence on the migrated image of the deep structure.By using the surface reflected PpPs multiples instead of the commonly used Ps converted phases,a curved Moho is coherently imaged,showing a thinned crust of 30 km in the basin area compared with the >40-km thick crust in the west mountain range.By incorporating the sedimentary velocity model into migration,both the 410-km and the 660-km discontinuities present a simple structural feature with relatively flat topography within the basin’s interior,although possible local structural complexities may exist at the base of the upper mantle around the boundary areas of the basin.The Mantle transition zone is on average 10-15 km thicker than the global average,reflecting a cold lower upper mantle environment that is distinct from the warm shallow upper mantle of the region.

关键词： Bohai Bay Basin Receiver function Migration Mantle transition zone Sediment influence

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Seismic signature of the collision between the east Tibetan escape flow and the Sichuan Basin

Seismic signature of the collision between the east Tibetan ...

引用

中国科学院地质与地球物理研究所第十届(2010年度)学...

作者： Rainer Kind Deutsches GeoForschungsZentrum GFZ Telegrafenberg14473 PotsdamGermany Freie Universitat Berlin Germany

GPS displacement vectors show that the crust in east Tibet is being squeezed in an easterly direction by the northward motion of the Indian plate,and the Sichuan Basin is resisting this stream and redirecting it mainly towards Indochina.The Longmen Shan,containing the steepest rise to the high plateau anywhere in Tibet, results from the strong interaction between the east Tibetan escape flow and the rigid Yangtze block (Sichuan Basin),but the kinematics and dynamics of this interaction are still the subject of some debates.We herein present results from a dense passive-source seismic profile from the Sichuan Basin into eastern Tibet in order to study the deep structure of this collision zone.Using P and S receiver function images we observe a sudden rise of the Lithosphere-Asthenosphere Boundary(LAB) from 120 to 150 km beneath the Sichuan Basin and from 70 to 80 km beneath eastern Tibet.In contrast,the depth of the crust-mantle boundary (Moho) increases from 36 to 40 km beneath the Sichuan Basin and from 55 to 60 km beneath eastern Tibet. The 410km discontinuity is depressed below eastern Tibet by about 30 km,although the 660 remains at nearly the same depth throughout the LMS.From these observations,we conclude that the mode of collision that occurs between Tibet and the Sichuan Basin is very different to that found between India and Tibet.In southern Tibet,we observe in essence the subduction of the Indian plate,which penetrates northwards for several hundred kilometers under central Tibet.The very thin mantle part of the lithosphere beneath eastern Tibet may indicate delamination or removal of the bottom of the lithosphere by hot asthenospheric escape flow.This process leads to the exceptionally steep topography at the eastern Tibetan margin as a result of gravitational buoyancy.This view is supported by the very unusual depression of the 410 km discontinuity beneath eastern Tibet,which could be caused by the dynamics of the sub-vertical downward asthenospheric flow.

关键词： east Tibetan escape flow Sichuan Basin receiver function imaging Mantle transition zone

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Structure of crust and upper mantle beneath the Ordos Block and the Yinshan Mountains revealed by receiver function analysis

Structure of crust and upper mantle beneath the Ordos Block ...

引用

中国科学院地质与地球物理研究所第11届（2011年度）...

作者： Xiaobo Tian~*,Jiwen Teng,Hongshuang Zhang,Zhongjie Zhang,Yongqian Zhang,Hui Yang,Keke Zhang (phd.Editor) State Key Laboratory of Lithospheric Evolution,Institute of Geology and Geophysics,Chinese Academy of Sciences,No.19,Beitucheng Xilu,Chaoyang,Beijing 100029,China

A temporary seismological network of broadband three-component stations has been deployed N-S to investigate the crust and upper mantle structure across the Ordos Block and the Yinshan Mountains. P wave receiver functions reveal the Moho depth to be about 41 km beneath the central Ordos Block and down to 45 km beneath the northern Ordos Block,a slight uplifting to 42-43 km beneath the Hetao Graben,increasing to 47-48 km beneath the Yinshan Mountains and then decreasing to 44 km beneath the northern Yinshan Mountains along the profile.In the Ordos Block,the crustal Vp/Vs ratio(about 1.80) south to the Hetao Graben differs from that(about 1.75) beneath the center Ordos Block.The crustal Vp/Vs ratio is significantly lower(about 1.65-1.70) beneath the Yinshan Mountains.The P wave receiver function migration imaging suggests relatively flat discontinuities at 410 and 660 km,indicating the lack of a strong thermal anomaly beneath this profile at these depths,and a low S wave velocity anomaly in the upper mantle beneath the Hetao Graben.We suggest that the low S wave velocity anomaly may be attributable to heat and that the thermal softening advances the evolution of the Hetao Graben,while the lower-crustal ductile flows transfer from the Hetao Graben to the northern Ordos Block,resulting in crustal thickening.

关键词： Receiver function Ordos Block Yinshan Mountains Hetao Graben Crust and upper mantle Mantle transition zone Lower-crustal ductile flows

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：