The Ailao Shan-Red River fault zone is the boundary between the Yangtze block to the northeast and the Indochina block to the southwest.It is an important tectonic zone due to its role in the southeastward extrusion o...The Ailao Shan-Red River fault zone is the boundary between the Yangtze block to the northeast and the Indochina block to the southwest.It is an important tectonic zone due to its role in the southeastward extrusion of the Indochina block during and subsequent to the Indian-Eurasian collision.Diancang Shan（DCS） high-grade metamorphic complex,located at the northwest extension along the Ailao Shan-Red River（ASRR） shear zone,is a representative metamorphic complex of the ASRR tectonic belt.Structural and microstructural analysis of sheared rocks in the high-grade metamorphic rocks reveals that they are coherent with solid-state high-temperature ductile deformation,which is attributed to left-lateral shearing along the ASRR shear zone.New LA-ICP-MS zircon U-Pb geochronological and microstructural studies of the post-kinematic granitic plutons provide a straightforward time constraint on the termination ductile left-lateral shearing and exhumation of the metamorphic massif in the ASRR shear zone.It is suggested that the left-lateral shearing along the ASRR shear zone ended at ca.21 Ma at relative lower-temperature or decreasing temperature conditions.During or after the emplacement of the young dikes at ca.21 Ma,rapid brittle deformation event occurred,which makes the DCS massif start fast uplift/exhumation and cooling to a shallow crustal level.展开更多
The uplift of the Ailao Shan-Diancang Shan （ASDS） along the Ailao Shan-Red River （ASRR） shear zone is an important geological event in the southeastern margin of Qinghai-Tibet Plateau tectonic domain in the Late C...The uplift of the Ailao Shan-Diancang Shan （ASDS） along the Ailao Shan-Red River （ASRR） shear zone is an important geological event in the southeastern margin of Qinghai-Tibet Plateau tectonic domain in the Late Cenozoic, and it preserves important information on the structures, exhumationai history and tectonic evolution of the ASRR shear zone. The uplift structural mode and uplift timing of the ASDS is currently an important scientific topic for understanding the ASDS formation and late stage movements and evolution of the ASRR shear zone. The formation of the ASDS has been widely considered to be the consequence of the strike-slip movements of the ASRR shear zone. However, the shaping of geomorphic units is generally direct results of the latest tectonic activities. In this study, we investigated the timing and uplift structural mechanism of the ASDS and provided the following lines of supportive evidence. Firstly, the primary tectonic foliation of the ASDS shows significant characteristic variations, with steeply dipping tectonic foliation developed on the east side of the ASDS and the relatively horizontal foliation on the west side. Secondly, from northeast to southwest direction, the deformation and metamorphism gradually weakened and this zone can be further divided into three different metamorphic degree belts. Thirdly, the contact relationship between the ASDS and the Chuxiong basin-Erhai lake is a normal fault contact which can be found on the east side of the ASDS. 40^Ar/^39 Argeochronology suggests that the Diancang Shan had experienced a fast cooling event during 3-4 Ma. The apatite fission track testing method gives the age of 6.6-10.7 Ma in the Diancang Shan and 4.6-8.4 Ma in the Ailao Shan, respectively. Therefore the uplift of the ASDS can be explained by tilted block mode in which the east side was uplifted much higher than the west side, and it is not main reason of the shearing movements of the ASRR shear zone. The most recent uplift stages of the ASDS happened in the Pliocene （3-4 Ma） and Late Miocene （6-10 Ma）.展开更多
Using arrival data of the body waves recorded by seismic stations, we reconstructed the velocity structure of the crust and upper mantle beneath the southeastern edge of the Tibetan Plateau and the northwestern contin...Using arrival data of the body waves recorded by seismic stations, we reconstructed the velocity structure of the crust and upper mantle beneath the southeastern edge of the Tibetan Plateau and the northwestern continental margin of the South China Sea through a travel time tomography technique. The result revealed the apparent tectonic variation along the Ailao Shan-Red River fault zone and its adjacent regions. High velocities are observed in the upper and middle crust beneath the Ailao Shan-Red River fault zone and they reflect the character of the fast uplifting and cooling of the metamorphic belt after the ductile shearing of the fault zone, while low velocities in the lower crust and near the Moho imply a relatively active crust-mantle boundary beneath the fault zone. On the west of the fault zone, the large-scale low velocities in the uppermost mantle beneath western Yunnan prove the influence of the mantle heat flow on volcano, hot spring and magma activities, however, the upper mantle on the east of the fault zone shows a relatively stable structure similar to the Yangtze block. The low velocities of the deep mantle beneath the southeastern extending segment of the fault zone are probably related to the mantle convection produced by the pull-apart of the South China Sea.展开更多
Using cooling curves of K-feldspars obtained by specific40Ar/39Ar step heating procedure and multiple diffusion domain modeling (MDD model), together with results of dating hornblende, biotite, muscovite, and apatite,...Using cooling curves of K-feldspars obtained by specific40Ar/39Ar step heating procedure and multiple diffusion domain modeling (MDD model), together with results of dating hornblende, biotite, muscovite, and apatite, this research relates the cooling history of 3 areas, from Ejia in NW to Jinping in SE of Ailao Shan-Red River shear zone, and near Hekou (distance about 390 km). The results indicate that the slip distance of Ailao Shan-Red River shear zone is more than 350 km (at least based on the study done within China). And between the end of the left-lateral slip movement and the beginning of the right-lateral slip movement, the uplift of shear zone from SE to NW was homogeneously extended.展开更多
Two kinds of radiolarian silicalites at the bottom and top of the ophiolite in the Mount (Mt.) Ailao belt, Yunnan Province, are dealt with in this work in terms of geology, micro-paleontology, isotope and REE. The fir...Two kinds of radiolarian silicalites at the bottom and top of the ophiolite in the Mount (Mt.) Ailao belt, Yunnan Province, are dealt with in this work in terms of geology, micro-paleontology, isotope and REE. The first kind of silicalite was defined as the turbidite formation. In this category, the radiolarian species lived in the Late Devonian (D3). The corresponding ecologic assemblage, composed of δ30Si (0.4‰-0.5‰, average 0.03‰), δCe (0.77-0.97, average 0.85) and LaN/YbN (0.77-1.06, average 0.96) of silicalite, shows that it occurred in the abyssal environment. The second kind of silicalite was defined as the mud-siliceous formation. Contacting conformably with the basalt of the ophiolite suit, the radiolarian silicalite at the top of ophiolite was in the category of the component units of the ophiolite in the Mt. Ailao belt. In this category, the radiolarian species lived in the Early Carboniferous (C1). The corresponding ecologic assemblage, composed of δ30Si (0.2‰-1.3‰averaging 0.7‰), ?展开更多
The metamophic peridotite of ophiolite belt in Mt. Ailao is composed of lherzolite and harzburgite. The former shows the charateristics of primary pyrolite and the latter shows those of deleted (relict)pyrolite. By pa...The metamophic peridotite of ophiolite belt in Mt. Ailao is composed of lherzolite and harzburgite. The former shows the charateristics of primary pyrolite and the latter shows those of deleted (relict)pyrolite. By partial melting of lherzolite, two primary magmas: tholeiitic magma and picrite-basalt magma are formed. The former evoluted into gabbro-diabase-pyroxenic basalt rock series and show the characteristics of MORB; while the latter evoluted into gabbro-diorite-albite basalt-picrite basalt one, and show the characteristics of para-MORB.展开更多
【目的】全面揭示哀牢山国家级自然保护区蚂蚁物种的多样性。【方法】采用样地调查法对该保护区的蚂蚁物种分布格局进行调查。【结果】8个垂直带的58块样地共采集蚂蚁10亚科61属209种。水平分布上,西坡的蚂蚁物种数高于东坡(171 vs 145)...【目的】全面揭示哀牢山国家级自然保护区蚂蚁物种的多样性。【方法】采用样地调查法对该保护区的蚂蚁物种分布格局进行调查。【结果】8个垂直带的58块样地共采集蚂蚁10亚科61属209种。水平分布上,西坡的蚂蚁物种数高于东坡(171 vs 145),西坡特有种64种,东坡特有种38种,东、西坡共有种107种;垂直分布上,东、西坡的蚂蚁物种数均与海拔负相关(西坡R^(2)=0.65,东坡R^(2)=0.63);10类不同生境中,中低海拔的针阔混交林和季风常绿阔叶林中栖息的蚂蚁物种较为丰富(分别为127和104种),高海拔的苔藓矮林中蚂蚁物种最贫乏(3种);觅食和筑巢分析中,土壤为蚂蚁最喜欢的觅食和筑巢场所,其次为地表,最后为植物上。【结论】哀牢山国家级自然保护区资源丰富,植被保护整体良好,孕育着丰富的蚂蚁物种。低海拔的人为干扰对蚂蚁物种有不利影响。多数(超过70%)蚂蚁物种的水平分布、垂直分布和栖息生境都十分有限,生态位极其狭窄,具有极高的保护价值。展开更多
依托哀牢山按公里网格布设的20个亚热带常绿阔叶林1 hm^(2)动态样地,选取样地内所有胸径(Diameter at breast height,DBH)≥10 cm的木果柯(Lithocarpus xylocarpus)个体作为研究对象,测量其6个功能性状(叶面积、比叶面积、叶片厚度、叶...依托哀牢山按公里网格布设的20个亚热带常绿阔叶林1 hm^(2)动态样地,选取样地内所有胸径(Diameter at breast height,DBH)≥10 cm的木果柯(Lithocarpus xylocarpus)个体作为研究对象,测量其6个功能性状(叶面积、比叶面积、叶片厚度、叶干物质含量、叶绿素含量和枝条木质密度),利用基于距离矩阵的多元回归解析遗传变异、环境距离、个体发育阶段差异对木果柯功能性状种内变异的相对作用。结果表明:木果柯的功能性状均存在不同程度的种内变异,叶面积变异最大,其次是比叶面积和叶片厚度,木质密度、叶干物质含量和叶绿素含量变异较小;对种内变异程度最大的叶面积来说,个体发育阶段差异的正效应最强,其次是遗传变异,环境距离的正效应最弱;遗传变异对叶绿素含量种内变异的正效应在所有性状中最强,而环境距离对比叶面积的正效应在所有性状中最强。展开更多
基金support from the State Key Research"973"Plan of China(No. 2009CB421001)National Natural Science Foundation of China(40872139)+1 种基金the 111 Project(B07011) of the Ministry of Education,State Key Laboratory of Geological Processes and Mineral Resources (GPMR200837)the Fundamental Research Funds for the Central Universities(GPMR2009PY01)
文摘The Ailao Shan-Red River fault zone is the boundary between the Yangtze block to the northeast and the Indochina block to the southwest.It is an important tectonic zone due to its role in the southeastward extrusion of the Indochina block during and subsequent to the Indian-Eurasian collision.Diancang Shan（DCS） high-grade metamorphic complex,located at the northwest extension along the Ailao Shan-Red River（ASRR） shear zone,is a representative metamorphic complex of the ASRR tectonic belt.Structural and microstructural analysis of sheared rocks in the high-grade metamorphic rocks reveals that they are coherent with solid-state high-temperature ductile deformation,which is attributed to left-lateral shearing along the ASRR shear zone.New LA-ICP-MS zircon U-Pb geochronological and microstructural studies of the post-kinematic granitic plutons provide a straightforward time constraint on the termination ductile left-lateral shearing and exhumation of the metamorphic massif in the ASRR shear zone.It is suggested that the left-lateral shearing along the ASRR shear zone ended at ca.21 Ma at relative lower-temperature or decreasing temperature conditions.During or after the emplacement of the young dikes at ca.21 Ma,rapid brittle deformation event occurred,which makes the DCS massif start fast uplift/exhumation and cooling to a shallow crustal level.
基金supported by the National Natural Foundation of China(No.40872149,40472100 and 40930419)
文摘The uplift of the Ailao Shan-Diancang Shan （ASDS） along the Ailao Shan-Red River （ASRR） shear zone is an important geological event in the southeastern margin of Qinghai-Tibet Plateau tectonic domain in the Late Cenozoic, and it preserves important information on the structures, exhumationai history and tectonic evolution of the ASRR shear zone. The uplift structural mode and uplift timing of the ASDS is currently an important scientific topic for understanding the ASDS formation and late stage movements and evolution of the ASRR shear zone. The formation of the ASDS has been widely considered to be the consequence of the strike-slip movements of the ASRR shear zone. However, the shaping of geomorphic units is generally direct results of the latest tectonic activities. In this study, we investigated the timing and uplift structural mechanism of the ASDS and provided the following lines of supportive evidence. Firstly, the primary tectonic foliation of the ASDS shows significant characteristic variations, with steeply dipping tectonic foliation developed on the east side of the ASDS and the relatively horizontal foliation on the west side. Secondly, from northeast to southwest direction, the deformation and metamorphism gradually weakened and this zone can be further divided into three different metamorphic degree belts. Thirdly, the contact relationship between the ASDS and the Chuxiong basin-Erhai lake is a normal fault contact which can be found on the east side of the ASDS. 40^Ar/^39 Argeochronology suggests that the Diancang Shan had experienced a fast cooling event during 3-4 Ma. The apatite fission track testing method gives the age of 6.6-10.7 Ma in the Diancang Shan and 4.6-8.4 Ma in the Ailao Shan, respectively. Therefore the uplift of the ASDS can be explained by tilted block mode in which the east side was uplifted much higher than the west side, and it is not main reason of the shearing movements of the ASRR shear zone. The most recent uplift stages of the ASDS happened in the Pliocene （3-4 Ma） and Late Miocene （6-10 Ma）.
基金supported by the Chinese Academy of Sciences Grant No.KZCX2-209)the National Major Fundamental and Dev elopment Project(Grant No.G200046701)the National Natural Science Foundation of China(Grant No.40034010).
文摘Using arrival data of the body waves recorded by seismic stations, we reconstructed the velocity structure of the crust and upper mantle beneath the southeastern edge of the Tibetan Plateau and the northwestern continental margin of the South China Sea through a travel time tomography technique. The result revealed the apparent tectonic variation along the Ailao Shan-Red River fault zone and its adjacent regions. High velocities are observed in the upper and middle crust beneath the Ailao Shan-Red River fault zone and they reflect the character of the fast uplifting and cooling of the metamorphic belt after the ductile shearing of the fault zone, while low velocities in the lower crust and near the Moho imply a relatively active crust-mantle boundary beneath the fault zone. On the west of the fault zone, the large-scale low velocities in the uppermost mantle beneath western Yunnan prove the influence of the mantle heat flow on volcano, hot spring and magma activities, however, the upper mantle on the east of the fault zone shows a relatively stable structure similar to the Yangtze block. The low velocities of the deep mantle beneath the southeastern extending segment of the fault zone are probably related to the mantle convection produced by the pull-apart of the South China Sea.
基金the National Natural Science Foundation of China (Grant No.49572147). We thank Guo Shunmin and Ji Fengju both in the Institue of geology, China Seismological Bureau for their help in field trips in Yunnan.
文摘Using cooling curves of K-feldspars obtained by specific40Ar/39Ar step heating procedure and multiple diffusion domain modeling (MDD model), together with results of dating hornblende, biotite, muscovite, and apatite, this research relates the cooling history of 3 areas, from Ejia in NW to Jinping in SE of Ailao Shan-Red River shear zone, and near Hekou (distance about 390 km). The results indicate that the slip distance of Ailao Shan-Red River shear zone is more than 350 km (at least based on the study done within China). And between the end of the left-lateral slip movement and the beginning of the right-lateral slip movement, the uplift of shear zone from SE to NW was homogeneously extended.
文摘Two kinds of radiolarian silicalites at the bottom and top of the ophiolite in the Mount (Mt.) Ailao belt, Yunnan Province, are dealt with in this work in terms of geology, micro-paleontology, isotope and REE. The first kind of silicalite was defined as the turbidite formation. In this category, the radiolarian species lived in the Late Devonian (D3). The corresponding ecologic assemblage, composed of δ30Si (0.4‰-0.5‰, average 0.03‰), δCe (0.77-0.97, average 0.85) and LaN/YbN (0.77-1.06, average 0.96) of silicalite, shows that it occurred in the abyssal environment. The second kind of silicalite was defined as the mud-siliceous formation. Contacting conformably with the basalt of the ophiolite suit, the radiolarian silicalite at the top of ophiolite was in the category of the component units of the ophiolite in the Mt. Ailao belt. In this category, the radiolarian species lived in the Early Carboniferous (C1). The corresponding ecologic assemblage, composed of δ30Si (0.2‰-1.3‰averaging 0.7‰), ?
文摘The metamophic peridotite of ophiolite belt in Mt. Ailao is composed of lherzolite and harzburgite. The former shows the charateristics of primary pyrolite and the latter shows those of deleted (relict)pyrolite. By partial melting of lherzolite, two primary magmas: tholeiitic magma and picrite-basalt magma are formed. The former evoluted into gabbro-diabase-pyroxenic basalt rock series and show the characteristics of MORB; while the latter evoluted into gabbro-diorite-albite basalt-picrite basalt one, and show the characteristics of para-MORB.
文摘【目的】全面揭示哀牢山国家级自然保护区蚂蚁物种的多样性。【方法】采用样地调查法对该保护区的蚂蚁物种分布格局进行调查。【结果】8个垂直带的58块样地共采集蚂蚁10亚科61属209种。水平分布上,西坡的蚂蚁物种数高于东坡(171 vs 145),西坡特有种64种,东坡特有种38种,东、西坡共有种107种;垂直分布上,东、西坡的蚂蚁物种数均与海拔负相关(西坡R^(2)=0.65,东坡R^(2)=0.63);10类不同生境中,中低海拔的针阔混交林和季风常绿阔叶林中栖息的蚂蚁物种较为丰富(分别为127和104种),高海拔的苔藓矮林中蚂蚁物种最贫乏(3种);觅食和筑巢分析中,土壤为蚂蚁最喜欢的觅食和筑巢场所,其次为地表,最后为植物上。【结论】哀牢山国家级自然保护区资源丰富,植被保护整体良好,孕育着丰富的蚂蚁物种。低海拔的人为干扰对蚂蚁物种有不利影响。多数(超过70%)蚂蚁物种的水平分布、垂直分布和栖息生境都十分有限,生态位极其狭窄,具有极高的保护价值。
文摘依托哀牢山按公里网格布设的20个亚热带常绿阔叶林1 hm^(2)动态样地,选取样地内所有胸径(Diameter at breast height,DBH)≥10 cm的木果柯(Lithocarpus xylocarpus)个体作为研究对象,测量其6个功能性状(叶面积、比叶面积、叶片厚度、叶干物质含量、叶绿素含量和枝条木质密度),利用基于距离矩阵的多元回归解析遗传变异、环境距离、个体发育阶段差异对木果柯功能性状种内变异的相对作用。结果表明:木果柯的功能性状均存在不同程度的种内变异,叶面积变异最大,其次是比叶面积和叶片厚度,木质密度、叶干物质含量和叶绿素含量变异较小;对种内变异程度最大的叶面积来说,个体发育阶段差异的正效应最强,其次是遗传变异,环境距离的正效应最弱;遗传变异对叶绿素含量种内变异的正效应在所有性状中最强,而环境距离对比叶面积的正效应在所有性状中最强。
