In 2008 and 2009,we made continuous and repeated breeding surveys of the Scaly-sided Merganser(Mergus squamatus)in the Changbai Mountain range(China side),using a combination of rubber-boat drifting and walking.Each s...In 2008 and 2009,we made continuous and repeated breeding surveys of the Scaly-sided Merganser(Mergus squamatus)in the Changbai Mountain range(China side),using a combination of rubber-boat drifting and walking.Each survey consisted of a census of breeding pairs in the spring and broods in the summer.A total of 1553 km in length of 17 river stretches were surveyed in four different river systems of the Yalujiang,Songhuajiang,Tumenjiang and Mudanjiang rivers.A total of 1354 individuals of the Scaly-sided Merganser were recorded during the both surveys.The breeding density for all the stretches surveyed over both years averaged 0.26 ± 0.30 pairs per km;the population density in the spring averaged 0.75 ± 0.88 individuals per km.According to our survey results,we estimated that the breeding population in the Changbai Mountain range was about 170 breeding pairs of the Scaly-sided Merganser.Three major breeding sites of this bird were found in the Changbai Mountain range in these surveys.展开更多
We present detailed species accounts for fifty-nine(59) species of amphibians and reptiles(17 frogs, 14 skinks, 3 agamids, 6 gekkonid lizards, 2 varanids, and 17 snakes) from Pantabangan-Carranglan Watershed, which li...We present detailed species accounts for fifty-nine(59) species of amphibians and reptiles(17 frogs, 14 skinks, 3 agamids, 6 gekkonid lizards, 2 varanids, and 17 snakes) from Pantabangan-Carranglan Watershed, which lies within the Caraballo Mountain Range, whose biota is poorly-known. This was also the first extensive survey of herpetofauna within the watershed. Together with data from previous literature reviews, our records bring the total number of species of amphibians and reptiles for the Caraballo Mountain Range to 66. Forty-two(42) species from the area were Philippine endemics, with 25 species recorded only from Luzon faunal region. Seven species of herpetofauna are associated with unresolved taxonomic issues(new species and species complexes needing taxonomic partitioning, e.g. splitting of species groups). Two species recorded from the area were rarely represented in museum collections. Major distributional and elevational range extensions were recorded for several species. Comparison with Luzon’s other mountain ranges showed that the Caraballo Mountain Range is similar, in terms of species composition, to the northern Sierra Madre and Cordillera Mountain Ranges. The result of this survey showed the Caraballo Mountain Range and its mountains as a possible new center of herpetofaunal diversity and endemicity within Luzon. The importance of the Caraballo Mountain Range as an important biogeographic link merits further study.展开更多
Earthquakes play a fundamental role in the evolution of Earth’s topography through co-seismic uplift and subsidence,as well as erosion through widespread landslides induced by ground motion.Earthquake-induced landsli...Earthquakes play a fundamental role in the evolution of Earth’s topography through co-seismic uplift and subsidence,as well as erosion through widespread landslides induced by ground motion.Earthquake-induced landslides can result in exceptional increases in the transfer of mass from landscapes,supplying sediment to rivers where impacts can last for decades or longer.Landslides can also erode vegetation and soils,in addition to exposing freshly ground rock mass,which can both result in regionally significant carbon transfers.Recent work has sought to quantify the fluxes,rates,and temporal patterns of the impacts on earth surface processes generated by these tectonic events.In this review,we focus on the impacts of earthquake-induced landslides on erosion and sediment flux,river water chemistry,and carbon export through the lens of the well-studied 2008 Wenchuan earthquake.We then discuss these themes in the context of works from the 1999 Taiwan Chi-Chi earthquake,2015 Nepalese Gorkha earthquake,and New Zealand historical earthquakes,altogether highlighting an important role of earthquake-induced landslides in erosion and weathering along tectonically active mountain ranges.We suggest that more monitoring,geochemical tracing,paleo-records,and/or modelling studies are needed to compare the processes and fluxes of catchment erosion and weathering before and after earthquake events,which will help to deepen our understanding not only of the impacts of earthquake-induced landslides on earth surface processes,but also the linkage among high magnitude events,continental erosion and weathering,and the long-term global carbon cycle.展开更多
A synthesis involving the data for the Nalati mountain region(NMR) in west Tianshan with a dataset including zircon U-Pb ages, Hf isotopic composition, major and trace elements of Paleozoic intrusions are presented ...A synthesis involving the data for the Nalati mountain region(NMR) in west Tianshan with a dataset including zircon U-Pb ages, Hf isotopic composition, major and trace elements of Paleozoic intrusions are presented to improve the understanding of regional geodynamic evolution. Paleozoic intrusive rocks in the NMR could be classified into four categories based on chronological and geochemical data: 480?5 Ma, 445–410 Ma, 345–320 Ma, and 295 Ma, which correspond to(1) closure of the Terskey Ocean and the opening of the south Tianshan back-arc basin, which was followed with the opening of the south Tianshan Ocean,(2) initial subduction of the south Tianshan oceanic crust,(3) major subduction stage, and(4) collision to post-collisional stage, respectively. Following the closure of the Terskey Ocean, the south Tianshan Ocean opened at Early Silurian and subducted under Yili-central Tianshan by the end of Early Carboniferous Period. The following breakoff of the subducted slab triggered partial melting of continental crust and formed voluminous granitic rocks in the NMR.展开更多
The Dabie orogen, Eastern Qinling orogen and Eastern Kunlun orogen are the major components of the Central Mountain Ranges of China and each has distinctively metamorphic processes in their oldest rock units. The Dab...The Dabie orogen, Eastern Qinling orogen and Eastern Kunlun orogen are the major components of the Central Mountain Ranges of China and each has distinctively metamorphic processes in their oldest rock units. The Dabie orogen oldest rock units had experienced an intermediate-higher pressure, upper amphibolite to lower granulite facies metamorphism in the Indosinian intracontinental subduction collision event. The clockwise pt path, synchronous attainment of t max and p max and a segment of high slope retrograde path suggest a tectono driven rapid exhumation of the oldest rock units to upper middle crustal level following the end of the subduction collision process. The oldest rock units, also called Qinling Group, of Eastern Qinling Mountains suffered intensively collisional metamorphism at an immature plate tectonic framework during Jinningian movement about 1 000 Ma ago. The clockwise pt path with reach of t max following several hundreds of MPa decreasing from p max suggests that the denudation of the deeply burial rock units was due essentially to isostatic relaxation. During the Caledonian stage, the highly metamorphosed oldest rock units suffered from a high t thermal event in arc environment and superimposed by contact metamorphism. After thermal peaks, the rock units were exhumed in a short distance and cooled down isobarically. No regional metamorphism higher than upper greenschist facies condition since 300 Ma has been traced within exposed rocks in the eastern portion of Northern Qinling orogen. The oldest rock units in the Eastern Kunlun orogen were metamorphosed to upper amphibolite facies to lower granulite facies rocks early or during the Luliang movement (some 1 800 Ma ago). The high grade metamorphic rock units had a long resident time at the deep crustal level, and were exhumed to middle upper crustal level during the Caledonian to Hercynian tectonometamorphic events. Shallow erosion of the orogenic belt led to good preservation of the low pressure metamorphic belt.展开更多
The article provides new data on the butterfly fauna of the Peter the Great Mountain range, especially the first reports of the analysis of the quantitative accounts on the number of butterflies. However, the presente...The article provides new data on the butterfly fauna of the Peter the Great Mountain range, especially the first reports of the analysis of the quantitative accounts on the number of butterflies. However, the presented species in the work (51 species) is not the final, as not all parts of the mountain ran^ze were visited.展开更多
The Shotori mountain range is located along the northern terminus of the Nayband fault on the eastern and western domains of the Tabas and Lut blocks,respectively.This range with NNW-SSE trending and approximately 120...The Shotori mountain range is located along the northern terminus of the Nayband fault on the eastern and western domains of the Tabas and Lut blocks,respectively.This range with NNW-SSE trending and approximately 120 km long includes a series of thrust faults approaching the right-lateral strike-slip Nayband fault.Since the Shotori range has experienced various geological events since the Triassic,our investigations suggest that the basement of the Central Iranian subcontinent of the Shotori range contains the early Triassic deep sedimentary with normal faults which confirms Triassic tensional tectonic stress regime in the region.After the middle Triassic,the mountain range has experienced thrust and strike-slip regimes.Therefore,in this study,we reconstruct the stress regimes for different geological periods using fault-slip data.The inversion of faultslip data reveals drastic temporal changes in the maximum stress regime(σ1)over the Triassic,Jurassic,Cretaceous,Paleogene,Neogen,and Quaternary.The reconstruction of the stress field based on the age and direction of fault movement reveals that the direction of the maximum horizontal stress axis(σ1)under a tensional stress regime was approximately N129°in the Early Triassic.This stress regime is the cause of thinning and subsidence of the Shotori sedimentary basin.During the middle Triassic,theσ1 direction was about N81°and the upper Triassic,theσ1 direction was almost N115°.The middle Triassic and upper Triassic stress states exhibited two distinct strike-slip and compressive stress regimes.This stress regime led to the uplift of the Shotori sedimentary basin.During the Jurassic,the direction of the maximum horizontal stress axis(σ1)was~NW-SE under a compressive stress regime.During the Triassic,theσ1 direction was~N-S.This stress regime led to the formation of the high topography of the Shotori Mountain Range.In the Late Cretaceous,the direction of the maximum horizontal stress axis(σ1)under the extensional stress regime was~NE-SW.This stress regime led to the uplift of the Paleogen Dacite in eastern Iran.During the Neogene,theσ1 direction was~N60°.The Quaternary tectonic regime is strike-slip and theσ1 direction is~N50°,consistent with the current convergence direction of the Arabia–Eurasia plates.Our paleostress analysis reveals four recognized stress in this area,which includes compressional,transtensional,transpressional,and strike-slip regimes.Our findings indicated that the crustal diversity of the tectonic regimes was responsible for the formation of various geological structures,such as folds,faults by different mechanisms,and the present-day configuration of the Shotori sedimentary basin.展开更多
Layer LJ3 of Linjiang stratigraphic section in Dongjiang River valley in the south of the Nanling Mountains is a set of red sandy sediments.Measured by thermoluminescence(TL) dating,it was found to be formed in MIS2-9...Layer LJ3 of Linjiang stratigraphic section in Dongjiang River valley in the south of the Nanling Mountains is a set of red sandy sediments.Measured by thermoluminescence(TL) dating,it was found to be formed in MIS2-9,500 ± 800 yr to 19,600 ± 1,800 yr B.P.After analy-sis of the grain sizes of the 16 samples(LJ3-100 to LJ3-85) in this layer,it was discovered that(1) The contents of each grain group in dif-ferent samples are similar.(2) The values of Md,Mz,,Sk,and Kg vary from LJ3-100 to LJ3-85 in a narrow range.(3) The segments of each sample in the accumulative curves extend parallel with similar slopes.All the three aspects reveal the Aeolian characteristics of Layer LJ3.Therefore,it is thought that Layer LJ3 consists of red sandy sediments formed in MIS2 in the south of Nanling Mountain,which reflects the arid climate at that time.展开更多
This study aims to find the altitudinal distribution pattern of vascular plant species reported from high mountain of Nepal(Manang) along the whole Himalayan elevation gradient, and evaluate their fate against climate...This study aims to find the altitudinal distribution pattern of vascular plant species reported from high mountain of Nepal(Manang) along the whole Himalayan elevation gradient, and evaluate their fate against climate change. Data was gathered from multiple sources, field investigations, literatures, and herbarium specimens. Altogether, 303 vascular plant species were reported from Manang. We used a published data to calculate distribution range of each species by interpolating between its upper and lower elevation limits. The relationship between elevation and species richness is elucidated by generalized linear model. The consequence of global warming upon Manang's vascular plant species was estimated based on projected temperature change for next century and adiabatic lapse rate along the elevation gradient of the Himalayas. The vascular plant species richness has a unimodel relationship with elevation along the whole elevation gradient of Nepal as well as in three biogeographical regions of Nepal. Vascular plants of Manang are found distributed from low land Terai to high alpine regions of Nepal and their elevation distribution range varies from 200 to 4700 m. Out of 303 vascular plants of Manang, only seven species might be affected if temperature increase by 1.5°C, whereas at least 70 species will be affected with 5°C temperature increased. However, the majority of species(233 species) have wider distribution range(> 1000 m) and more than 5°C temperature tolerance range, thus they are likely to be less affected from global warming by the end of 21 st century.展开更多
Understanding the influence of environmental variables on the spatial distribution of ecological communities is essential to predict the response of vegetation to various environmental drivers.Ecological theory sugges...Understanding the influence of environmental variables on the spatial distribution of ecological communities is essential to predict the response of vegetation to various environmental drivers.Ecological theory suggests that multiple environmental factors shape local species assemblages and should influence the various components of community structure and composition in different ways.This study aimed to classify Pinus wallichiana dominated forests in the Swat Hindukush range mountains to understand the relative influence of multiple environmental filters on its composition and structure.These forests represent the most typical of the species distribution in northern Pakistan and were not subjected to any phytosociological study.For this purpose,thirty forest stands,spanning a wide range of physical habitats were sampled using 10 x 10 m plots and the importance value index was calculated.The floristic and environmental data were subjected to Ward’s agglomerative cluster analysis for objective classification and ordinated with NMS ordination for pattern description and testing the vegetation-environmental relationships.Three floristically and ecologically distinct communities were recognized along the topographic gradient(elevation,r=0.377;slope,r=0.5548) coupled with soil physical(clay,r=0.2782;silt,r=0.3225) and chemical properties(pH,r=0.4975;lime,r=3982).An elevation gradient of 100 m separated the low(Pinus wallichiana-Quercus dilatata community)and middle elevations forest stands(P.wallichiana pure population) from the highland population type(Pinus wallichiana-Cedrus deodara community).The floristics and structure of these forest types respond directly or indirectly to topographic and soil variables which were evidenced from the floristic composition,species richness,and community physiognomy.These characteristics of the communities changed from heterogenous,dense stands to sparsely dispersed conifers,broadleaved-evergreen,and deciduous vegetation types along the environmental gradients.We concluded that several factors explained the spatial pattern.Thus,we predict that elevation coupled with soil physical and chemical properties could be considered if the ultimate goal is the restoration and conservation of these forests.We also recommend broad-scale phytosociological study on P.wallichiana forests including multiple sampling from diverse locations to define the floristic diversity and to better understand its ecological requirements.展开更多
In large continental orogens, an important research topic is the behavior of deep crustal and upper mantle deformation, and the flow styles of ductile material. The morphology of the eastern margin of the Tibetan plat...In large continental orogens, an important research topic is the behavior of deep crustal and upper mantle deformation, and the flow styles of ductile material. The morphology of the eastern margin of the Tibetan plateau, adjacent to the Sichuan basin, is characterized by very steep relief with high mountain ranges. The crust beneath this region slows the velocities in the middle and lower crust. We have adopted a relatively dense network to inverse the detailed structure of the crust and upper mantle along the eastern margin of the Tibetan plateau and Sichuan basin, using teleseismic data via receiver function analysis. The results are in-line with the hypothesis that viscous crustal material is flowing beneath the eastern margin of the Tibetan plateau and that this process drives overlying crustal material around the strong and rigid Sichuan basin. When the viscous material hits this obstruction, flows are divided into two or more branches with different directions. The upper part of the upwelling viscous flow produces the pressure to intrude the upper crust, thereby driving uplift of mountain ranges and high peaks. In contrast, the lower part of the downwelling viscous flow produces the pressure to intrude the lower crust and upper mantle to deepen the Moho discontinuity, causing observed crustal thickening.展开更多
The genetic mechanism of the 5.12 Wenchuan Earthquake is still being debated and there is still no convincing general explanation for most of the phenomena. This is because researchers have ignored the important role ...The genetic mechanism of the 5.12 Wenchuan Earthquake is still being debated and there is still no convincing general explanation for most of the phenomena. This is because researchers have ignored the important role of the Minshan block in the seismogenic process. The authors present a new opinion based on geological survey and comprehensive analyses. The Minshan block is a key tectonic element of the earthquake occurrence in the northwest triangle faulty block of Sichuan Province. The Minshan block is bordered by Longmen Mountain Range fractures in the south, the Huya fracture in the east, the Tazang fracture in the north and the Mounigou Valley fracture in the west. The rigidity of the block is relatively larger than those of the adjacent regions. The block's eastward movement pushed by regional maximum main geo-stress is limited when it suddenly tapers off near the east triangle end with a bottle-neck effect, and this causes geo-stress concentration around it. The shape of the block is coffin-like, wide in the upper part and narrow in the lower part. When a strong earthquake occurs along the block margins, the lock-up effect temporarily released, resulting in geo-stress transmitted to the Pingwu-Qingchuan (Motianling block) region. This transmission caused the Wenchuan earthquake's aftershocks to be concentrated in Qingchuan region. As the block moved eastward, the back of the block, i.e. the south segment of Mounigou Valley fracture, became active after the Wenchuan Earthquake. Therefore the aftershocks were concentrated along the south segment of Mounigou Valley fracture. Because the south margin is composed of the front range fracture, the geo-stress gradually released, causing many aftershocks along the Guanxian-Anxian fracture. The geological survey made after the Wenchuan Earthquake reveals that the surface ruptures in the south margin of Minshan block occur not along the Beichuan-Yingxiu fracture (central fracture) also along the front range fracture. The length of the surface rupture in the south margin ranges from several meters to several kilometers and it is distributed in en echelon (closely-spaced, parallel or subparallel, step-like surface ruptures). The vertical and horizontal displacements range from place to place and the thrusting component is dominant in the middle segment of Longmen Mountain Range structure belt. Nevertheless, the strike slip of the surface ruptures is dominant in the north segment of Longmen Mountain Range structure belt. Therefore the south margin is the original seismic structure. The sudden thrusting of the south margin of the Minshan block is the source event for the Wenchuan Earthquake.展开更多
Rapid deglaciation is one of the most important challenges in the Earth science today.One reason of this is specific supraglacial sediments–cryoconites,which represent carbon-containing dust with organomineral matter...Rapid deglaciation is one of the most important challenges in the Earth science today.One reason of this is specific supraglacial sediments–cryoconites,which represent carbon-containing dust with organomineral matter and living organisms.Investigation of physical and chemical characteristics of cryoconites in the Central Caucasus is necessary in order to understand their influence on alpine territories biogeochemical cycles,pollution and development in conditions of intensive glacial melting and active anthropogenic influence.For this research cryoconites as well as moraines,soil-like bodies and soils have been sampled from the alpine Bezengi Glacier and adjacent Khulamo-Bezengi Gorge.Key physicochemical features(pH values,total organic carbon content,microbial respiration,particle-size distribution)as well as content of trace elements have been defined in sampled materials and several pollution indices(Geoaccumulation index,Contamination factor and Degree of pollution)have been calculated.Results obtained show low values of total organic carbon in cryoconites(max.0.23%)but high values(max.7.54%)in top horizon of soils located in floodplain,indicating its active fluvioglacial transfer which may further accelerate the development of soils.Microbiological activity in the studied soils was mostly influenced by additional input of labile organic carbon from cryoconites with water flows.Particle-size distribution was similar among the studied cryoconites,indicating dominance of sand fraction(up to 85.28%)while studied soils showed higher variability due to influence of weathering.Among the trace elements,cryoconites were mostly polluted by Zn(max.85.70 mg·kg^(-1))which corresponds to high pollution according to pollution indices;Pb(max.24.90 mg·kg^(-1))and Cu(max.17.40 mg·kg^(-1)),up to moderate pollution level.Redistribution of polluted cryoconite material as well as local anthropogenic activities increased pollution of periglacial soils by Zn(max.89.20 mg·kg^(-1)),Pb(max.15.00 mg·kg^(-1))and Cu(max.12.80 mg·kg^(-1)),which was also proven by the pollution indices with up to high level of pollution.展开更多
With the deepening of research in the tectonic evolution and stress fields of China in Meso-Cenozoic, some aspects of the Previous conclusion about the tectonogeomorphology of China are found to be open to question. T...With the deepening of research in the tectonic evolution and stress fields of China in Meso-Cenozoic, some aspects of the Previous conclusion about the tectonogeomorphology of China are found to be open to question. The author considers that the Sichuanian stage (135-52 Ma ) is the embryonic stage for forming the recent landform in eastern China;the appearance of the mountain ranges and drainage basin areas trending in east-west are the results of the north - south directional extension during the North Sinian stage(52 - 23.3 Ma );the formation of five mega - Step landforms from the Qinghai - Xizang Plateau to Pacific ocean and the seafloor spreading basins in the eastern margin of Asian continent as well as the l- up of drainage systems of both Yangtze and Yellow rivers are related to the northward compression, cast-west trending extension and the isostatic compensation of crust during Himalayan Stage (23.3-0.73 Ma ). Through the above three Stages of tectonic processes, a framework of landform of China finally took shape in the main.展开更多
This paper provides the diversity assessment of the tree species in Sitio <span style="white-space:nowrap;">Dicasalarin</span>, Barangay Zabali, Baler, Aurora including the endemism and ecologica...This paper provides the diversity assessment of the tree species in Sitio <span style="white-space:nowrap;">Dicasalarin</span>, Barangay Zabali, Baler, Aurora including the endemism and ecological status. A total of 2239 individuals from 139 morphospecies, 87 genera and 46 families were recorded. A total of 48 Philippine endemic species and 2 Aurora Endemic species were found and at least 29 threatened species were listed either in the IUCN Red List of Threatened Species and Philippine List of Threatened Species. Results of the tree diversity showed that the area is highly diverse being a well-protected and well-managed area.展开更多
基金sponsored by the Rufford Small Grant of the Rufford Foundation
文摘In 2008 and 2009,we made continuous and repeated breeding surveys of the Scaly-sided Merganser(Mergus squamatus)in the Changbai Mountain range(China side),using a combination of rubber-boat drifting and walking.Each survey consisted of a census of breeding pairs in the spring and broods in the summer.A total of 1553 km in length of 17 river stretches were surveyed in four different river systems of the Yalujiang,Songhuajiang,Tumenjiang and Mudanjiang rivers.A total of 1354 individuals of the Scaly-sided Merganser were recorded during the both surveys.The breeding density for all the stretches surveyed over both years averaged 0.26 ± 0.30 pairs per km;the population density in the spring averaged 0.75 ± 0.88 individuals per km.According to our survey results,we estimated that the breeding population in the Changbai Mountain range was about 170 breeding pairs of the Scaly-sided Merganser.Three major breeding sites of this bird were found in the Changbai Mountain range in these surveys.
基金the Rufford Small Grant for Nature Conservation (Project No. 19494-1)DOST-ASTHRDP-NSC and IdeaWild Organization for generously funding this research and for supporting the fieldworks
文摘We present detailed species accounts for fifty-nine(59) species of amphibians and reptiles(17 frogs, 14 skinks, 3 agamids, 6 gekkonid lizards, 2 varanids, and 17 snakes) from Pantabangan-Carranglan Watershed, which lies within the Caraballo Mountain Range, whose biota is poorly-known. This was also the first extensive survey of herpetofauna within the watershed. Together with data from previous literature reviews, our records bring the total number of species of amphibians and reptiles for the Caraballo Mountain Range to 66. Forty-two(42) species from the area were Philippine endemics, with 25 species recorded only from Luzon faunal region. Seven species of herpetofauna are associated with unresolved taxonomic issues(new species and species complexes needing taxonomic partitioning, e.g. splitting of species groups). Two species recorded from the area were rarely represented in museum collections. Major distributional and elevational range extensions were recorded for several species. Comparison with Luzon’s other mountain ranges showed that the Caraballo Mountain Range is similar, in terms of species composition, to the northern Sierra Madre and Cordillera Mountain Ranges. The result of this survey showed the Caraballo Mountain Range and its mountains as a possible new center of herpetofaunal diversity and endemicity within Luzon. The importance of the Caraballo Mountain Range as an important biogeographic link merits further study.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.41991322 and 41930864)the Key Research Program of the Chinese Academy of Sciences(Grant No.QYZDJ-SSW-DQC033)to Zhangdong JIN,and Chinese Academy of Sciences Fellowships for Young International Scientists to both A.Joshua WEST and Robert G.HILTON.
文摘Earthquakes play a fundamental role in the evolution of Earth’s topography through co-seismic uplift and subsidence,as well as erosion through widespread landslides induced by ground motion.Earthquake-induced landslides can result in exceptional increases in the transfer of mass from landscapes,supplying sediment to rivers where impacts can last for decades or longer.Landslides can also erode vegetation and soils,in addition to exposing freshly ground rock mass,which can both result in regionally significant carbon transfers.Recent work has sought to quantify the fluxes,rates,and temporal patterns of the impacts on earth surface processes generated by these tectonic events.In this review,we focus on the impacts of earthquake-induced landslides on erosion and sediment flux,river water chemistry,and carbon export through the lens of the well-studied 2008 Wenchuan earthquake.We then discuss these themes in the context of works from the 1999 Taiwan Chi-Chi earthquake,2015 Nepalese Gorkha earthquake,and New Zealand historical earthquakes,altogether highlighting an important role of earthquake-induced landslides in erosion and weathering along tectonically active mountain ranges.We suggest that more monitoring,geochemical tracing,paleo-records,and/or modelling studies are needed to compare the processes and fluxes of catchment erosion and weathering before and after earthquake events,which will help to deepen our understanding not only of the impacts of earthquake-induced landslides on earth surface processes,but also the linkage among high magnitude events,continental erosion and weathering,and the long-term global carbon cycle.
基金financially supported by the National Natural Science Foundation of China (Nos.41372062, 41330210, 41672047)
文摘A synthesis involving the data for the Nalati mountain region(NMR) in west Tianshan with a dataset including zircon U-Pb ages, Hf isotopic composition, major and trace elements of Paleozoic intrusions are presented to improve the understanding of regional geodynamic evolution. Paleozoic intrusive rocks in the NMR could be classified into four categories based on chronological and geochemical data: 480?5 Ma, 445–410 Ma, 345–320 Ma, and 295 Ma, which correspond to(1) closure of the Terskey Ocean and the opening of the south Tianshan back-arc basin, which was followed with the opening of the south Tianshan Ocean,(2) initial subduction of the south Tianshan oceanic crust,(3) major subduction stage, and(4) collision to post-collisional stage, respectively. Following the closure of the Terskey Ocean, the south Tianshan Ocean opened at Early Silurian and subducted under Yili-central Tianshan by the end of Early Carboniferous Period. The following breakoff of the subducted slab triggered partial melting of continental crust and formed voluminous granitic rocks in the NMR.
文摘The Dabie orogen, Eastern Qinling orogen and Eastern Kunlun orogen are the major components of the Central Mountain Ranges of China and each has distinctively metamorphic processes in their oldest rock units. The Dabie orogen oldest rock units had experienced an intermediate-higher pressure, upper amphibolite to lower granulite facies metamorphism in the Indosinian intracontinental subduction collision event. The clockwise pt path, synchronous attainment of t max and p max and a segment of high slope retrograde path suggest a tectono driven rapid exhumation of the oldest rock units to upper middle crustal level following the end of the subduction collision process. The oldest rock units, also called Qinling Group, of Eastern Qinling Mountains suffered intensively collisional metamorphism at an immature plate tectonic framework during Jinningian movement about 1 000 Ma ago. The clockwise pt path with reach of t max following several hundreds of MPa decreasing from p max suggests that the denudation of the deeply burial rock units was due essentially to isostatic relaxation. During the Caledonian stage, the highly metamorphosed oldest rock units suffered from a high t thermal event in arc environment and superimposed by contact metamorphism. After thermal peaks, the rock units were exhumed in a short distance and cooled down isobarically. No regional metamorphism higher than upper greenschist facies condition since 300 Ma has been traced within exposed rocks in the eastern portion of Northern Qinling orogen. The oldest rock units in the Eastern Kunlun orogen were metamorphosed to upper amphibolite facies to lower granulite facies rocks early or during the Luliang movement (some 1 800 Ma ago). The high grade metamorphic rock units had a long resident time at the deep crustal level, and were exhumed to middle upper crustal level during the Caledonian to Hercynian tectonometamorphic events. Shallow erosion of the orogenic belt led to good preservation of the low pressure metamorphic belt.
基金supported by the Minister of Science and Technology of the People’s Republic of China(2015DFR30790)the External Cooperation Program of BIC,Chinese Academy of Sciences(GJHZ201311)
文摘The article provides new data on the butterfly fauna of the Peter the Great Mountain range, especially the first reports of the analysis of the quantitative accounts on the number of butterflies. However, the presented species in the work (51 species) is not the final, as not all parts of the mountain ran^ze were visited.
文摘The Shotori mountain range is located along the northern terminus of the Nayband fault on the eastern and western domains of the Tabas and Lut blocks,respectively.This range with NNW-SSE trending and approximately 120 km long includes a series of thrust faults approaching the right-lateral strike-slip Nayband fault.Since the Shotori range has experienced various geological events since the Triassic,our investigations suggest that the basement of the Central Iranian subcontinent of the Shotori range contains the early Triassic deep sedimentary with normal faults which confirms Triassic tensional tectonic stress regime in the region.After the middle Triassic,the mountain range has experienced thrust and strike-slip regimes.Therefore,in this study,we reconstruct the stress regimes for different geological periods using fault-slip data.The inversion of faultslip data reveals drastic temporal changes in the maximum stress regime(σ1)over the Triassic,Jurassic,Cretaceous,Paleogene,Neogen,and Quaternary.The reconstruction of the stress field based on the age and direction of fault movement reveals that the direction of the maximum horizontal stress axis(σ1)under a tensional stress regime was approximately N129°in the Early Triassic.This stress regime is the cause of thinning and subsidence of the Shotori sedimentary basin.During the middle Triassic,theσ1 direction was about N81°and the upper Triassic,theσ1 direction was almost N115°.The middle Triassic and upper Triassic stress states exhibited two distinct strike-slip and compressive stress regimes.This stress regime led to the uplift of the Shotori sedimentary basin.During the Jurassic,the direction of the maximum horizontal stress axis(σ1)was~NW-SE under a compressive stress regime.During the Triassic,theσ1 direction was~N-S.This stress regime led to the formation of the high topography of the Shotori Mountain Range.In the Late Cretaceous,the direction of the maximum horizontal stress axis(σ1)under the extensional stress regime was~NE-SW.This stress regime led to the uplift of the Paleogen Dacite in eastern Iran.During the Neogene,theσ1 direction was~N60°.The Quaternary tectonic regime is strike-slip and theσ1 direction is~N50°,consistent with the current convergence direction of the Arabia–Eurasia plates.Our paleostress analysis reveals four recognized stress in this area,which includes compressional,transtensional,transpressional,and strike-slip regimes.Our findings indicated that the crustal diversity of the tectonic regimes was responsible for the formation of various geological structures,such as folds,faults by different mechanisms,and the present-day configuration of the Shotori sedimentary basin.
基金funded by the National Natural Science Foundation of China (No 40471139)National Basic Research Program of China (No 2004CB 720206)the State Key Laboratory of Loess and Quaternary Geology,Institute of Earth Environment, Chinese Academy of Sci-ences Foundation (No SKLLQG0309)
文摘Layer LJ3 of Linjiang stratigraphic section in Dongjiang River valley in the south of the Nanling Mountains is a set of red sandy sediments.Measured by thermoluminescence(TL) dating,it was found to be formed in MIS2-9,500 ± 800 yr to 19,600 ± 1,800 yr B.P.After analy-sis of the grain sizes of the 16 samples(LJ3-100 to LJ3-85) in this layer,it was discovered that(1) The contents of each grain group in dif-ferent samples are similar.(2) The values of Md,Mz,,Sk,and Kg vary from LJ3-100 to LJ3-85 in a narrow range.(3) The segments of each sample in the accumulative curves extend parallel with similar slopes.All the three aspects reveal the Aeolian characteristics of Layer LJ3.Therefore,it is thought that Layer LJ3 consists of red sandy sediments formed in MIS2 in the south of Nanling Mountain,which reflects the arid climate at that time.
基金supported by Norwegian Council for Higher Education’s Program for Development Research and Education
文摘This study aims to find the altitudinal distribution pattern of vascular plant species reported from high mountain of Nepal(Manang) along the whole Himalayan elevation gradient, and evaluate their fate against climate change. Data was gathered from multiple sources, field investigations, literatures, and herbarium specimens. Altogether, 303 vascular plant species were reported from Manang. We used a published data to calculate distribution range of each species by interpolating between its upper and lower elevation limits. The relationship between elevation and species richness is elucidated by generalized linear model. The consequence of global warming upon Manang's vascular plant species was estimated based on projected temperature change for next century and adiabatic lapse rate along the elevation gradient of the Himalayas. The vascular plant species richness has a unimodel relationship with elevation along the whole elevation gradient of Nepal as well as in three biogeographical regions of Nepal. Vascular plants of Manang are found distributed from low land Terai to high alpine regions of Nepal and their elevation distribution range varies from 200 to 4700 m. Out of 303 vascular plants of Manang, only seven species might be affected if temperature increase by 1.5°C, whereas at least 70 species will be affected with 5°C temperature increased. However, the majority of species(233 species) have wider distribution range(> 1000 m) and more than 5°C temperature tolerance range, thus they are likely to be less affected from global warming by the end of 21 st century.
基金supported by Higher Education Commission of Pakistan
文摘Understanding the influence of environmental variables on the spatial distribution of ecological communities is essential to predict the response of vegetation to various environmental drivers.Ecological theory suggests that multiple environmental factors shape local species assemblages and should influence the various components of community structure and composition in different ways.This study aimed to classify Pinus wallichiana dominated forests in the Swat Hindukush range mountains to understand the relative influence of multiple environmental filters on its composition and structure.These forests represent the most typical of the species distribution in northern Pakistan and were not subjected to any phytosociological study.For this purpose,thirty forest stands,spanning a wide range of physical habitats were sampled using 10 x 10 m plots and the importance value index was calculated.The floristic and environmental data were subjected to Ward’s agglomerative cluster analysis for objective classification and ordinated with NMS ordination for pattern description and testing the vegetation-environmental relationships.Three floristically and ecologically distinct communities were recognized along the topographic gradient(elevation,r=0.377;slope,r=0.5548) coupled with soil physical(clay,r=0.2782;silt,r=0.3225) and chemical properties(pH,r=0.4975;lime,r=3982).An elevation gradient of 100 m separated the low(Pinus wallichiana-Quercus dilatata community)and middle elevations forest stands(P.wallichiana pure population) from the highland population type(Pinus wallichiana-Cedrus deodara community).The floristics and structure of these forest types respond directly or indirectly to topographic and soil variables which were evidenced from the floristic composition,species richness,and community physiognomy.These characteristics of the communities changed from heterogenous,dense stands to sparsely dispersed conifers,broadleaved-evergreen,and deciduous vegetation types along the environmental gradients.We concluded that several factors explained the spatial pattern.Thus,we predict that elevation coupled with soil physical and chemical properties could be considered if the ultimate goal is the restoration and conservation of these forests.We also recommend broad-scale phytosociological study on P.wallichiana forests including multiple sampling from diverse locations to define the floristic diversity and to better understand its ecological requirements.
基金supported by National Natural Science Foundation of China under grant Nos. 40839909,41074062, and 40674040
文摘In large continental orogens, an important research topic is the behavior of deep crustal and upper mantle deformation, and the flow styles of ductile material. The morphology of the eastern margin of the Tibetan plateau, adjacent to the Sichuan basin, is characterized by very steep relief with high mountain ranges. The crust beneath this region slows the velocities in the middle and lower crust. We have adopted a relatively dense network to inverse the detailed structure of the crust and upper mantle along the eastern margin of the Tibetan plateau and Sichuan basin, using teleseismic data via receiver function analysis. The results are in-line with the hypothesis that viscous crustal material is flowing beneath the eastern margin of the Tibetan plateau and that this process drives overlying crustal material around the strong and rigid Sichuan basin. When the viscous material hits this obstruction, flows are divided into two or more branches with different directions. The upper part of the upwelling viscous flow produces the pressure to intrude the upper crust, thereby driving uplift of mountain ranges and high peaks. In contrast, the lower part of the downwelling viscous flow produces the pressure to intrude the lower crust and upper mantle to deepen the Moho discontinuity, causing observed crustal thickening.
基金supported by National Natural Science Foundation of China (NSFC), Grant No.2008CB425801, 41072231the China Geological Survey Bureau (Grant No. 1212010914010)
文摘The genetic mechanism of the 5.12 Wenchuan Earthquake is still being debated and there is still no convincing general explanation for most of the phenomena. This is because researchers have ignored the important role of the Minshan block in the seismogenic process. The authors present a new opinion based on geological survey and comprehensive analyses. The Minshan block is a key tectonic element of the earthquake occurrence in the northwest triangle faulty block of Sichuan Province. The Minshan block is bordered by Longmen Mountain Range fractures in the south, the Huya fracture in the east, the Tazang fracture in the north and the Mounigou Valley fracture in the west. The rigidity of the block is relatively larger than those of the adjacent regions. The block's eastward movement pushed by regional maximum main geo-stress is limited when it suddenly tapers off near the east triangle end with a bottle-neck effect, and this causes geo-stress concentration around it. The shape of the block is coffin-like, wide in the upper part and narrow in the lower part. When a strong earthquake occurs along the block margins, the lock-up effect temporarily released, resulting in geo-stress transmitted to the Pingwu-Qingchuan (Motianling block) region. This transmission caused the Wenchuan earthquake's aftershocks to be concentrated in Qingchuan region. As the block moved eastward, the back of the block, i.e. the south segment of Mounigou Valley fracture, became active after the Wenchuan Earthquake. Therefore the aftershocks were concentrated along the south segment of Mounigou Valley fracture. Because the south margin is composed of the front range fracture, the geo-stress gradually released, causing many aftershocks along the Guanxian-Anxian fracture. The geological survey made after the Wenchuan Earthquake reveals that the surface ruptures in the south margin of Minshan block occur not along the Beichuan-Yingxiu fracture (central fracture) also along the front range fracture. The length of the surface rupture in the south margin ranges from several meters to several kilometers and it is distributed in en echelon (closely-spaced, parallel or subparallel, step-like surface ruptures). The vertical and horizontal displacements range from place to place and the thrusting component is dominant in the middle segment of Longmen Mountain Range structure belt. Nevertheless, the strike slip of the surface ruptures is dominant in the north segment of Longmen Mountain Range structure belt. Therefore the south margin is the original seismic structure. The sudden thrusting of the south margin of the Minshan block is the source event for the Wenchuan Earthquake.
基金supported by the Russian Foundation for Basic Research,project No 19-05-50107。
文摘Rapid deglaciation is one of the most important challenges in the Earth science today.One reason of this is specific supraglacial sediments–cryoconites,which represent carbon-containing dust with organomineral matter and living organisms.Investigation of physical and chemical characteristics of cryoconites in the Central Caucasus is necessary in order to understand their influence on alpine territories biogeochemical cycles,pollution and development in conditions of intensive glacial melting and active anthropogenic influence.For this research cryoconites as well as moraines,soil-like bodies and soils have been sampled from the alpine Bezengi Glacier and adjacent Khulamo-Bezengi Gorge.Key physicochemical features(pH values,total organic carbon content,microbial respiration,particle-size distribution)as well as content of trace elements have been defined in sampled materials and several pollution indices(Geoaccumulation index,Contamination factor and Degree of pollution)have been calculated.Results obtained show low values of total organic carbon in cryoconites(max.0.23%)but high values(max.7.54%)in top horizon of soils located in floodplain,indicating its active fluvioglacial transfer which may further accelerate the development of soils.Microbiological activity in the studied soils was mostly influenced by additional input of labile organic carbon from cryoconites with water flows.Particle-size distribution was similar among the studied cryoconites,indicating dominance of sand fraction(up to 85.28%)while studied soils showed higher variability due to influence of weathering.Among the trace elements,cryoconites were mostly polluted by Zn(max.85.70 mg·kg^(-1))which corresponds to high pollution according to pollution indices;Pb(max.24.90 mg·kg^(-1))and Cu(max.17.40 mg·kg^(-1)),up to moderate pollution level.Redistribution of polluted cryoconite material as well as local anthropogenic activities increased pollution of periglacial soils by Zn(max.89.20 mg·kg^(-1)),Pb(max.15.00 mg·kg^(-1))and Cu(max.12.80 mg·kg^(-1)),which was also proven by the pollution indices with up to high level of pollution.
文摘With the deepening of research in the tectonic evolution and stress fields of China in Meso-Cenozoic, some aspects of the Previous conclusion about the tectonogeomorphology of China are found to be open to question. The author considers that the Sichuanian stage (135-52 Ma ) is the embryonic stage for forming the recent landform in eastern China;the appearance of the mountain ranges and drainage basin areas trending in east-west are the results of the north - south directional extension during the North Sinian stage(52 - 23.3 Ma );the formation of five mega - Step landforms from the Qinghai - Xizang Plateau to Pacific ocean and the seafloor spreading basins in the eastern margin of Asian continent as well as the l- up of drainage systems of both Yangtze and Yellow rivers are related to the northward compression, cast-west trending extension and the isostatic compensation of crust during Himalayan Stage (23.3-0.73 Ma ). Through the above three Stages of tectonic processes, a framework of landform of China finally took shape in the main.
文摘This paper provides the diversity assessment of the tree species in Sitio <span style="white-space:nowrap;">Dicasalarin</span>, Barangay Zabali, Baler, Aurora including the endemism and ecological status. A total of 2239 individuals from 139 morphospecies, 87 genera and 46 families were recorded. A total of 48 Philippine endemic species and 2 Aurora Endemic species were found and at least 29 threatened species were listed either in the IUCN Red List of Threatened Species and Philippine List of Threatened Species. Results of the tree diversity showed that the area is highly diverse being a well-protected and well-managed area.