The author affiliation and the funding information in the Acknowledgement section of the online version of the original article was revised.One affiliation(the 8th affiliation)of the first author is added.The Acknowle...The author affiliation and the funding information in the Acknowledgement section of the online version of the original article was revised.One affiliation(the 8th affiliation)of the first author is added.The Acknowledgement section of the original article has been revised to:Acknowledgments:This research was funded by the National University of Mongolia under grant agreement P2023(grant number P2023-4578)and supported by the Chey Institute for Advanced Studies“International Scholarship Exchange Fellowship for the academic year of 2024-2025”,Republic of Korea,and the National University of Mongolia.We would like to acknowledge the National University of Mongolia and Soumik Das from the Center for the Study of Regional Development,Jawaharlal Nehru University,New Delhi-110067,for his valuable assistance in preparing the geological maps.展开更多
As a highly coupled aggregate of tectonism,magmatism,and metamorphism,a gneiss dome is usually taken as a vital window for understanding the crustal internal structure and the exchange of material and energy during or...As a highly coupled aggregate of tectonism,magmatism,and metamorphism,a gneiss dome is usually taken as a vital window for understanding the crustal internal structure and the exchange of material and energy during orogenic exhumation.The Qinghe gneiss dome located in the eastern Chinese Altai orogen,lies in Qinghe County,Xinjiang,records important information of late accretionary orogeny associated with continental uplift and crustal growth.According to the field investigation,the dome shows core-mantle-margin domains,in which the core is composed of migmatized granite and gneiss,the mantle consists of banded gneiss,schist,and leptynite,and the margin has rock assemblages of phyllite,schist,and meta-sandstone.From the margin to the core,the dome can be divided into chlorite-sericite,andalusite-staurolite,sillimanite-biotite,and sillimanite-garnet metamorphic zones,recording progressive metamorphism.Detailed structural analyses in the Qinghe gneiss dome indicate progressive deformation from the margin to the core.Internal and external detachment faults are clarified,with the former characterized by inflow and outward migration of crustal material and the latter marked by brittle-ductile deformation with a lineation indicating lateral slip of the upper wall when the dome uplifted.Based on these faults,upper,middle,lower structural layers are observed from the outer to inner domains of the dome.Considering the general geological background and new data,the Qinghe gneiss dome probably predominantly underwent early ductile shear deformation and late heat-flow diapirism in the early Permian,closely related to upwelling of asthenosphere mantle that resulted from slab break-off in the extensional tectonic setting.展开更多
The physiological structure and growth of trees in extreme environments(freezing temperatures,prolonged drought,wildfires,pest infestations,and diseases)can be inhibited,including radial growth,and stagnant growth or ...The physiological structure and growth of trees in extreme environments(freezing temperatures,prolonged drought,wildfires,pest infestations,and diseases)can be inhibited,including radial growth,and stagnant growth or missing annual rings is highly possible.In this study,we analyzed the radial growth of Siberian larch(Larix sibirica)in the Hongshanzui area of the Altai Mountains,China.The overall missing ring rate at the sampling point was 2.39%,with years with the highest missing rings since meteorological site data were available(1960)identified as 1960,1961,1971,1973,1985,1987,and 1995.Radial growth in high altitudes was mainly affected by temperatures in May and June(average temperature,average minimum temperature,and average maximum temperature).Frequent periods of freezing may lead to missing annual rings.However,while Larix sibirica shows resilience after prolonged freezing temperatures,it still requires time for the trees to return to normal growth levels.展开更多
The Altai-Sayan region,an active intracontinental mountain belt characterized by high relief,has undergone multiple phases of intense mountain building and denudation throughout the Mesozoic and Cenozoic.As this mount...The Altai-Sayan region,an active intracontinental mountain belt characterized by high relief,has undergone multiple phases of intense mountain building and denudation throughout the Mesozoic and Cenozoic.As this mountain belt with remarkable topography is distant from any active plate margins,its mountain growth pattern and tectonic reactivation mechanism are of great significance to the study of intracontinental orogeny.展开更多
The 1931 M_(w)7.8 Fuyun earthquake occurred around the Altai mountains, an intracontinental deformation belt with limited active strain-rate accumulation. To explore whether seismic activity in this deformation belt w...The 1931 M_(w)7.8 Fuyun earthquake occurred around the Altai mountains, an intracontinental deformation belt with limited active strain-rate accumulation. To explore whether seismic activity in this deformation belt was affected by stress interaction among different active faults, we calculate the Coulomb failure stress change(ΔCFS) induced by the Fuyun earthquake due to coseismic deformation of the elastic crust and postseismic viscoelastic relaxation of the lower crust and upper mantle. Numerical results show that the total ΔCFS at a 10-km depth produced by the Fuyun earthquake attains approximately 0.015-0.134 bar near the epicenter, and just before the occurrence of the 2003 M_(w)7.2 Chuya earthquake, which distances about 400 km away from the Fuyun earthquake. Among the increased ΔCFS,viscoelastic relaxation from 1931 to 2003 contributes to approximately 0.014-0.131 bar, accounting for>90% of the total ΔCFS. More importantly, we find that for the recorded seismicity in the region with a radius of about 270 km to the Fuyun earthquake from 1970 to 2018, the percentage of earthquakes that fall in positive lobes of ΔCFS resolved on the NNW-SSE Fuyun strike-slip fault, on the NWW-SEE Irtysh strike-slip fault, and on the NW-SE Kurti reverse fault is up to 67.22%-91.36%. Therefore, the predictedΔCFS suggests that the impact of the 1931 M_(w)7.8 Fuyun earthquake on seismic activity around the Altai mountains is still significant as to hasten occurrence of the 2003 M_(w)7.2 Chuya earthquake at a relatively far distance and to trigger its aftershocks in the near-field even after several decades of the mainshock.展开更多
This study investigates the glacial lake outburst flood(GLOF)hazards in the Tsambagarav mountain range in Western Mongolia,focusing on the Khukhnuruu Valley and its interconnected proglacial lakes.Over the last 30 yea...This study investigates the glacial lake outburst flood(GLOF)hazards in the Tsambagarav mountain range in Western Mongolia,focusing on the Khukhnuruu Valley and its interconnected proglacial lakes.Over the last 30 years,significant glacier retreats,driven by rising temperatures and changing precipitation patterns,have led to the formation and expansion of several proglacial lakes.Fieldwork combined with satellite data and meteorological analysis was used to assess the dynamics of glacier and lake area changes,with particular focus on the flood events of July 2021.The research reveals a substantial reduction in glacier area,particularly in the Khukhnuruu E complex,where glacier area decreased by 19.3%.The study highlights the influence of increasing temperatures and summer precipitation,which have accelerated ice melt,contributing to the expansion and eventual breaching of lakes.Additionally,lake area changes were influenced by the steepness of the terrain,with steeper slopes exacerbating peak discharge during floods.Of the studied seven lakes(Lake 1 to Lake 7),Lake 1 experienced the most dramatic reduction,with a decrease in area by 73.51%and volume by 84.84%,followed by Lake 7.This study underscores the region's vulnerability to climate-induced hazards and stresses the need for a comprehensive early warning system and disaster preparedness measures to mitigate future risks.展开更多
Thermochronological datasets for the Kyrgyz Tianshan and Siberian Altai-Sayan within Central Asia reveal a punctuated exhumation history during the Meso-Cenozoic. In this paper, the datasets for both regions are colle...Thermochronological datasets for the Kyrgyz Tianshan and Siberian Altai-Sayan within Central Asia reveal a punctuated exhumation history during the Meso-Cenozoic. In this paper, the datasets for both regions are collectively reviewed in order to speculate on the links between the Meso-Cenozoic exhumation of the continental Eurasian interior and the prevailing tectonic processes at the plate margins. Whereas most of the thermochronological data across both regions document late Jurassic -Cretaceous regional basement cooling, older landscape relics and dissecting fault zones throughout both regions preserve Triassic and Cenozoic events of rapid cooling, respectively. Triassic cooling is thought to reflect the Qiangtang-Eurasia collision and/or rifting/subsidence in the West Siberian basin. Alternatively, this cooling signal could be related with the terminal terrane-amalgamation of the Central Asian Orogenic Belt. For the Kygyz Tianshan, late Jurassic-Cretaceous regional exhumation and Cenozoic fault reactivations can be linked with specific tectonic events during the closure of the Palaeo-Tethys and Neo-Tethys Oceans, respectively. The effect of the progressive consumption of these oceans and the associated collisions of Cimmeria and India with Eurasia probably only had a minor effect on the exhumation of the Siberian Altai-Sayan. More likely, tectonic forces from the east （present-day co- ordinates） as a result of the building and collapse of the Mongol-Okhotsk orogen and rifting in the Baikal region shaped the current Siberian Altai-Sayan topography. Although many of these hypothesised links need to be tested further, they allow a first-order insight into the dynamic response and the stress propagation pathways from the Eurasian margin into the continental interior.展开更多
Mass loss of glaciers in the Chinese Altai was detected using geodetic methods based on topographical maps(1959), the Shuttle Radar Topography Mission(SRTM) Digital Elevation Model(DEM)(2000), and the Advanced Space-b...Mass loss of glaciers in the Chinese Altai was detected using geodetic methods based on topographical maps(1959), the Shuttle Radar Topography Mission(SRTM) Digital Elevation Model(DEM)(2000), and the Advanced Space-borne Thermal Emission and Reflection Radiometer(ASTER) stereo images(2008). The results indicate that a continued and accelerating shrinkage has occurred in the Chinese Altai Mountains during the last 50 years, with mass deficits of 0.43 ± 0.02 and0.54 ± 0.13 m a-1 water equivalent(w.e.) during the periods 1959-1999 and 1999-2008, respectively.Overall, the Chinese Altai Mountains have lost 7.06 ±0.44 km3 in ice volume(equivalent to-0.43 ± 0.03 m a-1 w.e.) from 1959-2008. The spatial heterogeneity in mass loss was potentially affected by comprehensive changes in temperature and precipitation, and had a substantial correlation withglacier size and topographic settings. Comparison shows that in the Chinese Altai Mountains glaciers have experienced a more rapid mass loss than those in the Tianshan and northwestern Tibetan Plateau(TP), and the mass balance of glaciers was slightly less negative relative to those in the Russian Altai, Himalaya, and southern TP.展开更多
We outline the post-Late Paleozoic （latest Permian to Cenozoic） collisional framework of the southern Great Altai （Central Asia） produced by the convergence between the Tuva-Mongolia and Junggar continental terran...We outline the post-Late Paleozoic （latest Permian to Cenozoic） collisional framework of the southern Great Altai （Central Asia） produced by the convergence between the Tuva-Mongolia and Junggar continental terranes （microplates）. The collisional structures in the region classified on the basis of their geometry and deformation style, dynamic metamorphism, and compositions of tectonites are of three main types： （1） mosaic terranes made up of large weakly deformed Paleozoic blocks separated by younger shear zones; （2） contractional deformation systems involving structures formed in post-Late Paleozoic time, parallel faults oriented along collisional deformation systems, and relict lenses of Paleozoic orogenic complexes; and （3） isolated zones of dynamic metamorphism composed mostly of collisional tectonites different in composition and alteration grade.展开更多
The Chinese Altai in northwestern Xinjiang has numerous outcrops of granitoids which provide critical information on accretionary orogenic processes and crustal growth of the Central Asian Orogenic Belt.Zircon U-Pb ag...The Chinese Altai in northwestern Xinjiang has numerous outcrops of granitoids which provide critical information on accretionary orogenic processes and crustal growth of the Central Asian Orogenic Belt.Zircon U-Pb ages, Hf-isotopic compositions and whole-rock geochemistry of monzogranite and granodiorites in the Qinghe County are employed to elucidate Paleozoic tectonics of the Chinese Altai. Granodiorites have crystallization ages of 424.6 ± 3.1 Ma(MSWD = 0.23) and 404.0 ± 3.4 Ma(MSWD = 0.18);monzogranite was emplaced in the early Permian with a crystallization age of 293.7 ± 4.6 Ma(MSWD = 1.06). Both granodiorites and monzogranite are I-type granites with A/CNK ratios of 0.92 -0.97 and 1.03 -1.06, respectively. They also show similar geochemical features of high HREE and Y contents, low Sr contents and Sr/Y ratios, as well as enrichment of Cs, Rb, Th and U, and depletion of Nb, Ta, P and Ti.These geochemical features indicate that the monzogranite and granodiorites were formed in an arc setting related to subduction. The gneissic monzogranites display high SiO_2 and K_2 O contents, and belong to the high-K calc-alkaline series. In the chondrite normalized REE distribution pattern, the monzogranite samples exhibit enrichment of LREE with strong negative Eu anomalies(σE u =0.44 -0.53), zircon εHf(t) values from +7.24 to +12.63 and two-stage Hf model ages of 463 -740 Ma. This suggests that the monzogranite was generated from the mixing of pelitic and mantle material. The granodiorite samples are calc-alkaline granites with lower contents of Si O_2 and Na_2 O + K_2 O, higher contents of TiO_2, Fe_2O_3~t, MgO and CaO compared to the monzogranite samples. They also show enrichment of LREE and moderate negative Eu anomalies(σE u= 0.54 =0.81), as well as slightly higher differentiation of LREE than that of HREE. The425 Ma granodiorite has zircon εHf(t) values from -0.51 to +1.98 and two-stage Hf model ages of 1133 -1240 Ma, whereas the 404 Ma granodiorite displays those of +2.52 to +7.50 and 816 -1071 Ma.Geochemistry and zircon Hf isotopic compositions indicate that granodiorites were formed by partial melting of juvenile lower crust. Together with regional geology and previous data, the geochemical and geochronological data of the monzogranite and granodiorites from this study suggest long-lived subduction and accretion along the Altai Orogen during ca. 425 -294 Ma.展开更多
In order to study the chemical characteristics of snow-firn pack in Altai Mountains and its environmental significance, a 1.5-m deep snow-firn pack was dug in the accumulation zone （3 300 m a.s.I.） of the Kanas Glac...In order to study the chemical characteristics of snow-firn pack in Altai Mountains and its environmental significance, a 1.5-m deep snow-firn pack was dug in the accumulation zone （3 300 m a.s.I.） of the Kanas Glacier in August 2009. A total of 15 samples were analyzed for major ions. Results show that the concentrations of major ions in the snow-firn pack are NH4＋〉SO4 2-〉Ca2＋〉NO3＋〉 Na＋〉CI〉K＋〉Mg2＋. NH4＋ is the dominant cation with a medium value of 4.7 ueq-L-1, accounting for 39.8% of the total cations, and SO42- is the dominant anion, with a medium value of 4.0 ueq.L-I, which accounts for 33.9% of the total cations. Compared with Belukha Glacier （Altai）, Urumqi Glacier No. 1, and the Inilchek Glacier （Tienshan）, there is a lower ion concentrations in the Kanas snow-firn pack. Potential sources of these chemical species are explored using correlation and empirical orthogonal function （EOF） analyses. The analyses indicate that major ion concentrations （except NH4＋） originate from crustal dust. Backward trajectory analysis was applied to get the origin of the air mass to Kanas Glacier. The results suggest that air pollutants emitted by forest fires in Siberia could be transported and influence the NH4＋, NO3, and SO42 concentrations on the Kanas Glacier.展开更多
Altai (also named Altay in China) Mountain Country (Mountain System) is a unique natural region,located on the border between different floristic regimes of the Boreal and ancient Mediterranean sub-kingdoms,where dist...Altai (also named Altay in China) Mountain Country (Mountain System) is a unique natural region,located on the border between different floristic regimes of the Boreal and ancient Mediterranean sub-kingdoms,where distribution of plant species is actually limited. It is known to have sufficient endemic floral biodiversity in the Northern Asia. Many plants of Altai Mountain System need effective care and proper conservation measures for their survival and longer-term protection. Important Plant Area identified as the IUCN (the International Union for Conservation of Nature),specified criteria attract global attention for protection of floral biodiversity across the world. The records of 71 plant species from the Chinese Altai Mountains attributed to the criterion A and the dark conifer forests of Chinese Altai Mountains satisfied the criterion C,which may help qualify to fulfill the national obligation of the Convention on Biological Diversity.展开更多
With changing climatic conditions and snow cover regime, regional hydrological cycle for a snowy basin will change and further available surface water resources will be redistributed. Assessing snow meltwater effect o...With changing climatic conditions and snow cover regime, regional hydrological cycle for a snowy basin will change and further available surface water resources will be redistributed. Assessing snow meltwater effect on runoff is the key to water safety, under climate warming and fast social-economic developing status. In this study, stable isotopic technology was utilized to analyze the snow meltwater effect on regional hydrological processes, and to declare the response of snow hydrology to climate change and snow cover regime, together with longterm meteorological and hydrological observations, in the headwater of Irtysh River, Chinese Altai Mountains during 1961-2015. The average δ^(18) O values of rainfall, snowfall, meltwater, groundwater and river water for 2014–2015 hydrological year were-10.9‰,-22.3‰,-21.7‰,-15.7‰ and-16.0‰, respectively.The results from stable isotopes, snow melting observation and remote sensing indicated that the meltwater effect on hydrological processes in Kayiertesi River Basin mainly occurred during snowmelt supplying period from April to June. The contribution of meltwater to runoff reached 58.1% during this period, but rainfall, meltwater and groundwater supplied 49.1%, 36.9% and 14.0% of water resource to annual runoff, respectively. With rising air temperature and increasing snowfall in cold season, the snow water equivalent(SWE) had an increasing trend but the snow cover duration declined by about one month including 13-day delay of the first day and 17-day advancement of the end day during 1961–2016. Increase in SWE provided more available water resource. However, variations in snow cover timing had resulted in redistribution of surface water resource, represented by an increase of discharge percentage in April and May, and a decline in Juneand July. This trend of snow hydrology will render a deficit of water resource in June and July when the water resource demand is high for agricultural irrigation and industrial manufacture.展开更多
Voluminous Silurian–Devonian granitoids intruded a greywacke-dominated Ordovician accretionary wedge in the Chinese Altai. These granitoids are characterized by significant Nd-Hf isotopic decoupling, the underlying m...Voluminous Silurian–Devonian granitoids intruded a greywacke-dominated Ordovician accretionary wedge in the Chinese Altai. These granitoids are characterized by significant Nd-Hf isotopic decoupling, the underlying mechanism of which, so far, has been poorly understood. This issue is addressed in this study by the integration of our new and regional published geological and geochemical data. Geological studies indicated a close spatial relationship between the regional anatexis of the Ordovician wedge and the formation of the granitoids, which is characterized by a gradual textural evolution from the partial molten Ordovician wedge sedimentary rocks(the Habahe Group) to the granitoid bodies. Compositionally, these granitoids and the Ordovician Habahe Group rocks displayed close geochemical similarities, in the form of arclike trace elemental signatures as well as comparable Nd isotopic characteristics. Combined with regional available data, we suggest that the Silurian–Devonian granitoids originated from the immature and chemically primitive Habahe Group rocks. Since Nd and Hf isotopic data for the Habahe Group rocks show significant Nd-Hf isotopic decoupling, we propose that the Silurian–Devonian granitoids inherited the Nd and Hf isotopic signatures from their sources, i.e., the Habahe Group rocks. In other words, the Nd-Hf decoupling in the Habahe Group rocks is the primary causative factor leading to the prevailing Nd-Hf isotopic decoupling of the Silurian–Devonian granitoids in the Chinese Altai.展开更多
The paper reviews previous and recently obtained geological, stratigraphic and geochronological data on the Russian-Kazakh Altai orogen, which is located in the western Central Asian Orogenic Belt （CAOB）, between th...The paper reviews previous and recently obtained geological, stratigraphic and geochronological data on the Russian-Kazakh Altai orogen, which is located in the western Central Asian Orogenic Belt （CAOB）, between the Kazakhstan and Siberian continental blocks. The Russian-Kazakh Altai is a typical Pacific-type orogen, which represents a collage of oceanic, accretionary, fore-arc, island-arc and continental margin terranes of different ages separated by strike-slip faults and thrusts. Evidence for this comes from key indicative rock associations, such as boninite- and turbidite （graywacke）-bearing volcanogenic-sedimentary units, accreted pelagic chert, oceanic islands and plateaus, MORB-OIB-protolith blueschists. The three major tectonic domains of the Russian-Kazakh Altai are： （1） Altai-Mongolian terrane （AMT）; （2） subduction-accretionary （Rudny Altai, Gorny Altai） and collisional （Kalba-Narym） terranes; （3） Kurai, Charysh-Terekta, North-East, Irtysh and Char suture-shear zones （SSZ）. The evolution of this orogen proceeded in five major stages： （i） late Neoproterozoic-early Paleozoic subduction-accretion in the Paleo-Asian Ocean; （ii） Ordovician-Silurian passive margin; （iii） Devonian-Carboniferous active margin and collision of AMT with the Siberian conti- nent; （iv） late Paleozoic closure of the PAO and coeval collisional magmatism; （v） Mesozoic post-collisional deformation and anarogenic magmatism, which created the modern structural collage of the Russian- Kazakh Altai orogen. The major still unsolved problem of Altai geology is origin of the Altai-Mongolian terrane （continental versus active margin）, age of Altai basement, proportion of juvenile and recycled crust and origin of the middle Paleozoic units of the Gorny Altai and Rudny Altai terranes.展开更多
Altaids:The conception The Altaids is tectonically sandwiched between the Baltica and Siberia cratons to the north and the Tarim and North China cratons to the south(Sengor et al.,1993).This huge orogen has been also ...Altaids:The conception The Altaids is tectonically sandwiched between the Baltica and Siberia cratons to the north and the Tarim and North China cratons to the south(Sengor et al.,1993).This huge orogen has been also called the Altaid collage(Yakubchuk,2004),Central Asian Orogenic Belt(CAOB)(Jahn et al.,2000a),or Central Asian Orogenic System(Briggs et al.,2007).Long before these terms,the Altaids even had been called the Asian Foldbelt,Ural-Mongolian Foldbelt,or Ural-Amurian Foldbelt,mostly by the former Soviet Union scientists(Yakubchuk,2004).展开更多
To predict future spatio-temporal patterns of climate change, we should fully understand the spatio-temporal patterns of climate change during the past millennium. But, we are not yet able to delineate the patterns be...To predict future spatio-temporal patterns of climate change, we should fully understand the spatio-temporal patterns of climate change during the past millennium. But, we are not yet able to delineate the patterns because the qualities of the retrieved proxy records and the spatial coverage of those records are not adequate. Northern Xinjiang of China is one of such areas where the records are not adequate. Here, we present a 500-yr land-surface moisture sequence from Heiyangpo Peat(48.34°N, 87.18°E, 1353 m a.s.l) in the southern Altai Mountains within northern Xinjiang. Specifically, peat carbon isotope value of cellulose(δ^(13)C_(cellulose)) was used to estimate the warm-season moisture variations and the degree of humification was used to constrain the δ^(13)C_(cellulose)-based hydrological interpretation. The climatic attributions of the interpreted hydrological variations were based on the warm-season temperature reconstructed from Belukha ice core and the warm-season precipitation inferred from the reconstructed Atlantic Multidecadal Oscillations(AMO). The results show that humification decreased and the δ^(13)C_(celluose)-suggested moisture decreased from ~1510 to ~1775 AD, implying that a constant dryingcondition may have inhibited peat decay. Our comparison with reconstructed climatic parameters suggests that the moisture-level decline was most likely resulted from a constant decline of precipitation. The results also show that humification kept a stable level and the δ^(13)C_(celluose)-suggested moisture also decreased from ~1775 to ~2013 AD, implying that peat decay in the acrotelm primarily did not depend on the water availability or an aerobic environment. Again, our comparison with reconstructed climatic parameters suggests that the land-surface moisturelevel decline was most likely resulted from a steady warming of growing-season temperature.展开更多
Based on the analysis of the field data of nonstationary electromagnetic soundings with different installations,the evolution of the stressed state of the geological massif in the epicentral region of the destructive ...Based on the analysis of the field data of nonstationary electromagnetic soundings with different installations,the evolution of the stressed state of the geological massif in the epicentral region of the destructive 2003 M_w7.3 Chuya earthquake is investigated in the paper.The measurements by these methods were executed in a lot of regular points located at two sites of the western part of the Chuya basin of Gorny Altai(Russian Federation).The field works have been performed for 13 years.We developed a measurement technique using data from the three Transient Electromagnetic Method(TEM)method settings for determination of the resistivity anisotropy coefficient.Interpretation of the field data is carried out based on the inverse problem solution,and further,taking into account the geological structure and seismological data,variations of true electrophysical characteristics of the cross-section(electrical resistivity and resistivity anisotropy coefficient)are analyzed.According to the TEM data acquired in the 1980 s,the geoelectric parameters of rocks in the period of low seismic activity were estimated.Comparison of the results of quantitative interpretation of the modern measurements(2004-2016)with those taken before the Chuya event allows tracing a change in the geoelectric parameters of the cross-section in the aftershock period,and on this basis tracking the evolution of the rock massif after the destructive seismic impact.展开更多
This study presents the long-term temperature monitoring in the Russian Altai Mountains. In contrast to the Mongolian and Chinese parts, the modern temperature regime of the Russian Altai remains unclear. The complexi...This study presents the long-term temperature monitoring in the Russian Altai Mountains. In contrast to the Mongolian and Chinese parts, the modern temperature regime of the Russian Altai remains unclear. The complexity of a comprehensive understanding of permafrost conditions in the Russian Altai is related to the high dissection of the terrain, the paucity of the latest observational data, and the sparse population of permafrost areas. The general objective of this study is to determine the temperature regime on the surface,in the active layer, and in the zero annual amplitude(ZAA) layer, based on the known patterns of permafrost distribution in the region. Using automatic measuring equipment(loggers), we obtained information on the temperature of frozen and thawed ground within the altitudes from 1484 to 2879 m a. s. l. during the period from 2014 to 2020.An array of 15 loggers determined the temperature regime of bare and vegetated areas within watersheds,slopes, and valleys. N-factor parameters and surface temperature are similar to those in the Mongolian Altai, but the mean annual ground temperature at the depth of 1 m has a wide range of fluctuations(more than 32℃) based on research results, and we allocated it into three groups based on altitudinal zonality. Snow cover has a strong influence on the temperature regime, but the determination of the fine-scale variability requires additional study.Ground temperature regime during the observation period remained stable, but continued monitoring allows a more detailed assessment of the response to climatic changes.展开更多
文摘The author affiliation and the funding information in the Acknowledgement section of the online version of the original article was revised.One affiliation(the 8th affiliation)of the first author is added.The Acknowledgement section of the original article has been revised to:Acknowledgments:This research was funded by the National University of Mongolia under grant agreement P2023(grant number P2023-4578)and supported by the Chey Institute for Advanced Studies“International Scholarship Exchange Fellowship for the academic year of 2024-2025”,Republic of Korea,and the National University of Mongolia.We would like to acknowledge the National University of Mongolia and Soumik Das from the Center for the Study of Regional Development,Jawaharlal Nehru University,New Delhi-110067,for his valuable assistance in preparing the geological maps.
基金financially supported by the National Key Research and Development Program(Grant No.2021YFC2901802)the Shaanxi Province Natural Science Foundation(Grant No.2020JM-310)+2 种基金the Hong Kong RGC Co-funding Mechanism on Joint Laboratories with the Chinese Academy of Science(JLFS/P-702/24)the National Key R&D Program of China(Grant Nos.2018YFC0604000,2017YFC0601205)the National Natural Science Foundation of China(Grant Nos.41730213,42072264,41902229,41972237).
文摘As a highly coupled aggregate of tectonism,magmatism,and metamorphism,a gneiss dome is usually taken as a vital window for understanding the crustal internal structure and the exchange of material and energy during orogenic exhumation.The Qinghe gneiss dome located in the eastern Chinese Altai orogen,lies in Qinghe County,Xinjiang,records important information of late accretionary orogeny associated with continental uplift and crustal growth.According to the field investigation,the dome shows core-mantle-margin domains,in which the core is composed of migmatized granite and gneiss,the mantle consists of banded gneiss,schist,and leptynite,and the margin has rock assemblages of phyllite,schist,and meta-sandstone.From the margin to the core,the dome can be divided into chlorite-sericite,andalusite-staurolite,sillimanite-biotite,and sillimanite-garnet metamorphic zones,recording progressive metamorphism.Detailed structural analyses in the Qinghe gneiss dome indicate progressive deformation from the margin to the core.Internal and external detachment faults are clarified,with the former characterized by inflow and outward migration of crustal material and the latter marked by brittle-ductile deformation with a lineation indicating lateral slip of the upper wall when the dome uplifted.Based on these faults,upper,middle,lower structural layers are observed from the outer to inner domains of the dome.Considering the general geological background and new data,the Qinghe gneiss dome probably predominantly underwent early ductile shear deformation and late heat-flow diapirism in the early Permian,closely related to upwelling of asthenosphere mantle that resulted from slab break-off in the extensional tectonic setting.
基金supported by the Natural Science Foundation of Xinjiang Uigur Autonomous Region−Science Fund for Distinguished Young Scholars(2022D01E105)the Natural Key Research and Development Program(Inter-governmental Key and Special Project,2023YFE0102700)+2 种基金Tianshan Talent Training Program−Young Scientific and Technological Innovation Talent(2023TSYCCX0076)the Science and Technology Development Fund Project of Institute of Desert Meteorology,China Meteorological Administration(KJFZ202306,KJFZ202406)Xinjiang Regional collaborative innovation project(2022E01045)。
文摘The physiological structure and growth of trees in extreme environments(freezing temperatures,prolonged drought,wildfires,pest infestations,and diseases)can be inhibited,including radial growth,and stagnant growth or missing annual rings is highly possible.In this study,we analyzed the radial growth of Siberian larch(Larix sibirica)in the Hongshanzui area of the Altai Mountains,China.The overall missing ring rate at the sampling point was 2.39%,with years with the highest missing rings since meteorological site data were available(1960)identified as 1960,1961,1971,1973,1985,1987,and 1995.Radial growth in high altitudes was mainly affected by temperatures in May and June(average temperature,average minimum temperature,and average maximum temperature).Frequent periods of freezing may lead to missing annual rings.However,while Larix sibirica shows resilience after prolonged freezing temperatures,it still requires time for the trees to return to normal growth levels.
基金financially supported by the China Geological Survey(No.DD20230213)the National Key Research and Development Project(No.2019YFA0708601)Shanxi Province Natural Science Foundation(No.2020JM-310)。
文摘The Altai-Sayan region,an active intracontinental mountain belt characterized by high relief,has undergone multiple phases of intense mountain building and denudation throughout the Mesozoic and Cenozoic.As this mountain belt with remarkable topography is distant from any active plate margins,its mountain growth pattern and tectonic reactivation mechanism are of great significance to the study of intracontinental orogeny.
基金supported by the Natural Science Foundation of China(No.42120104004)the Second Tibetan Plateau Scientific Expedition and Research Program(Grant No.2019QZKK0708)。
文摘The 1931 M_(w)7.8 Fuyun earthquake occurred around the Altai mountains, an intracontinental deformation belt with limited active strain-rate accumulation. To explore whether seismic activity in this deformation belt was affected by stress interaction among different active faults, we calculate the Coulomb failure stress change(ΔCFS) induced by the Fuyun earthquake due to coseismic deformation of the elastic crust and postseismic viscoelastic relaxation of the lower crust and upper mantle. Numerical results show that the total ΔCFS at a 10-km depth produced by the Fuyun earthquake attains approximately 0.015-0.134 bar near the epicenter, and just before the occurrence of the 2003 M_(w)7.2 Chuya earthquake, which distances about 400 km away from the Fuyun earthquake. Among the increased ΔCFS,viscoelastic relaxation from 1931 to 2003 contributes to approximately 0.014-0.131 bar, accounting for>90% of the total ΔCFS. More importantly, we find that for the recorded seismicity in the region with a radius of about 270 km to the Fuyun earthquake from 1970 to 2018, the percentage of earthquakes that fall in positive lobes of ΔCFS resolved on the NNW-SSE Fuyun strike-slip fault, on the NWW-SEE Irtysh strike-slip fault, and on the NW-SE Kurti reverse fault is up to 67.22%-91.36%. Therefore, the predictedΔCFS suggests that the impact of the 1931 M_(w)7.8 Fuyun earthquake on seismic activity around the Altai mountains is still significant as to hasten occurrence of the 2003 M_(w)7.2 Chuya earthquake at a relatively far distance and to trigger its aftershocks in the near-field even after several decades of the mainshock.
基金funded by the National University of Mongolia under grant agreement P2023(grant number P2023-4578)。
文摘This study investigates the glacial lake outburst flood(GLOF)hazards in the Tsambagarav mountain range in Western Mongolia,focusing on the Khukhnuruu Valley and its interconnected proglacial lakes.Over the last 30 years,significant glacier retreats,driven by rising temperatures and changing precipitation patterns,have led to the formation and expansion of several proglacial lakes.Fieldwork combined with satellite data and meteorological analysis was used to assess the dynamics of glacier and lake area changes,with particular focus on the flood events of July 2021.The research reveals a substantial reduction in glacier area,particularly in the Khukhnuruu E complex,where glacier area decreased by 19.3%.The study highlights the influence of increasing temperatures and summer precipitation,which have accelerated ice melt,contributing to the expansion and eventual breaching of lakes.Additionally,lake area changes were influenced by the steepness of the terrain,with steeper slopes exacerbating peak discharge during floods.Of the studied seven lakes(Lake 1 to Lake 7),Lake 1 experienced the most dramatic reduction,with a decrease in area by 73.51%and volume by 84.84%,followed by Lake 7.This study underscores the region's vulnerability to climate-induced hazards and stresses the need for a comprehensive early warning system and disaster preparedness measures to mitigate future risks.
基金supported by grants from the Australian Research Council(DP150101730)the Fund for Scientific Research,FWO-Vlaanderen
文摘Thermochronological datasets for the Kyrgyz Tianshan and Siberian Altai-Sayan within Central Asia reveal a punctuated exhumation history during the Meso-Cenozoic. In this paper, the datasets for both regions are collectively reviewed in order to speculate on the links between the Meso-Cenozoic exhumation of the continental Eurasian interior and the prevailing tectonic processes at the plate margins. Whereas most of the thermochronological data across both regions document late Jurassic -Cretaceous regional basement cooling, older landscape relics and dissecting fault zones throughout both regions preserve Triassic and Cenozoic events of rapid cooling, respectively. Triassic cooling is thought to reflect the Qiangtang-Eurasia collision and/or rifting/subsidence in the West Siberian basin. Alternatively, this cooling signal could be related with the terminal terrane-amalgamation of the Central Asian Orogenic Belt. For the Kygyz Tianshan, late Jurassic-Cretaceous regional exhumation and Cenozoic fault reactivations can be linked with specific tectonic events during the closure of the Palaeo-Tethys and Neo-Tethys Oceans, respectively. The effect of the progressive consumption of these oceans and the associated collisions of Cimmeria and India with Eurasia probably only had a minor effect on the exhumation of the Siberian Altai-Sayan. More likely, tectonic forces from the east （present-day co- ordinates） as a result of the building and collapse of the Mongol-Okhotsk orogen and rifting in the Baikal region shaped the current Siberian Altai-Sayan topography. Although many of these hypothesised links need to be tested further, they allow a first-order insight into the dynamic response and the stress propagation pathways from the Eurasian margin into the continental interior.
基金supported by the Ministry of Science and Technology of China (MOST) (Grant No. 2013FY111400)the National Natural ScienceFoundation of China (NSFC) (Grant No. 41190084)+4 种基金the Chinese Academy of Sciences (CAS) (Grant No. XDA05090302)the State Key Laboratory of Cryospheric Sciences, Cold and Arid Regions Environmental and Engineering Research Institute (SKLCS, CAREERI), CAS (Grant No. SKLCS2012-09)the NSFC (Grant No.41471067)provided by "Investigation on glacier resources and their change in China" (Grant No. 2006FY110200)"Glacier change monitoring and its impact assessment research in west China" (Grant No. kzcx2-yw-301)
文摘Mass loss of glaciers in the Chinese Altai was detected using geodetic methods based on topographical maps(1959), the Shuttle Radar Topography Mission(SRTM) Digital Elevation Model(DEM)(2000), and the Advanced Space-borne Thermal Emission and Reflection Radiometer(ASTER) stereo images(2008). The results indicate that a continued and accelerating shrinkage has occurred in the Chinese Altai Mountains during the last 50 years, with mass deficits of 0.43 ± 0.02 and0.54 ± 0.13 m a-1 water equivalent(w.e.) during the periods 1959-1999 and 1999-2008, respectively.Overall, the Chinese Altai Mountains have lost 7.06 ±0.44 km3 in ice volume(equivalent to-0.43 ± 0.03 m a-1 w.e.) from 1959-2008. The spatial heterogeneity in mass loss was potentially affected by comprehensive changes in temperature and precipitation, and had a substantial correlation withglacier size and topographic settings. Comparison shows that in the Chinese Altai Mountains glaciers have experienced a more rapid mass loss than those in the Tianshan and northwestern Tibetan Plateau(TP), and the mass balance of glaciers was slightly less negative relative to those in the Russian Altai, Himalaya, and southern TP.
基金supported by V.S. Sobolev Institute of Geology and Mineralogy Siberian Branch of Russian Academy of Sciences (basic project)
文摘We outline the post-Late Paleozoic （latest Permian to Cenozoic） collisional framework of the southern Great Altai （Central Asia） produced by the convergence between the Tuva-Mongolia and Junggar continental terranes （microplates）. The collisional structures in the region classified on the basis of their geometry and deformation style, dynamic metamorphism, and compositions of tectonites are of three main types： （1） mosaic terranes made up of large weakly deformed Paleozoic blocks separated by younger shear zones; （2） contractional deformation systems involving structures formed in post-Late Paleozoic time, parallel faults oriented along collisional deformation systems, and relict lenses of Paleozoic orogenic complexes; and （3） isolated zones of dynamic metamorphism composed mostly of collisional tectonites different in composition and alteration grade.
基金Financial support for this study was jointly provided by the National Natural Science Foundation of China (Grant Nos. 41421002, 41225008, 41702231)Program for Changjiang Scholars and Innovative Research Team in University (Grant No. IRT1281)MOST Special Fund from the State Key Laboratory of Continental Dynamics, Northwest University, China
文摘The Chinese Altai in northwestern Xinjiang has numerous outcrops of granitoids which provide critical information on accretionary orogenic processes and crustal growth of the Central Asian Orogenic Belt.Zircon U-Pb ages, Hf-isotopic compositions and whole-rock geochemistry of monzogranite and granodiorites in the Qinghe County are employed to elucidate Paleozoic tectonics of the Chinese Altai. Granodiorites have crystallization ages of 424.6 ± 3.1 Ma(MSWD = 0.23) and 404.0 ± 3.4 Ma(MSWD = 0.18);monzogranite was emplaced in the early Permian with a crystallization age of 293.7 ± 4.6 Ma(MSWD = 1.06). Both granodiorites and monzogranite are I-type granites with A/CNK ratios of 0.92 -0.97 and 1.03 -1.06, respectively. They also show similar geochemical features of high HREE and Y contents, low Sr contents and Sr/Y ratios, as well as enrichment of Cs, Rb, Th and U, and depletion of Nb, Ta, P and Ti.These geochemical features indicate that the monzogranite and granodiorites were formed in an arc setting related to subduction. The gneissic monzogranites display high SiO_2 and K_2 O contents, and belong to the high-K calc-alkaline series. In the chondrite normalized REE distribution pattern, the monzogranite samples exhibit enrichment of LREE with strong negative Eu anomalies(σE u =0.44 -0.53), zircon εHf(t) values from +7.24 to +12.63 and two-stage Hf model ages of 463 -740 Ma. This suggests that the monzogranite was generated from the mixing of pelitic and mantle material. The granodiorite samples are calc-alkaline granites with lower contents of Si O_2 and Na_2 O + K_2 O, higher contents of TiO_2, Fe_2O_3~t, MgO and CaO compared to the monzogranite samples. They also show enrichment of LREE and moderate negative Eu anomalies(σE u= 0.54 =0.81), as well as slightly higher differentiation of LREE than that of HREE. The425 Ma granodiorite has zircon εHf(t) values from -0.51 to +1.98 and two-stage Hf model ages of 1133 -1240 Ma, whereas the 404 Ma granodiorite displays those of +2.52 to +7.50 and 816 -1071 Ma.Geochemistry and zircon Hf isotopic compositions indicate that granodiorites were formed by partial melting of juvenile lower crust. Together with regional geology and previous data, the geochemical and geochronological data of the monzogranite and granodiorites from this study suggest long-lived subduction and accretion along the Altai Orogen during ca. 425 -294 Ma.
基金supported by the Knowledge Innovation Project of the Chinese Academy of Sciences (No. KZCX2-EW-311)the National Basic Research Program of China (No. 2010CB951003)+2 种基金the National Natural Science Foundation of China (Nos. 91025012, 111141001, J0930003/J0109)the Program for New Century Excellent Talents in University (No. NCET-10-0019)the SKLCS founding (No. SKLCS-ZZ-2010-04)
文摘In order to study the chemical characteristics of snow-firn pack in Altai Mountains and its environmental significance, a 1.5-m deep snow-firn pack was dug in the accumulation zone （3 300 m a.s.I.） of the Kanas Glacier in August 2009. A total of 15 samples were analyzed for major ions. Results show that the concentrations of major ions in the snow-firn pack are NH4＋〉SO4 2-〉Ca2＋〉NO3＋〉 Na＋〉CI〉K＋〉Mg2＋. NH4＋ is the dominant cation with a medium value of 4.7 ueq-L-1, accounting for 39.8% of the total cations, and SO42- is the dominant anion, with a medium value of 4.0 ueq.L-I, which accounts for 33.9% of the total cations. Compared with Belukha Glacier （Altai）, Urumqi Glacier No. 1, and the Inilchek Glacier （Tienshan）, there is a lower ion concentrations in the Kanas snow-firn pack. Potential sources of these chemical species are explored using correlation and empirical orthogonal function （EOF） analyses. The analyses indicate that major ion concentrations （except NH4＋） originate from crustal dust. Backward trajectory analysis was applied to get the origin of the air mass to Kanas Glacier. The results suggest that air pollutants emitted by forest fires in Siberia could be transported and influence the NH4＋, NO3, and SO42 concentrations on the Kanas Glacier.
基金supported by the Xinjiang Committee of Science and Technology (200933122)
文摘Altai (also named Altay in China) Mountain Country (Mountain System) is a unique natural region,located on the border between different floristic regimes of the Boreal and ancient Mediterranean sub-kingdoms,where distribution of plant species is actually limited. It is known to have sufficient endemic floral biodiversity in the Northern Asia. Many plants of Altai Mountain System need effective care and proper conservation measures for their survival and longer-term protection. Important Plant Area identified as the IUCN (the International Union for Conservation of Nature),specified criteria attract global attention for protection of floral biodiversity across the world. The records of 71 plant species from the Chinese Altai Mountains attributed to the criterion A and the dark conifer forests of Chinese Altai Mountains satisfied the criterion C,which may help qualify to fulfill the national obligation of the Convention on Biological Diversity.
基金funded by the Chinese Academy of Sciences (KJZD-EW-G03-04, QYZDJSSW-DQC039)the National Science Foundation of China (NSFC 41630754, 41690144, 41421061)the Foundation of the State Key Laboratory of Cryospheric Sciences (SKLCS) at Northwest Institute of Eco-Environment and Resources (NIEER), CAS (SKLCS-OP-2017-10, SKLCS-ZZ2016)
文摘With changing climatic conditions and snow cover regime, regional hydrological cycle for a snowy basin will change and further available surface water resources will be redistributed. Assessing snow meltwater effect on runoff is the key to water safety, under climate warming and fast social-economic developing status. In this study, stable isotopic technology was utilized to analyze the snow meltwater effect on regional hydrological processes, and to declare the response of snow hydrology to climate change and snow cover regime, together with longterm meteorological and hydrological observations, in the headwater of Irtysh River, Chinese Altai Mountains during 1961-2015. The average δ^(18) O values of rainfall, snowfall, meltwater, groundwater and river water for 2014–2015 hydrological year were-10.9‰,-22.3‰,-21.7‰,-15.7‰ and-16.0‰, respectively.The results from stable isotopes, snow melting observation and remote sensing indicated that the meltwater effect on hydrological processes in Kayiertesi River Basin mainly occurred during snowmelt supplying period from April to June. The contribution of meltwater to runoff reached 58.1% during this period, but rainfall, meltwater and groundwater supplied 49.1%, 36.9% and 14.0% of water resource to annual runoff, respectively. With rising air temperature and increasing snowfall in cold season, the snow water equivalent(SWE) had an increasing trend but the snow cover duration declined by about one month including 13-day delay of the first day and 17-day advancement of the end day during 1961–2016. Increase in SWE provided more available water resource. However, variations in snow cover timing had resulted in redistribution of surface water resource, represented by an increase of discharge percentage in April and May, and a decline in Juneand July. This trend of snow hydrology will render a deficit of water resource in June and July when the water resource demand is high for agricultural irrigation and industrial manufacture.
基金supported by the National Key R&D Program of China(No.2017YFC0601205)the Strategic Priority Research Program(B)of the CAS(No.XDB18020203)+4 种基金the NSF China(No.41672056)the Guangdong Special Support ProgramGIG-CAS 135 Project(No.135TP201601)A 100 Talents Program of the CAS to Yingde Jianga China Postdoctoral Science Foundation to Yu Yang(No.2018M633172)
文摘Voluminous Silurian–Devonian granitoids intruded a greywacke-dominated Ordovician accretionary wedge in the Chinese Altai. These granitoids are characterized by significant Nd-Hf isotopic decoupling, the underlying mechanism of which, so far, has been poorly understood. This issue is addressed in this study by the integration of our new and regional published geological and geochemical data. Geological studies indicated a close spatial relationship between the regional anatexis of the Ordovician wedge and the formation of the granitoids, which is characterized by a gradual textural evolution from the partial molten Ordovician wedge sedimentary rocks(the Habahe Group) to the granitoid bodies. Compositionally, these granitoids and the Ordovician Habahe Group rocks displayed close geochemical similarities, in the form of arclike trace elemental signatures as well as comparable Nd isotopic characteristics. Combined with regional available data, we suggest that the Silurian–Devonian granitoids originated from the immature and chemically primitive Habahe Group rocks. Since Nd and Hf isotopic data for the Habahe Group rocks show significant Nd-Hf isotopic decoupling, we propose that the Silurian–Devonian granitoids inherited the Nd and Hf isotopic signatures from their sources, i.e., the Habahe Group rocks. In other words, the Nd-Hf decoupling in the Habahe Group rocks is the primary causative factor leading to the prevailing Nd-Hf isotopic decoupling of the Silurian–Devonian granitoids in the Chinese Altai.
基金the Scientific Project of the Institute of Geology and Mineralogy SB RASIGCP#592 Project "Continental construction in Central Asia" under the patronage of UNESCO-IUGS
文摘The paper reviews previous and recently obtained geological, stratigraphic and geochronological data on the Russian-Kazakh Altai orogen, which is located in the western Central Asian Orogenic Belt （CAOB）, between the Kazakhstan and Siberian continental blocks. The Russian-Kazakh Altai is a typical Pacific-type orogen, which represents a collage of oceanic, accretionary, fore-arc, island-arc and continental margin terranes of different ages separated by strike-slip faults and thrusts. Evidence for this comes from key indicative rock associations, such as boninite- and turbidite （graywacke）-bearing volcanogenic-sedimentary units, accreted pelagic chert, oceanic islands and plateaus, MORB-OIB-protolith blueschists. The three major tectonic domains of the Russian-Kazakh Altai are： （1） Altai-Mongolian terrane （AMT）; （2） subduction-accretionary （Rudny Altai, Gorny Altai） and collisional （Kalba-Narym） terranes; （3） Kurai, Charysh-Terekta, North-East, Irtysh and Char suture-shear zones （SSZ）. The evolution of this orogen proceeded in five major stages： （i） late Neoproterozoic-early Paleozoic subduction-accretion in the Paleo-Asian Ocean; （ii） Ordovician-Silurian passive margin; （iii） Devonian-Carboniferous active margin and collision of AMT with the Siberian conti- nent; （iv） late Paleozoic closure of the PAO and coeval collisional magmatism; （v） Mesozoic post-collisional deformation and anarogenic magmatism, which created the modern structural collage of the Russian- Kazakh Altai orogen. The major still unsolved problem of Altai geology is origin of the Altai-Mongolian terrane （continental versus active margin）, age of Altai basement, proportion of juvenile and recycled crust and origin of the middle Paleozoic units of the Gorny Altai and Rudny Altai terranes.
文摘Altaids:The conception The Altaids is tectonically sandwiched between the Baltica and Siberia cratons to the north and the Tarim and North China cratons to the south(Sengor et al.,1993).This huge orogen has been also called the Altaid collage(Yakubchuk,2004),Central Asian Orogenic Belt(CAOB)(Jahn et al.,2000a),or Central Asian Orogenic System(Briggs et al.,2007).Long before these terms,the Altaids even had been called the Asian Foldbelt,Ural-Mongolian Foldbelt,or Ural-Amurian Foldbelt,mostly by the former Soviet Union scientists(Yakubchuk,2004).
基金financially supported by Chinese Natural Science International Cooperation Program Foundation Grant (No. 41361140361)Chinese Natural Science Foundation Grant (No. U1203821L08)Chinese Academy Sciences International Cooperation Program (No. GJHZ201315)
文摘To predict future spatio-temporal patterns of climate change, we should fully understand the spatio-temporal patterns of climate change during the past millennium. But, we are not yet able to delineate the patterns because the qualities of the retrieved proxy records and the spatial coverage of those records are not adequate. Northern Xinjiang of China is one of such areas where the records are not adequate. Here, we present a 500-yr land-surface moisture sequence from Heiyangpo Peat(48.34°N, 87.18°E, 1353 m a.s.l) in the southern Altai Mountains within northern Xinjiang. Specifically, peat carbon isotope value of cellulose(δ^(13)C_(cellulose)) was used to estimate the warm-season moisture variations and the degree of humification was used to constrain the δ^(13)C_(cellulose)-based hydrological interpretation. The climatic attributions of the interpreted hydrological variations were based on the warm-season temperature reconstructed from Belukha ice core and the warm-season precipitation inferred from the reconstructed Atlantic Multidecadal Oscillations(AMO). The results show that humification decreased and the δ^(13)C_(celluose)-suggested moisture decreased from ~1510 to ~1775 AD, implying that a constant dryingcondition may have inhibited peat decay. Our comparison with reconstructed climatic parameters suggests that the moisture-level decline was most likely resulted from a constant decline of precipitation. The results also show that humification kept a stable level and the δ^(13)C_(celluose)-suggested moisture also decreased from ~1775 to ~2013 AD, implying that peat decay in the acrotelm primarily did not depend on the water availability or an aerobic environment. Again, our comparison with reconstructed climatic parameters suggests that the land-surface moisturelevel decline was most likely resulted from a steady warming of growing-season temperature.
基金partially supported by projects of Fundamental research (Ministry of Science and Higher Education of Russian Federation)No 0331-2016-0035Russian Foundation for Fundamental Investigations No 17-05-00654
文摘Based on the analysis of the field data of nonstationary electromagnetic soundings with different installations,the evolution of the stressed state of the geological massif in the epicentral region of the destructive 2003 M_w7.3 Chuya earthquake is investigated in the paper.The measurements by these methods were executed in a lot of regular points located at two sites of the western part of the Chuya basin of Gorny Altai(Russian Federation).The field works have been performed for 13 years.We developed a measurement technique using data from the three Transient Electromagnetic Method(TEM)method settings for determination of the resistivity anisotropy coefficient.Interpretation of the field data is carried out based on the inverse problem solution,and further,taking into account the geological structure and seismological data,variations of true electrophysical characteristics of the cross-section(electrical resistivity and resistivity anisotropy coefficient)are analyzed.According to the TEM data acquired in the 1980 s,the geoelectric parameters of rocks in the period of low seismic activity were estimated.Comparison of the results of quantitative interpretation of the modern measurements(2004-2016)with those taken before the Chuya event allows tracing a change in the geoelectric parameters of the cross-section in the aftershock period,and on this basis tracking the evolution of the rock massif after the destructive seismic impact.
基金supported by the Russian Science Fund under basic project No.IX.135.2“Geotemperature field and transformation of the permafrost zone of North Asia and mountainous regions of Central Asia”。
文摘This study presents the long-term temperature monitoring in the Russian Altai Mountains. In contrast to the Mongolian and Chinese parts, the modern temperature regime of the Russian Altai remains unclear. The complexity of a comprehensive understanding of permafrost conditions in the Russian Altai is related to the high dissection of the terrain, the paucity of the latest observational data, and the sparse population of permafrost areas. The general objective of this study is to determine the temperature regime on the surface,in the active layer, and in the zero annual amplitude(ZAA) layer, based on the known patterns of permafrost distribution in the region. Using automatic measuring equipment(loggers), we obtained information on the temperature of frozen and thawed ground within the altitudes from 1484 to 2879 m a. s. l. during the period from 2014 to 2020.An array of 15 loggers determined the temperature regime of bare and vegetated areas within watersheds,slopes, and valleys. N-factor parameters and surface temperature are similar to those in the Mongolian Altai, but the mean annual ground temperature at the depth of 1 m has a wide range of fluctuations(more than 32℃) based on research results, and we allocated it into three groups based on altitudinal zonality. Snow cover has a strong influence on the temperature regime, but the determination of the fine-scale variability requires additional study.Ground temperature regime during the observation period remained stable, but continued monitoring allows a more detailed assessment of the response to climatic changes.
