Pamirs Research Articles

Sex differences in the association between waist circumference and physical fitness index among Tajik adolescents in the Pamir Mountains of Xinjiang, China: an observational study

BackgroundIt has been reported in the literature that waist circumference (WC) was related to physical fitness in adolescents. However, the association between WC and PFI(physical fitness index), a comprehensive indicator of physical fitness, has been less studied. In addition, it is not clear whether the association between WC and PFI changes depending on altitude, ethnicity, and sex. This study further revealed the correlation between WC and PFI among adolescents in high-altitude areas and provided references for the physical and healthy development of adolescents in high-altitude areas.MethodsIn this study, a total of 1705 Tajik adolescents aged 13–15 years were selected using stratified whole-population sampling. WC and physical fitness items (grip strength, standing long jump, 50 m dash, and endurance run) were assessed and a standardized method was used to calculate PFI. The association between WC and PFI was analyzed by curvilinear regression analysis.ResultsThe mean and standard deviation of WC and PFI for Tajik adolescents aged 13–15 years old on the Pamir Plateau in Xinjiang, China, were 68.26 ± 7.75 cm and − 2.00 ± 3.47 respectively. Comparison of PFI between groups of Tajik adolescents with different WC showed that inter-group comparisons had significant effects with effect size above 0.2. The Tajik adolescents’ PFI reached its highest when WC was 61 cm for boys(-1.3207), and 60 cm for girls (-1.0556).ConclusionsThe association between WC and PFI in Tajik adolescents showed an inverted “U” curve, with no sex difference. It is recommended that the WC of Tajik adolescents should be controlled between 60 and 61 cm to maintain better PFI levels. The study provides support and reference for educational policy-making and public health prevention in the Pamir Plateau in Xinjiang, China.

Surface Rupture of the 2008 Mw 6.6 Nura Earthquake: Triggered Flexural‐Slip Faulting in the Pamir‐Tien Shan Collision Zone

AbstractThis study investigates the intricate relationship between earthquake sources and seismogenic surface ruptures in a complex tectonic setting with active faults in the continental collision zone between the southern Tien Shan and the northern Pamir Mountains in Central Asia. The study focuses on the 2008 Mw 6.6 Nura earthquake along the Pamir Frontal Thrust, where the seismogenic surface rupture occurred unexpectedly within the footwall and 10 km away from the source thrust fault. This discrepancy raises questions about the interactions and potential trigger mechanisms between tectonic structures during earthquake rupture. Using unmanned aerial vehicle photography and field inspection, our investigation integrates detailed fault‐zone mapping with tectono‐geomorphic observations to unravel potential interactions between subsurface structures and surface‐deformation phenomena. Our findings suggest that a combination of slip along deep‐seated basement faults and remotely triggered flexural slip within folded Paleogene strata led to surface rupture of overlying Quaternary glacial deposits. Geomorphological and geochronological analyses coupled with systematic displacement measurements furthermore reveal evidence of similar past ruptures within the regional fault system, suggesting a recurrence interval of 1.7 kyr and a Holocene vertical offset rate of 0.4 mm/yr. The analysis of the Nura rupture zone contributes significantly to evaluate linkages between surface and subsurface structures regarding fault‐zone behavior and seismic hazard assessments. Importantly, our results highlight the critical role of on‐site investigations in regions with poorly defined surface ruptures, where misinterpretation may lead to the underestimation of the impact of seismic events and limitations in assessing earthquake history and strain accumulation.

Unveiling the future water pulse of central asia: a comprehensive 21st century hydrological forecast from stochastic water balance modeling

This study uses a new dataset on gauge locations and catchments to assess the impact of 21st-century climate change on the hydrology of 221 high-mountain catchments in Central Asia. A steady-state stochastic soil moisture water balance model was employed to project changes in runoff and evaporation for 2011–2040, 2041–2070, and 2071–2100, compared to the baseline period of 1979–2011. Baseline climate data were sourced from CHELSA V21 climatology, providing daily temperature and precipitation for each subcatchment. Future projections used bias-corrected outputs from four General Circulation Models under four pathways/scenarios (SSP1 RCP 2.6, SSP2 RCP 4.5, SSP3 RCP 7.0, SSP5 RCP 8.5). Global datasets informed soil parameter distribution, and glacier ablation data were integrated to refine discharge modeling and validated against long-term catchment discharge data. The atmospheric models predict an increase in median precipitation between 5.5% to 10.1% and a rise in median temperatures by 1.9 °C to 5.6 °C by the end of the 21st century, depending on the scenario and relative to the baseline. Hydrological model projections for this period indicate increases in actual evaporation between 7.3% to 17.4% and changes in discharge between + 1.1% to –2.7% for the SSP1 RCP 2.6 and SSP5 RCP 8.5 scenarios, respectively. Under the most extreme climate scenario (SSP5-8.5), discharge increases of 3.8% and 5.0% are anticipated during the first and second future periods, followed by a decrease of -2.7% in the third period. Significant glacier wastage is expected in lower-lying runoff zones, with overall discharge reductions in parts of the Tien Shan, including the Naryn catchment. Conversely, high-elevation areas in the Gissar-Alay and Pamir mountains are projected to experience discharge increases, driven by enhanced glacier ablation and delayed peak water, among other things. Shifts in precipitation patterns suggest more extreme but less frequent events, potentially altering the hydroclimate risk landscape in the region. Our findings highlight varied hydrological responses to climate change throughout high-mountain Central Asia. These insights inform strategies for effective and sustainable water management at the national and transboundary levels and help guide local stakeholders.

New data on Dysderoidea (Arachnida: Araneae) of the Pamir Mountains, Tajikistan

Two new species of two dysderoid families are described based on specimens collected from the Pamir Mountains in Tajikistan: the dysderid Dysdera bartang sp. n. (male) and the segestriid Segestria pamirica sp. n. (female). Both species were collected at elevations of 2200–2500 m a.s.l. (above sea level). Detailed descriptions, figures, diagnoses, habitat photographs and a distribution map are provided. The altitudinal limit of the species of Dysdera and Segestria in Central Asia is briefly discussed. Segestria pamirica sp. n. is likely to be the most high-altitude species of the genus in Central Asia and even in the world. An identification key to females of the Central Asian species of Segestria is also provided.

Effect of plant roots on the radiocarbon age of loess deposits in arid central Asia

Radiocarbon and OSL dating are the two main approaches used to date aeolian deposits in arid central Asia (ACA). Previous results showed that, compared with OSL dating, the 14C ages of loess deposits in ACA are underestimated when the loess age is beyond ∼25 ka. However, the cause of this radiocarbon age underestimation has not been adequately addressed. In this study, we measured the 14C ages of different dating materials, including pyrolysis volatile (Py-V), pyrolysis residue (Py-R), humin, and total organic carbon fractions from two loess sections in ACA (the Hoalin section in the western Pamir Mountains, and the TLD16 section in the northern Tianshan Mountains). The results show that different dating material yielded different 14C ages for all the loess samples, and all the radiocarbon ages obtained are younger than their corresponding OSL ages. Based on these results, together with a regional comparison of 78 14C ages from ACA with their corresponding OSL ages, we propose that the 14C age underestimation is mainly due to the contamination by the deep penetration of the extended root systems of the plants that grow in arid areas, whereas this effect is less significant in the summer monsoon–dominated Chinese Loess Plateau.

Luminescence dating of the MIS 6 glaciation of the Pamir mountains (Central Asia)

The Pamir Mountains are one of the highest mountain systems in the world; they act as sources of fresh water for the main rivers of Central Asia: the Amudaria and Syrdaria. Throughout the Quaternary, the Pamirs played a major role in controlling atmospheric circulation and land-surface processes, and provided great volumes of terrigenous sediments for transport by large rivers to the depressions in the Aral and Caspian regions. These ultimately provided broad aeolian cover in the sandy deserts, and finer dust for the widely distributed loess-palaeosol sequences. The glaciation history of this highly dynamic region provides an important basis for understanding climate change, sediment source and landscape evolution in Central Asia during the Quaternary. The question of the number, distribution, extent and timing of Pleistocene glaciations in the Pamir is debated. One of the main obstacles to research, together with difficulties of access and severity of current climate, is the varying degree of preservation of traces of previous glaciations in the western and eastern Pamir. As a result of a geological survey, we for the first time identified a thick lacustrine deposit at high altitudes in a tributary of the Panj – the valley of the Sary-Shitharv River – this records the damming of the Panj River valley by a large glacier. Luminescence measurements were undertaken to obtain the age of the Sary-Shitharv glacially-dammed lake. As often in mountain catchments the quartz OSL signal was unsuitable for dose estimation, and so the chronology of the Sary-Shitharv section is based entirely on post-IR IRSL signals from K-rich feldspar. We used pIRIR50,290 and pIRIR200,290 protocols and obtained indistinguishable ages from both protocols. Given the high sedimentation rates deduced from the structure of lacustrine deposits, the entire sequence must have been accumulated rather quickly, over a period of no more than a few thousand years. The average age over the whole series of dates is 165 ± 11 ka. This places the existence of the glacially-dammed lake at Sary-Shitharv in late MIS 6, a result that fits well with the general course of the glacial history of the Pamirs.

Multivariate analysis of land surface dynamics in Central Asia: patterns of trends and drivers under a changing climate

ABSTRACT With temperatures in Central Asia (CA) increasing more than the global average, this region is one of the global hotspots affected by climate change. CA is mostly characterized by arid climate, which is why available water resources are of paramount importance for the societies, economies, and the environment. In this regard, quantifying changes on the land surface and controlling factors that influence land surface dynamics are of great interest to improve our understanding of climate change impacts in this region. Hence, this study analyzes multivariate time series covering climatic, hydrological and Earth observation (EO)-based land surface variables. The used EO time series characterize the land surface and include data on the normalized difference vegetation index (NDVI), surface water area (SWA), and snow cover area (SCA) between December 2002 to November 2021. To analyze these time series, we employ trend analyses and a causal discovery algorithm. Both analyses were carried out at multiple spatial and temporal scales. The results show that NDVI trends were mostly significantly negative in the Northwest and positive in the Northeast of CA in summer. In summer and autumn, the percentage of significant negative NDVI trends outweighed the positive trends. For SWA, the detected trends were mostly significant negative throughout all scales. Significant negative trends were retrieved for SCA across all seasons, except for autumn regionally. Particularly the Tian Shan and Pamir mountains show significant declines of SCA in winter and spring. The causal analyses revealed that the NDVI is mostly controlled by water availability in summer. In spring and autumn, temperature is the leading driver on the NDVI. Likewise, temperature is found to largely control SWA in spring and autumn. SCA is mostly negatively coupled to temperature during spring and autumn. A positive coupling between SCA and precipitation is identified in winter.

Current Status of Marco Polo Sheep (Ovis ammon polii) in the Pamir Mountains of Badakhshan Province, Afghanistan

Current Status of Marco Polo Sheep (Ovis ammon polii) in the Pamir Mountains of Badakhshan Province, Afghanistan

Using the Sensible Heat Flux Eddy Covariance-Based Exchange Coefficient to Calculate Latent Heat Flux from Moisture Mean Gradients Over Snow

In absence of the high-frequency measurements of wind components, sonic temperature and water vapour required by the eddy covariance (EC) method, Monin–Obukhov similarity theory (MOST) is often used to calculate heat fluxes. However, MOST requires assumptions of stability corrections and roughness lengths. In most environments and weather situations, roughness length and stability corrections have high uncertainty. Here, we revisit the modified Bowen-ratio method, which we call C-method, to calculate the latent heat flux over snow. In the absence of high-frequency water vapour measurements, we use sonic anemometer data, which have become much more standard. This method uses the exchange coefficient for sensible heat flux to estimate latent-heat flux. Theory predicts the two exchange coefficients to be equal and the method avoids assuming roughness lengths and stability corrections. We apply this method to two datasets from high mountain (Alps) and polar (Antarctica) environments and compare it with MOST and the three-layer model (3LM). We show that roughness length has a great impact on heat fluxes calculated using MOST and that different calculation methods over snow lead to very different results. Instead, the 3LM leads to good results, in part due to the fact that it avoids roughness length assumptions to calculate heat fluxes. The C-method presented performs overall better or comparable to established MOST with different stability corrections and provides results comparable to the direct EC method. An application of this method is provided for a new station installed in the Pamir mountains.

Circumscription and diagnosis of the Arge ochropus species–group (Hymenoptera: Argidae), with a description of Arge gussakovskiji sp. nov. from the Pamir Mountains in Tajikistan

The species composition and diagnostic characters of the Arge ochropus species–group are reviewed. This species group is circumscribed based on the structure of the genitalia. It contains only four species, including A. gussakovskiji sp. nov. described here from the Pamir Mountains in the Gorno-Badakhshan Province of Tajikistan. A key to the Palaearctic species of the A. ochropus group is provided. The differences between the A. ochropus group and the other species groups of the genus Arge Schrank, 1802 with similar coloration are discussed.

Comparative molecular analyses of Eimeria Schneider (Apicomplexa: Eimeriidae) species from rock ptarmigan in Iceland, Svalbard-Norway, and Japan.

The rock ptarmigan (Lagopus muta) has a Holarctic breeding distribution and is found in arctic and sub-arctic regions. Isolated populations and glacial relicts occur in alpine areas south of the main range, like the Pyrenees in Europe, the Pamir mountains in Central Asia, and the Japanese Alps. In recent decades considerable effort has been made to clarify parasite infections in the rock ptarmigan. Seven Eimeria spp. have been reported parasitizing rock ptarmigan. Two of those species, E. uekii and E. raichoi parasitizing rock ptarmigan (L. m. japonica) in Japan, have been identified genetically. Here we compare partial sequences of nuclear (18S rRNA) and mitochondrial (COI) genes and we detail the morphology of sporulated oocysts of E. uekii and E. raichoi from Japan, E. muta and E. rjupa, from the rock ptarmigan (L. m. islandorum) in Iceland, and two undescribed eimerian morphotypes, Eimeria sp. A, and Eimeria sp. B, from rock ptarmigan (L. m. hyperborea) in Norway (Svalbard in the Norwegian Archipelago). Two morphotypes, ellipsoidal and spheroidal, are recognized for each of the three host subspecies. Our phylogenetic analysis suggests that the ellipsoidal oocyst types, E. uekii, E. muta, and Eimeria sp. A (Svalbard-Norway) are identical and infects rock ptarmigan in Japan, Iceland, and Svalbard-Norway, respectively. Eimeria uekii was first described in Japan in 1981 so that E. muta, described in Iceland in 2007, and Eimeria sp. A in Svalbard-Norway are junior synonyms of E. uekii. Also, phylogenetic analysis shows that the spheroidal oocyst types, E. rjupa and Eimeria sp. B (Svalbard-Norway), are identical, indicating that rock ptarmigan in Iceland and Svalbard-Norway are infected by the same Eimeria species and differ from E. raichoi in Japan.

Hydrological regimes and evaporative flux partitioning at the climatic ends of high mountain Asia

Abstract High elevation headwater catchments are complex hydrological systems that seasonally buffer water and release it in the form of snow and ice melt, modulating downstream runoff regimes and water availability. In High Mountain Asia (HMA), where a wide range of climates from semi-arid to monsoonal exist, the importance of the cryospheric contributions to the water budget varies with the amount and seasonal distribution of precipitation. Losses due to evapotranspiration and sublimation are to date largely unquantified components of the water budget in such catchments, although they can be comparable in magnitude to glacier melt contributions to streamflow. Here, we simulate the hydrology of three high elevation headwater catchments in distinct climates in HMA over 10 years using an ecohydrological model geared towards high-mountain areas including snow and glaciers, forced with reanalysis data. Our results show that evapotranspiration and sublimation together are most important at the semi-arid site, Kyzylsu, on the northernmost slopes of the Pamir mountain range. Here, the evaporative loss amounts to 28% of the water throughput, which we define as the total water added to, or removed from the water balance within a year. In comparison, evaporative losses are 19% at the Central Himalayan site Langtang and 13% at the wettest site, 24 K, on the Southeastern Tibetan Plateau. At the three sites, respectively, sublimation removes 15%, 13% and 6% of snowfall, while evapotranspiration removes the equivalent of 76%, 28% and 19% of rainfall. In absolute terms, and across a comparable elevation range, the highest ET flux is 413 mm yr−1 at 24 K, while the highest sublimation flux is 91 mm yr−1 at Kyzylsu. During warm and dry years, glacier melt was found to only partially compensate for the annual supply deficit.

Fluoritites Produced by Crystallization of Carbonate–Fluoride Magma

Abstract Fluorite-dominated rocks are occasionally found in association with carbonatites, but their geologic and petrologic relations are rarely reported. The Dunkeldyk area of the Pamir mountains in south-eastern Tajikistan contains dikes of distinctive rocks composed of calcite, fluorite, celestine-barite, sulfides, apatite, with minor quartz, biotite, and REE fluorcarbonates. The dikes have sharp contacts with the host (meta-)sedimentary rocks and layering with ribbons, ranging from fluorite-bearing calcite carbonatites to fluoritites (rocks with >50% fluorite). The fluoritites are characterized by high Ca, F, Ba, Sr, REE, and S coupled with anomalously low O. The geologic relations and textures suggest a magmatic origin of the dikes from melts close to calcite–fluorite eutectic that experienced nucleation-controlled differentiation during the crystallization of dikes and the formation of fluoritite cumulates in larger intrusions. The Dunkeldyk dikes demonstrate that sizable geological bodies of fluorite-dominated rocks could form from carbonate–fluoride melts originating from the differentiation of alkaline silicate magmas.

Constraining the exhumation history of the northwestern margin of Tibet with a comparison to the adjacent Pamir

Regional variations in the evolution of the Tibetan Plateau have important implications for our understanding of crustal deformation processes. There have been few studies of the evolution of the NW margin of the plateau and its transition to the Pamir Mountains to the west. We focus on this region with a multi-technique detrital study of two sedimentary sections in the Tarim Basin. Our provenance data show that an appreciable component of the detrital material in the sedimentary sections was derived from the Songpan-Ganzi–Tianshuihai composite terrane, with some contribution from the Karakoram and/or West Qiangtang. Given the proximity of the West Kunlun terrane to the sedimentary sections under study, and its long history of exhumation, this terrane in all likelihood also contributed to the studied successions. Our thermochronological data record phases of exhumation in the hinterland in the Triassic, Early Cretaceous and Oligo-Miocene. Similar to the Pamir Mountains, the Triassic and Oligo-Miocene periods of exhumation are attributed to the Cimmerian and Himalayan orogenies, respectively. The Early Cretaceous signal may reflect the distal effects of the Lhasa–Qiangtang collision. Coevality with deformation in the Pamir Mountains suggests a coupled geodynamic system, with retro-arc deformation associated with Neotethyan subduction in the west and terrane accretion in the east. Supplementary material: Detailed analytical method, sample information, petrographic, geochronological and low-temperature thermochronological data are available at https://doi.org/10.6084/m9.figshare.c.7040686

GEMS v1.0: Generalizable Empirical Model of Snow Accumulation and Melt, based on daily snow mass changes in response to climate and topographic drivers

Abstract. Snow modelling is often hampered by the availability of input and calibration data, which can affect the choice of models, their complexity, and transferability. To address the trade-off between model parsimony and transferability, we present the Generalizable Empirical Model of Snow Accumulation and Melt (GEMS), a machine-learning-based model, which requires only daily precipitation, temperature or its daily diurnal cycle, and basic topographic features to simulate snow water equivalent (SWE). The model embeds a support vector regression pretrained on a large dataset of daily observations from a diverse set of the SNOwpack TELemetry Network (SNOTEL) stations in the United States. GEMS does not require any user calibration, except for the option to adjust the temperature threshold for rain–snow partitioning, though the model achieves robust simulation results with the default value. We validated the model with long-term daily observations from numerous independent SNOTEL stations not included in the training and with data from reference stations of the Earth System Model–Snow Model Intercomparison Project. We demonstrate how the model advances large-scale SWE modelling in regions with complex terrain that lack in situ snow mass observations for calibration, such as the Pamir and Andes mountains, by assessing the model's ability to reproduce daily snow cover dynamics. Future model improvements should consider the effects of vegetation, improve simulation accuracy for shallow snow in warm locations at lower elevations, and possibly address wind-induced snow redistribution. Overall, GEMS provides a new approach for snow modelling that can be useful for hydroclimatic research and operational monitoring in regions where in situ snow observations are scarce.

Hybrids as mirrors of the past: genomic footprints reveal spatio-temporal dynamics and extinction risk of alpine extremophytes in the mountains of Central Asia.

Hybridization is one of the key processes shaping lineage diversification, particularly in regions that experienced strong climate oscillations. The alpine biome with its rich history of glacial-interglacial cycles and complex patterns of species distribution shifts offers an excellent system to investigate the impact of gene flow on population dynamics and speciation, important issues for evolutionary biology and biodiversity conservation. In this study, we combined genomic data (DArTseq), chloroplast markers, and morphology to examine phylogenetic relationships and the permeability of species boundaries and their evolutionary outcomes among the alpine extremophilic species of Puccinellia (Poaceae) in the Pamir Mountains, a part of the Mountains of Central Asia biodiversity hotspot. We determined the occurrence of interspecific hybrids between P. himalaica and P. pamirica, which demonstrated almost symmetric ancestry from their parental species and did not show signals of introgression. According to our integrative revision, the natural hybrids between P. himalaica and P. pamirica should be classified as Puccinellia ×vachanica (pro species). Using approximate Bayesian computation for population history inference, we uncovered that P. himalaica hybridized with P. pamirica independently in multiple localities over the Holocene. Hybrids inherited the fine-scale genetic structure from their parental species, which developed these patterns earlier, during the Late Pleistocene. Hybridization had different consequences for the involved parental lineages, likely playing an important role in a continuing decline of P. himalaica in the Pamir Mountains over the Holocene. Our results show that P. himalaica should be considered a critically endangered species in the Pamir Mountains and could also be retreating across its entire range of distribution in High Mountain Asia. Using a comparative phylogeographic framework, we revealed the risk of extinction of a cold-adapted alpine species in a global biodiversity hotspot. This study highlights that genomics could unravel diversity trends under climate change and provides valuable evidence for conservation management.

Can Bergmann’s Rule and the Thermal Melanism Hypothesis explain the variation in colour and size observed in the wild bee Eoanthidium insulare (Apoidea: Megachilidae) across its Palaearctic range?

To analyse geographic variation patterns and assess the applicability of biogeographical rules in insects, the West Palaearctic anthidiine bee Eoanthidium insulare serves as an excellent model. This species showcases a highly variable black-and-yellow colour pattern, with a distribution spanning over 4400 km from the Adriatic Sea to the Pamir Mountains and extending over 1660 km in a south-north direction. We examined 214 specimens from all geographic regions of its distribution and identified a significant increase in both body size and the proportion of black in the integument from south to north. This phenomenon may be attributed to a more efficient exploitation of solar energy through a larger integument surface area (Bergmann’s Rule) and enhanced heat retention due to lower skin reflectance (Thermal Melanism Hypothesis). These two processes, therefore, complement each other. However, despite the cooler climates at higher altitudes, we found no correlations between body size and altitude. Furthermore, while we observed an increase in the proportion of black in the integument from east to west, there was no significant increase in body size. Notably, no correlation between body size and body colouration was identified, suggesting that size and colour adaptation are independent processes. Given that the various colour and size patterns were identified as clinal rather than discontinuous, and the intraspecific genetic distance across the distribution area was remarkably low (0.00138), featuring only four distinct haplotypes of the mitochondrial COI region DNA sequence, we suggest that the subspecies E. i. persicolum and E. i. lemesium be regarded as synonymous with the nominate subspecies (syn. nov.). These findings suggest that, although Bergmann’s Rule and the Thermal Melanism Hypothesis can account for certain aspects of geographic variation in the body size and colouration of E. insulare, their effects may be influenced or superimposed by factors such as genetic constitution.

Contractional deformation between extensional dome exhumation in Central Pamir at 17–15 Ma constrained by metamorphic and paleomagnetic data from the Bartang volcanic rocks, Tajikistan

The debated mechanism and timing of formation of the Pamir orogenic salient provides an ideal case to combine paleomagnetic and metamorphic analyses. Opposing views argue for either oroclinal bending of the Pamir since the India-Asia collision or for an originally arcuate shape, which can be tested using paleomagnetism to estimate vertical-axis rotations. Furthermore, Pamir deformation can be dated and characterized by the analysis of a well-expressed regional metamorphism. However, paleomagnetism is seldom applied to metamorphic rocks such that the significance of their rock magnetic signal with respect to deformation remains poorly understood. We studied a > 2 km thick sequence of slightly metamorphosed Cretaceous-Paleogene volcanic and volcaniclastic rocks from the western Central Pamir Mountains using metamorphic petrology, geochronology, and paleomagnetic analyses. These rocks present a medium-grade metamorphism and have undergone fine grained recrystallisation of biotite due to NW-SE compression. 40Ar/39Ar and Rb/Sr ages (∼17 to 15 Ma) on whole rock and biotite, confirm that the greenschist facies metamorphism is related to the coeval exhumation of Pamir gneiss domes during the Middle Miocene. The rocks generally show homogenous magnetic properties. High field magnetic properties and SEM/EDS data show that the main magnetic remanent carrier is titano-hematite. Thermal demagnetizations yield complex characteristic remanent magnetization with site-mean directions obtained for only 14 of the 44 studied sites but scattered mainly within the foliation plane defined by the anisotropy of magnetic susceptibility (AMS). These rocks have also unusual magnetic characteristics where strong-field isothermal remanent magnetizations induce an AMS fabric, likely related to the specific composition and structure of the metamorphic titano-hematite but independent of the original anisotropy fabrics. Combined paleomagnetic and geochronological data from the Bartang volcaniclastics rocks enable us to identify a ∼ 17–15 Ma compressive deformation event contemporaneous with the emplacement of the gneiss domes and suggest no oroclinal bending since that event.

Three Pleistocene glacial advances and a warm episode during MIS-3: Towards a more complete glacial history of the Pamir mountains

Determining the spatial and temporal variations of Pleistocene glaciations is key to understanding present-day climate-driven glacier changes. Glacial chronologies of high-mountain Asia, which are mostly based on cosmogenic 10Be exposure dating of moraine boulders, remain scarce and often inaccurate due to geologically induced age scatter. We present 53 new 10Be exposure ages from rockslides, glacial sediment deposits and glacial erosion surfaces in the southwestern Pamir. In conjunction with previously published 10Be data, we constrain the timing and extent of three major glacial stages in the Pamir. During the Middle Pleistocene, a continuous ice sheet covered most of the Pamir. This stage is older than 200 ka and may have occurred during Marine Isotope Stages (MIS) 8, 10, or 12. The deep valleys of the western Pamir, which contrast with the eastern Pamir plateau, are partly attributed to Middle Pleistocene glacial erosion. Successively less extensive glacial advances occurred during MIS-4/5 (between 60 and 100 ka ago) and during MIS-2 (at 18–22 ka). The last glacial maximum was synchronous in most of the Pamir, except for prolonged glaciation of the Muztagh Ata ice cap until 14 ka ago. Similar to today, Late Pleistocene glaciers were precipitation-limited, with moisture mainly supplied by westerly winds. An episode of increased mass wasting (e.g. Zuvor rockslide: 34 ± 1 ka) and glacier surging correlates with a peak in δ18O values in the Guliya ice core and is attributed to a warmer climate.

A gradual increase of aerosol pollution in the Third Pole during the past four decades: Implication for regional climate change

We analyse the long-term (1980–2020) changes in aerosols over the Third Pole (TP) and assess the changes in radiative forcing (RF) using satellite, ground-based and reanalysis data. The annual mean aerosol optical depth (AOD) varies from 0.06 to 0.24, with the highest values of around 0.2 in the north and southwest TP, which are dominated by dust from Taklimakan and Thar deserts, respectively. However, Organic Carbon (OC), Black Carbon (BC) and sulphate aerosols have significant contributions to the total AOD in the south and east TP. High amounts of dust are observed in spring and summer, but BC in winter. Trajectory analysis reveals that the air mass originated from East and South Asia carries BC and OC, whereas the air from South Asia, Central Asia and Middle East brings dust to TP. Significant positive trends in AOD is found in TP, with high values of about 0.002/yr in the eastern and southern TP. There is a gradual increase in BC and OC concentrations during 1980–2020, but the change from 2000 is phenomenal. The RF at the top of the atmosphere varies from -10 to 2 W/m2 in TP, and high positive RF of about 2 W/m2 is estimated in Pamir, Karakoram and Nyainquentanglha mountains, where the massive glacier mass exists. The RF has increased in much of TP during recent decades (2001–2020) with respect to previous decades (1981–2000), which can be due to the rise in BC and dust during the latter period. Therefore, the positive trend in BC and its associated change in RF can amplify the regional warming, and thus, the melting of glaciers or ice in TP. This is a great concern as it is directly connected to the water security of many South Asian countries.