Search

Thermodynamic and liquid water profiles can be retrieved by a ground-based microwave radiometer (MWR) in nearly all weather conditions, which is useful for detecting mesoscale phenomena. This paper reviews the advances in remote sensing of atmospheric profiles and cloud properties by MWR in central China. Comparative studies indicate that MWR retrieval accuracy is different under various skies, especially those that decay under precipitation. The off-zenith method is proven to be capable of reducing the impact of precipitation and snow on MWR retrieval accuracy. Application studies demonstrate that MWR retrievals are helpful for early warning of rainstorms, hailstorms, and thunderstorms. Moreover, MWR retrievals provide a way to study cloud properties. The temporal variations of cloud occurrence frequency (COF) and liquid water path (LWP) are different for low, middle, and high clouds, and the vertical distribution of COF is also different in autumn and other seasons. Note that MWR can infer valid retrievals over the eastern Tibetan Plateau due to the weak precipitation over there. Also, cloud properties over the eastern Tibetan Plateau present differences from those over central China, and this is related to the different characteristics of atmospheric water vapor between these two regions. To bring more benefits for mechanism study and early warning of severe weather and numerical weather prediction, the decayed accuracy of MWR zenith retrievals under precipitation should be resolved. And combining MWR with other instruments is necessary for MWR application in detecting multi-layer clouds and ice clouds. [ABSTRACT FROM AUTHOR]

In recent years, numerous ancient landslides initially triggered by historic earthquakes on the eastern Tibetan Plateau have been reactivated by fault activity and heavy rainfall, causing severe human and economic losses. Previous studies have indicated that short-term heavy rainfall plays a crucial role in the reactivation of ancient landslides. However, the deformation behavior and reactivation mechanisms of seasonal rainfall-induced ancient landslides remain poorly understood. In this paper, taking the Dandu ancient landslide as an example, field investigations, ring shear experiments, and interferometric synthetic aperture radar (InSAR) deformation monitoring were performed. The cracks in the landslide, formed by fault creeping and seismic activity, provide pathways for rainwater infiltration, ultimately reducing the shear resistance of the slip zone and causing reactivation and deformation of the Dandu landslide. The deformation behavior of landslides is very responsive to seasonal rainfall, with sliding movements beginning to accelerate sharply during the rainy season and decelerating during the dry season. However, this response generally lags by several weeks, indicating that rainfall takes time to infiltrate into the slip zone. These research results could help us better understand the reactivation mechanism of ancient landslides triggered by seasonal rainfall. Furthermore, these findings explain why many slope failures take place in the dry season, which typically occurs approximately a month after the rainy season, rather than in the rainy season itself. [ABSTRACT FROM AUTHOR]

The Sichuan-Yunnan area is located at the southeastern margin of the Tibetan Plateau, where tectonic movement is strong with deep and large faults distributed in a staggered manner, which results in strong seismic activities and severe earthquake hazards. Since the 21st century, several earthquakes of magnitude 7.0 or above occurred in this region, which have caused huge casualties and economic losses, especially the 2008 Ms8.0 Wenchuan earthquake. At present, earthquake monitoring and source parameter inversion, strong earthquake hazard analysis and disaster assessment are still the focus of seismological researches in the Sichuan-Yunnan region. Regional high-precision 3D community velocity models are fundamental for these studies. In this paper, by assembling seismic observations at permanent seismic stations and several temporary dense seismic arrays in this region, we obtained about 7.06 million body wave travel time data (including absolute and differential travel times) using a newly developed artificial intelligence body wave arrival time picking method and about 100,000 Rayleigh wave phase velocity dispersion data in the period range of 5–50 s from ambient noise cross-correlation technique. Based on this abundant dataset, we obtained the three-dimensional high resolution Vp and Vs model in the crust and uppermost mantle of southwest (SW) China by adopting the joint body and surface wave travel time tomography method considering the topography effect starting from the first version of community velocity model in SW China (SWChinaCVM-1.0). Compared to SWChinaCVM-1.0, this newly determined velocity model has higher resolution and better data fitness. It is accepted by the China Seismic Experimental Site as the second version of the community velocity model in SW China (SWChinaCVM-2.0). The new model shows strong lateral heterogeneities in the shallow crust. Two disconnected low velocity zones are observed in the middle to lower crust, which is located in the Songpan-Ganzi block and the northern Chuandian block to the west of the Longmenshan-Lijiang-Xiaojinhe fault, and beneath the Xiaojiang fault zone, respectively. The inner zone of the Emeishan large igneous province (ELIP) exhibits a high velocity anomaly, which separates the two aforementioned low velocity anomalies. Low velocity anomaly is also shown beneath the Tengchong volcano. The velocity structures in the vicinity of the 2008 Ms8.0 Wenchuan earthquake, the 2013 Ms7.0 Lushan earthquake and the 2017 Ms7.0 Jiuzhaigou earthquake mainly show high Vp and Vs anomalies and the mainshocks are basically located at the transition zone between the high and low velocity anomalies. Along with the segmentation characteristics of seismic activity, we suggest that areas with significant changes in velocity structures, especially in active fault zones, might have a greater potential to generate moderate to strong earthquakes. [ABSTRACT FROM AUTHOR]

The Wudaoliang–Changshagongma fault is one of the NW-trending faults located within the southern Bayan Har Block of the Tibetan Plateau in China. In this paper, we used high-resolution imagery and digital elevation model data to study the geomorphological and geological characteristics of the fault. Furthermore, the result also determined the fault trace and estimated the average horizontal slip rate of the fault since the late Quaternary to have been 2.6 ± 0.6 mm/a. This slip rate is approximately equivalent to that of the Awancang, Madoi–Garde, and Dari faults, which are also located within the block. Furthermore, the slip rates of these faults obtained by remote sensing and geological methods are consistent with GPS observations. It indicates that tectonic deformation within the block is continuous and diffuse. Using trenching study results and sedimentary radiocarbon dating, we identified four paleoearthquake events that occurred at 42,378–32,975, 33,935–20,663, 5052–4862, and after 673–628 cal BP, respectively. The recurrence intervals of large earthquakes on the faults within the block are much longer than those of the boundary faults, and the slip rates are also smaller, indicating that faults within the block play a regulatory role in the tectonic deformation of the Bayan Har Block. [ABSTRACT FROM AUTHOR]

Phase change materials are used in passive solar house construction with light steel structure walls, which can overcome the problems of weak heat storage capacity and poor utilization of solar heat and effectively solve the thermal defects of light steel structure walls. Based on this, on the basis of preliminary experimental research, this study further carried out theoretical analysis and simulation research on the thermal performance of a light steel structure passive solar house (Trombe form) with PCM walls. Through the heat balance analysis of heat transfer in the heat collecting partition wall, the theoretical calculation formula of the phase change temperature of the PCM was obtained, and it verified theoretically that the phase change temperature value should be 1–3 °C higher than the target indoor air temperature. The evaluation index "accumulated daily indoor temperature offset value" was proposed for evaluating the effect of phase change materials on the indoor temperature of the passive solar house, and "EnergyPlus" software was used to study the influence of the phase change temperature, the amount of material, and the thickness of the insulation layer on the indoor air temperature in a natural day. The results showed that there was a coupling relationship among the performance and between of the thickness of the PCM layer and the phase change temperature. Under typical diurnal climate conditions in the northern Tibetan Plateau of China, the optimal combination of the phase change temperature and the layer thickness was 17 °C and 15 mm, respectively. Especially at a certain temperature, excessive increases in the thickness of the phase transition layer could not improve the indoor thermal environment. For this transition temperature, there exists an optimal transition layer thickness. For a Trombe solar house, the thickness of the insulation layer has an independent impact on indoor temperature compared to other factors, which has an economic value, such as 50 mm in this case. In general, this paper studied the relationship between several important parameters of the phase change wall of a solar house by using numerical simulation methods and quantitatively calculated the optimal parameters under typical meteorological conditions, thus providing a feasible simulation design method for similar engineering applications. [ABSTRACT FROM AUTHOR]

The Daliang Shan is a tectonic unit that connects the active southeastern Tibetan Plateau with the stable South China block. As a newly generated (formed later than the Xianshuihe–Xiaojiang active fault system) seismotectonic zone induced by the Tibetan tectonics, the detailed constraints of the crustal deformation are central to the understanding of the kinematics and dynamics of the Tibetan expansion. This paper establishes and analyses a high-spatial resolution global positioning system (GPS) velocity field from a dense GPS network in this region. Our modelling results indicate that, in contrast to the equivalent sinistral strike-slip rate of approximately 5 mm yr–1 on the Anninghe–Zemuhe and Daliangshan faults, their inferred interseismic locking depth varies within a large range. The southern segment of the Anninghe Fault and the middle segment of the Daliangshan Fault have deep locking depths of ∼13 km, indicating that the seismic risk is high in these areas. In addition, the detectable counter-clockwise rotation rate of 0.35 ± 0.12° Myr–1 of the Mabian block makes a significant contribution of ∼50 per cent to the strike-slip motion on its boundary faults. This counter-clockwise rotation may be induced by a left-lateral shear gradient with southeastward motion relative to the South China-fixed reference frame, indicating the significance of a simple-shear pattern in exploring the kinematics of the encroachment of the Tibetan tectonics upon a stable block (craton). [ABSTRACT FROM AUTHOR]

Simple Summary: In this study, we describe the well-preserved fossil seed cones of Nothotsuga found in the Mula Basin, Litang County, Sichuan Province, southwestern China. By detailed morphological comparisons, a new fossil species, Nothotsuga mulaensis Z. Li et J. L. Dong sp. nov. is named. This discovery suggests that Nothotsuga had a more northern distribution during the Miocene. In addition, it suggests that the Mula region had a humid and warm climate during this period. The ancient landform presents an intermountain lake basin, which would have been surrounded by higher mountains. After the Miocene, due to the uplift of the Tibetan Plateau, Nothotsuga was either unable to adapt to the extinction of the local environmental or was able to migrate to several scattered places in southern China. In this paper, we describe a new fossil species, Nothotsuga mulaensis Z. Li & J.L. Dong sp. nov. The discovery of the fossil species was based on well-preserved fossil seed cones that were found in the Mula Basin in Xiamula village, Litang County, Sichuan Province, southwestern China. The shapes of these fossils were characterized by ovate seed cones, rhombic or suborbicular scales with auriculate bases, and the bracts were ligulate-spathulate in shape. This finding suggests that Nothotsuga once had a wide distribution range in China and that it also inhabited the eastern Tibetan Plateau (TP). Nothotsuga mulaensis was distributed in an intermountain lake basin, at altitudes from 2000 to 2300 m, in a warm and humid environment. This finding also suggests that the eastern TP may have provided good habitat for Nothotsuga during the Miocene. In addition, we propose that the uplift, accompanied by the severe cooling and aridification that occurred after the Miocene, caused the disappearance of this species of Nothotsuga in the eastern TP. [ABSTRACT FROM AUTHOR]

The western area of the Chinese Loess Plateau (CLP) is close to the northeastern margin of the Tibetan Plateau (NTP) and arid regions of northern China. Loess-paleosol sequence is a good archive for studying the variation of the East Asian summer monsoon (EASM) and the evolutionary history of paleoclimate. However, excessive remagnetization makes it challenging to infer the location of the time-scaled strata, and only a few high-resolution long scale paleomagnetic data are available from the western CLP. To solve this problem, this paper presents a study on establishing a Quaternary chronological framework using the traditional paleomagnetic method and quartz electron spin resonance (ESR) dating. The result is validated by comparing sequences in a variation of magnetic susceptibility and grain-size. Detailed thermal demagnetization records show that declination is reversed, but the inclination reversal is not apparent between S7 and S8. ESR estimated that the three samples collected at a depth of ∼112–145 m were 853.51 ± 133.43 ka, 962.12 ± 144.30 ka, and 1004.27 ± 206.86 ka, respectively. Constrained by these ESR dates, the age of the L9-L15 is defined as ∼0.9–1.2 Ma, which is corroborated the observation in the field stratigraphic survey, the characteristics of magnetic susceptibility and grain-size data. Based on these ages, the Matuyama and Brunhes boundary (MBB, ∼0.78 Ma) is deduced in L8 as inferred from the declination sequence. The bottom age of the loess-paleosol sequence extrapolated from the sedimentation rate is 2.13 Ma. The chronological sequence is therefore established. Several environmental indexes were changed coordinately in broad areas based on the chronological framework, indicating that it is logical and reliable. [ABSTRACT FROM AUTHOR]

The relationship between mafic magmatic enclaves (MMEs) and host granitoids is ongoing debate due to their significant roles in understanding deep magmatisms and geodynamic processes. This paper reports on Early Palaeozoic granitoids and associated MMEs from the Delingha pluton in the South Qilian Accretionary Belt (NW China) to constrain their petrogenesis and draw implications. The MMEs, occurring as ellipsoidal to rounded shapes, are andesitic and have the same crystallization age (~445 Ma) and mineral assemblage as the host granitoids. However, minor isotopic differences between them and compositional and textural disequilibria on minerals (e.g. plagioclase and amphibole) do not support a cumulate origin that the MMEs were formed at earlier stage of the same magmatic system, but forcefully reflect magma hybridization processes between mafic and felsic magmas, during which the hybridized magma was broken up into discrete enclaves by convective motion in the host felsic magma. Accordingly, the primitive compositions of the MMEs likely originated from metasomatized mantle wedge source, while mantle-derived melt underplated and partially melted the lower continental crust to form the host rocks with a certain mantle contribution. Thus, the Delingha pluton is the product of crust-mantle interaction at an active continental margin subduction setting rather than syn-collisional environment, indicating that subduction of the South Qilian Ocean located between the Central Qilian Block and the Oulongbuluke Block may have lasted till to ~445 Ma. [ABSTRACT FROM AUTHOR]

Both the regional earthquake surface wave and seismic ambient noise provide important constraints on the Earth's structure, and yet no study satisfactorily combined them for the best imaging of subsurface seismic structure. In this study, we address this issue by developing a new method to simultaneously determine surface wave phase velocity and earthquake centroid parameters in three steps: (a) preliminary phase velocity inversion based on seismic ambient noise, (b) preliminary earthquake relocation based on earthquake surface wave data, and (c) simultaneous inversion for phase velocity and earthquake centroid parameters with constraints of interstation phase velocity measurements based on seismic ambient noise and event‐station phase velocity measurements based on earthquake surface wave data. Application of the method in the North South Seismic Belt region in China results in high‐resolution Rayleigh wave phase velocity maps and accurate earthquake centroid parameters. The additional earthquake data notably improve resolution of the inverted phase velocity model in west Yunnan and central Tibetan blocks, the regions with sparse seismic station coverage. The inverted phase velocity model exhibits high‐velocity anomalies in cratonic regions and the Emeishan Large Igneous Province, and low‐velocity anomalies in the interior and surrounding regions of the Tibetan Plateau. Relocation places earthquakes in shallow depths with geotherm above the crustal rock's brittle‐ductile transition temperature of ∼400℃ $\sim 400\textdegree$, revealing thermal control on thickness of the seismogenic zone. With earthquake centroid parameters constrained, earthquake data are expected to provide further constraints on the deep seismic structure that is beyond the sampling limit of seismic ambient noise. Plain Language Summary: High‐resolution seismic image of the Earth's interior provides significant physical and structural information inside the Earth. Whereas both the regional earthquake data and seismic ambient noise provide constraints on the seismic imaging, no study yet satisfactorily combined these two types of data for the best results. In this paper, we develop a new method to combine both types of seismic data to better image seismic structure and apply the new method in the North South Seismic Belt region in China. The method consists of three steps to simultaneously determine seismic structure and earthquake source parameters. The resultant seismic images exhibit noted improvement in revealing high‐resolution seismic structure in regions with sparse seismic station coverage, such as the Tibetan Plateau and its adjacent regions. The redetermined earthquake depths reveal thermal control on the maximal depth of earthquake occurrence in the region, with earthquakes occurring at the shallow depths colder than rock's brittle‐ductile transition temperature of ∼400℃ $\sim 400\textdegree$. Key Points: A new method is developed to simultaneously determine surface wave phase velocity and earthquake centroid parametersApplication of the method in the North South Seismic Belt region in China yields high resolution phase velocity maps and event parametersAdditional earthquake data significantly improve the resolution and accuracy of surface wave phase velocity model [ABSTRACT FROM AUTHOR]

This paper collects and analyzes the 1954–2017 monthly average reanalysis data from the U.S. National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR), the 1954–2017 haze days observation data from the National Meteorological Information Center/China Meteorological Administration (NMIC/CMA) and the PM2.5 daily average mass concentration data in 2013–2017 from the China Air Quality Online Monitoring Platform. The atmospheric apparent heat source Q1 (negative Q1 means cold source in winter) over the Tibetan Plateau in December of 1954–2017 is estimated based on thermodynamic equations, and the East Asian winter monsoon index (EAWMI) is calculated. In addition, the discrepancies of the air quality among China's five typical regions (Beijing–Tianjin–Hebei, Fen-Wei Plain, Yangtze River Delta, Pearl River Delta and Sichuan-Chongqing regions) under the joint influence of the Q1 and EAWMI are studied. Results show that when it is a strong cold source year, abnormal downdrafts and "temperature inversion covers" occur in areas far from the high terrain, resulting in increased pollution, while the opposite is true in weak cold source years. In strong EAWMI years, there is an abnormal northerly sinking cold flow in the lower layers of mid-high latitudes, which increases the pollution in the area south of 30° N, and the opposite is true in weak EAWMI years. Affected by the combined activities of the Q1 and the EAWMI, the meteorological conditions of the five typical regions are different, and thus present different air pollution characteristics. [ABSTRACT FROM AUTHOR]

The lightning clustering algorithm for spaceborne lightning observations clusters events into flash products and plays a crucial role in lightning-related research. This paper modified the lightning clustering algorithm based on the routine algorithm of Lightning Mapping Imager (LMI) and applied it to lightning events recorded by the LMI in 2019 to study the flash duration and flash area and specially to reveal the extreme lightning. To reveal the temporal and spatial features of lightning, the MCA (modified cluster algorithm) flash products defined flash duration and flash area. The results showed that continental regions have higher lightning frequencies but smaller events per flash, flash durations and flash areas than the ocean. The Tibetan Plateau has a low lightning frequency and smaller flash duration and area than eastern China. The flash count, events per flash, flash duration and flash area are higher during nighttime than during daytime. The relationship between flash duration and flash area showed distinct regional differences. In the MCA flash product, about 0.6% (0.1%) flashes have duration (area) that exceeds 1.0 s (5,000 km2). Finally, we analyzed two extreme lightning cases in eastern China, where the longest flash duration was 4.748 s and the largest flash area was 17,100 km2. This research contributes to advancing our understanding in the features of space-based lightning in the Eastern Hemisphere and applications to convection study. • Clustering algorithm was modified to study lightning with extreme duration and area. • Lightning duration and area both implied regional differences. • Quantitative relationship of duration and area was established in different regions. • The longest flash duration/largest flash area was 4.75 s/17100 km2 in eastern China. [ABSTRACT FROM AUTHOR]

The Qiangtang Basin is one of the largest Mesozoic petroliferous basins in China that is still unexploited for the petroleum industry. The basic geological issues and synthesis of the Qiangtang Basin related to the Tethyan evolution are still poorly understood. This volume presents 20 research papers to address the tectonic settings, basin evolution, and sedimentary environments of the Qiangtang Basin, which are key factors for a better understanding of the overall petroleum system. The Qiangtang Basin holds a Precambrian base developed in response to the Paleo-Tethys Hol Xil-Jinshajiang Ocean evolution, with enhanced sedimentary basin infilling during the opening and expansion of the Neo-Tethys Bangong-Nujiang Ocean in the Mesozoic. The Paleozoic basin framework of the Qiangtang demised as the Paleo-Tethys Ocean closed at the latest Permian, while the Early-Middle Triassic foreland basin underwent a negative basin inversion during the Late Triassic. The latter initiated a new sedimentary filling cycle of the Qiangtang Basin, which was triggered by the active extensional rifting and the onset of the bimodal volcanic eruption. Recent scientific exploratory drilling (QK-1 well) found that the Qiangtang Basin is characterized by multiple source rocks, of which the upper Triassic Bagong Formation and the lower Quse Formation exhibit the most hydrocarbon generation potential. The development of high quality and quantity source rocks in the Qiangtang Basin is ensured by regional to global-scale bottom-water anoxia and high primary productivity in the eastern Tethys realm in the Late Triassic and the Early Jurassic. The main reservoirs in the Qiangtang Basin include the Middle Jurassic reef-beach facies, the Upper Triassic carbonates, and the Lower Jurassic terrestrial clastic rocks. Two very-thick caprocks of gypsum in the Lower Jurassic and gypsum mudstones in the Middle Jurassic strata are found during the scientific drilling, which is interpreted as favorable regional-scale seals for petroleum entrapment in the Qiangtang Basin. [ABSTRACT FROM AUTHOR]

Geofluids from natural springs connect with the crust and/or mantle in many cases, and their geochemical anomalies could be significant for the study on faults activity and even earthquakes. Several natural springs are distributed along the Lenglongling fault zone (LLLFZ) in the northeastern margin of the Tibetan Plateau, where the M s 6.9 Menyuan earthquake occurred on January 8th, 2022. Based on chemical and isotopic compositions (δD, δ18O, δ13C, and 3He/4He) of water and gas samples, the origin of geofluids and their potential correlation with fault activity even including earthquakes are preliminarily assessed in this paper. The δ13C CO2 values and 3He/4He ratios showed that the gas originating from the crust was associated with the metamorphism of carbonate rocks, whereas the δ18O and δD values of water samples indicated that the natural springs were predominantly infiltrated with precipitations from local mountains ranging 3.7 - 5.5 km in height. Obvious changes of Ca2+ and HCO 3 − concentrations in SZK spring waters in the surface rupture zones were observed in a short period (about three months) after the main shock, in contrast to those of the GSK springs far from the surface rupture zones. Such variations might be correlated with the stress increase prior to the 2022 Menyuan M s 6.9 earthquake. The mechanical fracturing of surrounding limestone rocks during the slipping movement of LLLF could facilitate the water-rock interactions. Compared to three-month observations after the main shock, relatively higher concentrations of HCO 3 − and heavier δ18O H 2 O values of the LHG springs were also observed in the short-term period. The shallow stored formation water might be squeezed along the cracks and rose to the surface during earthquake tremors, causing a sandblasting water phenomenon. • Ionic concentration of spring water showed anomalies with Menyuan M S 6.9 earthquake. • Two distinct causes of hydro-chemical anomalies revealed. • Bubbling CO 2 originated mainly from metamorphic and weathering carbonate in the crust. [ABSTRACT FROM AUTHOR]

This paper examines the local and non-local climatic effects of wetter arid areas of Northwestern China (ANWC) in summer using a fully coupled climate model. In response to soil moisture increase, the local air temperature significantly decreases, and precipitation increases in summer. The wetter ANWC results in a warmer and rainless climate over the Central part of North China Plain (CNCP). While the influence of increasing soil moisture on the Tibetan Plateau (TP) precipitation is negligible due to the high altitude. A cooler climate over ANWC leads to an abnormal descending motion occurring. Meanwhile, an anomalous high pressure and an abnormal anticyclonic circulation occurs in 500 hPa over the west of ANWC. Correspondingly, a huge anomalous cyclone circulation occurs over the northeastern part of China and Mongolia, which can hinder the northward movement of the East Asian summer Monsoon (EASM) and reduce the water vapor transport into Central China Plain. As a result, the weakened EASM thus leads to rainless over CNCP. As soil moisture increases over ANWC is stronger, the magnitudes of the influence on the atmospheric field become larger. This study highlights the wetter ANWC effect on local climate and provides more information about the mechanism of wetter ANWC remote effect on non-local climate. • This paper examines the local and non-local climatic effects of wetter arid areas of Northwestern China (ANWC) in summer using a fully coupled climate model. • It finds that the wetter ANWC can result in a warmer and rainless climate over the Central part of North China Plain (CNCP) through a complex atmospheric circulation response. • A cooler climate leads to an abnormal descending motion occurring over ANWC. • A huge anomalous cyclone circulation over the northeastern part of China and Mongolia can block the East Asian summer Monsoon northward and decrease the water vapor transport into Central China Plain. • This study highlights the wetter ANWC effect on local climate and provides more information about the mechanism of wetter ANWC remote effect on non-local climate. [ABSTRACT FROM AUTHOR]

The Qilian-Qaidam Orogenic Belt is a component of the western Central China Orogenic Belt, and records a nearly complete evolutionary history of the South Qilian and North Qaidam oceans (branches of the Proto-Tethyan Ocean). However, the timing and process of amalgamation of the microblocks of the western Central China Orogenic Belt and the closure time of the South Qilian and North Qaidam oceans remain uncertain. The Olongbuluke Terrane (OLT), located in the central of the Qilian-Qaidam Orogenic Belt, contains well-developed Precambrian to Paleozoic sedimentary successions that shed light on the tectonic history of these ocean basins. In this paper, detrital zircon U Pb ages combined with ophiolitic, magmatic and high-pressure to ultrahigh-pressure metamorphic records and field investigations, indicate that the OLT was part of a passive continental margin during the early Paleozoic and there was a microblock, named the North Qaidam Terrane (NQT), lying between the Qaidam Block and the OLT. A marked provenance change occurs in the OLT after ca. 517 Ma, which is inferred to record the collision between the OLT and NQT. Later, the North Qaidam oceanic plate subducted under the NQT, and the North Qaidam Ocean closed at ca. 450 Ma. The similar detrital zircon U Pb age spectra of contemporaneous deposit flysch sequences in the Shihuigou Formation (OLT) and the Balonggonggaer Formation (the South Qilian Accretionary Belt) indicates the onset of collision between the OLT and Central Qilian Terrane occurred at ca. 458 Ma. The detrital zircon U Pb age spectra of microblocks from the early Paleozoic strata of the northern Tibetan Plateau share a North Indian affinity, indicating that the closure of the Proto-Tethyan Ocean may relate to the formation of the Gondwanan landmass. • The North Qaidam Terrane may exist between the Qaidam Block and the Olongbuluke Terrane. • The Olongbuluke Terrane collided to the North Qaidam Terrane at ca. 517 Ma. • The onset of collision between the Olongbuluke Terrane and the Central Qilian Terrane at ca. 458 Ma. • The closure of Proto-Tethys may relate to the formation of the Gondwana landmass. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The geometric distribution and activity of the Mengzi fault has been studied. • The horizontal slip rate of the fault has been obtained via the offset gullies and terraces. • Three paleo-events since 30–40 ka BP have been observed, with a 10-ka major earthquake recurrence period. • The Mengzi fault plays an important role in the adjustment of the large slip rate loss for the southern Xiaojiang fault. Abstract Few studies have been conducted on the activity of the Mengzi fault system, which is located to the southeast of the Sichuan-Yunnan block. The Mengzi fault is distributed along the eastern margin of the Mengzi basin. However, little is known about the location, length, and activity of the fault or the occurrence of paleo-earthquakes during the late Quaternary. This paper studies the geometric distribution and activity of the fault via remote sensing imagery interpretation, fault outcrops in the area, faulted landforms and chronological analyses. The results show that the Mengzi fault extends from Nandong (Kaiyuan basin) in the north through the eastern margin of the Mengzi basin to Pingbian in the southeast, eventually intersecting with the Honghe fault. The Mengzi fault is approximately 250 km long and is characterized as a reverse strike-slip fault. We survey and calculate the offset gullies and terraces dislocated by the fault; combined with sample dating, we calculate the horizontal slip rate of the fault since 30 ka BP to be 0.91–1.56 mm/a. Three paleo-events since 30–40 ka BP are observed with a 10-ka major earthquake recurrence period. We analyze the relationships among the Mengzi fault, southern Xiaojiang fault, and Qujiang-Jianshui fault and note a slip rate loss of ≥8 mm/a from the southern Xiaojiang fault that was absorbed by reverse dextral strike-slip faulting and lateral shortening of the Qujiang-Jianshui fault and the Mengzi fault. The Mengzi fault plays an important role in the adjustment of the large slip rate reduction along the southern Xiaojiang fault. Moreover, the Mengzi fault has a similar tectonic position to the seismogenic faults of the 2008 Wenchuan earthquake, 2013 Lushan earthquake and 2014 Ludian earthquake, and the Mengzi fault and southern Xiaojiang fault both accumulate the energy generated by the southeastward movement of the Sichuan-Yunnan block. Studies on the Mengzi fault are helpful for renewing our understanding of the tectonic patterns of the southeastern Sichuan-Yunnan block and delimiting the boundary of the southeastern block margin. Furthermore, because the cities of Mengzi and Kaiyuan are located along the Mengzi fault, this study has practical significance for earthquake disaster mitigation. [ABSTRACT FROM AUTHOR]

The Xining basin is located in the northeastern margin of the Qinghai‐Tibet Plateau. It is a rift basin formed in Mesozoic and Cenozoic and structurally belongs to the intersection of Kunlun and Qilian Mountains. Cenozoic fluvial and lacustrine sedimentary strata are continuous in the Xining basin, with a thickness of more than 800 m, completely recording the deformation uplifting, weathering and denudation history and climate change process of the northeastern plateau. Currently, early Miocene Xijia fauna, early Middle Miocene Danshuilu fauna and late Middle Miocene Diaogou fauna are discovered in the Xining basin, which provide an important basis for the stratigraphic correlation of the Cenozoic strata in the Xining basin. However, in the next few decades, there are no reports about the large mammal fossils in the Xining basin, especially about late Miocene fauna. The author discovered a large amount of mammal fossils in the Neogene sedimentary strata in Huzhu area, Xining basin. According to the identification results of the Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, these fossils mainly included Hipparion dongxiangense, Chilotherium sp., Parelasmotherium sp., Stephanocemas sp. and Kubanochoerus sp. and their age was early Late Miocene. Since the discovery of this set of fossils directly filled the blank that there were no large mammal fossils in the Xining basin in Late Miocene, it was very important for studying the magnetic stratigraphic chronology of fossil‐forming strata and establishing the paleomagnetic chronology scale plate of mammal fossils. In this paper, the paleomagnetic data of the fossil‐forming stratigraphic profile, Banyan profile, were measured and the paleomagnetic records were collected through high density sampling, and finally the paleomagnetic polarity column of the profile was established. The results showed that five positive and five negative polarity segments were recorded in Banyan profile, which corresponded well to the polarity between C3Br.1n‐C4n.2n in the standard polarity column. The age of profile top was about 7.25 Ma and profile bottom was about 8.4 Ma, with an age range of 1.15 Ma. The mammal fossils discovered this time were exposed between positive and negative polarities N5 and R5 at the bottom of the profile, corresponding to C4r.1r at negative polarity and C4n.2n at positive polarity in the standard polarity column. The age of mammal fossils was about 8.3 Ma. The paleomagnetic chronology of the strata and paleontological fossils determined the absolute age of late Miocene mammal fossils and expanded the upper age of late Miocene Xianshuihe Formation (N1xn) in the Xining basin, which had provided new basic data for further studying the stratigraphic deposition and correlation of late Cenozoic strata and regional environmental evolution. [ABSTRACT FROM AUTHOR]

Farmer's ability to rapidly grow their populations has been seen as an advantage in allowing them to either engulf or simply do away with foragers. Research on agriculture's spread in East Asia has followed an underlying assumption: that farming produced equally reliable returns across the vast expanse of territories into which it spread. Farmers are thus always seen as being at a demographic advantage. However, in some parts of Asia, ecological barriers to growing crops may have meant that the opposite was true. In order to illuminate how foragers and farmers might have interacted in environments marginal to crop cultivation, I argue that we first need to outline where the barriers to farmer expansion in prehistory lay. Using ecological niche modeling combined with an analysis of recent archaeological data, this paper contrasts forager farmer interaction in two different areas of the Tibetan Plateau. It argues that the higher elevation reaches of the “third pole” constituted a barrier for early millet farmers expanding into the region. In these areas foragers may have maintained a competitive advantage. [ABSTRACT FROM AUTHOR]

In this paper, we analyze the Holocene record of extreme flood events in the upper Minjiang River valley of the eastern Tibetan Plateau, China. Slackwater deposits (SWDs), the fine-grained sediments of palaeofloods, were identified within debris flow deposits at a tributary mouth and in channel expansions along the bedrock gorge. Eight palaeoflood SWDs were dated to between 6.0 ± 0.9 ka and 4.6 ± 0.9 ka using optically-stimulated luminescence analysis in combination with the minimum age model and represent at least two phases of palaeoflood events. The palaeoflood history in the upper Minjiang River Valley is consistent with the record of the mid-Holocene flood events in the mainstream of the Yangtze River. These mid-Holocene extreme flood events were closely related to strong ENSO activity and variability of the monsoon climate in the eastern Tibetan Plateau. In our study area, minimum palaeoflood discharges were estimated as 6500–7800 m3/s by the step-backwater method. These estimated discharges are less than the values inferred for the outburst flood that occurred in the upper Minjiang River Valley in 1933. Flood-inundation maps show that palaeoflood SWDs were deposited in low-velocity backwater zones. Our palaeoflood reconstructions are important for improving regional records of maximum flood and help to develop risk analysis for rare flood events. • Sedimentary characteristics of palaeoflood records in complex environment were identified. • Palaeoflood discharges were estimated to be 6500–7800 m3/s at the three study sites. • Palaeoflood results redefine the envelope curve of the regional maximum floods. • Response of mid-Holocene (6.0–4.6 ka) extreme flood events to climate variability. • Palaeoflood reconstructions help to develop risk analysis for rare flood events. [ABSTRACT FROM AUTHOR]

This paper explores the Chinese government's efforts to develop housing projects in Sichuan Province, and to encourage Tibetan herders to settle and enter the market economy. The paper uses primary sources to analyse how media and government reports provide a constructed image of Tibetan herders and their cultural landscape. These reports depict Tibetan traditions, including Buddhism, as impediments to modernisation, secularisation, market-oriented logic, materialism, and governmentality. Finally, the reports are contextualised in a larger governmental effort to continue with housing and economic projects in the Eastern Tibetan Plateau. [ABSTRACT FROM AUTHOR]

This paper describes the study of the relationship between the thermal configuration of the Bay of Bengal (BOB)-Tibetan Plateau (TP) region and the precipitation anomaly in Yunnan, a province in China, in May using ERA-Interim data and precipitation data for May from 125 meteorological stations across Yunnan for 1979-2014. Results from the analysis indicate that the interannual variability of May precipitation in Yunnan is significantly modulated by the BOB-TP thermal configuration. Model runs with a linear baroclinic model suggest physical consistency. The thermal conditions over the BOB mainly impact the May precipitation anomaly in Yunnan via changes in water vapor transport from the eastern BOB northeastward to southwestern Yunnan. The second factor influencing precipitation anomalies relates to the characteristics and variability of cold air transport from the TP to northeastern Yunnan. When the BOB (the TP) is occupied by positive (negative) diabatic heating, a thermal gradient with a warmer (colder) center over the BOB and a colder (warmer) center over the TP is established, and more-than-normal (less than normal) precipitation in Yunnan will occur in May. This relationship can persist from April to the following May to some extent; therefore, the BOB-TP thermal configuration in April could be used to forecast May precipitation in Yunnan. [ABSTRACT FROM AUTHOR]

This paper combines observations, climatic analysis, and numerical modeling to investigate the Tibetan Plateau's (TP) surface heating conditions' influence on extreme persistent precipitation events (PEPEs) in southeastern China. Observations indicated an increase of TP surface air temperature 3-4 days prior to extreme persistent precipitation events in southeastern China. NCEP reanalysis data revealed a significant low pressure anomaly in southern China and a high pressure anomaly in northern China during extreme persistent precipitation event periods. Using correlation analysis and random resampling nonparametric statistics, a typical PEPE event from 17 to 25 June 2010 was selected for numerical simulation. The Weather Research and Forecasting (WRF) Model was used to investigate the impact of the TP's surface heating on the evolution of this event. Three contrasting WRF experiments were conducted with different surface heating strengths by changing initial soil moisture over the TP. Different soil conditions generate different intensities of surface sensible heat fluxes and boundary layer structures over the TP resulting in two main effects on downstream convective rainfall: modulating large-scale atmospheric circulations and modifying the water vapor transport at southern China. Increased surface heating in the TP strengthens a high pressure system over the Yangtze Plain, thereby blocking the northward movement of precipitation. It also enhances the water vapor transport from the South China Sea to southern China. The combined effects substantially increase precipitation over most of the southeastern China region. [ABSTRACT FROM AUTHOR]

Five large earthquakes of M ≥ 7.0 (based on the magnitude scale of the China Earthquake Networks Center) occurred in and near the Tibetan Plateau during 2008-2014, including the Wenchuan M8.0 earthquake on May 12, 2008 (BJT). In this paper, the Tibetan Plateau was chosen to be the study region, and calculating parameters of pattern informatics (PI) method with grid of 1° × 1° and forecasting time interval of 8 years were employed for the retrospective study according to the previous studies for M7 earthquake forecasting. The sliding step of forecasting interval was 1 year, and the hotspot diagrams of each forecasting interval since 2008 were obtained year by year. The relationships among the hotspots and the M ≥ 7.0 earthquakes that occurred during the forecast intervals were studied. The predictability of PI method was tested by verification of receiver-operating characteristic curve (ROC) and R score. The results show that the successive obvious hotspots occurred during the sliding forecasting intervals before four of the five earthquakes, while hotspots only occurred in one forecasted interval without successive evolution process before one of the five earthquakes, which indicates that four of the five large earthquakes could be forecasted well by PI method. Test results of the predictability of PI method by ROC and R score show that positive prospect of PI method could be expected for long-term earthquake forecast. [ABSTRACT FROM AUTHOR]

The Longxi region contains different kinds of Cenozoic sediments, including eolian deposits, reworked loess, fluvial and lacustrine deposits. The provenance evolution of these sediments is of great significance in exploring the uplift, tectonic deformation and associated with geomorphic evolution of the Northeastern Tibetan Plateau. In this paper, we used the single-grain zircon provenance analysis to constrain the provenances for the Paleogene alluvial conglomerates and for the Neogene fluvial-lacustrine sediments, and compared them with results from the loess deposits since the Miocene. The results show that: (1) the Paleogene alluvial conglomerates contain a large number of detrital zircons ranging from 560 to 1100 Ma that were derived from the Yangzi Block. However, the sediments of early Miocene have much fewer zircons of this age span, which are characterized by an abundance of zircon ages in the ranges of 200-360 Ma. This indicates that the Paleogene alluvial conglomerates mainly come from the middle and/or southern West Qinling, and the early Miocene sediments are primarily from the northern West Qinling; (2) Late Neogene fluvial sediments (11.5 Ma onward) in Tianshui-Qinan region are dominated by zircon ages of 380-450 Ma. This zircon population is similar to that of the exposed intrusive rocks of southern part of the Liupan Mountains, implying that the southern part of Liupan Mountains probably had already uplifted by 11.5 Ma; (3) Late Miocene lacustrine sediments in Tianshui region have a zircon age spectra that is remarkably different from coeval fluvial deposits, but is similar to the zircon age distributions of the Miocene loess in Qinan region, late Miocene-Pliocene Hipparion red clay and Quaternary loess. This indicates that fine particles within these Miocene lacustrine sediments in Tianshui region may be dominated by aeolian materials. This study reveals that provenance changes of Cenozoic sediments in Tianshui-Qinan region and its geomorphic evolution are closely related to the multi-stage uplift of the Northeastern Tibetan Plateau. In particular, the major uplift of the Northern Tibetan Plateau during late Oligocene-early Miocene may have not only provided the source areas and wind dynamic conditions for the deposits of the Miocene loess, but also provided the geomorphic conditions for its accumulation. [ABSTRACT FROM AUTHOR]

The Siwanli landslide is located in the middle section of the Dadu River in the eastern part of the Qinghai-Tibet Plateau in a complex regional geological environment. Strong erosion of the river valley has caused numerous rockfalls and slides on both sides of the valley since the Late Pleistocene. A large number of landslide deposits provide the opportunity for examination of the sedimentary and erosional environment along the Dadu River. Identifying the spatial and temporal characteristics of the large, ancient landslides in the Dadu River valley can help improve understanding of the formation mechanism and evolutionary process of ancient and recurrent landslides. In this paper, the formation mechanism of the ancient, complex, and multistage Siwanli landslide is discussed, as well as an important link between river erosion and the formation and evolution of the landslide. In the first stage, the initial landslide blocked the Dadu River, forming a barrier lake, and multistage landslide dam breaches occurred. The entire landslide dam experienced creep deformation, and local minor multistage sliding occurred at the front and middle parts of the initial landslide. Subsequently, a large landslide formed at the scarp of the initial landslide. [ABSTRACT FROM AUTHOR]

The Nb-Ta-Zr-Hf-REY-Ga mineralization in the Late Permian coals in southwestern China has been well investigated by several studies and has generally been attributed to alkaline pyroclastics coupled with input from hydrothermal fluids. The Late Triassic is one of the important coal-forming periods but the critical element mineralization in coals of this geological age has not been well documented. In this paper, the mechanism of Nb-Ta-Zr-Hf-REE-Ga-Th-U mineralization in the K5 coal seam of the Upper Triassic Xujiahe Formation from the Gaosheng Mine, Sichuan Basin, southwestern China, was investigated. The K5 coal is a high-ash, low-sulfur, and low-volatile bituminous coal. The minerals in this coal include illite, kaolinite, quartz, and, to a lesser extent, anatase, calcite, chamosite, bassanite, and pyrite, along with traces of ankerite, rutile, and zircon. Compared with the averages of common world hard coals, the studied coals are enriched in critical elements including Zr (247 ppm), Hf (5.56 ppm), Nb (23 ppm), Ta (1.55 ppm), rare earth elements and yttrium (REY, 168 ppm), Ga (18.3 ppm), Th (14.1 ppm), and U (6.18 ppm) (all on a whole coal basis). The Al 2 O 3 /TiO 2 ratios, Eu anomalies, and the relationships of Al 2 O 3 /TiO 2 vs. Zr/TiO 2 and Nb/Yb suggest that the sediment-source rocks of the Gaosheng coals were Neoproterozoic and Early-Middle Triassic felsic-intermediate igneous rocks from the southeastern Qinling and Longmenshan Orogens, along with the Hannan and Micangshan-Dabashan Uplifts. Other probable sources are contemporaneous felsic-intermediate pyroclastics from the Late Triassic volcanic areas around the Sichuan Basin (i.e., East Kunlun Orogen, West Qinling Orogen, and East Tibetan Plateau). The relationships of Al 2 O 3 /TiO 2 vs. Zr/Al 2 O 3 , Al 2 O 3 /TiO 2 vs. Nb/Al 2 O 3 , Ga/Al 2 O 3 , and Al 2 O 3 /TiO 2 vs. LREY/Al 2 O 3 further indicate that the elevated concentrations of Nb(Ta)-Zr(Hf)-REY-Ga in the Gaosheng coal are probably sourced from both the erosion of sediment-source regions and contemporaneous pyroclastics. The illite-kaolinite aggregates with a vermicular texture and authigenic illite, quartz, anatase, pyrite, calcite, ankerite, barite, and REE-rich minerals, REY distribution patterns, as well as elemental variation trends of the coal seam, collectively indicate that the studied coals were likely influenced by multiple-stage infiltration of various solutions. These solutions leached the fresh pyroclastics and products of erosion derived from granites in the sediment-source regions, leading to redistribution of the critical elements (e.g., Zr, Nb, and HREY) between the roof, floor, and parting mudstones and the coal benches. The concentrations of (Nb,Ta) 2 O 5 , (Zr,Hf) 2 O 5 , and Ga in the coals are 107, 1093, and 57.6 ppm, respectively, close to or higher than the marginal grade of conventional ore deposits for these elements, and thus the Gaosheng coals have potential as raw materials for the recovery of the critical metals Nb, Ta, Zr, Hf, and Ga. [Display omitted] • The coal contains elevated concentrations of Nb, Ta, Zr, Hf, REE, Ga, Th, and U. • The sediment-source region of the coals was felsic-intermediate igneous rocks. • Elevated concentrations of critical elements in coal due to products of erosion and pyroclastics. • The coals are likely influenced by the multiple-stage infiltration of acid solutions. • The acid solutions leached the fresh pyroclastic and terrigenous materials. [ABSTRACT FROM AUTHOR]

In their thoughtful paper entitled "An equable subtropical climate throughout China in the Miocene based on palaeofloral evidence", Qing Wang, Yan Li, David K. Ferguson, Wen-Bo Mo, and Nan Yang (2021) imply that China exhibited negligible latitudinal mean annual precipitation (MAP) gradients and lacked arid regions during the Miocene. They also speculate that there was no abrupt change in elevation of the Tibetan Plateau, nor that the plateau attained its present altitude or orography during that period. These conclusions were derived mainly by using a co-existence approach (CA) and 'incomplete data'. Here, we use CA with training data and also integrate a coexistence likelihood estimation, a pollen-MAP boundary, a desert-MAP boundary, and other newly published MAP data to show that Northwest China consistently exhibited drier conditions than South China and East China during the entire Miocene, with our new values being 300–500 mm lower than those of Wang et al. (2021). This implies that there were large spatial gradients of MAP in China during the Miocene, which may be directly linked with the growth of the Tibetan Plateau, the global cooling, as well as other factors. We recommend the comprehensive consideration of multiple methods and proxies for reconstructing past climate conditions as opposed to a single proxy. [ABSTRACT FROM AUTHOR]

The Wenchuan earthquake Fault Scientific Drilling project-hole 1 (WFSD-1) offers a unique opportunity for studying the faulting behavior and the thermal regime of the Longmen Shan fault zone (LMFZ), east margin of Tibetan Plateau. Thermal conductivity of fault rocks within main fault zone shows strong negative interrelations with the porosity, the gamma ray and the P-wave slowness, as well as a positive interrelation with the density. Here we attribute these correlations to the fractures and the rock-fluid reaction generated from the earthquake, which will increase the porosity, the radioactivity and the P-wave slowness as well as decrease the density and the thermal conductivity, synchronously. 15 continuous temperature profiles were summarized in this paper. Based on integrated studies of temperature variations and thermal gradients, local temperature anomalies were detected at three depth ranges of 480–510 m, 580–610 m and 625–755 m, respectively. These anomalies seem to correspond to different fracture zones and may be attributed to fluid flow in the fractures. In addition, the non-uniform vertical distribution of these temperature anomalies was observed across the co-seismic slip surface at 589.2 m. In the below ∼200 m borehole depth, a prominent thermal anomaly zone was developed, implying more factures were generated in the footwall than the hanging wall during the Wenchuan earthquake. The heat flow ranges from 69 mW/m 2 to 72 mW/m 2 for different logs. The persistence of elevated heat flow in the LMFZ appears to rule out frictional heating on the Yingxiu-Beichuan fault (YBF) as the source of the WFSD-1 value, but is probably related to the regional tectonic evolution. [ABSTRACT FROM AUTHOR]

Previous studies have examined the projected climate types in China by 2100. This study identified the emergence time of climate shifts at a 1◦ scale over China from 1990 to 2100 and investigated the temporal evolution of Köppen-Geiger climate classifications computed from CMIP5 multi-model outputs. Climate shifts were detected in transition regions (7%-8% of China's land area) by 2010, including rapid replacement of mixed forest (Dwb) by deciduous forest (Dwa) over Northeast China, strong shrinkage of alpine climate type (ET) on the Tibetan Plateau, weak northward expansion of subtropical winterdry climate (Cwa) over Southeast China, and contraction of oceanic climate (Cwb) in Southwest China. Under all future RCP (Representative Concentration Pathway) scenarios, the reduction of Dwb in Northeast China and ET on the Tibetan Plateau was projected to accelerate substantially during 2010-30, and half of the total area occupied by ET in 1990 was projected to be redistributed by 2040. Under the most severe scenario (RCP8.5), sub-polar continental winter dry climate over Northeast China would disappear by 2040-50, ET on the Tibetan Plateau would disappear by 2070, and the climate types in 35.9% and 50.8% of China's land area would change by 2050 and 2100, respectively. The results presented in this paper indicate imperative impacts of anthropogenic climate change on China's ecoregions in future decades. [ABSTRACT FROM AUTHOR]

This paper estimates lake level variations over two small and adjacent lakes in the Tibetan plateau (TP), namely Gemang Co and Zhangnai Co, as well as the inland Dianchi Lake in China using CryoSat-2 SARIn-mode and LRM 20-Hz waveforms over the period of 2011–2018. Different retrackers and a dedicated data editing procedure have been used to process CryoSat-2 data for determining the lake level time series. The lake level estimations are indirectly validated against those from Jason-2 in TP and from in situ data in Dianchi Lake, both showing good agreement with strong correlation coefficients >0.74. The results of this paper suggest that the official ICE retracker for LRM data and APD-PPT retracker for SARIn-mode waveforms are the most appropriate retrackers over Dianchi Lake and TP lakes, respectively. The trend estimates of the time series derived by both retrackers are 61.0 ± 10.8 mm/yr for Gemang Co and Zhangnai Co in TP, and 30.9 ± 64.9 mm/yr for Dianchi Lake, indicating that the lake levels over three lakes were continuously rising over the study period. The results of this study show that CryoSat-2 SARIn-mode data can be used for monitoring many small lakes that have not been measured by other altimetry missions in TP. [ABSTRACT FROM AUTHOR]

This paper reviews progress in the study of Tibetan Plateau (TP) climate dynamics over the past decade. Several theoretical frameworks, including thermal adaptation and the TP sensible heat (SH) driving air-pump, have been developed to identify the mechanisms responsible for the circulation anomaly produced by thermal forcing of the TP. Numerical simulations demonstrate that the thermal effects of large-scale orography, including the Tibetan and Iranian Plateaus (TIP), are crucial for the formation of the East Asian and South Asian summer monsoons (SASM) because the surface SH of the TIP is the major driver of the water vapor transport required for the genesis of the north branch of the SASM.The large-scale orography of the TP affects the Asian climate through thermal forcing in spring and summer, and mechanical forcing in winter. The TP forcing can also influence the Asian summer monsoon (ASM) onset over the Bay of Bengal (BOB) by enhancing the BOB warm pool at the surface and by modulating the South Asian High (SAH) in the upper troposphere. On intra-seasonal timescales, the TP thermal forcing significantly modulates spring rainfall in southern China and generates the biweekly oscillation of the SAH in summer. Despite climate warming, the atmospheric heat source over the TP, particularly the spring SH, exhibits a clear weakening trend from the 1980s to 2000s. This weakening of the spring SH contributed to the anomalous 'dry in the north' and 'wet in the south' rainfall pattern observed over East China. Also discussed are challenges to further understanding the mechanism of TP forcing on the multi-scale variability of the ASM. [ABSTRACT FROM AUTHOR]

Based on isostasy, this paper elegantly explains the differential modern elevations of the large-scale cratonic basins around the Tibetan Plateau. The Qaidam and Tarim basins are endorheic regions with thick Cenozoic deposits, and they uplifted dramatically during the Cenozoic. In contrast, the Sichuan basin is exorheic and most Cenozoic sediments flowed out of the basin; no visible Cenozoic uplift is observed. We suggest that whether a basin is endorheic or exorheic significantly influences its modern elevation, illustrating how exogenic geological processes impact endogenic geological processes. In addition, a new method of estimating paleoelevation is proposed, which predicts successively accelerating uplift of the Qaidam basin during the Cenozoic and provides good constraints on the geological evolution of the northern Tibetan Plateau. [ABSTRACT FROM AUTHOR]

The palaeolake evolution across the Tibetan Plateau and adjacent areas has been extensively studied, but the timing of late Pleistocene lake highstands remains controversial. Robust dating of lacustrine deposits is of importance in resolving this issue. This paper presents C or optically stimulated luminescence (OSL) age estimates from two sets of late Quaternary lacustrine sequences in the Qaidam Basin and Tengger Desert (northeastern Tibetan Plateau). The updated dating results show: (1) the radiocarbon dating technique apparently underestimated the age of the strata of >30 ka BP in Qaidam Basin; (2) although OSL and C dating agreed with each other for Holocene age samples in the Tengger Desert area, there was a significant offset in dating results of sediments older than ∼30 ka BP, largely resulting from radiocarbon dating underestimation; (3) both cases imply that most of the published radiocarbon ages (e.g., older than ∼30 ka BP) should be treated with caution and perhaps its geological implication should be revaluated; and (4) the high lake events on the Tibetan Plateau and adjacent areas, traditionally assigned to MIS 3a based on C dating, are likely older than ∼80 ka based on OSL chronology. [ABSTRACT FROM AUTHOR]

A curved belt consisting of terranes or blocks and associated late Paleozoic to early Mesozoic sutures are features of the southeastern part of the Tibetan Plateau. The southeastern Tibetan Plateau Paleotethyan belt is divided into a northwestern segment (central Tibetan Plateau) and a southern segment (the Sanjiang orogenic belt). The Paleotethyan tectonic history of this belt remains a subject of considerable debate. A major controversy concerns whether or not it evolved as a single genetic element. This paper provides new geochronological, geochemical, and structural data to constrain the Paleotethyan tectonics of this belt. A detailed field study across three sections of the Sanjiang orogenic belt has identified two volcaniclastic successions separated by a regional angular unconformity in the northwestern segment, and one continuous volcaniclastic succession in the southern segment. New zircon U-Pb ages reveal that: (1) the lower succession of the northwestern segment was produced by three volcanic phases at ca. 272 Ma, 253-247 Ma, and 240-235 Ma; (2) the upper succession of the northwestern segment formed during a shorter period along the Yushu-Yidun arc from ca. 227 to 211 Ma; and (3) the single volcaniclastic succession of the southern segment was produced continuously from ca. 260 to 210 Ma. Whole-rock geochemical data including trace elements show that the late Paleozoic to early Mesozoic magmatic activity has a continental arc-like affinity. The spatial distribution and field relationships of the magmatic rocks define two continuous vol canic arcs in the southeastern Tibetan Plateau, which correspond to two phases of arclike magmatism. The Late Triassic Yushu-Yidun arc belt is exposed along the northern half of the northwestern segment to the south of the western Jinsha-Garzê-Litang suture. Southward subduction along the western Jinsha-Garzê-Litang suture is likely to have generated the Yushu-Yidun arc. The second arc (Jomda-Weixi-Yunxian) was diachronous and is continuous through the southeastern Tibetan Plateau. The northwestern part of the Jomda-Weixi-Yunxian arc belt is overlain by the Yushu-Yidun arc from the north. From northwest to southeast, the cessation of magmatism in the Jomda-Weixi-Yunxian arc varies from the Middle Triassic (ca. 235 Ma) to the Late Triassic (ca. 210 Ma), whereas the onset of magmatism appears to have been in the Early Permian throughout the arc. Zircon Lu-Hf isotopic data suggest that large degrees of melting of a depleted mantle source produced the earliest magmas in each segment of the Jomda-Weixi-Yunxian arc. The similarity in zircon ages of the ophiolitic units and their distribution imply that the Longmu Co-Shuanghu suture is a continuation of the Changning-Menglian suture. The spatial relationship between the Jomda-Weixi-Yunxian arc and the Longmu Co-Shuanghu-Changning-Menglian suture suggests that diachronous eastward subduction of part of the Paleotethys along the suture produced the Jomda-Weixi-Yunxian arc belt. Widespread folds of the continental arc-volcaniclastics with orogen-parallel hinges reflect compression perpendicular to the orogen, subsequent to arc magmatism. As such, the Paleotethyan tectonics of the southeastern Tibetan Plateau are characterized by two-phase subduction and subsequent two-phase continent-continent collision. [ABSTRACT FROM AUTHOR]

This paper uses the cloud resolving Active Tracer High-resolution Atmospheric Model coupled to the interactive surface model Hybrid in order to investigate the diurnal development of a lake-breeze system at the Nam Co Lake on the Tibetan Plateau. Simulations with several background wind speeds are conducted, and the interaction of the lake breeze with topography and background wind in triggering moist and deep convection is studied. The model is able to adequately simulate the systems most important dynamical features such as turbulent surface fluxes and the development of a lake breeze for the different wind conditions. We identify two different mechanisms for convection triggering that are dependent on the direction of the background wind: triggering over topography, when the background wind and the lake breeze have the same flow direction, and triggering due to convergence between the lake-breeze front and the background wind. Our research also suggests that precipitation measurements at the centre of the basins on the Tibetan Plateau are not representative for the basin as a whole as precipitation is expected to occur mainly in the vicinity of the topography. [ABSTRACT FROM AUTHOR]

From 7 July to 11 July 2013, an extreme rainstorm occurred in the Sichuan Basin (SCB) of China, which is located at the eastern edge of the Tibetan Plateau, causing severe floods and huge economic losses. The rainstorm event was associated with mesoscale convection systems (MCSs). In this paper, we analyze the evolution characteristics and formation conditions of the MCSs, and the results show that: (1) the continuous activity of MCSs was a direct cause of the formation of extreme rainstorms. Under an "east high and west low" circulation mode, the MCSs formed a "cloud cluster wave train" phenomenon from the plateau to the basin; that is, the MCSs over the basin developed strongly in the process of the MCSs over the plateau area weakening. (2) The activities of MCSs over the rainstorm area was related to ascending branches of the two vertical circulations and topographic gravity wave. Under the influence of meridional vertical circulation, MCSs could move in the south–north direction in the western SCB, while under the influence of zonal circulation, it was difficult for MCSs to develop in the descending airflow east of 106°E. (3) In the mountainous area of the western part of the SCB, the gravity wave stress was obvious and its direction was opposite to the direction of the lower southeast warm–moist airflow. This configuration was able to form a drag effect in the low-level airflow, which was conducive to the convergence of the wind field and strengthening of the vertical ascending movement. These findings help in further understanding the effects of vertical circulation and terrain on MCSs and extreme rainstorms. [ABSTRACT FROM AUTHOR]

An amendment to this paper has been published and can be accessed via the original article. [ABSTRACT FROM AUTHOR]