Atmospheric Sulfur and Nitrogen Deposition in Five Nature Reserves of Sichuan Basin to Qinghai-Tibetan Plateau Transect Region,Southwest-ern China

Enhanced sulfur and nitrogen deposition has been observed in many transect regions worldwide,from urban/agricultural areas to mountains.The Sichuan Basin(SCB),with 18 prefectural cities,is the most economically-developed region in western China,while the rural Qinghai-Tibetan Plateau(QTP)lies west of the SCB.Previous regional and national atmospheric modeling studies have sug-gested that large areas in the SCB-to-QTP transect region experience excessive deposition of sulfur and nitrogen.In this study,we applied a passive monitoring method at 11 sites(one in urban Chengdu and 10 from fivenature reserves)in this transect region from September 2021 to October 2022 to confirm the high sulfur and nitrogen deposition fluxes and to understand the gaps between the modeling and observation results for this transect region.These observations suggest that the five reserves are under eutrophication risk,and only two reserves are partially under acidification risk.Owing to the complex topography and landscapes,both sulfur and nitrogen deposition and critical loads exhibit large spatial variations within a reserve,such as Mount Emei.Regional atmospheric modeling may not accurately capture the spatial variations in deposition fluxes within a reserve;however,it can capture general spatial patterns over the entire transect.This study demonstrates that a combination of state-of-the-art atmospheric chemical models and low-cost monitoring methods is helpful for ecological risk assessments at a regional scale.

Hydrogeophysical and Structural Investigations Using VES: A Case Study of Dosso Region in the Southwestern Part of the Meso-Cenozoic Iullemmeden Basin (Southwestern Niger)

A regional study connecting geolelectrical surveys with geology and hydrogeology was carried out in the western part of the Iullemmeden basin, precisely in the Dosso region in Niger. One hundred and four (104) vertical electrical sounds have been realized, among them nineteen representative were thus be used as parametric surveys. The local resistivity values of the geological formations of Quaternary range from 100 Ω⋅m to 1000 Ω⋅m (sands and lateritic sandstones). The Oligo-Miocene formation of the Continental terminal (Ct) shows resistivity values ranging from 1 to 5 Ω⋅m (brackish groundwaters) to 1500 Ω⋅m (clay sandstones) while the Upper Cretaceous formation of the Continental “hamadien” (Ch) indicates values ranging from 20 Ω⋅m (sandy clay) to 5000 Ω⋅m (clayey sandstones). The geological formations of Paleocene have values from 2 Ω⋅m (marls) to 60 Ω⋅m (calcareous marl), while the Precambrian basement exhibits values of granite around 300 Ω⋅m to 60,000 Ω⋅m. The update of the structural settings reveals many faults in the study area which explain both the shape of the basin and the geometry of the aquifers. Tectonics is also consistent with the hydraulic characteristics of aquifers. In addition, brackish groundwaters were identified as perched aquifer groundwaters in different depths in Dosso region. They probably come from the marine brines during the regression of the Paleocene Sea.

Hydrological and water cycle processes of inland river basins in the arid region of Northwest China

The increasing shortage in water resources is a key factor affecting sustainable socio-economic development in the arid region of Northwest China(ARNC). Water shortages also affect the stability of the region's oasis ecosystem. This paper summarizes the hydrological processes and water cycle of inland river basins in the ARNC, focusing on the following aspects: the spatial-temporal features of water resources(including air water vapor resources, runoff, and glacial meltwater) and their driving forces; the characteristics of streamflow composition in the inland river basins; the characteristics and main controlling factors of baseflow in the inland rivers; and anticipated future changes in hydrological processes and water resources. The results indicate that:(1) although the runoff in most inland rivers in the ARNC showed a significant increasing trend, both the glaciated area and glacial ice reserves have been reduced in the mountains;(2) snow melt and glacier melt are extremely important hydrological processes in the ARNC, especially in the Kunlun and Tianshan mountains;(3) baseflow in the inland rivers of the ARNC is the result of climate change and human activities, with the main driving factors being the reduction in forest area and the over-exploitation and utilization of groundwater in the river basins; and(4) the contradictions among water resources, ecology and economy will further increase in the future. The findings of this study might also help strengthen the ecological, economic and social sustainable development in the study region.

Incorporating Groundwater Dynamics and Surface/Subsurface Runoff Mechanisms in Regional Climate Modeling over River Basins in China

To improve the capability of numerical modeling of climate-groundwater interactions, a groundwater component and new surface/subsurface runoff schemes were incorporated into the regional climate model RegCM3, renamed RegCM3_Hydro. 20-year simulations from both models were used to investigate the effects of groundwater dynamics and surface/subsurface runoff parameterizations on regional climate over seven river basins in China. A comparison of results shows that RegCM3_Hydro reduced the positive biases of annual and summer （June, July, August） precipitation over six river basins, while it slightly increased the bias over the Huaihe River Basin in eastern China. RegCM3_Hydro also reduced the cold bias of surface air temperature from RegCM3 across years, especially for the Haihe and the Huaihe river basins, with significant bias reductions of 0.80~C and 0.88~C, respectively. The spatial distribution and seasonal variations of water table depth were also well captured. With the new surface and subsurface runoff schemes, RegCM3_Hydro increased annual surface runoff by 0.11 0.62 mm d 1 over the seven basins. Though previous studies found that incorporating a groundwater component tends to increase soil moisture due to the consideration of upward groundwater recharge, our present work shows that the modified runoff schemes cause less infiltration, which outweigh the recharge from groundwater and result in drier soil, and consequently cause less latent heat and more sensible heat over most of the basins.

The Type and Evolution of Neoproterozoic Sedimentary Basin in the Dahongshan Region,Northern Margin of the Yangtze Block:An Insight from Sedimentary Characteristics of the Huashan Group

Objective The Huashan group（composed of the lower Hongshansi Formation and the upper Liufangzui Formation）is an important Neoproterozoic stratigraphic unit along the northern margin of the Yangtze Block.Previous documents have focused on the geochronological and geochemical aspects of the Neoproterozoic sedimentary basin in the Dahongshan region.However.

Geological characteristics and accumulation mechanisms of the "continuous" tight gas reservoirs of the Xu2 Member in the middle-south transition region,Sichuan Basin,China

＂Continuous＂ tight gas reservoirs are those reservoirs which develop in widespread tight sandstones with a continuous distribution of natural gas. In this paper, we summarize the geological features of the source rocks and ＂＇continuous＂ tight gas reservoirs in the Xujiahe Formation of the middle- south transition region, Sichuan Basin. The source rocks of the Xul Member and reservoir rocks of the Xu2 Member are thick （Xul Member： 40 m, Xu2 Member： 120 m） and are distributed continuously in this study area. The results of drilled wells show that the widespread sandstone reservoirs of the Xu2 Member are charged with natural gas. Therefore, the natural gas reservoirs of the Xu2 Member in the middle-south transition region are ＂continuous＂ tight gas reservoirs. The accumulation of ＂continuous＂ tight gas reservoirs is controlled by an adequate driving force of the pressure differences between source rocks and reservoirs, which is demonstrated by a ＂one-dimensional＂ physical simulation experiment. In this simulation, the natural gas of＂continuous＂ tight gas reservoirs moves tbrward with no preferential petroleum migration pathways （PPMP）, and the natural gas saturation of＂continuous＂ tight gas reservoirs is higher than that of conventional reservoirs.

Control of Facies and Potential on Jurassic Hydrocarbon Accumulation and Prediction of Favorable Targets in the Hinterland Region of the Junggar Basin

Exploration practices show that the Jurassic System in the hinterland region of the Junggar Basin has a low degree of exploration but huge potential, however the oil/gas accumulation rule is very complicated, and it is difficult to predict hydrocarbon-bearing properties. The research indicates that the oil and gas is controlled by structure facies belt and sedimentary system distribution macroscopically, and hydrocarbon-bearing properties of sand bodies are controlled by lithofacies and petrophysical facies microscopically. Controlled by ancient and current tectonic frameworks, most of the discovered oil and gas are distributed in the delta front sedimentary system of a palaeo-tectonic belt and an ancient slope belt. Subaqueous branch channels and estuary dams mainly with medium and fine sandstone are the main reservoirs and oil production layers, and sand bodies of high porosity and high permeability have good hydrocarbon-bearing properties; the facies controlling effect shows a reservoir controlling geologic model of relatively high porosity and permeability. The hydrocarbon distribution is also controlled by relatively low potential energy at the high points of local structure macroscopically, while most of the successful wells are distributed at the high points of local structure, and the hydrocarbon-bearing property is good at the place of relatively low potential energy; the hydrocarbon distribution is in close connection with faults, and the reservoirs near the fault in the region of relatively low pressure have good oil and gas shows; the distribution of lithologic reservoirs at the depression slope is controlled by the distribution of sand bodies at positions of relatively high porosity and permeability. The formation of the reservoir of the Jurassic in the Junggar Basin shows characteristics of favorable facies and low-potential coupling control, and among the currenffy discovered reservoirs and industrial hydrocarbon production wells, more than 90% are developed within the scope of facies- potential index FPI〉0.5, while the FPI and oil saturation of the discovered reservoir and unascertained traps have relatively good linear correlation. By establishing the relation model between hydrocarbon- bearing properties of traps and FPI, totally 43 favorable targets are predicted in four main target series of strata and mainly distributed in the Badaowan Formation and the Sangonghe Formation, and the most favorable targets include the north and east of the Shinan Sag, the middle and south of the Mobei Uplift, Cai-35 well area of the Cainan Oilfield, and North-74 well area of the Zhangbei fault-fold zone.

A research on the geothermal structure in Yanqing-Huailai Basin and its neighbouring region

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Cenozoic structural deformation in the Yuqia-Jiulongshan region, northern Qaidam Basin, China

Based on field geological survey, interpretation of seismic reflection profile and thermochronology dating, this paper systematically studied the structural deformation of the Yuqia-Jiulongshan region in northern Qaidam Basin during the Cenozoic. The results show that the area is primarily dominated by a large box-shaped anticline, with steep limbs and a wide and gently-deformed core. The Mahaigaxiu and Jiulongshan anticlines are secondary folds controlled by secondary faults in the limbs of the box-shaped anticline. Whereas the Yuqia and the Northern Yuqia anticlines are secondary folds within the wide core of the box-shaped anticline. The geometry of the box-shaped anticline is mainly controlled by some high-angle reverse faults with certain right-lateral strike-slip components, displaying distinct positive flower structures in section view. Combining the sedimentary correlation and detrital apatite fission track analysis, we believe that the Yuqia-Jiulongshan region was a paleo-uplift that developed slightly in the early Cenozoic, resulting in the relatively thin Cenozoic strata. The intense deformation that shaped the present-day structural framework occurred in or after the sedimentary period of Shizigou Formation. The Yuqia – Jiulongshan paleo-uplift is adjacent to the Sainan depression that is rich in Lower-Middle Jurassic source rocks, and thus has high potential for future hydrocarbon exploration.

A SYSTEMATIC STUDY ON LAND AND REGIONAL DEVELOPMENT OF THE TARIM RIVER DRAINAGE BASIN,XINJIANG PROVINCE,CHINA

A Systematic Study on Land (SSL), aiming at the investigation of the land complex, isone of the important parts of integrated physical geography. With systematic theory as guid-ance, the dissertaton carries out the comprehensive and systematic study of a series ofsubsystems like land classification, land structure analysis, comprehensive physicalregionalization, land evaluation, reasonable planning of land utilization as well as popula-

Genesis of lacustrine carbonate breccia and its significance for hydrocarbon exploration in Yingxi region, Qaidam Basin, NW China

To examine the reservoir type and distribution regularity of high-and stable-yield lacustrine carbonates in the upper Member of Paleogene Xiaganchaigou Formation of Yingxi region and to determine the high-efficiency hydrocarbon exploration direction, the origin and significance of carbonate breccia in this area were investigated based on comprehensive analysis of a large number of well cores, thin sections, rock and mineral testing and log-seismic data. The study reveals that the carbonate breccia has three origins:(1) Sedimentary breccia, formed by the event-related collapse, fragmentation and re-deposition of the early weakly consolidated carbonate rock in the steep slope of underwater paleohighs due to short-term high-energy water body reformation and other geological processes.(2) Diagenetic breccia, with breccia-like structure, formed by deformation or breaking of host rock due to growth of idiomorphic and coarse crystalline gypsum-salt minerals in the weakly consolidated argillaceous carbonate rock of the penecontemporaneous period.(3) Tectonic breccia, can be further divided into fault breccia and interlayer slip breccia according to their occurrence characteristics, both of which are closely related to activity of the Shizigou thrust Fault. With a large number of partially filled pores, vugs and fractures between breccia, the two types of tectonic breccia are high-and stable-yield reservoirs in deep Yingxi region, and may occur extensively under gypsum-salt detachment layers of adjacent areas, so they are the exploration targets in the next step. Sedimentary breccia and diagenetic breccia are of great significance in searching for large-scale carbonate reservoirs.

Application of hydrological models in a snowmelt region of Aksu River Basin

This study simulated and predicted the runoff of the Aksu River Basin, a typical river basin supplied by snowmelt in an arid mountain region, with a limited data set and few hydrological and meteorological stations. Two hydrological models, the snowmelt-runoff model （SRM） and the Danish NedbФr-AfstrФmnings rainfall-runoff model （NAM）, were used to simulate daily discharge processes in the Aksu River Basin. This study used the snow-covered area from MODIS remote sensing data as the SRM input. With the help of ArcGIS software, this study successfully derived the digital drainage network and elevation zones of the basin from digital elevation data. The simulation results showed that the SRM based on MODIS data was more accurate than NAM. This demonstrates that the application of remote sensing data to hydrological snowmelt models is a feasible and effective approach to runoff simulation and prediction in arid unguaged basins where snowmelt is a major runoff factor.

Regional Geochemistry and Fluid Flow in the Palaeogene Aquifers of the Gaoyou Subbasin in the Southern Part of North Jiangsu Basin, China

Chemical analysis of groundwater in petroliferous basins can be an effective way to determine the regional hydrogeological regime and to evaluate the preservation conditions of hydrocarbons. This paper presents the hydrochemical distribution of both individual aquifers and different structural units within the Palaeogene strata of the Gaoyou subbasin in the North Jiangsu Basin, east China. The results show that the salinity of the Palaeogene aquifers in the Gaoyou subbasin displays a systematic increase from the central deep depression to the periphery areas, and shows a reverse trend as the burial depth increases. Salinity maps of individual aquifers suggest that formation water in the deep layers at the centre of the study area probably retains original features of fresh lake water. Geofluids near the central deep depression of the Gaoyou subbasin migrate vertically through the Zhenwu and Hanliu faults, while those of the northern slope belt mainly flow laterally through aquifers. Both low and high salinity formation water can be found in the hydrocarbon producing areas. The low salinity zones commonly affected by infiltrated meteoric water are unfavourable conditions for the preservation of trapped hydrocarbons.

A stratigraphical-geochemical study on the Chaco Paraná continental rift basin—An approach study based on regional sedimentology and drill-hole core analyses, South América

This paper is focused on a geologic “regional rift basin system pattern” and its stratigraphical-geochemical relationship. This is mainly based on the littoral shallow marine sedimentary succession paleogeography and deposits. These successions characterize the large extensional intracratonic Chaco Paraná Basin rift system. The basin is located in South America west of the Brazilian Shield. The analyzed rift basin system evolved from the Upper Cretaceous (Late Campanian-Senonian-Maastrichtian-Early Paleocene) to Quaternary time. The siliciclastic littoral shallow marine successions were deposited from Early Senonian-Maastrichtian to Late Miocene during three main successive littoral shallow marine transgressions of continental extension.; These transgressions happened over the wide pediplanized terrains of South America. These lands exist west of the more positive areas, between the Brazilian Shield and the foreland massifs that were settled in the more westernwards areas. Later, these regional foreland massifs were coupled and raised to the Andean Orogen Belt during the last 5 million years.; The extensive intracratonic pediplanized low topographic relief areas were the reservoirs of siliciclastic littoral shallow marine succession deposits during the three successive widespread vast continental littoral shallow marine transgressions.; The first transgression began at the Latest Campanian-Senonian and/or Early Maastrichtian time. After this episode, the sedimentary depositional systems continued during the Cenozoic until the Latest Miocene. These successions constitute a major allostratigraphic unit. The limit with underlying units is the regional unconformity between the regional volcanic event (Jurassic-Cretacic and interleaved eolianite sandstones) at the base and the undifferentiated Quaternary sediments (called as the Pampeano and Post-Pampeano Formations sensu lato). Based on many facies analyses there had been checked out different levels in the eustatic sea level variations within the allostratigraphic unit.; Three major stages of extensional climax were recognized and related to the stages of conspicuous eustatical sea-level variations. They happened during the Latest Senonian-Paleocene, Eocene and Miocene.; The first transgression occurred during the Upper Cretaceous-Paleocene although the sedimentary deposits related to this event are scarce, which are only a few meters in thickness. However, the Upper Cretaceous-Paleocene succession is very well recognized in the actual pre-Andean zone in the north-west of Argentina and Bolivia (the Sierras Subandinas and the meridional imbricated fault systems just joint to the actual orogen, i.e., Quebrada de Humahuaca outcrops).; During the Eocene and Middle to Latest Miocene occurred the second and third extensive regional littoral shallow marine transgressions. They are present either in well log registers as in most widespread outcrops on the entire Southamerican continent.; The regional analysis led to the deduction of long periods of tectonic quiescence, at least three of them. They may be inferred and synchronously related with eustatic highstand sea level variations that occurred during the Late Paleocene-Early Eocene, Latest Eocene-Early to Mid Oligocene and Middle-to-Late Oligocene-Early Miocene.; The structural style is related with major extensional N-S strike faultings (regional tilted and faulting blocks). On the other hand, quite a number of strike-slip faults (mainly of regional characteristic) are present crossing the area. They have a clear influence on the accommodation and transfer zones of the rift basin system. The strike is north-west to south-east on the border of the basin, to the west, in the contact with the Pampean Ridges and the narrow-meridionally-extense Sub-Andean folded trend (mainly Paleozoic units belonging to the so-called Sierras Subandinas geological province). Also, at the western edge of thestudied area, there exist many large shear zones and upthrust faults. The strike-slip regional faults dislocated the Pampean and Sub-Andean blocks due to the interaction of crossing regional tilted and fault blocks. For this reason, an en echelon regional block model is characteristic. Incipient contaminated igneous activities were associated with this cortical weak zones.; Domes, needles and necks of volcanic and sub-volcanic origin appear as the landscape of the region. A part of the igneous activity was dated on Latest Pliocene although mainly corresponding to Pleistocene and Holocene. This deduction is obvious because their morphological constitution was never eroded. The volcanic aparatous are morphologically unmodified from their extrusion to present days.; All the studied successions seem to resemble a long persisting erosive, transportation and deposition episode. This phenomenon is linked to a large regional (continental) unconformity dated at Late Cretaceous. The entire analyzed sedimentary succession deposits and their siliciclastic facies associations correspond clearly to a “heterolithic facies succession” which is very common within persisting tide-dominated depositional systems (passive margins). In fact, this is what happened during Cenozoic times (Torra, 1998b, 2001a). The heterolithic Miocene facies deposits constitute one of the best continental exposed examples.; Paleogeographical evidence showed that the Paranense and Amazonic Sea transgressions had been a littoral shallow marine connection during long time from Middle to Late Miocene. During the Late Cretaceous and Eocene periods marine connections were also active in the region. This fact is strongly supported by the tectonic and geomorphological framework of the proto-Southamerican continent, fossil remains and similar sedimentary deposits.; The geochemical results showed an outstanding similarity among the three sandy-muddy successions herein studied. Both major and trace elements always show the same geochemical patterns. Specially mentioned are the elements gallium, cesium, chromium, barium, vanadium, thorium, zirconium, rubidium and strontium because they present very constant values through all successions.; The Paranense and Amazonic epicontinental seas had been connected to the Pacific Ocean during the three marine episodes. The connections were formed by narrow inter-mountain valleys, present in the pre-Andean foreland massifs. These events occurred prior to the main orogenesis elevation of the Andean orogen belt in the last 5 to 1 Ma (Pliocene-Latest Pleistocene).; This paper shows, for the first time, a synthetic stratigraphical-geochemical “regional model” for the Chaco Paraná Basin rift system which should be largely improved in later studies. The Chaco Paraná Basin carries many unexamined-unexplored natural resources which need more regional and local studies for their evaluation. This is in spite of the area that has the problem of a significative vegetation coberture and scarce good outcrops. The development of modern techniques of data acquisition will help to overcome these difficulties.

基于流域视角的新质生产力发展的区域差异及动态演进

为给区域因地制宜布局和发展新质生产力、制定有针对性的新质生产力协调发展政策提供依据,基于新型劳动者、新型劳动资料、新型劳动对象3个维度构建反映新质生产力发展水平的综合评价指标体系,并从流域视角出发,采用2015—2022年21个省(市、自治区)相关数据,运用熵权法、Dagum基尼系数及其分解法、Kernel核密度估计法实证考察长江、黄河、珠江三大流域新质生产力发展水平、区域差异及其动态演进趋势。结果表明:1)在时空分布上,三大流域新质生产力发展水平整体呈上升趋势,长江流域新质生产力及其构成要素的发展处于较高水平,珠江流域处于居中水平,黄河流域处于最低水平;2)在区域差异上,长江流域新质生产力内部差异最小,珠江流域内部差异最大,黄河流域与长江流域间差异最大,流域间差异是三大流域新质生产力总体差异的主要来源;3)在动态演进上,三大流域新质生产力发展水平的流域内差异均呈现减小趋势,尤其是长江流域新质生产力均衡化发展趋势更为明显,珠江流域新质生产力发展的非均衡问题较为突出,黄河流域非均衡发展问题虽然呈现减弱趋势,但总体发展水平相对较低,发展新质生产力任务更为艰巨。

黄河流域新质生产力发展水平测度、区域差异及动态演进

为了解黄河流域新质生产力发展水平,基于新质生产力高科技、高效能、高质量的特征构建评价指标体系,采用熵值法测度2012—2022年黄河流域新质生产力发展水平,利用Dagum基尼系数研究区域差异,运用HP滤波分解、核密度估计及自然断点法探究时空演变情况。研究结果表明:黄河流域新质生产力发展水平总体呈上升趋势;区域差异呈扩大态势,区域间差异是总体差异产生的主要来源;时序演变中周期波动较大,高质量维度时序演进与其他维度存在差异;空间分布呈现“一枝独秀”的断层式发展格局,两极分化严重。

以MIKE BASIN实现流域水资源三次供需平衡

三次供需平衡是现代水资源配置理论的核心,在系列年水资源供需平衡中,利用流域水资源规划管理工具MIKE BASIN,建立在ArcView地理信息系统平台上的各个水平年流域水资源系统网络模型,及包括径流、蒸发、需水及水源工程调度特征的数据管理系统,通过模拟运算得到各种情景下的水资源配置结果。利用云南省境内元江-红河流域的1956-2000年系列径流、需水,结合节水挖潜、污水处理回用及水源工程建设规划方案,分析得到2000年、2010年、2020年、2030年4个水平年的三次平衡结果。

黄河流域农民收入质量的区域差异及其影响因素研究

基于黄河流域2011—2022年9省(自治区)面板数据,构建农民收入质量评价指标体系,运用熵值法、Dagum基尼系数、固定效应模型等方法测度黄河流域农民收入质量、探讨区域差异,进一步研究其影响因素。结果表明:①2011—2022年黄河流域9省(自治区)农民收入质量整体呈现波动上升趋势,农民收入质量的区间差异较大,阶段性特征明显,区域间差距拉大。②黄河流域农民收入质量整体差异逐渐缩小,区域间差异是导致黄河流域农民收入质量相对差异的主要来源。③经济发展水平、社会保障、城镇化和财政支农促进农民收入质量的提高,而产业结构、人口结构等因素则不利于农民收入质量的提升。据此提出,关注农民收入质量,推动农民收入增长;补齐农民收入质量短板,提升农民收入质量水平;优化产业结构,完善农村社会保障体系等政策建议。

Performance of RegCM4 over Major River Basins in China

A long-term simulation for the period 1990–2010 is conducted with the latest version of the International Centre for Theoretical Physics＇ Regional Climate Model（RegCM4）, driven by ERA-Interim boundary conditions at a grid spacing of 25 km. The Community Land Model（CLM） is used to describe land surface processes, with updates in the surface parameters,including the land cover and surface emissivity. The simulation is compared against observations to evaluate the model performance in reproducing the present day climatology and interannual variability over the 10 main river basins in China,with focus on surface air temperature and precipitation. Temperature and precipitation from the ERA-Interim reanalysis are also considered in the model assessment. Results show that the model reproduces the present day climatology over China and its main river basins, with better performances in June–July–August compared to December–January–February（DJF）.In DJF, we find a warm bias at high latitudes, underestimated precipitation in the south, and overestimated precipitation in the north. The model in general captures the observed interannual variability, with greater skill for temperature. We also find an underestimation of heavy precipitation events in eastern China, and an underestimation of consecutive dry days in northern China and the Tibetan Plateau. Similar biases for both mean climatology and extremes are found in the ERA-Interim reanalysis, indicating the difficulties for climate models in simulating extreme monsoon climate events over East Asia.

The Late Triassic Sequence-Stratigraphic Framework of the Upper Yangtze Region,South China

In the transitional period between the Middle and the Late Triassic, the Indochina orogeny caused two tectonic events in South China：（1） the formation and uplift of the Qinling-Dabie orogenic belt along the northern margin of the South China Plate, due to its collision with the North China Plate; and 2） the development of a 1300-km-wide intra-continental orogen in the southeastern part of the South China Plate, which led to a northwestward movement of the foreland thrust-fold zone. These tectonic events resulted in the ending of the Yangtze Platform, and were a stable paleogeographic factor from the Eidacaran to the end of the Middle Triassic. This platform was characterized by the widespread development of shallow-water carbonates. After the end of the Yangtze Platform, the upper Yangtze foreland basin（or Sichuan foreland basin） was formed during the Late Triassic and became a accumulation site of fluvial deposits that are composed of related strata of the Xujiahe Formation. In western Sichuan Province, the Xujiahe Formation overlies the Maantang Formation shallow-water carbonate rocks of the Xiaotangzi Formation siliciclastic rocks（from shelf shales to littoral facies）. The sequence-stratigraphic framework of the Upper Triassic in the upper Yangtze foreland basin indicates a particular alluvial architecture, characterized by sequences composed of（1） successions of low-energy fluvial deposits of high-accommodation phases, including coal seams, and（2） high-energy fluvial deposits of low-accommodation phases, including amalgamated river-channel sandstones. The spatial distribution of these fluvial deposits belonging to the Xujiahe Formation and its relative strata is characterized by gradual thinning-out, overlapping, and pinching-out toward both the east and south. This sedimentary record therefore expresses a particular sequence-stratigraphic succession of fluvial deposits within the filling succession of the foreland basin. The sequence-stratigraphic framework for the Upper Triassic in the Upper Yangtze region provides a record of the end of the Yangtze Platform and the formation of the upper Yangtze foreland basin.