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Proper agricultural water management in arid regions is the key to tackling climatic risks. However, an effective assessment of the current response to climate change in agricultural water use is the precondition for a group adaptation strategy. The paper, taking the Tarim River basin (TRB) as an example, aims to examine the agricultural water use sustainability of water resource increase caused by climatic variability. In order to describe the response result, groundwater change has been estimated based on the Gravity Recovery and Climate Experiment (GRACE) and the Global Land Data Assimilation System (GLDAS)-Noah land surface model (NOAH) data. In order to better understand the relationship between water resource increase and agricultural water consumption, an agricultural water stress index has been established. Agricultural water stress has been in a severe state during the whole period, although it alleviated somewhat in the mid-late period. This paper illustrates that an increase in water supply could not satisfy agricultural production expansion. Thus, seasonal groundwater loss and a regional water shortage occurred. Particularly in 2008 and 2009, the sharp shortage of water supply in the Tarim River basin directly led to a serious groundwater drop by nearly 20 mm from the end of 2009 to early 2010. At the same time, a regional water shortage led to water scarcity for the whole basin, because the water consumption, which was mainly distributed around Source Rivers, resulted in break-off discharge in the mainstream. Therefore, current agricultural development in the Tarim River basin is unsustainable in the context of water supply under climatic risks. Under the control of irrigation, spatial and temporal water allocation optimization is the key to the sustainable management of the basin. [ABSTRACT FROM AUTHOR]

The southern margin of the Ordos Basin is covered by thick loess sediments. This area is typically characterized by frequent geologic hazards and is rich in energy resources. Identifying the velocity structure of the loess layer is of great significance for geologic hazard prevention and resource explorations in this area. In this paper, we utilize Rayleigh-wave data for imaging the shear-wave velocity (vs) of the loess sediments in the Dongjiahe area, in the southern margin of the Ordos Basin. The data collected in the Dongjiahe area is dominated by the higher-order mode Rayleigh-wave; the dispersive energy of the fundamental mode Rayleigh-wave is weak and suppressed in some frequency bands. An improved frequency–wavenumber (F-K) transform method which can enhance the dispersive energy and expand the frequency range of the weaker fundamental (or higher) mode Rayleigh-wave is proposed in this paper. Numerically simulated data are first utilized to show the processes and effectiveness of the improved F-K transform method. Then, we utilize the improved F-K transform to generate multi-mode dispersive spectrums and extract dispersion curves of the real-world data collected in the Dongjiahe area. Dispersion curves are inverted for vs structure using the Levenberg–Marquardt method. The pattern of the two-dimensional vs section of the study area indicates that the loess sediments mainly distributes as approximate flat layers with vs gradually increasing as the depth increases. In addition, the results also reveal the bedrock depth of some parts of the survey line. [ABSTRACT FROM AUTHOR]

During the flood season of 2016, the middle and lower reaches of the Yangtze River suffered the worst flooding since 1999, involving Hunan, Hubei, Anhui, Jiangxi and Jiangsu provinces and the Taihu Basin. Based on the field survey at eight counties on both sides along the Yangtze River in Anhui Province, this paper analyses the features of rainstorm, flood and the resulting disaster in 2016 over there, and identifies problems and difficulties existing in flood prevention and disaster reduction under the new situation of social and economic development. Furthermore, this paper discusses the coping strategies and measures on advancing the comprehensive flood management mode of human-water harmony, managing middle and small rivers and strengthening the key basic research on flood control and disaster reduction under the new situation. [ABSTRACT FROM AUTHOR]

In order to better understand the impact of fractal features of pore-throat structures on effective physical properties of tight gas sandstones, this paper carried out constant-rate mercury injection tests, gas-water permeability analyses, helium-based porosity and nitrogen pulse decay permeability measurements, and SEM and casting thin-section analyses on 20 sandstone samples of the Shihezi Formation from 16 wells of the Sulige Gas Field in the Ordos Basin, China. The fractal dimensions of pores corresponding to two pore radius ranges, namely fractal dimensions and , and those of throats also corresponding to two throat radius ranges, namely fractal dimensions and , were then calculated using the constant-rate mercury injection data. Fractal dimensions and are negatively correlated with the average pore radius and pore volume as well as quartz content, and they are positively related to contents of clay minerals and lithic fragments. Compared with pore fractal dimensions, throat fractal dimensions have lower correlations with throat structural parameters, and show vague relations with mineral compositions. Although the effects imposed by mineral compositions upon throat structures are similar to those upon pore structures, the flake-like and curved shapes of throats result in irregularity of fractal dimensions. Tight gas sandstones, with smaller fractal dimensions and , have larger effective porosity, indicating that more gas volumes can be replaced by liquids. As for tight gas sandstones with lower fractal dimensions and , the effective gas permeability is relatively high. In such cases, gas can flow more easily through the reservoir. [ABSTRACT FROM AUTHOR]

This paper reports the findings based on ALOS-1 and GRACE satellite data for the purpose of monitoring land surface subsidence due to groundwater extraction and underground mining activities in the Ordos Basin, China. 42 ALOS-1 PALSAR data (22 images from Frame 790 while 20 scenes from Frame 780) acquired between 8 January 2007 and 19 January 2011 are utilized in the time-series InSAR (TS-InSAR) analysis while the total water storage observations derived from the Gravity Recovery and Climate Experiment (GRACE) satellite data are integrated with hydrological modeling results (for soil moisture modelling) to estimate the groundwater depletion rate. Since the results have vast difference in spatial resolution between GRACE (~300 km) and InSAR (~10's of meters), the two measurements are not comparable over the same region. Instead, we applied them to Haolebaoji surrounding region and ALOS covered area, respectively. The groundwater change series of about -7.3 mm yr-1 between December 2006 and June 2012 is detected, which is then being exploited to explain the groundwater induced subsidence in Haolebaoji, Inner Mongolia. Within ALOS covered region, time-series analysis was carried out to explain the local subsidence. Then the total area size of underground mining sites is estimated, and we concluded that human involved activities contribute a lot to the total velocity and this part of subsidence should be excluded before estimating the final mean velocity (-4.9 mm yr-1 in vertical direction) when comparing with GRACE-based groundwater depletion series. Last but not least, some suggestions are given on how to make a rational comparison between the InSAR derived mean velocity with GRACE-based groundwater depletion trend together. This study could help the local government and associated geotechnical engineers to have a better understanding of the groundwater induced subsidence in this region. [ABSTRACT FROM AUTHOR]

The East China Sea Shelf Basin (ECSSB) is a typical Meso-Cenozoic superimposed basin characterized by different tectonic frameworks, suffering multi-stage tectonism (e.g. the Indosinian, the Yanshanian and the Himalayan) since the Mesozoic. The Mesozoic ECSSB is a key place to our understanding of the tectonic evolution and dynamic mechanism in eastern South China and the subduction of the Izanagi Plate. Based on geological and geophysical results acquired over the last 10 years, this paper provides a summary of the distribution of Mesozoic strata, ascertains boundaries of the Mesozoic basin and proposes the division of the Mesozoic tectonic units in the ECSSB. The Mesozoic ECSSB was subdivided into the Western Fault Depression (WFD) characterized by dispersed Cretaceous half-grabens and the East Depression (ED) characterized by depressions at the early stage and grabens at the later stage. The WFD is composed of half-grabens formed under transtension, and the ED is composed of depression zones on the pre-Mesozoic basement under regional compression, indicating different dynamic mechanisms from the Cenozoic basins. Formation of the Mesozoic tectonic framework was controlled by the collision, compression and subduction of the Izanagi Plate and the Pacific Plate and also affected by the Indian Plate at a later stage. By comparison, this paper preliminarily proposes that the northern South China Sea and the ED of the ECSSB were originally a unified basin and jointly constituted a huge Mesozoic proto-basin in the East Asian continental margin. The Mesozoic tectonic unit division is helpful not only to discuss and resolve problems of ocean-continent differences and boundaries in southeastern South China but also to understand the tectonic nature of the East Asian continental margin, the dynamic mechanism of the Mesozoic basins and the transition of continental margin types. It also provides scientific support for petroleum exploration of the Mesozoic strata in the East China Sea. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Tectonic migration is a common geological process during basin formation and development. However, there are many disputes about the tectonic migration and its dynamic mechanism in the Bohai Bay Basin. By analysis of Cenozoic tectonic, sedimentation and magmatism migration processes in the Bohai Bay Basin, combined with previous studies, the Cenozoic tectonic migration law in the Bohai Bay Basin is summarized in this paper. Affected by the subduction of the Indian Plate to the Eurasian Plate, its far-field effect of the related eastward asthenospheric extrusion and the subduction of the Pacific Plate to the Eurasian Plate, the Cenozoic Bohai Bay Basin is characterized by the gradual northeastward and eastward/seaward migration of tectonic units. The tectonic migration is accompanied by eastward migrations and younging of faulting, depressions in the Bohai Bay Basin, depocentres and subsidence centres and magmatism. Finally, based on intraplate and plate marginal processes and mechanisms, the tectonic migration mechanism in the Cenozoic Bohai Bay Basin is discussed in this paper. The gradual migration of tectonic-sedimentary-basin-forming movements is younger and younger towards the east, resulting from the combined effect of the collision and subduction among the Indian Plate and the Pacific Plate to the Eurasian Plate. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The geological storage of CO2 is potentially one of the most effective methods to reduce the CO2 concentration in the atmosphere. Coalbeds are possibly suitable storage reservoirs, meaning that evaluating the suitability of individual coalbeds and associated engineering and construction is an important step in developing geological CO2 storage. This evaluation requires the development of a reasonable evaluation index system and associated weightings. This paper focuses on coal-bearing basins in China and outlines a technical process whereby the CO2 storage suitability of these basins can be comprehensively evaluated. This study uses an earth system science approach to determine the uncertainties involved in identifying ideal CO2 storage sites, develops an index that outlines the conditions related to the suitability of Chinese coal-bearing basins for geological CO2 storage, and incorporates this index into a hierarchical index system model for geological CO2 storage suitability that allows the comprehensive evaluation of coal-bearing basins and includes 5 aspects, 23 indexes, and 5 index levels. The weighting assigned to each evaluation index was determined using the analytic hierarchy process (AHP) and was subsequently incorporated into a fuzzy logic-based comprehensive evaluation approach. This approach was applied to assess the suitability of the Qinshui Basin for geological CO2 storage, revealing that this basin is indeed a suitable coalbed reservoir. The comprehensive geological CO2 storage evaluation model outlined here can also assess the CO2 storage suitability and capacity of other coal-bearing basins elsewhere in China and globally. [ABSTRACT FROM AUTHOR]

Uranium is of great importance to China's nuclear energy and national defense. As a clean energy, the nuclear energy helps to adjust and optimize the energy structure, improve the ecoenvironment, and reduce the CO2 and S emissions, paving the way to sustainable development and ecological civilization. The sandstone-type uranium deposit, one of the four types of uranium deposits for industrial use, is an important supplier in China. This type of uranium deposit mainly exists in sandstone basins. And the basin is a complex space of different sedimentary strata and facies. Hence, basin analysis is an essential approach to determine the distribution and variation law of uranium resources. This paper mainly studies the sandstone-type uranium deposits on the northern margin of the Ordos Basin, China. Firstly, the author collected typical data of the geological features on the basin, and sorted data gathered from typical boreholes. Next, the Markov process model was adopted to analyze the sedimentary sequence and evolution in the basin. Finally, the relationship was clarified between the spatial distribution of uranium resources and the stratum evolution of the sedimentary basin. [ABSTRACT FROM AUTHOR]

The Ganges, Brahmaputra, and Meghna (GBM) river system flows through five countries – Bangladesh, Bhutan, China, India, and Nepal – characterized by large population, limited land resources, and frequent floods and natural hazards. Although the GBM region is well endowed with water sources, this is one of the poorest regions in the world. Its economy and human and environmental health depend on water, and water is thus at the heart of sustainable development, economic growth, and poverty reduction. This paper examines the opportunities for, and potential socio-economic benefits of, water resource management in the GBM region in the face of changing climate. It argues that water can be an entry point for addressing challenges common to the region, particularly through multi-purpose river projects that store monsoon water, mitigate the effects of floods and droughts, augment dry season river flows, expand irrigation and navigation facilities, generate hydropower, and enhance energy and environmental security. The paper emphasizes the importance of effective regional cooperation in water management to achieve these benefits. Upstream–downstream interdependencies necessitate development of a shared river system in an integrated and collaborative manner. [ABSTRACT FROM PUBLISHER]

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]

The Sichuan Basin is endowed with unique natural and cultural conditions, which provide good conditions for the creation of traditional "shan-shui cities". As an important constituent element of "shanshui cities", boundaries delimit cities and nature and determine the scope and scale of cities. This paper divides the boundaries into city boundary, mountain boundary, water boundary and celestial horizon, which integrate with each other and embody the boundary feature of four in one. [ABSTRACT FROM AUTHOR]

It is necessary to identify the hydrogeochemical processes and analyze the causes of groundwater pollution due to the lack of knowledge about the groundwater chemical characteristics and the endemic diseases caused by groundwater pollution in the northern Ordos Cretaceous Basin. In this paper, groundwater chemical facies were obtained using the piper trilinear diagram based on the analysis of 190 samples. The hydrogeochemical processes were identified using ionic ratio coefficient, such as leaching, evaporation and condensation. The causes and sources of groundwater pollution were analyzed by correspondence analysis, and the spatial distribution and enrichment reasons of fluoride ion were analyzed considering the endemic fluorosis emphatically. The results show that leaching, evaporation and condensation, mixing, and anthropogenic activities all had significant impact on hydrogeochemical processes in the study area. However, cation exchange and adsorption effects were strong in the S2 and S3 groundwater flow systems, but weak in S1. Groundwater is mainly polluted by Mn and CODMn in the study area. The landfill leachate, domestic sewage, and other organic pollutants, excessive use of pesticides and fertilizers in agriculture, and pyrite oxidation from long-term and large-scale exploitation of coal are the sources of groundwater pollution. The S1 has the highest degree of groundwater pollution, followed by S2 and S3. High concentration of fluoride ion is mainly distributed in the north and west of study area. Evaporation and condensation and groundwater chemistry component are the most important causes of fluoride ion enrichment. The results obtained in this study will be useful for understanding the groundwater quality for effective management and utilization of groundwater resources and assurance of drinking water safety. [ABSTRACT FROM AUTHOR]

Ecosystem services are the basis of human living and development. Land use has significant effects on the ecosystem structure and functions, even its services. Using the remote sensing (RS), geographical information system and ecological economy theory, this paper analyzed land use changes of different eco-economic functional areas in Manas River Basin during the period 1958-2006 using different stage RS images. This paper selects the evaluation method obtained by Costanza et al. and Xie Gaodi, and the ecological sensitivity coefficient analysis, which analyzed the variation characteristics of eco-service values of different eco-economic functional areas. The results showed that the land use pattern has changed greatly from 1958 to 2006. The area of farmland and industrial area increased rapidly, while the forest area, grassland, water area and unutilized area decreased greatly. The total eco-service value of the river basin decreased from 3,529.64 US$ × 10 in 1958 to 2,559.88 US$ × 10 in 2006. There was 27.47 % net loss of 969.76 US$ × 10. The eco-service values of various land use types in the study area were close to the regional real values and the results were credible. There existed apparent temporal and spatial changes in the eco-service values of different eco-economic functional areas, and this significant change in the eco-service values was driven by economic development. Consequently, in view of eco-economic characteristics and ecological issues of various eco-economic functional areas, relevant strategies of ecological conservation were proposed for enhancing the general eco-service value of the river basin and realizing the regional sustainable development. The ''yuan'' is Chinese money unit (¥), US$1 = ¥6.27 (yuan). [ABSTRACT FROM AUTHOR]

The exploration achievements in the eastern‐central Ordos Basin have attracted tremendous attention in recent years. However, only a few studies were carried out on the relationship between formation pressure and distribution of natural gas in this area. The formation pressure of 293 wells, logging data of 154 wells, and fluid inclusion samples of 53 wells were analysed in this paper, and the results show that the mudstones from Permian Upper Shihezi Formation to Permian Taiyuan Formation are mostly undercompacted. Four gas‐bearing layers with significant differences in pressure profile can be further divided into Permian negative pressure system and Carboniferous normal pressure system. The distribution of current formation pressure is high in the east and north areas but low in the west and south areas. The sedimentary facies and distribution of formation pressure in Permian have a good consistency. The vertical development (zonation) of gas reservoirs is controlled by the undercompacted mudstone layers, and the reservoirs can be found in the “low pressure” areas of negative pressure strata in the Permian and “high pressure” regions of normal pressure strata in the Carboniferous. The pressure evolution and accumulation process can be divided into 3 stages: hydrocarbon‐generation supercharging accumulation during Late Jurassic—end of Early Cretaceous, sandstone resilience discharging accumulation during end of Early Cretaceous—Paleogene, and adjusting accumulation during Paleogene—Quaternary. The discovery of the relationship between formation pressure and gas reservoirs is significant to the future natural gas exploration in this area. [ABSTRACT FROM AUTHOR]

Development of fan deltas alongside intrabasinal structural highs has been overlooked compared to those forming on basin margins. However, these fan deltas may provide important clues regarding the tectonic and climatic controls on deposition during rift development. This paper documents fan delta deposition alongside an intrabasinal structural high within the Early Cretaceous Xiagou Formation of the Jiuquan Basin, China, using subsurface geological and geophysical data. Deposits observed in drill core support fan delta deposition occurring almost exclusively through subaerial and subaqueous gravity flows. Subsurface mapping reveals a consistent decrease in the areal extent of fan deltas from lowstand to highstand system tracts, suggesting that deposition alongside the structural high is sensitive to lake-level changes. The temporal and spatial distribution of the fan deltas display retrogradational stacking patterns, where fan deltas exhibit a decreasing lateral extent up-sequence until fan delta deposition terminated and was replaced by deposition of fine-grained lacustrine deposits. The retrogradational stacking patterns observed alongside the intrabasinal structural high are not observed in fan deltas along the basin margin in the lower parts of the Xiagou Formation. Subsidence profiles also show differential subsidence across the basin during the earliest stages of this formation, likely resulting from border fault movements. These data suggest that non-uniform stacking patterns in the lower parts of the Xiagou Formation reflect basin-scale tectonic movements as the dominant control on synrift deposition patterns. However, later stages of Xiagou Formation deposition were characterized by uniform subsidence across the basin, and uniform retrogradational stacking patterns for fan deltas alongside the intrabasinal structural high and border fault. These observations suggest that basin-scale tectonic movements played a relatively limited role in controlling sediment deposition, and imply a potential change to regional-scale processes affecting fan delta deposition during later synrift stages. Climate change is favored here as the region-scale control on the uniform retrogradational fan delta stacking patterns. This assertion is supported by pollen assemblages, isotope signatures, and organic geochemical analyses, which collectively suggest a change from a humid to semi-arid environment during later synrift stages. We suggest that variations in stacking patterns between different fan delta systems can provide insights into the basin- and regional-scale processes that control rift basin deposition. [ABSTRACT FROM AUTHOR]

In this paper, in a case study of Santanghu Basin in China, the morphological characteristics and size distribution of nanoscale pores in the volcanic rocks of the Haerjiawu Formation were investigated using the results of low temperature nitrogen adsorption experiments. This research showed that within the target layer, a large number of nanoscale, eroded pores showed an 'ink bottle' morphology with narrow pore mouths and wide bodies. The fractal dimension of pores increases gradually with increasing depth. Moreover, as fractal dimension increases, BET-specific surface area gradually increases, average pore diameter decreases and total pore volume gradually increases. The deeper burial of the Haerjiawu volcanic rocks in the Santanghu Basin leads to more intense erosion by organic acids derived from the basin's source rocks. Furthermore, the internal surface roughness of these corrosion pores results in poor connectivity. As stated above, the corrosion process is directly related to the organic acids generated by the source rock of the interbedded volcanic rocks. The deeper the reservoir, the more the organic acids being released from the source rock. However, due to the fact that the Haerjiawu volcanic rocks are tight reservoirs and have complicated pore-throat systems, while organic acids dissolve unstable minerals such as feldspars which improve the effective reservoir space; the dissolution of feldspars results in the formation of new minerals, which cannot be expelled from the tight reservoirs. They are instead precipitated in the fine pore throats, thereby reducing pore connectivity, while enhancing reservoir micro-preservation conditions. [ABSTRACT FROM AUTHOR]

The southwestern area of the Ordos Basin, China, contains good oil/gas systems, similar to the main basin. However, no oil/gas reserves have been found because some magmatic rocks with different occurrences developed in the region, it resulted in the suspension of oil/gas exploration in the 1980s. By means of integrated research based on field investigation, geophysical interpretation, and data of drilling wells, this paper indicates that magmatic activities in the southwestern Ordos Basin display different properties over multiple periods. The Proterozoic and Palaeozoic magmatic rocks are mainly distributed as a large batholith in the Qinling Orogen, and the Qilian Orogen around the southwestern margin of the Ordos Basin. These Proterozoic and Paleozoic plutons have no effect on hydrocarbon source rocks and oil/gas generation in the Ordos Basin. However, the Mesozoic magmatic activities developed within the basin have obvious effects on oil/gas generation. Three kinds of exploration regions were selected within the southwestern Ordos Basin according to the distribution of hydrocarbon source and magmatic rocks as well as the thermal degree: (a) the marginal area of the basin, (b) the region of the Longmen Uplift distributed with concealed magmatic rocks within the basin, and (c) the region within the basin far away from concealed magmatic rocks. Three sets of gas source rocks, that is, the Upper Proterozoic algal dolostone, the Middle Ordovician dark shale, the Upper Paleozoic black mudstone of coal system, and one set of oil source rocks of the Upper Triassic lacustrine black mudstone and oil shale, are exposed in outcrops near the margin of the basin. They all display a low thermal degree with vitrinite reflectance (Ro) below 1.3%, and they do not contribute to oil/gas accumulation because of earlier tectonic uplift. The gas source rocks and oil source rocks, which occur within the basin area of the Longmen Uplift, where the concealed magmatic rocks, display an abnormal thermal degree of over maturation with Ro over 3.4% and underwent dry gas generation because of heating from magmatic activity, and they have gas exploration potential. The source rocks distributed within the basin area away from concealed magmatic rocks display a normal thermal degree and oil/gas generation. The Ro of the Upper Triassic oil source rock is 1.0–1.6%, which is under the thermal maturity stage of liquid oil generation, whereas that of the Upper Paleozoic gas source rocks is 2.0–2.5% under the thermal maturity stage of gas generation. Measured Ro and burial depth of source rocks in the region show a linear relationship, which indicate that source rocks experienced thermal evolution and oil/gas generation under the normal burial thermal condition rather than the magmatic activity. This region has the most potential for both oil and gas exploration. [ABSTRACT FROM AUTHOR]

This paper investigated the porosity controlling factors for tight sandstone reservoir in the Daniudi gas field, Ordos Basin based on an integrated petrographic, petrophysical and geostatistical analyses, and proposed a comprehensive prediction model for reservoir porosity. Compaction was found to be a key factor for causing reservoir densification. The degree of sandstone compaction appears to be affected by grain sizes and sorting. Under normal compaction conditions (e.g., cement content less than 6%, and with no dissolution), the variation in reservoir porosity with burial depth can be well correlated with grain compositions, grain sizes, and sorting. Based on qualitative examination of the controlling factors for reservoir porosities, geostatistics were used to quantify the effects of various geological parameters on reservoir porosities. A statistical model for comprehensive prediction of porosity was then established, on the assumption that the present reservoir porosity directly relates to both normal compaction and diagenesis. This model is easy to use, and has been validated with measured porosity data. The porosity controlling factors and the comprehensive porosity prediction can be used to quantify effects of the main controlling factors and their interaction on reservoir property evolution, and may provide a reference model for log interpretation. [ABSTRACT FROM AUTHOR]

Based on the sedimentary and tectonic background of the Termit Basin, this paper focuses on the Upper Cretaceous Yogou Formation and uses organic geochemistry, logging, oil testing and seismic data to analyze the primary control factors of the hydrocarbon accumulation and establish corresponding model in order to predict favorable exploration target zones of hydrocarbon reservoirs. This study demonstrates that the Upper Cretaceous Yogou Formation is a self-generation and self-accumulation type reservoir. The Yogou Formation hydrocarbon reservoirs in the Koulele area are controlled by four factors: (1) the source rock is controlled by a wide range of YS1-YS2 marine shale, (2) the sandstone reservoir is controlled by the YS3 underwater distributary channel and storm dunes, (3) migration of hydrocarbons is controlled by faults and the regional monocline structure, and (4) the accumulation of hydrocarbons is controlled by lateral seal. The structures in the western Koulele area are primarily reverse fault-blocks with large throws, and the structures in the east are dominantly fault-blocks with small throws (co-rotating and reverse) and a fault-nose. In the western Koulele area, where the facies are dominated by storm dunes on a larger scale, it is easier to form lithologic reservoirs of sandstone lens. In the eastern Koulele area, high-quality channel sandstone reservoirs, fault-blocks with small throws, and the monocline structure benefit for the formation of updip pinch out lithologic traps, fault lithologic reservoirs and fault-nose structural reservoirs. Future exploration targets should be focused in the western storm dunes zone and eastern distributary channel sand zone with small fault-blocks. [ABSTRACT FROM AUTHOR]

Shale parasequence analysis is an important part of sequence stratigraphy sudies. This paper proposed a systematic research method for analyzing shale parasequences including their delineation, division, characteristics and origins. The division method is established on the basis of lithofacies. Multi-method analysis and mutual verification were implemented by using auxiliary indicators (such as mineral compositions, geochemical indicators and wavelet values). A typical shale parasequence comprises a lower interval of deepening water-depth and an upper interval of shallowing water-depth (e.g., a shale parasequence including a high-total organic carbon (TOC) shale-low-TOC limy shale). Abrupt increases in pyrite content, TOC value, relative hydrocarbon generation potential ((S1+S2)/TOC), and wavelet values are indicative of parasequence boundaries. The proposed research method was applied to study the upper fourth member of the Shahejie Formation in the Dongying depression, Bohai Bay Basin. Results show that there were seven types of parasequences developed. A singular and a dual structured parasequences were identified. Three factors controlling the development of the shale parasequences were identified including relative lake level change, terrestrial input and transgression. The development of high-TOC (>2%) shale parasequences was mainly controlled by biological and chemical sedimentation. The low-TOC (<2%) shale parasequences were mainly deposited by chemical sedimentation. The diversities of shale parasequences were caused by four major controlling factors including climate, relative lake level change, terrestrial input and emergency (e.g., transgression). [ABSTRACT FROM AUTHOR]

The Huadian Basin is an oil shale-bearing basin located in northeastern China. Thirteen oil shale layers deposited in this basin, and the characteristics of oil shale are different among these oil shale layers. Based on the core observation and microscope identification, using the organic and inorganic data from borehole HD3 and outcrops, the formation conditions of different grade oil shale have been evaluated. Based on measuring oil yield (OY in short) of an oil shale to determine its grade, this paper classifies the oil shale as high grade (OY≥10%), medium grade (10%>OY≥5%) and low grade (5%>OY≥3.5%). The high grade oil shale is mainly in brown or dark brown, and the bulk density ranges from 1.59 to 1.81 g/cm. The results of X-ray diffraction indicate the content of carbonate minerals is 28.0%. The HI (hydrogen index)- T , HI-OI (oxygen index) and S-TOC (total organic carbon) diagrams indicate the kerogen types are I and II1. The high grade oil shale generally formed in the relatively arid paleoclimate, deposited in the brackish water, dysoxic environment, when the bioprodctivity is extremely high, and the information is mainly from the inorganic parameters diagrams of chemical index of alteration (CIA), Sr/Ba and V/(V+Ni). The medium grade oil shale mainly shows grey-black or black-brown color and the bulk density ranges from 1.87 to 2.08 g/cm. The average content of carbonate minerals is 16.4%, far less than high grade oil shale and the kerogen type is mainly II1. The inorganic parameters diagrams reflect the medium grade oil shale generally formed in the less humid paleoclimate, deposited in the brackish water, dysoxic to anoxic environment, when the bioproductivity is medium. The color of low grade oil shale is major in grey-black or dark grey and the bulk density ranges from 2.00 to 2.15 g/cm. The average content of carbonate minerals is sharply decreased and the kerogen type is mainly II1. The inorganic parameters diagrams indicate the low grade oil shale generally formed in the relatively humid paleoclimate, deposited in the freshwater to brackish water, anoxic environment, when the bioproductivity is relatively low. Comprehensive study suggest the increasing precipitation caused by a relatively humid paleoclimate resulted in decreasing oxygen concentration and salinity in the bottom water, restrained the salinity stratification, and tended to form the low grade oil shale. The strong evaporation leading to relatively arid paleoclimate resulted in increasing oxygen concentration and salinity in the bottom water, and promoted the salinity stratification. The area with well preservation conditions caused by the relative high sedimentary rate and salinity stratification are favorable to high grade oil shale deposit. In summary, the bioproductivity and the paleoclimate are the main factors controlling the oil shale grade in the Huadian Basin, when the bioproductivity is relatively high and the paleoclimate is relatively arid, it is prone to form the high grade oil shale. However the low grade oil shale developed in the low bioproductivity and relatively humid paleoclimate. [ABSTRACT FROM AUTHOR]

The Banqiao area in the Bohai Bay Basin has experienced three stages of extensional deformation, leading to the formation of numerous fault-bound traps. Faults, acting as boundary conditions for these traps, play a crucial role in hydrocarbon accumulation. In this study, we conducted a 3D structural modeling of the area using high-resolution 3D seismic data and established a fault-reservoir database based on previous research. Our findings reveal four levels of faults in the Banqiao area: basin-controlling faults, boundary faults, derivative master faults, and secondary adjusting faults. The structural units can be categorized into subsag areas, slope areas, stress tran-sition zones, bifurcation and main incised fault zones, and southern block areas. The segmented growth of the main boundary faults controls the evolution of the subsags, with the subsidence center gradually shifting eastward from Rift Phase I to Rift Phase II, aligning with the distribution of source rocks. Fault-bound traps in the Banqiao area include single faults, intersecting faults, and side faults. Faults primarily act as barriers to lateral hydrocarbon migration during the process of hydrocarbon accumulation, while also providing pathways to a lesser extent. By integrating the fault-reservoir database with the fault system classification, we identified four types of fault-controlled hydro-carbon accumulation models: like-dipping fault barrier model, oppositely-dipping fault barrier model, intersecting fault barrier model, and reactivation-controlled secondary hydrocarbon ac-cumulation model. This structural geological model effectively demonstrates the spatial configuration of faults and their role in hydrocarbon accumulation in the Banqiao area. The fault control mechanisms presented in the model can also be applied to other blocks in the Bohai Bay Basin, laying a foundation for future petroleum exploration in continental rifted basins and facilitating the ap-plication of big data algorithms in various geoscientific research fields. [ABSTRACT FROM AUTHOR]

This paper investigates hydrological responses to climate change in the Luan River basin in North China. The average outputs of IPCC AR4 multi-models under different scenarios (SRES-A2, A1B and B1) are used to drive the SWAT model after calibration to simulate hydrological processes during 2011–2099. Results show increasing trends for precipitation, temperature and runoff under all scenarios, while compared to the baseline, the annual runoff decreases except for a slight increase during the 2080s under the A2 and A1B scenarios; meanwhile, the runoff in spring, autumn and winter decreases except for a slight increase during the 2080s under A2. [ABSTRACT FROM AUTHOR]

The article presents a clarification to a study which examined the use of inter-basin water diversion to solve a problem related to water shortage at the Biliu River Reservoir in China, in response to a comment about a paper published in this journal. Several issues are explained including the randomness of genetic algorithm (GA) and a heuristic-based optimization algorithm, the use of linear optimization models, and a comparison of a nonlinear objective function with a linear function.

Middle and eastern routes of the South-North Water Diversion Project (SNWDP) of China, which are approximately located within the area 28°-42°N and 110°-122°E, are being constructed. This paper investigates the past climatic variations on various time scales using instrumental and proxy data. It is found that annual mean surface air temperature has increased significantly during the past 50-100 years, and winter and spring temperatures in the northern part of the region have undergone the most significant changes. A much more significant increase occurs for annual mean minimum temperature and extreme low temperature than for annual mean maximum temperature and extreme high temperature. No significant trend in annual precipitation is found for the region as a whole for the last 50 and 100 years, although obvious decadal and spatial variation is detectable. A seesaw pattern of annual and summer precipitation variability between the north and the south of the region is evident. Over the last 100 years, the Haihe River basin has witnessed a significant negative trend of annual precipitation, but no similar trend is detected for the Yangtze and Huaihe River basins. Pan evaporation has significantly decreased since the mid-1960s in the region in spite of the fact that the trend appears to have ended in the early 1990s. The negative trend of pan evaporation is very significant in the plain area between the Yangtze and Yellow Rivers. There was a notable series of dry intervals lasting decades in the north of the region. The northern drought of the past 30 years is not the most severe in view of the past 500 years; however, the southern drought during the period from the 1960s to the 1980s may have been unprecedented. The dryness-wetness index (DWI) shows significant oscillations with periodicities of 9.5 and 20 years in the south and 10.5 and 25 years in the north. Longer periodicities in the DWI series include 160-170- and 70-80-yr oscillations in the north, and 100-150-yr oscillations in the south. The observed climate change could have implications for the construction and management of the SNWDP. The official approval and start of the hydro project was catalyzed by the severe multiyear drought of 1997-2003 in the north, and the operation and management of the project in the future will also be influenced by climate change-in particular by precipitation variability. This paper provides a preliminary discussion of the potential implications of observed climate change for the SNWDP. [ABSTRACT FROM AUTHOR]

Natural gases of shallow reservoirs with the carbon isotopic compositions of methane ranging from -50‰ to -60‰ (PDB) were considered as mixed gases of biogenic and thermogenic origins previously and some of them were considered as low-mature (or low temperature thermogenic) gases lately. In this paper natural gases with the carbon isotopic compositions of methane in the above range were identified using the molecular and stable carbon isotopic compositions of methane, ethane and propane. The mixed gases of biogenic and mature thermogenic origins display the characteristics of δ 13C1 ranging from -50‰ to -60‰, δ 13C2 > -35‰, Δ values (δ 13C3 - δ 13C3) < 5‰ and C1/ΣC2+ ratios < 40. Immature to low-mature gases display the characteristics of δ 13C1 ranging from - 50‰ to - 60‰, δ 13C1 < -40‰, Δ values (δ 13C3 - δ 13C3) > 7‰, and C1/ΣC2+ ratios >60. [ABSTRACT FROM AUTHOR]

The East China Sea Shelf Basin lies between the Pacific Subduction and Indian-Eurasian Collision tectonic domains and records Cenozoic tectonic inversion, especially in the Xihu Sag. To improve the understanding of the evolution and mechanism of tectonic inversion, this paper employs analogue modelling to reproduce the evolutionary process. Combined with the structural analysis of seismic profile, this paper determines the pattern of basement-involved faults. Simulation results show that under the transtension, two subsidence centers developed and a number of normal faults assembled in two flower structures. When the stress field turned into transpression, the geometry and deformation of inversion basin inherited the previous transtensional basin and pre-existing faults, respectively. The geometry and fault patterns in models are well consistent with those observed in the Xihu Sag, which indicates the plausibility of similar deformation controls. The formation of the tectonic inversion is related to the variation in stress field caused by the changes in the rates and directions of the subduction of the Pacific Plate and the collision of the Indian Plate with Eurasian Plate. [ABSTRACT FROM AUTHOR]

Exploring the cause and origin of coal-bed gas serves as a guide on the exploration, evaluation and development of coal-bed gas. Based on test of coal-bed gas samples, this paper analyses the composition of coal-bed gas in southern Qinshui basin and the distribution of methane carbon isotope [13C(CH4)] and CO2 carbon isotope [13C(CO2)], and discusses the origin of coal-bed gas in southern Qinshui basin in consideration of the thermal maturity of coal, groundwater dynamic conditions and the generation of biogas through bacteria degradation. The following conclusions are drawn from the research: first, the coal-bed gas in southern Qinshui basin is an extremely dry gas mainly made up of methane, plus a very small amount of ethane and non-hydrocarbon components; second, δ13C(CH4) follows unimodal distribution, falling in the range between -38.8 and -23.52%.; third, the change of δ13C(CH4) has a positive correlation with the variation of groundwater salinity, and has nothing to do with the change of coal rank; fourth, the generation of biogas through bacteria degradation is one of the possible causes to the phenomena that δ13C(CH4) gets heavier from the groundwater recharge zone to the central stagnant zone, while δ13C(CO2) changes in the opposite way. [ABSTRACT FROM AUTHOR]

The East China Sea Shelf Basin (ECSSB), the Pearl River Mouth Basin (PRMB) and the Taixinan Basin (TXNB) in the northern continental margin of the South China Sea (SCS) are important oil- and gas-bearing basins on the Western Pacific Continental Margin. During the Paleocene to Late Miocene, their strata can be compared, and the lithofacies were continuous from the TXNB, via the Taixi Basin (TXB) to the ECSSB. The lithologies mainly consist of interbedded shale, sandstone and mudstone layers. In addition, these basins have similar tectonic and sedimentation features. The three basins had similar marine-terrigenous facies in the Paleocene and marine-lacustrine-fluvial facies during the Eocene and Late Miocene. The basins experienced several coeval tectonic movements and episodes, and they developed a series of NE- and NNE-trending faults during the Paleocene and Eocene, which controlled the structure of the basins. During the Early Oligocene and Middle Miocene, they developed a series of NW- and WNW-trending strike-slip faults, reverse folds and flower-like strike-slip faults. However, there were obvious differences in sedimentary and tectonic evolution since the Late Miocene. The TXNB and TXB developed marine facies after the Late Miocene, while in the Quaternary, open marine facies replaced the Pliocene terrigenous facies in the ECSSB. Since the Late Miocene, the south of the ECSSB developed into a subsidence stage, and fault activity stopped. The TXB and TXNB developed some inverse structures and then developed into a thermal subsidence episode after the Dongsha Movement. Thus, this paper proposes that the ECSSB and the Cenozoic basins in the SCS were originally a unified basin and then subsequently separated into two basins as a result of the indentation of the Philippine Sea Plate (PSP) and the arc-continent collision between the Luzon Arc and the Eurasian Plate. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Lithology estimation of rocks, especially volcanic lithology, is one of the major goals of geophysical exploration. In this paper, we propose the use of binary and multiclass support vector machine models with geophysical log data to estimate the volcanic lithology of the Liaohe Basin, China. Using neutron (CNL), density (DEN), acoustic (AC), deep lateral resistivity (RLLD), and gamma-ray (GR) log data from 40 wells (a total of 1200 log data points) in the Liaohe Basin, China,we first construct the binary support vector machine model to classify volcanic rock and non-volcanic rock. Then, we expand the binary model to a multiclass model using the approach of directed acyclic graphs, and construct multiclass models to classify six types of volcanic rocks: basalt, non-compacted basalt, trachyte, non-compacted trachyte, gabbro and diabase. Toassess the accuracy of these two models, we compare their predictions with core data from four wells (at 800 different depth points in total). Results indicate that the accuracy of the binary and multiclass models are 98.4% and 87%, respectively, demonstrating that binary and multiclass support vector machine models are effective methods for classifying volcanic lithology. [ABSTRACT FROM AUTHOR]

Thirteen ichnogenera and seventeen ichnospecies were recognised in carbonate rocks from the Lower Permian Taiyuan Formation in North China Basin. Based on the composition, occurrence and diversity of ichnofossils, intensity of bioturbation, lithologic characteristics, especially on the variation of individual size and the filling colour diversities of theZoophycosburrows, four types of ichnofabrics were recognised, that is (1) epigenic tiering ichnofabric – mainly appeared on or near the bedding plane and formed in restricted bay or lagoon sedimentary environments; (2) shallow tiering ichnofabric – developed less than 15 cm under the bedding plane and occurred in the upper shallow-marine environment; (3) medium tiering ichnofabric – mainly distributed from 15 to 20 cm under the bedding plane and generated in the mid-upper shallow sea (restricted–open platform); (4) deep tiering ichnofabric – distributed from 25 to 30 cm under the bedding plane and occurred in lower shallow sea (open platform) far from shore. Based on ichnological and sedimentological analyses above four types of ichnofabrics, the sedimentary environment model of the ichnofabrics in carbonate rocks from the Taiyuan Formation in North China Basin is proposed in this paper. [ABSTRACT FROM AUTHOR]

In this paper, we implement three scales of fracture integrated prediction study by classifying it to macro- (> 1/4 λ), meso- (> 1/100 λ and < 1/4 λ) and micro- (< 1/100 λ) scales. Based on the multi-scales rock physics modelling technique, the seismic azimuthal anisotropy characteristic is analyzed for distinguishing the fractures of meso-scale. Furthermore, by integrating geological core fracture description, image well-logging fracture interpretation, seismic attributes macro-scale fracture prediction and core slice micro-scale fracture characterization, an comprehensive multi-scale fracture prediction methodology and technique workflow are proposed by using geology, well-logging and seismic multi-attributes. Firstly, utilizing the geology core slice observation (Fractures description) and image well-logging data interpretation results, the main governing factors of fracture development are obtained, and then the control factors of the development of regional macro-scale fractures are carried out via modelling of the tectonic stress field. For the meso-scale fracture description, the poststack geometric attributes are used to describe the macro-scale fracture as well, the prestack attenuation seismic attribute is used to predict the meso-scale fracture. Finally, by combining lithological statistic inversion with superposed results of faults, the relationship of the meso-scale fractures, lithology and faults can be reasonably interpreted and the cause of meso-scale fractures can be verified. The micro-scale fracture description is mainly implemented by using the electron microscope scanning of cores. Therefore, the development of fractures in reservoirs is assessed by valuating three classes of fracture prediction results. An integrated fracture prediction application to a real field in Sichuan basin, where limestone reservoir fractures developed, is implemented. The application results in the study area indicates that the proposed multi-scales integrated fracture prediction method and the technique procedureare able to deal with the strong heterogeneity and multi-scales problems in fracture prediction. Moreover, the multi-scale fracture prediction technique integrated with geology, well-logging and seismic multi-information can help improve the reservoir characterization and sweet-spots prediction for the fractured hydrocarbon reservoirs. [ABSTRACT FROM AUTHOR]

Xiangxi River Basin, located in western Hubei Province in central China, is a karst ridge-trough area with an inhomogeneous and complicated distribution of water resources. This paper compares the characteristics of surface and subsurface floods in this karst basin, utilizing a one-parameter Darcian model and the traditional exponential model. The observed hydrographs and inferred water components are strikingly similar for surface and subsurface floods. The Darcian model and the exponential model are based on different views of the flood generation process, with the former fitting the entire hydrograph with a single time constant, and the latter fitting only the recession limb with multiple time constants. Due to the anisotropy and heterogeneity of karst media, a combination of physical and chemical techniques including the use of 3S (remote sensing, geographical information system, global positioning system) method is proposed for an enhanced hydrological investigation to assess and characterize karst water resources in mountainous areas. [ABSTRACT FROM AUTHOR]

Recent researches have illustrated with the image tracking method that Ordos, China is suffering from a significant drop in earth surface level. However, such method can lead to bias in terms of its accuracy. In this paper, land displacement in Ordos between 8 January 2007 and 19 January 2011 was mapped using L-band ALOS Phased Array type L-band Synthetic Aperture Radar (PALSAR) data. Twenty PALSAR images were utilized to generate both Differential Synthetic Aperture Radar Interferometry (DInSAR) and time-series InSAR (TS-InSAR) results. Several locations in the eastern Ordos experiencing rapid land subsidence were identified. The subsidence rates ranging from −30 mm year−1to 30 mm year−1were measured in line-of-sight direction. The comparison between TS-InSAR and DInSAR results, although showing good agreement in general, reveals some gaps in time-series map near Qu Jia Liang coalmine mainly due to sudden changes within the four-year period. DInSAR result was exploited to fill these gaps after removing the tropospheric stratification phase delay and the verification step was conducted over the relatively stable region identified by TS-InSAR analysis. At last, the refined DInSAR result was converted into time-series velocity map and superimposed to TS-InSAR outcome to generate a final product. [ABSTRACT FROM PUBLISHER]

This paper analyzed the physico-chemical characteristics of natural waters in a drainage system of the Jungar Basin, northwestern China to identify chemical evolution and recharge mechanisms of natural waters in an arid environment. The waters studied are different in mineralization, but are typically carbonate rivers and alkaline in nature. No Cl-dominated water type occurs, indicating an early stage of water evolution. Regolith and geomorphological parameters controlling ground-surface temperature may play a large role in the geological evolution of the water. Three main morphological and hydrological units are reflected in water physico-chemistry. Climate influences the salinization of natural waters substantially. Direct recharge from seasonal snow and ice-melt water and infiltration of rain to the ground are significant recharge processes for natural waters, but recharge from potential deep groundwater may be less important. The enrichment of ions in lakes has been mainly caused by evaporation rather than through the quality change of the recharged water. [ABSTRACT FROM AUTHOR]

Tight reservoir is characterized with low porosity and ultra-low permeability. Horizontal well with multi-stage fracturing is the key technique to maximize stimulated reservoir volume and achieve commercial production. The spacing between perforations has a significant impact on well production. Perforation spacing is currently optimized from the aspects of reservoir simulation. The methods ignore the fact that fracture will generate induced stress field, which may significantly affect the geometry of subsequent fracture. Based on the displacement discontinuity method, this paper established a multi-fracture stress interference model which is able to simulate non-isometric half-length, unequal fracture spacing and arbitrary angle between fracture and wellbore. Data from a tight sandstone reservoir in Sichuan Basin of China are used to analyze the stress field changes and verify the model. The results show that the induced stress creates the maximum compressive stress on both sides of the fracture, and the maximum tensile stress at the fracture tip by stress concentration. The fracture will change the differential horizontal stress ratio in the surrounding area. Position where the differential horizontal stress ratio is lower than 0.3 will be the optimal site to create the complex fractures. Multi-stage fracturing with multiple perforation clusters in one stage is more favorable for complex fracture formation than single perforation cluster in each stage. Data from field verified the proposed perforation optimization method. [ABSTRACT FROM AUTHOR]

The Shulu Sag is a typical rift valley basin in Eastern China, where the formation mechanism of Cenozoic salt-bearing series has been poorly understood. In this paper, petrologic analysis, X-ray powder Diffraction (XRD) analysis and the analysis of halite ion concentrations of the first member of the Shahejie Formation from two drilling cores were conducted to interpret the formation mechanism of these salt-bearing series in Shulu Sag. The results indicated that the salt-bearing series is mainly composed of calcilutite or mudstone at top and bottom, and anhydrite-bearing halite and thin interbeds of salt-bearing calcilutite and dark grey shale in the middle part. These thin interbeds with porphyritic or petalshaped glauberite crystals or some thinner dark grey shale interbeds separated halites into several members with the average thickness of only 9~12 cm in the two drilling holes. This typical rhythmic pattern due to frequent alternation of concentration was evidenced by the variation of chemical composition and hydrogen isotopes of halite fluid inclusions. The presence of large number of primary fluid inclusions within chevron crystals and vertically oriented bottom-growth crystals showed that the halite were precipitated in shallow water (<60 cm). These features are direct evidence for this frequent alternation of dissolution and concentration of brines and terrigenous detrital-chemical shallow-water sedimentary model of these small rift-valley basins in Eastern China. [ABSTRACT FROM AUTHOR]

Under the background of climate change and man-made alterations to the environment, there has been an increase in the frequency of droughts and the range of their impact. Droughts may give rise to a series of resource, environmental and ecological effects, i.e., water shortage, water quality deterioration, as well as the decrease in the diversity of aquatic organisms. This paper, above all, identifies the impact mechanism of drought on the surface water quality of the basin, and then systematically studies the laws of generation, transfer, transformation and degradation of pollutants during the drought, finding that the alternating droughts and floods stage is the critical period during which the surface water quality is affected. Secondly, through employing indoor orthogonality experiments, serving drought degree, rainfall intensity and rainfall duration as the main elements and designing various scenario models, the study inspects the effects of various factors on the nitrogen loss in soil, as well as the loss of nonpoint source pollution and the leaching rate of nitrogen under the different alternating scenarios of drought and flood. It comes to the conclusion that the various factors and the loss of nonpoint source pollution are positively correlated, and under the alternating scenarios of drought and flood, there is an exacerbation in the loss of ammonium nitrogen and nitrate nitrogen in soil, which generates the transfer and transformation mechanisms of nonpoint source pollution from a micro level. [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]

Herein we would like to comment on the paper 'Estimation of potential distribution of gas hydrate in the northern South China Sea' by Wang et al. 2010 in Chinese Journal of Oceanology and Limnology, 28(3): 693-699. The purpose of this comment is to point out that the given probabilities of gas hydrate occurrence in the northern Zhujiang Mouth Basin and the Yinggehai Basin in the figure of Wang et al. (2010) are improper. After introducing our work of estimation of gas hydrate stability distribution in the northern South China Sea, we suggest that Wang et al. (2010) dismissed the basic P-T rule for the existence of gas hydrate. They should consider more the variables of water depth, seabed temperature and geothermal gradient in their gas hydrate distribution model in future studies. [ABSTRACT FROM AUTHOR]

One of the potential impacts of global warming is likely to be experienced through changes in flood frequency and magnitude, which poses a potential threat to the downstream reservoir flood control system. In this paper, the downscaling results of the multimodel dataset from phases 3 and 5 of the Coupled Model Intercomparison Project (CMIP3 and CMIP5, respectively) were coupled with the Variable Infiltration Capacity (VIC) model to evaluate the impact of climate change on the Feilaixia reservoir flood control in the Beijiang River basin for the first time. Four emissions scenarios [A1B and representative concentration pathway (RCP) scenarios RCP2.6, RCP4.5, and RCP8.5] were chosen. Results indicate that annual distribution and interannual variability of temperature and precipitation are well simulated by the downscaling results of the CMIP3 and CMIP5 multimodel dataset. The VIC model, which performs reasonably well in simulating runoff processes with high model efficiency and low relative error, is suitable for the study area. Overall, annual maximum 1-day precipitation in 2020-50 would increase under all the scenarios (relative to the baseline period 1970-2000). However, the spatial distribution patterns of changes in projected extreme precipitation are uneven under different scenarios. Extreme precipitation is most closely associated with extreme floods in the study area. There is a gradual increase in extreme floods in 2020-50 under any of the different emission scenarios. The increases in 500-yr return period daily discharge of the Feilaixia reservoir have been found to be from 4.35% to 9.18% in 2020-50. The reservoir would be likely to undergo more flooding in 2020-50. [ABSTRACT FROM AUTHOR]

Hydropower and irrigation developments to address rising demand for food and energy are modifying the water balance of the Mekong Basin. Infrastructure investment decisions are also frequently made from a sub-catchment perspective. This paper compares river flows with irrigation development stages in the Nam Ngum sub-basin where the potential for irrigation and hydropower expansion is largely untapped. It shows that full hydropower development in this basin allows irrigation water use to triple, even as it reduces competition with environmental flow requirements. The implications for the wider Mekong are, however, unclear, particularly given uncertainty over parallel transformations elsewhere in the basin. [ABSTRACT FROM AUTHOR]

The Junggar Basin is one of the main oil basins in Northwest China, and the north‐west part of the basin is a significant petroleum exploration target. Mesozoic structural activity had an important influence on the present structural characteristics of the north‐west Junggar Basin. In this paper, we discuss the tectonic evolution of the Junggar Basin by studying the structural characteristics of the Ke‐Bai Fault. Our results suggest that the Ke‐Bai Fault has obvious strike‐slip characteristics and that it is an important basin‐controlling fault that has controlled the tectonic evolution of the north‐west Junggar Basin. The Junggar Basin was a rift basin in the Early Permian, but it experienced a tectonic reversal during the Middle Permian to the Triassic. The Ke‐Bai Fault changed from a normal fault into a thrust fault from the Early Permian to the Triassic. During the Jurassic, dextral strike‐slip structures developed along the Ke‐Bai Fault, horsetail splay faults developed in its north segment, and there is evidence that it was under WNW–ESE compression. The dextral strike‐slip faulting of the Ke‐Bai Fault is consistent with tectonic movement along the Kelameili, Sangequan, Wu‐Xia, Hong‐Che, and North Tianshan fault systems in the Junggar Basin. We therefore infer that counterclockwise rotation occurred in the Junggar Basin in the Jurassic. [ABSTRACT FROM AUTHOR]

Carbon dioxide capture and storage (CCS) is the only technology currently available that can significantly reduce carbon dioxide (CO2) emissions from conventional fossil fuel use. Depleted oil/gas fields, unmineable coal seams, and deep saline aquifers are generally considered to be the main storage options. In this paper, the authors consider opportunities presented by aquifers close to hydrocarbon fields in the northern Songliao Basin (China) for storage. Data obtained during exploration and production often delineates nearby structures filled with saline water which have not been charged with hydrocarbons but could offer an opportunity for CO2 storage. Based on published data and production data from hydrocarbon fields in the northern Songliao Basin, the potential for geological storage of CO2 in these hydrocarbon field saline aquifers (HFSA) has been assessed and in the northern Songliao Basin, the central and western regions offer great potential for CO2 storage in HFSA. Out of the 42 identified oil/gas fields, aquifers near 24 of the fields offer promising storage potential with an estimated potential storage capacity of 9.8 × 109 tonnes (t) CO2, which is more than 100 times the current annual emissions of large point sources in the Songliao Basin. [ABSTRACT FROM AUTHOR]

The widespread occurrence of evaporites is an important feature of the Middle Triassic Leikoupo Formation in the Sichuan Basin, southwest China. Their origins and geological implications, however, have not been well addressed so far. The issues were preliminarily discussed in this paper. The evaporites include two genetic types. The first is found predominantly in the first to third members of the formation, exhibits a uniform lateral distribution, and presents fairly thin (<5 m) individual layers with a cumulative thickness of <50 m. These evaporites show predominantly laminar bedding with massive beds locally, and their origin is inferred to be from lagoon deposition. The second genetic type was formed later, and occurs from the middle part of the third member to the middle part of the fourth member of the formation. The lithology includes massive gypsum rocks and halites. There is marked variation in both the thickness and lateral distribution of the second type of deposits, and they are inferred to have been deposited in evaporitic depressions whose depositional centers were located in the western and northern basins. These results have implications for the understanding of the region's tectonics. The tectonic stress field of the Sichuan Basin during the Middle Triassic was subject to a transition from extensional to compressive stress. The time interval represented by the first member to the lower part of the third member of the formation encompassed a stable tectonic stage during which the transition was initiated. In contrast, the time interval represented by the middle part of the third member to the middle part of the fourth member was characterized by an active tectonic phase. During that time, the NW-SE and NE-SW trending stresses became activated, resulting in the formation of new depositional centers. Strong evaporation led to the rapid deposition of evaporites in structural lows. The findings provide a new understanding of the geology of the Lower Triassic Leikoupo Formation in the Sichuan Basin. [ABSTRACT FROM AUTHOR]