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The alluvial plain of many of the world's large rivers is generally an area with concentrated urban distribution and a long history of development. In eastern China, the alluvial plains downstream of large rivers such as the Haihe River are the most densely populated and economically developed regions. Beijing, the capital of China, is located on the Haihe Plain. It is a matter of great significance that the region's capacity for livability and sustainable development be improved. Using the river geomorphic data and historical town information, methods of spatial statistical analysis and historical literature research, this paper analyzes the spatial relationship between the distribution of urban centers and the fluvial geomorphology of the Haihe Plain over more than 2,200 years. The research finds that: first, different levels of cities and towns have led to varying choices regarding the fluvial geomorphic environment. Second, in different periods in which different transportations were dominant, the distribution of cities and towns has adapted to the fluvial geomorphology. In the land transportation period, urban settlements mainly concentrated on the diluvial‐alluvial fans at the foot of the Taihang Mountain; in the inland shipping period, they focused on gathering at the confluence of rivers on the central plain and along the canals; in the period of global trade, Tianjin, a trade center, established itself at the mouth of the Haihe River. Third, humans intend to rebuild water system structures (such as the Grand Canal) in the context of major water conservancy projects in the basin to meet the needs of the expanding regions and towns. The research shows that the urban development of the Haihe Plain should adapt to the natural regional pattern and establish a solution based on respecting the natural conditions of the basin, to make the regional sustainable development more resilient. [ABSTRACT FROM AUTHOR]

Previous scientific research on reservoirs of the Deng IV Member in the Gaoshiti-Moxi area, the main production area of the Anyue gas field with reserves of tens of billions of cubic metres, has focused on karst palaeogeomorphology reconstruction, the facies distribution on platform margins, and their effects on creating favourable reservoirs. However, the quality of microbial carbonate reservoirs is also closely related to their original depositional environments on both inner and marginal platforms. Therefore, this paper attempts to reveal favourable microbial carbonate reservoir characteristics and the sedimentary effects on their distribution and prediction based predominantly on a synthetic analysis of the sequence stratigraphy and depositional facies. The results show that favourable reservoirs of the Deng IV Member are classified into three types according to their reservoir spaces: fracture-cavity, pore-cavity and pore reservoirs. Secondary dissolution pores and cavities are primary reservoir spaces developed mainly in nonskeletal grain dolomites with sparry cements, thrombolites, and stromatolites. The physical properties of the fracture-cavity and pore-cavity types of reservoirs are better than those of pore reservoirs and have porosities between 1 and 5% and permeabilities between 0.01 × 10–3 and 1 × 10–3 μm2. Vertically, favourable reservoirs are developed mainly in parasequence set 6 (PSS6) and PSS7 and are laterally distributed in well zone MX9-MX19-MX1 for the fracture-cavity type, MX105-MX110-GS20 for the pore-cavity type and MX17-MX107-MX41-MX102-GS102 for the pore type. Moreover, depositional effects on reservoirs in terms of depositional sequences, seismic facies, microfacies and microfacies associations indicate that to some extent, the fracture-cavity type of reservoir is constrained by the top boundaries of PSS7, PSS2, parasequence 17 (PS17) and PS14; the pore-cavity type of reservoir is constrained by the top boundaries of PSS7, PSS4, PS18 and PS12; and the pore type of reservoir is constrained by the top boundaries of PSS7, PSS6, PSS3, PSS2, PS18, PS17, PS14, and PS12. Seismic facies associated with shoals and mound-flat complexes are related to the facies distributions of pore cavities and pore reservoirs. MA1, MA3, MA7, and MA8 are predominant microfacies associations of favourable reservoirs of the Deng IV Member in the Gaoshiti-Moxi area. The above results are significant for further petroleum exploration and exploitation of ultradeep microbial carbonate reservoirs in this area. [ABSTRACT FROM AUTHOR]

Cavefishes represent a taxon that has experienced natural selection pressures. This paper summarizes the results with respect to the taxonomy, diversity, phylogeny, and adaptation aspects of cavefishes research. It showed that: 1) These studies suggest that cavefishes play important roles in the study of geologic history and adaptation to extreme environments, but the mechanisms involved 168 species of cavefishes belonging to 17 genera, four families, and two orders have been recorded in China. Meanwhile, more new species are being discovered recently, and the species diversity of cavefishes are still underestimated, indicating the need to strengthen the survey in field. 2) The biogeography of cavefishes have focused on Sinocyclocheilus and Triplophysa, that have helped understand the geomorphology of karst areas in southern China and the spatial pattern of species diversity. These studies revealed the influences of evolution and geological history in Sinocyclocheilus, but there are still many species that have not been studied accordingly. 3) Some adaptive mechanistic studies have been conducted on cavefishes, primarily focusing on eye and body color degradation and energy metabolism in the genus Sinocyclocheilus to reveal adaptive mechanisms in the dark environment. 4) The IUCN list of protected cavefishes species in China only includes 21 species. The List of Key Protected Wild Animals for 2021 includes all species of Sinocyclocheilus as National Class II.It is necessary to strengthen the research on the biodiversity and adaptation and need consider the conservation actions for cavefishes. [ABSTRACT FROM AUTHOR]

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Based on the digital elevation data, snow depth and snow cover remote sensing data, this paper divides six snow evolution areas and geographical partitions, extracts the geographical partitions of each evolution area and obtains the geographical characteristics of the evolution area for analysis. The results show that: (1) From 2003 to 2017, the average snow area decreased at a rate of − 0.004, and the average snow depth increased at a rate of 0.03. (2) The snow in the middle altitude hill with shady gentle slope area is the most obvious in the seasonal evolution, and the percentage of this region in the seasonal snow evolution area is 5.46%, the snow depth in the middle altitude hill with sunny and gentle slopes area increased and decreased significantly in the past 15 years, and the percentage of this region in the SD significant changes evolution area was 6.32%. The snow in the low relief middle altitude mountain with shady and moderate slope area not only shows obvious seasonal evolution, but also increases and decreases significantly in snow depth. And the percentage of this region in the seasonal snow significant evolution area is 5.82%. (3) The geographical partitions with the largest area in all evolution areas is the middle altitude hill with sunny and gentle slopes area (4.75%). (4) The geographical partition with the largest variation of snow depth in Tianshan region is the low relief middle altitude mountain with shady and moderate slope area (12.02 cm). (5) The snow accumulation and melting are obvious in the range of 1000–3500 m above altitude, different geomorphology types lead to obvious differences in snow characteristics. The snow melting is most obvious in the gentle slope area of the low topographic relief geomorphology types, and the snow accumulation is most obvious in the steep slope area of the middle relief geomorphology types. [ABSTRACT FROM AUTHOR]

The study on morphology and distribution of sublacustrine fan are necessary for the exploration of oil and gas, which could help to effectively predict the reservoirs of sublacustrine fans. In this paper, the distribution and geomorphology of sublacustrine fans of Dongying Formation in Liaoxi uplift (Bohai Bay Basin, East China) and their controlling factors (including shape and formations) have been analyzed in detail based on seismic, core, and logging data. The main conclusions achieved in this study are: (1) During the sequence of the third member of Dongying Formation (SQd3), two types of sublacustrine fan, including channelized fan (in channel shape) and non-channelized fan (in tongue shape and lobe shape), developed on the eastern slope of Liaoxi uplift, which inherited the characteristics of sediments structural maturity in braided river delta front (good sandstone sorting and high structural maturity); (2) Steep slope was favorable for forming tongue shape sublacustrine fans with large ratio of length and width, while gentle slope tended to deposit lobe shape fans; high mud content tended to form stable channels with strong erosion on the slope end, while high sand content tended to form continuous lobes with lobe shape; (3) In the basin with uplift, the beneficial combination among provenance, relative lake level change and paleomorphology, determines the development and distribution of sublacustrine fan, and the sublacustrine fan deposits are mainly concentrated in the TST. The Yanshan fold belt in the west provided sufficient sediments to the Liaodong Bay during LST for the development of a sublacustrine fan in the east slope of Liaoxi uplift since the Liaoxi uplift sunk into the water, with the result that the deposition of braided river delta front can overlap the uplift. The incised canyons in the Liaoxi uplift provided the channels for sediments entering into the eastern slope, and the main sedimentary location of lacustrine fans was between two stages of faults. This study could provide a theoretical basis for researching the characteristics and distribution of other sublacustrine fans in similar basin backgrounds. [ABSTRACT FROM AUTHOR]

The residual oil in the fluvial reservoir of Gudong Oilfield is still widely developed even after decades of development. In order to explore the remaining oil in the subsurface fluvial reservoir, we need to have a better understanding on fluvial sandbody characteristics. This paper aims to demonstrate how to quantify anatomy on meandering fluvial architecture. Sedimentologic data from core descriptions of Guantao Formation in Gudong Oilfield were used to identify architectural elements. The upper Guantao Formation consists of ten lithofacies composing five different types of architectural elements. By integrating the available core, well logs, and seismic data, the fluvial sandbody distribution was analyzed. To characterize the fluvial channel geomorphology, we used seismic inversion to explore the stratigraphic correlation and stacking patterns of different channels, and the sandbody isopach map was obtained by the sandbody thickness in each layer. The architectural elements distribution in the plane was mapped by the sandbody isopach map and its profile characteristics. According to the investigation of meandering fluvial outcrops, subsurface meandering fluvial seismic geomorphology, and modern river morphology, the upstream-bar portions are always eroded because of the downstream channel migration. Statistics on the morphometric parameters (bar width/looplength, upstream deflection angle, downstream deflection angle, etc.) of modern meandering river (Ob River) were obtained from the Google Earth. It is found that the bar width/looplength and upstream deflection angle, upstream deflection angle and downstream deflection angle in modern meandering river have a good relationship, and we can have a quantitative architectural characterization on the point bar. This study quantified lithofacies thickness and proportion in different architectural elements of Guantao Formation, which ensures a high resolution anatomy on the small scale architecture. By using this method, the lithofacies proportion in each architectural element was computed, and through the statistics of architectural elements proportion in the Gudong Oilfield, the different lithofacies proportions in the block 6 can be computed. [ABSTRACT FROM AUTHOR]

This paper has conducted a high‐resolution characterization of a deeply buried carbonate karst in the Tarim Basin of China by utilizing the FMI (Full‐bore Formation Micro Image) method integrated with seismic data, drilling cores and thin sections. It was found that the type and scale of wellbore karst architecture are mainly controlled by karst paleogeomorphology and vertical faults. The karst highlands and slopes, respectively, develop vadose karst and phreatic karst, with different compositions of karst elements. In terms of the karst thickness in the wellbore, the vertical fault development zone is almost twice that of the non‐development zone, both for the vadose karst and phreatic karst. Furthermore, the vertical fault is also able to promote the development of mixing karst. The mixing zone is located 55 m below the water table, with a strata thickness of approximately 25 m, a net reservoir thickness of 5–15 m, and an average porosity of 4%–8%, which serves as an effective hydrocarbon reservoir in the Yingshan Formation. The results will provide insights into the vertical division of karst reservoir and help predict reservoirs using well logs. [ABSTRACT FROM AUTHOR]

Although volcanism is an important process in the evolution of rift basins, current tectono‐sedimentary models largely neglect its impact on sediment supply, transport pathways, and depositional systems. In this paper, we integrate core, well logs, and 3D seismic data from the Palaeogene‐Neogene Shaleitian (SLT) uplift and surrounding sub‐basins, Bohai Bay Basin, China, to investigate the sedimentology and geomorphology of a volcanic rift basin. Results of this study show that the spatial distribution of extrusive centres was strongly controlled by basement‐involved intra‐basin normal faults. During the early part of the syn‐rift stage, the SLT uplift supplied sediments to transverse fan deltas and braided‐river deltas that fringed the adjacent syn‐rift depocentres. Volcanic deposits mainly occurred as relatively thin lava flow and pyroclastic facies that partially filled fault‐controlled topographic lows, reducing topographic rugosity, and enhanced breaching of basement highs between syn‐rift depocentres. Integration of drainage to the syn‐rift depocentres and development of through‐flowing axial depositional systems was enhanced. During the later part of syn‐rift and in early post‐rift stages, the SLT uplift was progressively inundated, reducing sediment supply to the fringing transverse depositional systems. In contrast, axial braided‐river deltas became the main depositional systems, sourced by large hinterland drainage from the Yanshan fold‐belt to the northwest. Volcanism in the late syn‐rift and early post‐rift occurs as thick lava flow and pyroclastic facies that infill rift topographic lows and locally blocked axial fluvial systems creating isolated lakes. Within hanging wall depocentres, volcanic topographic highs split and diverted axial fluvial and deltaic systems. Furthermore, volcanism supplied large volumes of volcanic sediment to the rift resulting in increased sedimentation rates, and the development of unstable subaerial and subaqueous slopes and deposits, increasing the occurrence of landslides. Based on the observations of this study we update tectono‐sedimentary models for rift basins to include volcanism. [ABSTRACT FROM AUTHOR]

Star dune is one typical kind of aeolian geomorphology in global sand seas. It has attracted scholars in various research fields for years because of its unique morphologic features like Egyptian pyramid. The landform pattern of star dune is mainly dominated by factors such as regional wind regime, sand availability, and local topography. Star dunes grow vertically as they accumulate sand brought in from different directions; however, little is known regarding morphologic changes during this process. The stability of star dunes based on quantitative data is another unsolved question due to the limitation in measuring equipment or other factors. And whether the star dune can grow into star sand hills is another scientific problem which needs to be discussed. In this paper, the heightening development process and morphological changes of star dunes were monitored in Mingsha Mountain of Dunhuang with the 3D laser scanner. Results show that the star dunes in Mingsha Mountain were formed by a group of relatively steady winds, which were northwest, northeast and south winds. With the increase of the height of the star dunes, the morphological parameters of the dune, such as the volume and bottom area, did not show regular changes. The surface erosion of both Dune 1 and Dune 2 during the observation period was closely related to the regional wind conditions. During the growth of the star dunes, the overall trend of the dunes was relatively steady and the dune shape maintained its stability although the aspect and slope of the sand dunes changed, indicating that the stability of star dune was not complete and was dynamic. Moreover, the variation range of the dune slope was proportional to the volume change of the dune. [ABSTRACT FROM AUTHOR]

Urban heat islands (UHIs) have a significant and negative impact on the urban ecological environment and on human health, and it is imperative to examine factors that lead to UHIs. Although numerous studies have been conducted in this field, little research has considered seasonal variations in UHIs in coastal cities. Moreover, parametric statistical analyses, such as regression and correlation analyses, have been typically applied to examine the influential factors. Such analyses are flawed because they cannot uncover the complicated relationships between UHIs and their factors. Taking Dalian, a coastal city in China, as an example, this paper reveals the dynamic mechanism of the UHI effect for different seasons using the cubist regression tree algorithm. Analyses suggest that the UHI effect only exists in spring and summer, and no obvious UHIs can be found in autumn and winter. The adjacency to the sea leads to moderate UHI effects in spring and summer and no UHI or urban cooling island (UCI) effects in autumn and winter. The distance to the coastline, however, does not play a role in the UHI effect. Furthermore, as one of the most important factors, the vegetation coverage plays a significant role in the UHI effect in spring and summer and significantly mediates the UHI in autumn and winter. Comparatively, the elevation (e.g., digital elevation models (DEMs)) is consistently negatively associated with the land surface temperature in all seasons, although a stronger relationship was found in spring and summer. In addition, the surface slope is also a significant factor in spring and winter, and the population density impacts the UHI distribution in summer as well. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Coal mine methane (CMM) accumulation and permeability distribution characterization are the bases for a successful CMM drainage design. Before extending degassing activities, the prediction of the gas pressure and permeability distributions of the pre-drainage area is recommended. The effects of CMM geology on gas occurrence and coal permeability have drawn much attention and contributed to numerous research findings. However, the loco-regional distribution characteristics of the gas occurrence and coal permeability induced by landform characteristics have barely been investigated. This paper presents a quantitative case study on the non-uniform distributions of the gas pressure and coal permeability induced by the Loess Plateau geomorphology. Based on the collection and analysis of a large amount of data, the non-uniform distribution of the burial depth was first obtained. The relationship between the burial depth and gas pressure was analyzed by using the safety line method. A series of efforts were made to perform experimental tests for determining the competing influences of the effective stresses and sorption-induced strain on the coal permeability, and the relationship between the burial depth and coal permeability was analyzed by using the modified PM model. Finally, a quantitative evaluation of the non-uniform distributions of the gas pressure and coal permeability induced by the Loess Plateau geomorphology was achieved. The results showed that the statistical burial depth, gas pressure, and permeability of the No. 3 coal seam were irregular with large loco-regional changes, and the range of the burial depth was from 349 to 479 m. Further, the predicted pressure was from 0.81 to 1.66 MPa, and the predicted permeability was from 0.0155 to 0.01968 mD. When using both the gas pressure and coal permeability as the evaluation indices of the difficulty of gas drainage, the study area could be divided into six parts and classified into two groups. The division of a coal seam influenced by the Loess Plateau geomorphology will provide essential information formulation and economical plan to degas it. [ABSTRACT FROM AUTHOR]

The Lower Paleozoic gas reservoirs in central Sulige gas field are mainly accumulated in Ordovician ancient weathering crust karst carbonate reservoirs, and they are especially rich in the upper assemblage of Ordovician Majiagou formation (Ma51–Ma54 sub-members). However, the spatial distribution of gas is unclear yet because of the different denudation degree and uneven development of paleokarstification. This paper mainly focuses on the characteristics of paleogeomorphology and paleokarstification and their impact on natural gas accumulation. Geological stratifying has been done based on the observation of cores and thin sections, and the analysis of drilling, logging and seismic data. The paleogeologic map of pre-carboniferous was depicted according to the ancient weathering crust outcropped strata. Paleogeomorphology reconstruction is based on a comprehensive method combining the moulage method with the residual thickness method. Result indicates that the paleogeomorphology can be divided into western karst highland and eastern karst slope in the area investigated, and the denudation degree of ancient weathering crust in the west is more serious than that in the east. The karst highland can be divided into remnant hill and depression while the karst slope can be divided into gentle hill and shallow depression in detail. Paleokarst section can be vertically divided into epikarstic zone, vertical vadose zone, horizontal phreatic zone and deep slow flow zone based on the analysis of paleokarst identification mark and vertical dissection of single well. By analyzing the relationship between paleokarst characteristics and production data, the study shows that paleogeomorphology and paleokarstification have a significant control on nature gas accumulation and distribution. Gentle hills on karst slope are expected to be the most favorable areas for reservoirs horizontally, horizontal phreatic zone is more advantageous vertically, and second the vertical vadose zone. [ABSTRACT FROM AUTHOR]

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of South Architecture / Nanfang Jianzhu is the property of South Architecture Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The study of gully characteristics is one of the most effective ways to explore the loess landform development in the Loess Plateau of China. However, current studies mostly focus on gullies' overall characteristics and ignore the different composition of the whole gully system. Therefore, a new perspective is provided in this paper for exploring loess landform development from the population characteristics of the gully system. Firstly, different types of gullies were extracted based on DEM and high-resolution images in three sample watersheds, including hillslope ephemeral gully, bank gully and different-level valley gully. Secondly, population characteristics from the amount, length, age structure and convergent relationship were calculated and analyzed by referring to the biological population in ecology. Finally, the development stages of loess landform in three watersheds were explored based on their population characteristics. The results showed that: (1) The population characteristics, including number density, length density, age structure and convergence, were obviously different in three sample watersheds. (2) The development differences of three watersheds were obtained by synthesizing all population characteristics: Linjiajian was the most developed and oldest watershed, followed by Yangjiaju and then Wangjiagou. (3) The comparison based on the existing soil erosion intensity map and predisposing factors proved that the findings of this paper were more reasonable than that of the traditional hypsometric integral. This research provides a new quantitative-based approach to explore the development degree of loess landform from the gully population, and is a beneficial attempt to combine geomorphology and ecology, further supplementing and improving the study of loess landform development. [ABSTRACT FROM AUTHOR]

This paper demonstrates the impact of an endemic fossorial animal, plateau pika (Ochotona curzoniae), on soil properties and N2O flux at the Zoige Wetland. Pika burrow and control sites without disturbance by pika were selected to measure the soil water content, bulk density, soil organic matter (SOM), NH4-N content and NO3-N content in August 2012. N2O fluxes were measured with static opaque chambers at these sites in June and August 2012. Pika burrowing altered soil aeration by transferring deeper soil to the surface and by constructing underground burrows, which significantly increased bulk density, and reduced soil water content, SOM and NH4-N content at 0–10 cm and 10–20 cm soil depth. N2O flux had a significant correlation with bulk density, SOM and NH4-N content. Pika burrowing significantly influenced N2O flux by increasing N2O flux at the control site from near zero to 0.063±0.011 mg m-2 h-1. Our findings described how pika burrowing influences the soil traits and significantly increases the principal greenhouse gas N2O emission. As plateau pika was commonly considered as a pest, our findings give a novel clue to effectively manage populations of plateau pika on the Qinghai-Tibet Plateau from the perspective of greenhouse gas emission. [ABSTRACT FROM AUTHOR]

The Qarhan Desert in the Qaidam Basin is a high‐elevation geomorphic depression characterized by low temperatures, resulting in an environment similar to those predicted to exist on Mars. As a result, this desert has attracted many aeolian researchers. However, relatively little research has addressed the factors that control dune formation in this region. In this paper, we used observational wind data and sediment characteristics to analyze the formation and development of 3 dune types. The spatial distribution of the Qarhan Desert dune types is controlled by both wind regime and surface characteristics (primarily surface barriers, i.e., yardangs). Linear dunes formed on the leeside of yardangs and became elongated under a bimodal wind regime. The elongation direction of the linear dunes (295°) was similar to the direction of potential sand transport (290° to 296°). Linear dune development experienced different erosion and deposition processes under different climate regimes, and the dunes can be divided into developed and developing linear dunes at present. The movement of developed linear dunes included elongation and lateral movement; however, the movement of developing linear dunes was restricted to elongation. The mean elongation movement rate of the developing and developed linear dunes was approximately 16.87 and 4.84 m/yr, respectively. [ABSTRACT FROM AUTHOR]

In this paper a geomorphic-centered system was proposed for classifying the wetlands on the Qinghai-Tibet Plateau in western China, where the flora comprises primarily grasses. Although the geomorphic properties (e.g., elevation and morphology) of wetlands form the primary criteria of classification, this system also takes hydrological processes into implicit consideration. It represents an improvement over the hydrogeomorphic perspective as the relative importance of the two components (wetness and landform) of wetlands is clearly differentiated. This geomorphic-centered perspective yields insights into the hydrogeomorphic dynamics of plateau wetlands while indicates their vulnerability to change and degradation indirectly. According to this geomorphic-centered perspective, all plateau wetlands fall into one of the seven types of alpine, piedmont, valley, terrace, floodplain, lacustrine, and riverine in three elevational categories of upland, midland, and lowland. Upland (alpine and piedmont) wetlands with the steepest topography are the most sensitive to change whereas midland (floodplain, terrace and valley) wetlands are less vulnerable to degradation owing to a high water reserve except terrace wetlands. They have a dry surface caused by infrequent hydrological replenishment owing to their higher elevation than the channel. Low lying (lacustrine and riverine) wetlands are the most resilient. The geomorphic-centered perspective developed in this paper provides a framework for improving recognition and management of wetlands on the Plateau. Resilient wetlands can be grazed more intensively without the risk of degradation. Fragile and vulnerable wetlands require careful management to avoid degradation. [ABSTRACT FROM AUTHOR]

This paper describes a site-based, ecological asset-based, holistic environmental flows assessment approach, and demonstrates its application to reaches of the Jiaojiang (Jiao River) Basin, Taizhou, Zhejiang Province, the People's Republic of China. The methodology broadly combines information on ecological and other assets associated with the river system (in this case, fish, vegetation, water quality and geomorphology) together with information that links these assets to aspects of the flow regime via hydraulic relationships. This is a site-based methodology, and it requires a medium-level effort and budget. The methodology hinges on being able to gain a basic understanding of the ecology and geomorphology of the stream system, having daily flow series' available, and having the capacity to develop hydraulic models. A comparison of the flow regimes recommended for the Jiaojiang reaches with recommendations derived from two hydrology-only methods found little correspondence. This was explained by the failure of hydrology-only methodologies to take into account the downstream change in the relationship between a river's geomorphic and hydrologic characteristics (i.e. expressed as hydraulics). Also, the ecological assumptions made by the hydrology-only methods cannot necessarily be applied in a generic way. [ABSTRACT FROM AUTHOR]

This paper reviews the course of research on environmental flows in China. It briefly summarizes the history of environmental flows research and introduces twenty approaches used in China to calculate environmental flows. This includes methods adapted from overseas applications and those developed in China to tackle specific environmental issues. The paper gives examples of the implementation of environmental flows in China and identifies some of the deficiencies in environmental flow methodologies. Finally, it discusses obstacles facing the successful implementation of environmental flows in China and suggests the steps required to relieve these impediments. [ABSTRACT FROM AUTHOR]

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

Global management of wetlands to suppress greenhouse gas (GHG) emissions, facilitate carbon (C) sequestration, and reduce atmospheric CO2 concentrations while simultaneously promoting agricultural gains is paramount. However, studies that relate variability in CO2 and CH4 emissions at large spatial scales are limited. We investigated three-year emissions of soil CO2 and CH4 from the primary wetland types of the Liaohe Delta, China, by focusing on a total wetland area of 3287 km2. One percent is Suaeda salsa, 24% is Phragmites australis, and 75% is rice. While S. salsa wetlands are under somewhat natural tidal influence, P. australis and rice are managed hydrologically for paper and food, respectively. Total C emissions from CO2 and CH4 from these wetland soils were 2.9 Tg C/year, ranging from 2.5 to 3.3 Tg C/year depending on the year assessed. Primary emissions were from CO2 (~98%). Photosynthetic uptake of CO2 would mitigate most of the soil CO2 emissions, but CH4 emissions would persist. Overall, CH4 fluxes were high when soil temperatures were >18°C and pore water salinity <18 PSU. CH4 emissions from rice habitat alone in the Liaohe Delta represent 0.2% of CH4 carbon emissions globally from rice. With such a large area and interannual sensitivity in soil GHG fluxes, management practices in the Delta and similar wetlands around the world have the potential not only to influence local C budgeting, but also to influence global biogeochemical cycling. [ABSTRACT FROM AUTHOR]

Rock collapse with large volumes can attain high speeds during their freefall motion. The impact of such a falling mass on the ground surface can initiate a powerful air blast with far-field destructive impact. To investigate the formation, disaster-causing mechanism and dynamic characteristics of rock collapse-induced air blasts, an existing coupled discrete-element method (DEM)–computational fluid dynamics (CFD) approach is employed on a rock collapse-generated air blast in Zengziyan, China (ZRC). The generated air blast shows a maximum velocity of over 50 m/s and subsequently dissipated rapidly. The high consistency between the simulated air blast dynamics and the video verified the DEM–CFD coupled method in the air blast modeling. Combined with the ZRC-induced air blast analysis, a simplified generalized model was designed to observe the potential effect of geomorphology. Results highlight the great contribution of geomorphology, to both air blast initiation and propagation. Collapsed rock mass with a free fall motion is prone to generate significant air blasts when colliding with the slope surface. Tremendous energy was transferred to the surrounding air at the moment. Compared with falling straight down, air blasts resulting from an airborne trajectory case show a longer propagation because the collapsed materials impart air a higher initial momentum parallel to the slope surface. In addition, air blast propagation in wide distribution areas in comparison to narrow valleys shows greater attenuation. This study will aid in understanding the mechanism of a rock collapse-induced air blast as well as the forward simulation of similar events for risk assessment. Highlights: DEM-CFD coupled method provides good performance in simulating the air blast dynamics. Large rock collapse with a free fall motion is prone to generate powerful air blasts when colliding with the slope surface. Geomorphology is greatly influential in both air blast initiation and propagation. [ABSTRACT FROM AUTHOR]

This paper examines the topographic and geometric controls on glacier changes in area and equilibrium-line altitude (ELA) in the central Tien Shan, China, since the Little Ice Age (LIA). We delineate the extents of 487 modern glaciers and their corresponding maximum LIA glacial advances using satellite imagery in Google Earth, and analyze the relationships between the magnitude of glacier changes and a set of local topographic/geometric factors including glacier area, slope, aspect, shape, hypsometry and mean elevation. Our results show that: (1) glacier area decreased from 460.2km² during the LIA to 265.6km² in the 2000s (a loss of 42.3%), with an average ELA increase of ~100 m; (2) relative area changes of glaciers are strongly affected by two of these local factors (glacier area and mean elevation); and (3) ELA change does not show a strong relationship with local factors, suggesting that it may be controlled mainly by climatic factors. This study provides important insights into the local controls on glacier changes at the centennial timescale, which are of critical importance to assess future glacier changes in this arid and semi-arid region. [ABSTRACT FROM AUTHOR]

Variation of streamflow and sediment load in the Yellow River basin has received considerable attention due to its drastic reduction during the past several decades. This paper presents a detailed investigation on the changes of streamflow and sediment load from 1952 to 2011 using monthly observations at four gauging stations along the Yellow River. The results show significant decreasing trends for both streamflow and sediment load at all four gauging stations over the past 60 years. The wavelet transform demonstrated discontinuous periodicities from 1969 to 1973 and after 1986 due to the construction of large reservoirs and implementation of numerous soil and water conservations practices. The sediment rating curves with the power-law function was applied to investigate the relationship between discharge and sediment load. The results indicate distinct variations of the relationship between streamflow and sediment and implied significant hydro-morphological changes within different periods. The reducing sediment supply from the source region and the increased erosive power of the river are detected at Lanzhou station, while the decrease of the transport capacity at Toudaoguai is caused by severe siltation. Significant changes in the relationship between streamflow and sediment load are found at Huayuankou and Gaocun stations, which are largely induced by evident sediment income and trapping effects of large reservoirs. It is estimated that numerous reservoirs have strongly altered the regime and magnitude of streamflow and trapped large amount of sediment, leading to severe siltation and evident reduction of their total volumes. A decrease in precipitation, incoming water from the upper reaches, soil and water conservation measures as well as water consumption contribute most to the significant reduction of streamflow. The decrease of sediment load mainly resulted from various soil and water conservation measures and trapping in reservoirs from 1986 to 2011. [ABSTRACT FROM AUTHOR]

The unique linear dunes in the northern Kumtagh Desert of northwest China have inspired enthusiastic debate among aeolian geomorphologists over their origins and classification. Their uniqueness lies not only in their morphology, but also in their geomorphological patterns. In this paper, the geomorphological patterns and ages of the linear dunes in the northern Kumtagh Desert are analyzed using the pattern analysis method that was recently adopted by geomorphologists. The analysis suggests that these linear dunes have developed since 13 ka BP, during the late part of the most recent deglaciation stage, when the region's dry climate was favorable for dune formation. The differences in dune construction time within this region result from the complex factors that control their formation and spatial variations in the local environment, but these factors were not strong enough to prevent us from estimating the dune age recorded by the geomorphological patterns with acceptable precision. It is also suggested that the pattern analysis method can be used to estimate dune ages in the absence of more reliable dating methods. [ABSTRACT FROM AUTHOR]

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

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The formation and geomorphic evolution of the Jiuduansha Shoal are investigated over the past 50 years in this paper. The sedimentary processes, formation, and geomorphic evolution of the Jiuduansha Shoal in the Yangtze River Estuary, eastern China, are analyzed based on digitized sea maps from 1945 to 2001, satellite images from 1975 to 2001, and field survey data in the spring-neap tidal cycle in the dry and flood seasons in 2003. The suspended sediment concentration and hydrodynamics of the North Passage and South Passage during the dry and flood seasons in the spring-neap tidal cycle in 2003 were investigated, and relations between the North Passage and South Passage of the Jiuduansha Shoal are analyzed. Results show that seasonal and spring-neap tidal cycle variations in sediment and water discharge from the drainage basin correspond to erosion and deposition on the Jiuduansha Shoal. The results and data can provide useful information for the management of the Yangtze River Estuary and restoration of the estuarine tidal flat ecology. [ABSTRACT FROM AUTHOR]

Based on the analysis of major-element compositions of detrital sediments from the Taklamakan Desert of northwestern China, this paper aims to study chemical weathering in a hyper-arid desert environment. The major-element compositions are basically similar to the Upper Continental Crust but show a clear enrichment of CaO and depletion of Na2O and K2O, indicating the enrichment of carbonates and the decomposition of sodium and potassium silicates. The indexes of chemical alteration are relatively low and correlate negatively with the content of Na2O, implying that the degree of chemical weathering is weak and mainly controlled by the weathering of sodium feldspars. An A-CN-K model demonstrates that the detrital sediments from the Taklamakan Desert have a high homogeneity in the trend of chemical weathering. They are weathered less than sands and soil in many other Chinese deserts, and also less than similar detrital sediments in many other countries. This evidence suggests a low degree of mineralogical maturity in the Taklamakan Desert. The aeolian sediments of different ages have similar indexes of chemical weathering, suggesting that the degree of chemical weathering was consistent in the Taklamakan Desert throughout the period of aeolian deposition. The low degree of chemical weathering is caused principally by extreme aridity, rapid rejuvenation of detrital sediments associated with strong aeolian processes, and an intensive input of fluvial deposits, as well as a lack of vegetation. Due to the high concentration of erodible minerals, the desert is quite vulnerable to soil erosion and land degradation. [ABSTRACT FROM AUTHOR]

This paper presents preliminary findings of research examining the movement patterns of tourists within a destination. The study focuses on fully independent individual travellers visiting Hong Kong. Little research has been conducted looking at movements within a destination. Macro or inter-destination movement patterns may inform intra-destination movements. Factors affecting tourists' choices of itineraries give reasons to support the shaping of the patterns. These factors include human factors (type of individual, travel party, motivations, etc), physical factors (destination geomorphology), trip factors (main or secondary destination, first-time or repeat visitor, etc) and the time factor (length of stay in destination, total trip duration). Geographic Information System is used for documenting spatial–temporal movements of tourists through mapping.Tourism and Hospitality Research (2007) 7, 39–49. doi:10.1057/palgrave.thr.6050027 [ABSTRACT FROM AUTHOR]

This paper proposes a new method to distinguish between interglacial deposits and pedogenically-overprinted glacial loess based on the concentration variations of coarse-grained aeolian (magnetically pseudo-single domain and multidomain) magnetite. We apply the method to a sequence from the upper part of the loess unit L2 (marine isotope stage MIS 6) to the sub-loess unit S1L2 (MIS 5d) at the YuanBo (YB) section in the Chinese Loess Plateau. The method is based on the differences in low temperature properties between the coarse-grained (multidomain and pseudo-single domain) detrital magnetite and the pedogenic magnetic particles including superparamagnetic (SP) particles and relatively larger (>SP) maghemite particles. The former is characterized by a crystallographic Verwey transition around 120 K. In contrast, the magnetization of the latter continuously decreases in intensity with increasing temperatures. The method involves two steps: (1) calculating the first-derivative of the low temperature thermal demagnetization of the saturated isothermal remanent magnetization acquired at 20 K (LT-SIRM), which enhances the behaviour related to the Verwey transition, and (2) fitting a third-order polynomial background to the data between both 50–70 and 150–300 K, and then subtracting this background from the total derivative curves. The area under the background-corrected derivative curves represents the absolute intensity drop associated with the Verwey transition (Δ JTV ). This is caused by the aeolian coarse-grained magnetite, which is very sensitive to the changes in the intensity of the winter monsoon, and in turn related to the changes in palaeoclimate. The results show that the sharp drop of Δ JTV at 39.44 m corresponds to the climatic boundary from L2 (MIS 6) to S1S3 (MIS 5e), and not at 39.8 m as thought previously. Thus, the palaeosol deposits just below this boundary are in fact highly altered L2 materials instead of S1S3 accumulations. [ABSTRACT FROM AUTHOR]

The accuracy of gridded precipitation products is uncertain in different temporal and spatial dimensions. Analyzing the applicability of precipitation products is a prerequisite before applying them to hydrometeorological and other related research. In this study, we selected three gridded precipitation products, Integrated Multi-satellitE Retrievals for Global Precipitation Measurement (IMERG), Global Satellite Mapping of Precipitation (GSMaP), and the fifth generation of atmospheric reanalysis of the European Centre for Medium-Range Weather Forecasts (ERA5), including their data from 2001 to 2020. Using the data from 699 ground observation stations, we evaluated the applicability of these three precipitation products in China. Based on five statistical and five classification indicators, we first assessed the applicability of the three precipitation products on daily, monthly, and annual time scales, respectively, and then evaluated their applicability in different spatial dimensions, including basins, agriculture, and geomorphology. The results showed that: (1) IMERG data had the best accuracy on annual and monthly time scales, with both correlation coefficient (CC) values greater than 0.95 and Kling–Gupta efficiency (KGE) values greater than 0.90. On a daily time scale, the accuracy of all three precipitation products differed when statistical or categorical indicators were considered alone. However, the applicability of IMERG data was best among the three precipitation products when both types of indicators were considered. (2) The accuracy of the three precipitation products gradually decreased along the southeast–northwest direction. The applicability of ERA5 data was better in northern regions than in other regions in China, especially in arid and semi-arid regions in northern China. The applicability of IMERG data was better in southern regions with more precipitation and in high-altitude regions than in other regions in China. (3) The applicability of the three precipitation products in plain areas was generally better than in mountain areas. Among them, ERA5 data were more accurate in plain areas, while IMERG data were more accurate in mountain areas. This study can provide a reference for the selection of data sources of gridded precipitation products in different time scales and spatial dimensions in China. [ABSTRACT FROM AUTHOR]

Even today, there is no analogous term to "geoarchaeology" in Chinese, with the closest terms being environmental archaeology ( ), geographic archaeology ( ), and archaeological science ( ) (Jing, [15]; Xia, [40]; Zhou, [46]; Zhu et al., [50]). Over the past several decades, Chinese archaeology has rapidly developed into a scientific enterprise. THE DEVELOPMENT OF GEOARCHAEOLOGY IN CHINA: AN ABBREVIATED HISTORY Chinese scientists have blended geology, geography, and archaeology into a distinct geoarchaeological tradition for over a century (Storozum et al., [36]). A CONCLUDING THOUGHT: FUTURE PROSPECTS FOR GEOARCHAEOLOGY IN CHINA As the contributions to this special issue show, geoarchaeological investigation in China is a well-established subfield of Chinese archaeology. [Extracted from the article]

The China–Russia crude oil pipeline (CRCOP) traverses rivers, forests, and mountains over permafrost regions in northeastern China. Water accumulates beside the pipe embankment, which disturbs the hydrothermal balance of permafrost underlying the pipeline. Ground surface flows along the pipeline erode the pipe embankment, which threatens the CRCOP's operational safety. Additionally, frost heave and thaw settlement can induce differential deformation of the pipes. Therefore, it is necessary to acquire the spatial distribution of water features along the CRCOP, and analyze the various hazard probabilities and their controlling factors. In this paper, information regarding the permafrost type, buried depth of the pipe, soil type, landforms, and vegetation were collected along the CRCOP every 2 km. Ponding and erosive damage caused by surface flows were measured via field investigations and remote sensing images. Two hundred and sixty-four pond sites were extracted from Landsat 8 images, in which the areas of 46.8% of the ponds were larger than 500 m2. Several influential factors related to freeze–thaw hazards and erosive damage were selected and put into a logistic regression model to determine their corresponding risk probabilities. The results reflected the distributions, and forecasted the occurrences, of freeze–thaw hazards and erosive damage. The sections of pipe with the highest risks of freeze–thaw and erosive damage accounted for 2.4% and 6.7%, respectively, of the pipeline. Permafrost type and the position where runoff encounters the pipeline were the dominant influences on the freeze–thaw hazards, while the runoff–pipe position, buried depth of the pipe, and landform types played a dominant role in erosive damage along the CRCOP. Combined with the geographic information system (GIS), field surveys, image interpretation and model calculations are effective methods for assessing the various hazards along the CRCOP in permafrost regions. [ABSTRACT FROM AUTHOR]

China, the largest coal consumer in the world, is one of the countries that experience the most coal fires. Hence, it is critical for China to monitor coal fires and carry out coal fire monitoring, assessment, and appropriate suppression work. The Wuda coalfield, located in China's Inner Mongolia Autonomous Region, was selected as the study area. This paper was aiming to analyze spatiotemporal changes of coal fires located in Wuda of China from 2000 to 2015 and focused on the assessment of fire protection project during 2006–2008. Landsat Thematic Mapper and Enhanced Thematic Mapper Plus images were used to detect changes in coal fires over the last 16 years by utilizing a generalized single-channel method to retrieve land surface temperature data and natural breaks extracting coal fire zones. The results showed that: 1) the changes of coal fires area represented obvious three stages: Stage I (2000–2006) was before the fire suppression project with fire spread and expansion; Stage II (2006–2008) was the implementation of this project with rapid reduction of fire area; Stage III (2008–2015) was after this project with stable fire area at a low level; 2) the fire suppression work was highly successful; the area of coal fires basically remained at 192.98 ha, a reduction by 45.74% from 2000 and 62.40% from 2006 (before fire suppression projects); 3) fire suppression work in the south (zone F) and in the northwest (zone A) was the most successful, while some new patches sporadically appeared in other regions (zone B, C and D); 4) coal fire suppression methods have led to significant destruction of local geomorphology; 5) it was difficult to completely extinct coal fires underground with current suppression method. Compared with previous studies, this research paid more attention to the estimation of fire suppression projections which provided an available way for environment decision makers and coal energy producers to qualitatively assess the status and effectiveness of coal fire suppression projects. [ABSTRACT FROM AUTHOR]

The identification of favourable shale-gas areas in marine-continental transitional shales are challenging because of the multiple thin producing layers and abrupt lateral pinch-outs. Using data obtained from drilling, logging, and 3D seismic and natural gamma spectroscopic logging, this paper investigates the control of early Permian palaeogeomorphology on the distribution of organic-rich shale in the southeastern Ordos Basin. Using the impression method and de-compaction correction of strata thickness based on seismic velocity reconstruction, we restore the karst palaeogeomorphology at the top of the Taiyuan Formation for the early Permian. Three geomorphic units including karst highland, karst slope, and karst depression are identified, and constitute a geomorphological pattern of interjacent depressions and highlands. In addition, based on the multi-lithological eigenvalue method, the spatial distribution of transitional shales in the Shan 2 lower sub-member of the lower Permian Shanxi Formation was inferred using post-stack seismic parameter inversion. Our results show that organic-rich shale is distributed mainly in the low section of Shan 2 lower sub-member, which is controlled by karst palaeogeomorphology mainly distributed in karst depressions. Organic-rich shale distributed in karst depressions are characterised by large cumulative thickness, high TOC, moderate thermal maturity, strong hydrocarbon generation intensity, and relatively high gas content, indicating that shale-gas sweet spots should be distributed mainly in karst depressions rather than in highlands or slope areas. Meanwhile, Th/U and Th/K ratios, which indicate paleo-environment during the period of shale deposition, show that the strength of reducing conditions was greatest in karst depressions, moderate in karst slopes, and lowest in karst highlands. Therefore, it is inferred that the distribution of shale-gas sweet spots may be related to the weakly reducing environment, which favoured the preservation of organic-rich sediments during sedimentation. The upper section of Shan 2 lower sub-member was dominated by a high-energy transitional sedimentary environment, and the paleo-redox conditions tended to be oxic, disfavouring the preservation of shale organic matter, and the organic-rich shale in the upper section is relatively poorly developed. This study shows that palaeogeomorphology and paleo-redox conditions affect the deposition and preservation of organic-rich sediments in lower section, the relationship between palaeogeomorphology and the distribution of organic-rich shale can provide reference for shale gas sweet spots prediction and promote the rapid exploitation of shale gas in eastern Ordos Basin. • Karst palaeogeomorphology at the top of the Taiyuan Formation was restored. • The karst geomorphology controlled the redox environment, distribution of organic-rich shale and gas-bearing. • The relationship between the palaeogeomorphology and the distribution of organic-rich shale in transitional facies was established. • We propose a model for the development of organic-rich shale in transitional facies. [ABSTRACT FROM AUTHOR]

Deep-water gravity-flow sandstones are important hydrocarbon exploration and production targets in the Bohai Bay Basin, a Paleogene intra-continental rift basin in eastern China. In this paper, the seismic-sedimentology techniques are used to characterize, in plan view, the temporal and spatial evolution of a gravity-flow-channel complex of the Paleogene Shahejie Formation (Es) on the Qinan faulted-monoslope (Qinan Slope), Bohai Bay Basin. The results show that two or three gravity-flow channels, 9–12 km long and 0.5–2 km wide, were successively developed in later Es (Es1z–Es1s). The channels initially experienced westward migration and then shifted eastward. The corresponding wireline logs of the channel-fill sequences mainly present blocky-shaped or bell-like configurations, whereas their seismic profile features are characterized by strong amplitude reflections, such as U-shaped, plate-like, spindle-shaped and lenticular configurations. The syndepositional activity of three normal faults, i.e., the Nandagang Fault to the northwest, the Zhangbei Fault to the northeast and the Zhaobei Fault to the east led to gradient changes of the Qinan Slope, which have controlled the plan morphology (width, curvature, and bifurcation) of the gravity-flow channels. In the medium-late period of Es1z, triggered by intensive faulting on the three faults, the gradient of the Qinan Slope was steepened abruptly, resulting in an increase of flow velocity and erosion amplitude to underlying deposits. As a result, channels exhibiting narrow and straight configurations in plan view were formed. During the stage of early Es1z and Es1s, tectonic activity intensity was relatively low and the gradient of the Qinan Slope was gentle, so channels with great width and curvature were bifurcated and merged downstream. Comparison of the faulting amplitude of the three syndepositional faults suggests that the Nandagang and Zhaobei faults were inversely strengthened in the Es1z and Es1s. The Nandagang Fault to the west was found to be more active than the Zhaobei Fault to the east in the Es1z stage. This condition was reversed in Es1s. For that reason, the channels migrated to the west in the Es1z stage and then went back to the east during Es1s. Core analysis shows that the channel fills are mainly composed of sandy-debrites, slumps and turbidites. Among them, sandy debrites dominate deposition in terms of reservoir volume and hydrocarbon potential. These units primarily consist of sandstones and gravel-bearing sandstones, with bed thicknesses ranging from 10 to 40 m, an average porosity of 11% and a permeability of 25 mD. Being mostly encased in organic-rich dark mudstones, these sandy debrites are significant hydrocarbon exploration targets. The results of this study are not only useful to the hydrocarbon exploration and development planning for the Qinan Slope, but also helpful when considering other faulted-depressions in the Bohai Bay Basin and other intra-continent rifted basins around the world, particularly in terms of gravity-flow hydrocarbon exploration and research. [ABSTRACT FROM AUTHOR]

Basin response to precipitation variability by terrestrial hydrological processes may be manifested at different timescales and vary from one basin to another. A quantitative grasp of natural variability modulation is desirable for characterizing basin tendency or vulnerability on floods and droughts; quantification is not always straightforward, however. Using a macro-scale hydrological model, the Variable Infiltration Capacity (VIC) model, the hydrological time series (runoff, soil moisture, and evapotranspiration) were obtained for the 10 sub-basins over the Pearl River basin in South China for the period 1952–2000. A continuous wavelet transform was used to identify the characteristics of the temporal scales of basin-featured extreme events and related multiple-scale variabilities. By use of wavelet coherence analysis and rank correlation method, the cross correlations of monthly anomalies of hydrological processes were examined. The results showed that the runoff correlated most with, and the evapotranspiration had less response to, the precipitation variability. The analyzed results revealed that the attenuation effect of runoff in response to precipitation variability was mainly within the timescale of 2 yr in the Pearl River basin. The soil moisture variability can extend precipitation variation along with timescales. With understanding of the variability features of the terrestrial hydrological processes, this paper showed one geomorphic index, a basin form factor (FF), can represent the wavelet-based indices for high- and low-frequency responses to precipitation variability. It was found that, for a sub-basin with a higher FF value, precipitation variability can be represented more by runoff variability at less than 2-yr timescales; such a sub-basin is apt to have serious floods. With a lower FF value, a sub-basin has longer memory of soil moisture, leading to severe droughts during dry periods. This finding would be valuable to evaluate the tendency on occurrence of floods and droughts in the Pearl River basin, a humid region, which may be transferable to other basins in the globe. [ABSTRACT FROM AUTHOR]

Summary Flash flooding is one of the most common natural hazards in China, particularly in mountainous areas, and usually causes heavy damage and casualties. However, the forecasting of flash flooding in mountainous regions remains challenging because of the short response time and limited monitoring capacity. This paper aims to establish a strategy for flash flood warnings in mountainous ungauged catchments across humid, semi-humid and semi-arid regions of China. First, we implement a geomorphology-based hydrological model (GBHM) in four mountainous catchments with drainage areas that ranges from 493 to 1601 km 2 . The results show that the GBHM can simulate flash floods appropriately in these four study catchments. We propose a method to determine the rainfall threshold for flood warning by using frequency analysis and binary classification based on long-term GBHM simulations that are forced by historical rainfall data to create a practically easy and straightforward approach for flash flood forecasting in ungauged mountainous catchments with drainage areas from tens to hundreds of square kilometers. The results show that the rainfall threshold value decreases significantly with increasing antecedent soil moisture in humid regions, while this value decreases slightly with increasing soil moisture in semi-humid and semi-arid regions. We also find that accumulative rainfall over a certain time span (or rainfall over a long time span) is an appropriate threshold for flash flood warnings in humid regions because the runoff is dominated by excess saturation. However, the rainfall intensity (or rainfall over a short time span) is more suitable in semi-humid and semi-arid regions because excess infiltration dominates the runoff in these regions. We conduct a comprehensive evaluation of the rainfall threshold and find that the proposed method produces reasonably accurate flash flood warnings in the study catchments. An evaluation of the performance at uncalibrated interior points in the four gauged catchments provides results that are indicative of the expected performance at ungauged locations. We also find that insufficient historical data lengths (13 years with a 5-year flood return period in this study) may introduce uncertainty in the estimation of the flood/rainfall threshold because of the small number of flood events that are used in binary classification. A data sample that contains enough flood events (10 events suggested in the present study) that exceed the threshold value is necessary to obtain acceptable results from binary classification. [ABSTRACT FROM AUTHOR]

Coastal wetlands are key features of the Earth's surface and are characterized by a diverse array of coupled geomorphological and biological processes. However, the links between the distribution of biodiversity (for example, species and structural diversity) and the formation of coastal geomorphology are not well‐understood on a landscape scale most useful to coastal zone managers. This study describes the relationship between select geomorphological and biological mangrove community features (i.e. species composition and functional root type) in a landscape‐distributed coastal zone of Dongzhaigang Bay, north‐eastern Hainan Island, China. A total of 11 mangrove species and five functional aerial root types were encountered, with the location of species by root types being controlled by the elevation of the soil surface. Plank roots, prop roots and pneumatophores occupied the lowest intertidal elevations, while knee roots and fibrous roots of the mangrove fern, Acrostichum aureum, preferred the highest intertidal elevations. Surface sediment deposition in areas with mangroves was greater than deposition in non‐mangrove forest zones, establishing an important biological mechanism for this large‐area response because surface erosion/compaction was also more prominent within mangrove roots. Indeed, functional root type influenced the magnitude of deposition, erosion and compaction, with knee roots and pneumatophores being more effective in promoting deposition and preventing surface erosion/compaction than prop roots. These results indicate a potential role for vegetation type (especially functional root type) to influence coastal geomorphological processes at large landscape scales. While soil surface elevation is correlated to the distribution of mangrove species and functional root types, a significant feedback exists between elevation change and the capacity of those root types to influence coastal geomorphological differentiation within sustainable intertidal elevations. An enhanced understanding of geomorphological development, mangrove species distribution and functional root type may improve management to support nature‐based solutions that adjust more effectively to sea‐level rise through feedbacks. [ABSTRACT FROM AUTHOR]

With the development of social economy and human activities, the geomorphology and hydrodynamic conditions of coasts have been dramatically changed, causing serious environmental pollution and resource depletion. Taking Quanzhou Bay as an example, this study combined geomorphologic change with a hydrodynamic model to simulate the change in tidal currents in different periods. The results show a change in the coastline was the main cause of hydrodynamic change during the industrialization reform. During the past 70 years, the tidal prism decreased year by year, and the average velocity of the tidal current in the channel decreased by 33.7% and 30.8% at flood and ebb tide, respectively. In the early stages of industrialization, reclamation land was used in a single way. The tidal prism decreased by 22.2% and 29.8% in the spring and neap tide, respectively. In the middle and later stages, the tidal current velocity increased, and reclamation land was used in a variety of ways. In modern society, the reclamation land-use type was unitary. Based on this research, we show the influence of human activities on the evolution of the bay's geomorphology and provide suggestions for the management of the bay. [ABSTRACT FROM AUTHOR]

This paper is the second part of a new geohazards analysis applied to a large part of the Tien Shan, Central Asia, focused on landslide susceptibility computations that are based on recently compiled geographic, geological and geomorphological data. The core data are a digital elevation model, an updated earthquake catalogue, an active fault map as well as a new landslide inventory. The most recently added digital data are a new simplified geological map, an annual precipitation map, as well as river and road network maps that were produced for the Kyrgyz and Tajik parts of the Tien Shan. On the basis of these records we determine landslide densities with respect to morphological (M), geological (G), river distance (R), precipitation (P), earthquake (E) and fault (F) distance factors. Correlations were also established between scarp locations and the slope angle, distance to rivers, curvature. These correlations show that scarps tend to be located on steeper slopes, farther from rivers and on more convex terrain than the entire landslides. On the basis of the landslide density values computed for each class of the aforementioned factors, two landslide susceptibility maps are created according to the Landslide Factor analysis: the first one considers correlations between the landslide occurrences and the first four factors (MGRP); the second one is based on the first map (MGRP) combined with the seismo-tectonic influence (+ E + F) on landslide distributions. From the comparison of these two maps with actual landslide distributions we infer that the distances to rivers as well as to faults and past earthquakes most strongly constrain the susceptibility of slopes to landslides. We highlight several zones where the landslide susceptibilities computed for the MGRP + E + F factors fit better the observed concentration of landslides than those computed for the MGRP factors alone. For a few zones, both maps produce high landslide susceptibilities that do not well reflect the observed low sub-regional landslide activity; for some cases, we consider that some influencing factors must not have been well taken into consideration, for others we show that we simply had missed landslide detections. At the scale of the mountain range, the computed landslide susceptibility maps fit the observed landslide distributions relatively well, but these maps only represent the spatial component of landslide hazards. Temporal aspects are not considered by this analysis. [ABSTRACT FROM AUTHOR]

To identify the developmental characteristics and controlling factors of the beach‐bar sandstone in saline lake basins in the Qaidam Basin, China, the lithology and bedding structure of some representative outcrops of the Neogene saline lake basins were comprehensively investigated by means of experimental test data of local drilling cores, casting thin sections, and grain size, together with field outcrops in the basin and the modern salt lake deposition record of Qinghai Lake. Two types of sand bodies in the saline lake basins, that is, delta sand bodies and shore‐shallow lake beach‐bar facies were revealed. Neogene saline lake basins were found to host widespread beach‐bar sand bodies. Lithologically, the sand bodies were composed of fine‐grained sandstone and siltstone, with wavy bedding, low‐angle cross‐bedding, and bimodal cross‐bedding. The beach‐bar sandstone was characterized by multi‐layer superimposition, lateral migration, and NW–SE wide‐coverage continuation. Drilling data showed that beach‐bar sand bodies extended from 10 to 35 km in width and most of them occurred 3–15 km away from braided river delta front. It has been predicted that the total area of beach‐bar sand bodies of 14 sand groups in the Neogene spread across 5,000 km2. Four factors, that is, lake water salinity, terrigenous input, palaeogeomorphology, and monsoons, controlled the construction of the beach‐bar sand bodies developed in the Neogene saline lake of the Qaidam Basin. We can conclude that the settling velocity and transport distance of the sand bodies were affected by the water body salinity in such saline lake basins. Also, the distribution range of the beach‐bar sand bodies was affected by the clastic input from a terrigenous provenance. Furthermore, the wide‐coverage distribution and local enrichment of the beach‐bar sandstone were affected by palaeogeomorphology, and the distribution direction of the beach‐bar sandstone was affected by the driving effect of NW monsoons. We propose a deposition model of the beach‐bar sandstone in saline lake basins that can predict favourable beach‐bar sand body regions, to support the major discoveries of lithologic traps in southwestern Qaidam, China. [ABSTRACT FROM AUTHOR]

Contrasting landscape and climate settings generate different catenas for alpine steppe grasslands at Maduo (4200 m asl) and alpine meadow grasslands at Maqin (3750 m asl) on the Qinghai-Tibet Plateau. These place-based catenal models can be used as transferable archetypes in environmental management. [Display omitted] • Catenal models are developed for alpine steppe and alpine meadow grasslands on the QTP. • Implications for the generalised use of place-based catenal models are explored. • Research needs and management applications of the catenal models are scoped. Careful development of place-based catenal models and their application as transferable archetypes provides an integrative and generalisable framework for scientifically-informed approaches to environmental management. A workshop and field excursion to the Source Zone of the Yellow River in western China in July 2019 brought together local experts and a team of international researchers to co-develop cross-disciplinary, process-based catenal models that summarise controls on the character and behaviour of grassland environments in alpine meadow (3800 m asl) and alpine steppe (4200 m asl) landscapes. Water, sediment and nutrient fluxes, soil material properties, ground cover (especially percentage bare ground) and the role of small mammals (especially pika) are critical drivers of process linkages in the catenal models. Geologic, climatic and anthropogenic controls on these drivers vary in alpine steppe and alpine meadow settings. While these process interactions have supported grazing adapted ecosystems and sustained biodiversity values in this area for millennia, anthropogenic and climate change disturbances threaten the integrity of these landscapes and their capacity to provide ecosystem services and sustain livelihoods into the future. The place-based catenal models presented in this paper can be used to support applications that appropriately target key attributes, linkages and fluxes that may require conservation, maintenance or treatment in the management of alpine steppe and alpine meadow landscapes. [ABSTRACT FROM AUTHOR]