As one of the main areas of tropical storm action in the northwestern Pacific Ocean,South China experiences several typhoons each year,and coastal erosion is a problem,making the area a natural testing ground for stud...As one of the main areas of tropical storm action in the northwestern Pacific Ocean,South China experiences several typhoons each year,and coastal erosion is a problem,making the area a natural testing ground for studying the dynamic geomorphological processes and storm response of promontory-straight coasts.This study is based on three years of topographic data and remote sensing imagery of Gulei Beach and uses topographic profile morphology,single width erosion-accretion and mean change,combined with the Coastsat model to quantify the seasonal and interannual variability and storm response of the beach and to explain the evolution of shoreline change and beach dynamics geomorphology in the last decade.Gulei Beach has been in a state of overall erosion and local accretion for a long time,with relatively obvious cyclical changes;seasonal changes are also obvious,which are mainly characterized by summer accretion and winter erosion,with accretion at the top of the bay and accretion and erosion on the north and south sides of the bay corner,respectively;the seasonal erosion-accretion volume of the beach profile ranges from-80 m3/m to 95.52 m3/m,and the interannual erosion-accretion volume ranges from-69.09 m3/m to 87.31 m3/m.The response of beaches to typhoons with different paths varies greatly depending on the length,slope,orientation and scale of beach development.The large and gently developing Futou beach is less responsive to storms,while the less developed headlands in the southern Gulei Peninsula are more susceptible to disturbance by external factors and respond more strongly to typhoons.Storm distance is more influential than storm intensity.Under the influence of human activities,obvious erosion hotspots develop during normal weather,but storm processes produce redistribution of beach material patterns,and erosion hotspots disappear after storms.The results of this study enrich the theory of beach dynamics geomorphology and provide technical support for disaster prevention and mitigation,as well as ecological restoration of coastal zones.展开更多
Fluvial dynamic landform is produced by reaction between fluvial bchaviour and suffoce matenal. It possesses apparent environmental effects. As a branch of gcomorphology, the fiuvial dynandc gcomorphology is a margina...Fluvial dynamic landform is produced by reaction between fluvial bchaviour and suffoce matenal. It possesses apparent environmental effects. As a branch of gcomorphology, the fiuvial dynandc gcomorphology is a marginal science among fiuid dynalnics, sediment mechaltics and fluvial goomorphology. With physical modelling by sindlarity based on Newtonian mechanics, and pnnciple of the same effect bot diffend struCture based on systelnahc theory, it is possible to study propenies, formation and processes in fluvial dynamic gcomorphology. A new research method, which is a combination of mathematical simulation by computer with physical modelling will be deveoped.展开更多
Atrak River region, northeast Iran is a quaternary tectonically active region. There are many geologic structures that they are formed by the collision of the Arabian and Eurasian plates. This area has extended from n...Atrak River region, northeast Iran is a quaternary tectonically active region. There are many geologic structures that they are formed by the collision of the Arabian and Eurasian plates. This area has extended from north east Iran to the of kope dagh zone. The study area is Atrak river basin and it has been divided to 56 Sub-basin for calculation of 6 geomorphic indices. Finally, this region was classified in 4 relative tectonic activity classes.展开更多
1 Introduction Morphological analysis on the planform migration structure of meandering river is an important basis for the reconstruction of evolution of paleochannel.Besides,it is a significant method for restoratio...1 Introduction Morphological analysis on the planform migration structure of meandering river is an important basis for the reconstruction of evolution of paleochannel.Besides,it is a significant method for restoration of rivers through展开更多
Based on analysis of outcrop,drilling,logging and seismic data,and geotectonic background,the lithofacies paleogeography and paleokarst geomorphology of the Middle Permian Maokou Formation in the northwestern Sichuan ...Based on analysis of outcrop,drilling,logging and seismic data,and geotectonic background,the lithofacies paleogeography and paleokarst geomorphology of the Middle Permian Maokou Formation in the northwestern Sichuan Basin were reconstructed,and the petroleum geological significance of the lithofacies paleogeography and paleokarst geomorphology were discussed.The Maokou Formation is divided into 3 long-term cycles,namely LSCl,LSC2 and LSC3,which correspond to the Member 1,Member 2 and Member 3 of the Maokou Formation,respectively.Controlled by the extensional structure caused by opening of the Mianlue Ocean in the north margin of the upper Yangtze blocks and basement faults produced by mantle plume uplifting,the area had tectonic differentiation in NWW and NE,and sedimentary basement took on episodic settlement from north to south,as a result,the sedimentary systems of Member 1 to Member 3 gradually evolved from carbonate platform to platform-slope-continental shelf.According to the residual thickness,paleokarst geomorphologic units such as karst highland,karst slope and karst depression at different stages were reconstructed.The karst geomorphological units were developed successively on the basis of sedimentary geomorphology.Sedimentary facies and paleokarst geomorphology are of great significance for oil and gas accumulation.The Maokou Formation in northwestern Sichuan has two kinds of most favorable reservoir zone combinations:high energy grain shoal and karst monadnock,platform margin slope and karst slope.Based on this understanding,the planar distribution of the two kinds of reservoir zones were predicted by overlapping the favorable reservoir facies belt with paleokarst geomorphology.The study results provide a new idea and reference for the exploration deployment of the Middle Permian Maokou Formation in the Sichuan Basin.展开更多
Biostratigraphic Zones Bb. Bz. H. I-V distinguished in C<sup>14</sup> dated Peat, peaty clay sediments above arid, Barren zone have identified distinct environment of deposition as fresh water mixed b...Biostratigraphic Zones Bb. Bz. H. I-V distinguished in C<sup>14</sup> dated Peat, peaty clay sediments above arid, Barren zone have identified distinct environment of deposition as fresh water mixed brackish water to shallow marine to brackish water mangrove swamp, brackish water mixed fresh water swamp followed by colonization of non-littoral species to fresh water swamp during Holocene in the Bengal basin, India in chronological succession. The successive phases of depositional environment have identified the events of sea level rise, marine transgression and sea ward movement of the sea. The unique database has explored successive changes in the geomorphology of South Bengal from upland dry to marine deltaic environment to fresh water upland condition.展开更多
There widely occur stretches of permafrost at more than 3,800-4,200 meters above sea level in the source area of the Huanghe (Yellow) River. The periglacial geomorphology develops quite well, including frozen disinteg...There widely occur stretches of permafrost at more than 3,800-4,200 meters above sea level in the source area of the Huanghe (Yellow) River. The periglacial geomorphology develops quite well, including frozen disintegration geomorphology, freezing and thawing geomorphology in cold environments, periglacial dune, buried ices and fossil periglacial phenomena. In light of the relation between stratigraphy and periglacial phenomena, three periglacial periods can be divided, which are the Middle Pleistocene periglacial period, the Late Pleistocene periglacial period and modern periglacial period.展开更多
As for the formation of the submerged trough of Maxwell Bay and the external agent geomorphic-phenomena of Fildes Peninsula, we can use glaciated theory to explain them. Moreover, based on a large number of field inve...As for the formation of the submerged trough of Maxwell Bay and the external agent geomorphic-phenomena of Fildes Peninsula, we can use glaciated theory to explain them. Moreover, based on a large number of field investigation by foreign colleagues and the authors, we can consider that the last glaciated ice-stream which had a great effect on current periglacio-landform distribution, mainly flowed along the direction from northwest to southeast. The periglacio-geomorphic distribution of the peninsula has a deep brand of glaciated history. Three kinds of different profile assemblage features show that the periglacial landform have an internal relationship in genesis. They also show a difference between stoss and leeward slopes by glaciated effect.展开更多
High-resolution multi-beam/single-beam bathymetric data and seismic profiling data from the latest surveys are used to map and interpret the detailed seafloor geomorphology of the western region of the North Yellow Se...High-resolution multi-beam/single-beam bathymetric data and seismic profiling data from the latest surveys are used to map and interpret the detailed seafloor geomorphology of the western region of the North Yellow Sea(NYS),China.The mapping area covers 156410 km^(2),and incorporates a flat shelf plain,subaqueous accumulation shoals,tidal scouring troughs,and tidal sand ridge groups.Offshore areas with water depths less than 50 m in the western region of the NYS are mainly covered by thick,loose sediments,forming wide spread accumulation geomorphological features;these include the Liaodong Peninsula subaqueous accumulation system containing shoals and rugged scouring troughs,and the large mud wedge of the Shandong Peninsula.In the central part of the NYS,there is a relatively flat residual shelf plain with coarser sediment deposits.This flat shelf plain has a water depth larger than 50 m and a thin layer of sediment,on which there is a large pockmark field caused by seafloor seepage.These geomorphological structures indicate that modern sedimentary processes are the main driving force controlling the sculpture of the current seafloor surface landform.Extensive strong tidal current systems and abundant sediment sources provide the critical external forces and essential conditions for the formation of seafloor geomorphology.The tectonic basement controls the macroscopic morphological shape of the NYS,but is reflected very little in the seafloor geomorphic elements.Our results provide a detailed seafloor geomorphological map of the western region of the NYS,an area that has not previously mapped and also provide a scientific framework for further research into offshore seafloor geomorphology,shelf sedimentary processes,and submarine engineering construction in this region.展开更多
Kuwait is considered one of the desert regions of the Arabian Peninsula, that subjected to geomorphological processes forming the earth’s surface features. The anthropogenic activities through urbanization affected t...Kuwait is considered one of the desert regions of the Arabian Peninsula, that subjected to geomorphological processes forming the earth’s surface features. The anthropogenic activities through urbanization affected the earth geomorphology in the southern coastal sabkhas of Kuwait such as (Al-Jailiaha, Az-Zor and Al-Khiran). This study aims to monitor the geomorphological changes on the southern coastal sabkhas due to the urbanization expansion. Geographic information systems (GIS) and remote sensing (RS) techniques were used to study these changes, determine the areas of the coastal sabkhas in the southern part of Kuwait, following the developments, and identifying land cover in the area and its coastal strip including tourist resorts, sand dunes, and smooth sand sheets. The satellite images used in this study based on the data of Landsat-5 (TM) 1985, and Landsat-5 (TM) 1990, Landsat-7 (ETM+) 2001, visuals Landsat-8 (OLI) 2016 covering the years of (1985, 1990, 2001, 2016), in order to detect changes in the sabkhas and the extension of urbanization in the region. Digital Maps were made to show how extent the study area was affected by urbanization. Urbanization mostly expanded to the south in the study area on the account of the coastal sabkhas, where the area of the coastal sabkhas in 1985 was about 103.1 km2 and in 1990 it was about 84.1 km2. This led to the shrinking of the sabkhas area and extension of the resort area within the areas of sabkhas and sand dunes, particularly in Al-Khiran coastal area exposing it to the problem of sand drift and sand encroachment, which resulted in changes of the characteristics of the sabkhas, shrinkage of their area, and adverse impacts on their geomorphology.展开更多
Brief introduction of experiments,laboratories and stations in geomorphology.The achievements in experimental fluvial geomorphology gained in the last 30 years in China include channel pattern modelling,studies on inf...Brief introduction of experiments,laboratories and stations in geomorphology.The achievements in experimental fluvial geomorphology gained in the last 30 years in China include channel pattern modelling,studies on influence of boundary conditions,applications of fluvial geomorphology,its experimental theories and techniques,etc.Problems in fluvial geomorphic experiments are indicated,tendencies in the development of this branch of geomorphology are predicted,and suggestions are made.展开更多
Iran has a various salt structures that their tectonic geomorphology is subject of this paper. Geologic situation of salt structures in Iran have determinate. According to age and geological setting of salt deposits t...Iran has a various salt structures that their tectonic geomorphology is subject of this paper. Geologic situation of salt structures in Iran have determinate. According to age and geological setting of salt deposits that revealed by tectonic geomorphology methods, salt structure provinces of the Central and Southern Iran have been distinguished. Also, critical concepts of salt diapirism in the Southern Iran and Central Iran salt basins have explained. Therefore, Central Iran’s salt diapirs have triggered by tectonic forces, but salt diapirism in the Southern Iran has triggered by halokinesis, then it has effected by tectonic forces, especially in Zagros fold and thrust belt.展开更多
The present study is about to find out different attributes of soil as well as geomorphology. It is very much relevant to the study of land use land cover (LULC). Garpanchkot hill is situated in Purulia district of We...The present study is about to find out different attributes of soil as well as geomorphology. It is very much relevant to the study of land use land cover (LULC). Garpanchkot hill is situated in Purulia district of West Bengal. There are two geomorphological and seven pedological parameters that have been selected for the study. Shuttle radar topographic mission (SRTM) and advanced land observing satellite (ALOS) data are analyzed by remote sensing software to find out the geomorphological character of the area. There are twenty soil samples that have been taken from top of the hill to foothill pediment area with the change of elevation and slope for laboratory analysis. Different statistical techniques are used for representation. Foot hill area of the Garpanchkot hill can be determined by less than 150 m elevation and 5o slope. Elevation and slope of rest of the hill area (greater than 150 m and 5o) are fully dominated by forest and scattered vegetation. Elevated area (greater than 205 m) with less slope (10o - 15o) is associated with dense forest. Escarpment area is associated with grass land and scattered vegetation. Foothill area is bearing the signature of scattered vegetation, bare soil ground and agriculture. The richness of clay minerals plays an important role in the foothill pediment area for development of agriculture. Sandy loam is dominating soil texture in the rest of the hill area. Percentage of organic matter (1.8%), status of salinity (6.65 - 7.72) and alkalinity (up to 138.6 μs/cm) remain high in the high elevated area due to forest cover. The area is very dry, only fed by the rainfall during monsoon season. Artificial reservoir feeds the foothill agriculture system. Rice, wheat, maize, sugarcane, pulses chili and vegetables are the main crops of this area.展开更多
[Objectives]To explore the problem of"secondary desertification"caused by coal mining subsidence in sandy area and its control countermeasures.[Methods]The collapse fissure changes,vegetation displacement an...[Objectives]To explore the problem of"secondary desertification"caused by coal mining subsidence in sandy area and its control countermeasures.[Methods]The collapse fissure changes,vegetation displacement and tilt,dry sand layer and wind erosion/aeolian deposit rate of the edge,middle and basin of subsidence area were studied in detail.[Results]The width and density of fissures at the edge of subsidence area were the smallest,followed by those in the center,and the width and density of fissures in the basin of the subsidence area were the greatest,while the staggering and surface damage showed the opposite trend.The average displacement length of vegetation in the subsidence area reached 60 cm,the slope was 5.67-28.63,and the maximum wind erosion/aeolian deposit at the trunk roots was-30.52 cm/+25.41 cm,most serious at the edge of subsidence.The changes in displacement length and slope of vegetation were positively linearly correlated with the height and surface damage of collapse fissures.The thickness of dry land layer at the edge of the subsidence area reached 14 cm,4-6 cm greater than that of the control,and the thickness of dry land layer in the middle and basin of the subsidence area was both about 11 cm,1-4 cm greater than that of non-subsidence area.The wind erosion rate at the edge of the subsidence area was up to 83.34%,followed by that(52.06%)in the middle.The aeolian deposit rate in the subsidence basin was 51.84%.[Conclusions]The subsidence edge has the strongest impact on the sandy geomorphology and vegetation habitat,and is a key area for ecological restoration.It is recommended that the coal mining subsidence should be treated in a timely manner to avoid the occurrence of"secondary desertification".展开更多
The Holocene alluvial fans and flood plains formed by the Sho and Oyabe Rivers spread out in the Tonami plain from the central through the northern parts in the Toyama Prefecture, central Japan. Along the foot of the ...The Holocene alluvial fans and flood plains formed by the Sho and Oyabe Rivers spread out in the Tonami plain from the central through the northern parts in the Toyama Prefecture, central Japan. Along the foot of the surrounding mountains and hills, higher, middle and lower terraces of late Pleistocene-Holocene in age are distributed. These terraces have been displaced, by the reverse dip-slip activities of Tonami-heiya fault zone in a sense of upheaval in the mountains side, even during the Holocene time. We examined stratigraphic cross section utilizing borehole data and geomorphologically analyzed 5 m-DEM data in order to elucidate the fault trace of the Isurugi fault which Tonami-heiya fault zone. As the results, the northern segment of Isurugi fault seems to run along the northeastern foot of Hodatsu Hills and extends underground through the lower-most Oyabe River into the Toyama Bay. Consequently, its total length reaches about 30 km. In the southern segment, a continuous fault scarplet was recognized to cut across the lower dissected fans. The slip-rate of Isurugi fault is estimated to be 0.31 - 0.64 m/kyr. In the Hokuriku region, reverse faulting and related folding with strike in a NE-SW direction have occurred during the late Quaternary. The hinge line of block movement due to the activities of the Tonami-heiya fault zone is revealed to have shifted from the mountain side into the plain side within the Holocene time. In conclusion, the Quaternary folding and faulting associated with the crustal warping at a wavelength of about 20 km is currently in progress, causing both the subsidence of Tonami plain and the upheaval of surrounding mountains and hills.展开更多
This paper examines the geomorphology and hydrology of the Benin Region, Edo State, Nigeria. The major landform features and processes of the region are highlighted. This region is a strategic and significant landscap...This paper examines the geomorphology and hydrology of the Benin Region, Edo State, Nigeria. The major landform features and processes of the region are highlighted. This region is a strategic and significant landscape in Nigeria. Information was gathered on the various aspects of the landscape, including the Geology, Physiography (Relief) and Geomorphology, Geomorphic processes, Weathering, Drainage processes, Landforms, Surface Water Hydrology and Water Resources. The Benin Region is underlained by sedimentary formation of the South Sedimentary Basin. The geology is generally marked by top reddish earth, composed of ferruginized or literalized clay sand. Geologically, the Benin Region comprises of 1) the Benin formation;2) alluvium;3) drift/top soil and 4) Azagba-Ogwashi (Asuba-Ogwashi) formation. Several parts of the region are surrounded by the Benin historical moats. The region has been described as a tilled plain in the south western direction. The local relief of the region is 91 m. Boreholes records in the Benin Region show evidence of deep chemical weathering overtime. Soil profile reveals that the region is composed mainly of reddish brown sandy laterite. Intermittent layers of porous sands of sandy clays may reach a large depth as found in the borehole drilled in the region. These are products of deep chemical decay of the original parent rock materials. Three river systems drain the Benin Region. They are the Ikpoba River, the Ogba River and Owigie-Ogbovben River systems. The mean annual discharge of Ikpoba River for 1982-1983 and 1993-2002 was 1411 mm/yr, which was 1.019 × 10<sup>9</sup> m<sup>3</sup> with a mean annual baseflow of 1256.23 mm (0. 907 × 109 m<sup>3</sup>). This constitutes 87.65% of the total flow. It has a mean annual surface runoff of 225.18 mm (0.112 × 10<sup>9</sup> m<sup>3</sup>) or 24.4 % of the total discharge. The water resources of the region include surface water and underground water.展开更多
Defining impact significance is the main technical task that influences decision-making during the Environmental Licensing Procedure(ELP).The ELP begins with screening to determine potentially significant impacts of t...Defining impact significance is the main technical task that influences decision-making during the Environmental Licensing Procedure(ELP).The ELP begins with screening to determine potentially significant impacts of the proposed project.Scoping then follows to address any interventions deemed worthy of attention in the production of an Environmental Impact Assessment(EIA).This will include consideration of relevant landforms and geomorphological processes.However,preliminary assessments of environmental impacts often lack the scientific robustness to procure substantive and transactive effectiveness.This review presents an examination of the established practices of screening and scoping while highlighting the foremost challenges to improve the technical grounds of the ELP.The analysis of screening and scoping practices stresses the need for novel methods that ensure the sequential reasoning between their criteria while improving the preliminary evaluation of impact significance.Reducing the inherent subjectivity of discretionary judgment requires scientific methodologies that acknowledge the interaction between the natural system and human interventions,which has been addressed by geomorphological research.The knowledge consolidated in this review opens the gate to explore the compatibility between the United Nations strategy of Ecosystem Approach(EA)with the ELP through a novel geomorphological interpretation of the EIA.Therefore,this diagnosis demonstrate that screening and scoping practices would benefit from reliable methods that balance the precautionary principle with the efficient character required in the ELP.展开更多
Digital elevation model(DEM)plays a fundamental role in the study of the earth system by expressing surface configuration,understanding surface process,and revealing surface mechanism.DEM is widely used in analysis an...Digital elevation model(DEM)plays a fundamental role in the study of the earth system by expressing surface configuration,understanding surface process,and revealing surface mechanism.DEM is widely used in analysis and modeling in the field of geoscience.However,traditional DEM has the defect of single attribute,which is difficult to support the research in earth system science oriented to geoscience process and mechanism mining.Hence,realizing the value-added data model on the basis of traditional DEM is necessary to serve digital elevation modeling and terrain analysis under the background of a new geomorphology research paradigm and earth observation technology.A theoretical framework for value-added DEM that mainly includes concept,connotation,content,and categories,is constructed in this study.The relationship between different types of value-added DEMs as well as the research significance and application category of this theoretical framework are also proposed.The following are different methods of value-added DEMs:(1)value-added methods of DEM space and time dimensions that emphasize the integration of the ground and underground as well as coupling of time and space,(2)attribute-based value-added methods composed of material(including underground,surface,and ground)and morphological properties,and(3)value-added methods of features and physical elements that consider geographical objects and landform features formed by natural processes and artificial effects.The digital terrace,slope,and watershed models are used as examples to illustrate application scenarios of the three kinds of value-added methods.This study aims to improve expression methods of DEMs under the background of new surveying and mapping technologies by adding value to the DEM at three levels of dimensions,attributes,and elements as well as support knowledge-driven digital geomorphological analysis in the era of big data.展开更多
基金The National Natural Science Foundation of China under contract Nos 42076058 and 41930538the National Key Research and Development Program of China under contract No.2022YFC3106104the Scientific Research Foundation of Third Institute of Oceanography,Ministry of Natural Resources under contract Nos 2023023 and 2019017。
文摘As one of the main areas of tropical storm action in the northwestern Pacific Ocean,South China experiences several typhoons each year,and coastal erosion is a problem,making the area a natural testing ground for studying the dynamic geomorphological processes and storm response of promontory-straight coasts.This study is based on three years of topographic data and remote sensing imagery of Gulei Beach and uses topographic profile morphology,single width erosion-accretion and mean change,combined with the Coastsat model to quantify the seasonal and interannual variability and storm response of the beach and to explain the evolution of shoreline change and beach dynamics geomorphology in the last decade.Gulei Beach has been in a state of overall erosion and local accretion for a long time,with relatively obvious cyclical changes;seasonal changes are also obvious,which are mainly characterized by summer accretion and winter erosion,with accretion at the top of the bay and accretion and erosion on the north and south sides of the bay corner,respectively;the seasonal erosion-accretion volume of the beach profile ranges from-80 m3/m to 95.52 m3/m,and the interannual erosion-accretion volume ranges from-69.09 m3/m to 87.31 m3/m.The response of beaches to typhoons with different paths varies greatly depending on the length,slope,orientation and scale of beach development.The large and gently developing Futou beach is less responsive to storms,while the less developed headlands in the southern Gulei Peninsula are more susceptible to disturbance by external factors and respond more strongly to typhoons.Storm distance is more influential than storm intensity.Under the influence of human activities,obvious erosion hotspots develop during normal weather,but storm processes produce redistribution of beach material patterns,and erosion hotspots disappear after storms.The results of this study enrich the theory of beach dynamics geomorphology and provide technical support for disaster prevention and mitigation,as well as ecological restoration of coastal zones.
文摘Fluvial dynamic landform is produced by reaction between fluvial bchaviour and suffoce matenal. It possesses apparent environmental effects. As a branch of gcomorphology, the fiuvial dynandc gcomorphology is a marginal science among fiuid dynalnics, sediment mechaltics and fluvial goomorphology. With physical modelling by sindlarity based on Newtonian mechanics, and pnnciple of the same effect bot diffend struCture based on systelnahc theory, it is possible to study propenies, formation and processes in fluvial dynamic gcomorphology. A new research method, which is a combination of mathematical simulation by computer with physical modelling will be deveoped.
文摘Atrak River region, northeast Iran is a quaternary tectonically active region. There are many geologic structures that they are formed by the collision of the Arabian and Eurasian plates. This area has extended from north east Iran to the of kope dagh zone. The study area is Atrak river basin and it has been divided to 56 Sub-basin for calculation of 6 geomorphic indices. Finally, this region was classified in 4 relative tectonic activity classes.
基金supported by National Natural Sciences Fund (No. 41372125)Fund of Ministry of Education of Hubei Province (No. Q20121210)
文摘1 Introduction Morphological analysis on the planform migration structure of meandering river is an important basis for the reconstruction of evolution of paleochannel.Besides,it is a significant method for restoration of rivers through
基金Supported by the National Natural Science Foundation of China (41802147)China Postdoctoral Science(2019M651785)。
文摘Based on analysis of outcrop,drilling,logging and seismic data,and geotectonic background,the lithofacies paleogeography and paleokarst geomorphology of the Middle Permian Maokou Formation in the northwestern Sichuan Basin were reconstructed,and the petroleum geological significance of the lithofacies paleogeography and paleokarst geomorphology were discussed.The Maokou Formation is divided into 3 long-term cycles,namely LSCl,LSC2 and LSC3,which correspond to the Member 1,Member 2 and Member 3 of the Maokou Formation,respectively.Controlled by the extensional structure caused by opening of the Mianlue Ocean in the north margin of the upper Yangtze blocks and basement faults produced by mantle plume uplifting,the area had tectonic differentiation in NWW and NE,and sedimentary basement took on episodic settlement from north to south,as a result,the sedimentary systems of Member 1 to Member 3 gradually evolved from carbonate platform to platform-slope-continental shelf.According to the residual thickness,paleokarst geomorphologic units such as karst highland,karst slope and karst depression at different stages were reconstructed.The karst geomorphological units were developed successively on the basis of sedimentary geomorphology.Sedimentary facies and paleokarst geomorphology are of great significance for oil and gas accumulation.The Maokou Formation in northwestern Sichuan has two kinds of most favorable reservoir zone combinations:high energy grain shoal and karst monadnock,platform margin slope and karst slope.Based on this understanding,the planar distribution of the two kinds of reservoir zones were predicted by overlapping the favorable reservoir facies belt with paleokarst geomorphology.The study results provide a new idea and reference for the exploration deployment of the Middle Permian Maokou Formation in the Sichuan Basin.
文摘Biostratigraphic Zones Bb. Bz. H. I-V distinguished in C<sup>14</sup> dated Peat, peaty clay sediments above arid, Barren zone have identified distinct environment of deposition as fresh water mixed brackish water to shallow marine to brackish water mangrove swamp, brackish water mixed fresh water swamp followed by colonization of non-littoral species to fresh water swamp during Holocene in the Bengal basin, India in chronological succession. The successive phases of depositional environment have identified the events of sea level rise, marine transgression and sea ward movement of the sea. The unique database has explored successive changes in the geomorphology of South Bengal from upland dry to marine deltaic environment to fresh water upland condition.
文摘There widely occur stretches of permafrost at more than 3,800-4,200 meters above sea level in the source area of the Huanghe (Yellow) River. The periglacial geomorphology develops quite well, including frozen disintegration geomorphology, freezing and thawing geomorphology in cold environments, periglacial dune, buried ices and fossil periglacial phenomena. In light of the relation between stratigraphy and periglacial phenomena, three periglacial periods can be divided, which are the Middle Pleistocene periglacial period, the Late Pleistocene periglacial period and modern periglacial period.
文摘As for the formation of the submerged trough of Maxwell Bay and the external agent geomorphic-phenomena of Fildes Peninsula, we can use glaciated theory to explain them. Moreover, based on a large number of field investigation by foreign colleagues and the authors, we can consider that the last glaciated ice-stream which had a great effect on current periglacio-landform distribution, mainly flowed along the direction from northwest to southeast. The periglacio-geomorphic distribution of the peninsula has a deep brand of glaciated history. Three kinds of different profile assemblage features show that the periglacial landform have an internal relationship in genesis. They also show a difference between stoss and leeward slopes by glaciated effect.
基金The National Natural Science Foundation of China under contract Nos 41506069,41876111the Open Fund of Key Laboratory of Marine Surveying and Mapping of the Ministry of Natural Resources under contract No.2021B01.
文摘High-resolution multi-beam/single-beam bathymetric data and seismic profiling data from the latest surveys are used to map and interpret the detailed seafloor geomorphology of the western region of the North Yellow Sea(NYS),China.The mapping area covers 156410 km^(2),and incorporates a flat shelf plain,subaqueous accumulation shoals,tidal scouring troughs,and tidal sand ridge groups.Offshore areas with water depths less than 50 m in the western region of the NYS are mainly covered by thick,loose sediments,forming wide spread accumulation geomorphological features;these include the Liaodong Peninsula subaqueous accumulation system containing shoals and rugged scouring troughs,and the large mud wedge of the Shandong Peninsula.In the central part of the NYS,there is a relatively flat residual shelf plain with coarser sediment deposits.This flat shelf plain has a water depth larger than 50 m and a thin layer of sediment,on which there is a large pockmark field caused by seafloor seepage.These geomorphological structures indicate that modern sedimentary processes are the main driving force controlling the sculpture of the current seafloor surface landform.Extensive strong tidal current systems and abundant sediment sources provide the critical external forces and essential conditions for the formation of seafloor geomorphology.The tectonic basement controls the macroscopic morphological shape of the NYS,but is reflected very little in the seafloor geomorphic elements.Our results provide a detailed seafloor geomorphological map of the western region of the NYS,an area that has not previously mapped and also provide a scientific framework for further research into offshore seafloor geomorphology,shelf sedimentary processes,and submarine engineering construction in this region.
文摘Kuwait is considered one of the desert regions of the Arabian Peninsula, that subjected to geomorphological processes forming the earth’s surface features. The anthropogenic activities through urbanization affected the earth geomorphology in the southern coastal sabkhas of Kuwait such as (Al-Jailiaha, Az-Zor and Al-Khiran). This study aims to monitor the geomorphological changes on the southern coastal sabkhas due to the urbanization expansion. Geographic information systems (GIS) and remote sensing (RS) techniques were used to study these changes, determine the areas of the coastal sabkhas in the southern part of Kuwait, following the developments, and identifying land cover in the area and its coastal strip including tourist resorts, sand dunes, and smooth sand sheets. The satellite images used in this study based on the data of Landsat-5 (TM) 1985, and Landsat-5 (TM) 1990, Landsat-7 (ETM+) 2001, visuals Landsat-8 (OLI) 2016 covering the years of (1985, 1990, 2001, 2016), in order to detect changes in the sabkhas and the extension of urbanization in the region. Digital Maps were made to show how extent the study area was affected by urbanization. Urbanization mostly expanded to the south in the study area on the account of the coastal sabkhas, where the area of the coastal sabkhas in 1985 was about 103.1 km2 and in 1990 it was about 84.1 km2. This led to the shrinking of the sabkhas area and extension of the resort area within the areas of sabkhas and sand dunes, particularly in Al-Khiran coastal area exposing it to the problem of sand drift and sand encroachment, which resulted in changes of the characteristics of the sabkhas, shrinkage of their area, and adverse impacts on their geomorphology.
文摘Brief introduction of experiments,laboratories and stations in geomorphology.The achievements in experimental fluvial geomorphology gained in the last 30 years in China include channel pattern modelling,studies on influence of boundary conditions,applications of fluvial geomorphology,its experimental theories and techniques,etc.Problems in fluvial geomorphic experiments are indicated,tendencies in the development of this branch of geomorphology are predicted,and suggestions are made.
文摘Iran has a various salt structures that their tectonic geomorphology is subject of this paper. Geologic situation of salt structures in Iran have determinate. According to age and geological setting of salt deposits that revealed by tectonic geomorphology methods, salt structure provinces of the Central and Southern Iran have been distinguished. Also, critical concepts of salt diapirism in the Southern Iran and Central Iran salt basins have explained. Therefore, Central Iran’s salt diapirs have triggered by tectonic forces, but salt diapirism in the Southern Iran has triggered by halokinesis, then it has effected by tectonic forces, especially in Zagros fold and thrust belt.
文摘The present study is about to find out different attributes of soil as well as geomorphology. It is very much relevant to the study of land use land cover (LULC). Garpanchkot hill is situated in Purulia district of West Bengal. There are two geomorphological and seven pedological parameters that have been selected for the study. Shuttle radar topographic mission (SRTM) and advanced land observing satellite (ALOS) data are analyzed by remote sensing software to find out the geomorphological character of the area. There are twenty soil samples that have been taken from top of the hill to foothill pediment area with the change of elevation and slope for laboratory analysis. Different statistical techniques are used for representation. Foot hill area of the Garpanchkot hill can be determined by less than 150 m elevation and 5o slope. Elevation and slope of rest of the hill area (greater than 150 m and 5o) are fully dominated by forest and scattered vegetation. Elevated area (greater than 205 m) with less slope (10o - 15o) is associated with dense forest. Escarpment area is associated with grass land and scattered vegetation. Foothill area is bearing the signature of scattered vegetation, bare soil ground and agriculture. The richness of clay minerals plays an important role in the foothill pediment area for development of agriculture. Sandy loam is dominating soil texture in the rest of the hill area. Percentage of organic matter (1.8%), status of salinity (6.65 - 7.72) and alkalinity (up to 138.6 μs/cm) remain high in the high elevated area due to forest cover. The area is very dry, only fed by the rainfall during monsoon season. Artificial reservoir feeds the foothill agriculture system. Rice, wheat, maize, sugarcane, pulses chili and vegetables are the main crops of this area.
基金Key R&D Program of Shaanxi Province(2018ZDXM-GY-030)National Natural Science Foundation of China(41661062)Forestry Intellectual Property Transformation and Application Project of National Forestry and Grassland Administration of China(Zhi Zhuan 2017-7).
文摘[Objectives]To explore the problem of"secondary desertification"caused by coal mining subsidence in sandy area and its control countermeasures.[Methods]The collapse fissure changes,vegetation displacement and tilt,dry sand layer and wind erosion/aeolian deposit rate of the edge,middle and basin of subsidence area were studied in detail.[Results]The width and density of fissures at the edge of subsidence area were the smallest,followed by those in the center,and the width and density of fissures in the basin of the subsidence area were the greatest,while the staggering and surface damage showed the opposite trend.The average displacement length of vegetation in the subsidence area reached 60 cm,the slope was 5.67-28.63,and the maximum wind erosion/aeolian deposit at the trunk roots was-30.52 cm/+25.41 cm,most serious at the edge of subsidence.The changes in displacement length and slope of vegetation were positively linearly correlated with the height and surface damage of collapse fissures.The thickness of dry land layer at the edge of the subsidence area reached 14 cm,4-6 cm greater than that of the control,and the thickness of dry land layer in the middle and basin of the subsidence area was both about 11 cm,1-4 cm greater than that of non-subsidence area.The wind erosion rate at the edge of the subsidence area was up to 83.34%,followed by that(52.06%)in the middle.The aeolian deposit rate in the subsidence basin was 51.84%.[Conclusions]The subsidence edge has the strongest impact on the sandy geomorphology and vegetation habitat,and is a key area for ecological restoration.It is recommended that the coal mining subsidence should be treated in a timely manner to avoid the occurrence of"secondary desertification".
文摘The Holocene alluvial fans and flood plains formed by the Sho and Oyabe Rivers spread out in the Tonami plain from the central through the northern parts in the Toyama Prefecture, central Japan. Along the foot of the surrounding mountains and hills, higher, middle and lower terraces of late Pleistocene-Holocene in age are distributed. These terraces have been displaced, by the reverse dip-slip activities of Tonami-heiya fault zone in a sense of upheaval in the mountains side, even during the Holocene time. We examined stratigraphic cross section utilizing borehole data and geomorphologically analyzed 5 m-DEM data in order to elucidate the fault trace of the Isurugi fault which Tonami-heiya fault zone. As the results, the northern segment of Isurugi fault seems to run along the northeastern foot of Hodatsu Hills and extends underground through the lower-most Oyabe River into the Toyama Bay. Consequently, its total length reaches about 30 km. In the southern segment, a continuous fault scarplet was recognized to cut across the lower dissected fans. The slip-rate of Isurugi fault is estimated to be 0.31 - 0.64 m/kyr. In the Hokuriku region, reverse faulting and related folding with strike in a NE-SW direction have occurred during the late Quaternary. The hinge line of block movement due to the activities of the Tonami-heiya fault zone is revealed to have shifted from the mountain side into the plain side within the Holocene time. In conclusion, the Quaternary folding and faulting associated with the crustal warping at a wavelength of about 20 km is currently in progress, causing both the subsidence of Tonami plain and the upheaval of surrounding mountains and hills.
文摘This paper examines the geomorphology and hydrology of the Benin Region, Edo State, Nigeria. The major landform features and processes of the region are highlighted. This region is a strategic and significant landscape in Nigeria. Information was gathered on the various aspects of the landscape, including the Geology, Physiography (Relief) and Geomorphology, Geomorphic processes, Weathering, Drainage processes, Landforms, Surface Water Hydrology and Water Resources. The Benin Region is underlained by sedimentary formation of the South Sedimentary Basin. The geology is generally marked by top reddish earth, composed of ferruginized or literalized clay sand. Geologically, the Benin Region comprises of 1) the Benin formation;2) alluvium;3) drift/top soil and 4) Azagba-Ogwashi (Asuba-Ogwashi) formation. Several parts of the region are surrounded by the Benin historical moats. The region has been described as a tilled plain in the south western direction. The local relief of the region is 91 m. Boreholes records in the Benin Region show evidence of deep chemical weathering overtime. Soil profile reveals that the region is composed mainly of reddish brown sandy laterite. Intermittent layers of porous sands of sandy clays may reach a large depth as found in the borehole drilled in the region. These are products of deep chemical decay of the original parent rock materials. Three river systems drain the Benin Region. They are the Ikpoba River, the Ogba River and Owigie-Ogbovben River systems. The mean annual discharge of Ikpoba River for 1982-1983 and 1993-2002 was 1411 mm/yr, which was 1.019 × 10<sup>9</sup> m<sup>3</sup> with a mean annual baseflow of 1256.23 mm (0. 907 × 109 m<sup>3</sup>). This constitutes 87.65% of the total flow. It has a mean annual surface runoff of 225.18 mm (0.112 × 10<sup>9</sup> m<sup>3</sup>) or 24.4 % of the total discharge. The water resources of the region include surface water and underground water.
基金This contribution is a product of the post-doctoral research No 80740-103-2020,financed by the National Financing Fund"FRANCISCO JOSéDE CALDAS"the Ministry of Science,Technology and Innovation of ColombiaProject INDEX No.INV.1106-01-002-15"Cultural practices and environmental certification of beaches:a contribution for the sustainable development in the insular states"of Universidad de la Costa of Barranquilla,Colombia。
文摘Defining impact significance is the main technical task that influences decision-making during the Environmental Licensing Procedure(ELP).The ELP begins with screening to determine potentially significant impacts of the proposed project.Scoping then follows to address any interventions deemed worthy of attention in the production of an Environmental Impact Assessment(EIA).This will include consideration of relevant landforms and geomorphological processes.However,preliminary assessments of environmental impacts often lack the scientific robustness to procure substantive and transactive effectiveness.This review presents an examination of the established practices of screening and scoping while highlighting the foremost challenges to improve the technical grounds of the ELP.The analysis of screening and scoping practices stresses the need for novel methods that ensure the sequential reasoning between their criteria while improving the preliminary evaluation of impact significance.Reducing the inherent subjectivity of discretionary judgment requires scientific methodologies that acknowledge the interaction between the natural system and human interventions,which has been addressed by geomorphological research.The knowledge consolidated in this review opens the gate to explore the compatibility between the United Nations strategy of Ecosystem Approach(EA)with the ELP through a novel geomorphological interpretation of the EIA.Therefore,this diagnosis demonstrate that screening and scoping practices would benefit from reliable methods that balance the precautionary principle with the efficient character required in the ELP.
基金National Natural Science Foundation of China,No.41930102。
文摘Digital elevation model(DEM)plays a fundamental role in the study of the earth system by expressing surface configuration,understanding surface process,and revealing surface mechanism.DEM is widely used in analysis and modeling in the field of geoscience.However,traditional DEM has the defect of single attribute,which is difficult to support the research in earth system science oriented to geoscience process and mechanism mining.Hence,realizing the value-added data model on the basis of traditional DEM is necessary to serve digital elevation modeling and terrain analysis under the background of a new geomorphology research paradigm and earth observation technology.A theoretical framework for value-added DEM that mainly includes concept,connotation,content,and categories,is constructed in this study.The relationship between different types of value-added DEMs as well as the research significance and application category of this theoretical framework are also proposed.The following are different methods of value-added DEMs:(1)value-added methods of DEM space and time dimensions that emphasize the integration of the ground and underground as well as coupling of time and space,(2)attribute-based value-added methods composed of material(including underground,surface,and ground)and morphological properties,and(3)value-added methods of features and physical elements that consider geographical objects and landform features formed by natural processes and artificial effects.The digital terrace,slope,and watershed models are used as examples to illustrate application scenarios of the three kinds of value-added methods.This study aims to improve expression methods of DEMs under the background of new surveying and mapping technologies by adding value to the DEM at three levels of dimensions,attributes,and elements as well as support knowledge-driven digital geomorphological analysis in the era of big data.
