Freeze-thaw cycles and associated geomorphology in a post-glacial environment:current glacial,paraglacial,periglacial and proglacial scenarios at Pico de Orizaba volcano,Mexico

The glacial history of Pico de Orizaba indicates that during the Last Glacial Maximum,its icecap covered up to~3000 m asl;due to the air temperature increasing,its main glacier has retreated to 5050 m asl.The retraction of the glacier has left behind an intense climatic instability that causes a high frequency of freeze-thaw cycles of great intensity;the resulting geomorphological processes are represented by the fragmentation of the bedrock that occupies the upper parts of the mountain.There is a notable lack of studies regarding the fragmentation and erosion occurring in tropical high mountains,and the associated geomorphological risks;for this reason,as a first stage of future continuous research,this study analyzes the freezing and thawing cycles that occur above 4000 m asl,through continuous monitoring of surface ground temperature.The results allow us to identify and characterize four zones:glacial,paraglacial,periglacial and proglacial.It was found that the paraglacial zone presents an intense drop of temperature,of up to~9℃ in only sixty minutes.The rock fatigue and intense freeze-thaw cycles that occur in this area are responsible for the high rate of rock disintegration and represent the main factor of the constant slope dynamics that occur at the site.This activity decreases,both in frequency and intensity,according to the distance to the glacier,which is where the temperature presents a certain degree of stability,until reaching the proglacial zone,where cycles are almost non-existent,and therefore there is no gelifraction activity.The geomorphological processes have resulted in significant alterations to the mountain slopes,which can have severe consequences in terms of risk and water.

Dynamic geomorphology and storm response characteristics of the promontory-straight beach-a case of Gulei Beach, Fujian

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.

Rehabilitation and Identification of Ancient Geomorphology in Pre-Carboniferous to the East Region of the 7^(th) Well in Lungu

After the break of sedimentation from middle Ordovician to early Carboniferous, Lunnan ancient buried hill received deposition again in the middle of Carboniferous. According to the seismic structural explanation and analysis of structural background, the research was carried out upon Ordovician soluble stratum and the distribution of soluble regions to the east of the 7th well in Lungu. In light of impression method and residual thickness method, and through the analysis of corresponding relations between upper and lower strata of ancient weathering crust in the research area, the gap between the bottom of doublet limestone, the symbol stratum in Carboniferous regions, and Ordovician buried hill stratum was filled. By applying impression method and residual thickness method, pre-Carboniferous paleokarst geomorphology in this region was rehabilitated, so as to prepare for the identification of ancient geomorphology. Geomorphic units such as karst highlands, karst gentle slopes and karst peak-cluster valleys were distinguished as alternative objective regions for further reservoir prediction work.

Late Cenozoic Geomorphology, Geochronology and Physiography of Yuntaishan in Southern Taihang Mountain, North China

The late Cenozoic geomorphic features and geochronologic data of the Zhingfang River catchment in the Yuntaishan World Geopark are studied. Several quarternary geochronologic methods, including electron spin resonance （ESR）, optically stimulated luminescence （OSL）, thermo-luminescence （TL） and U-series are presented in this paper. The results suggest that there are two planation surfaces, named as the Taihang surface which is a peneplain of Taihang stage formed during Oligocene or Oligocene to early-middle Miocene period, and Tang-hien surface which is a mature wide valley of Tang-hien stage formed during late Miocene-Pliocene or Piiocene-early Pleistocene period and probably ended prior to 2.2-2.6 Ma based on ESR dating. After the Tang-hien stage, the incision and aggradation of the river formed six stream terraces with heights of 3-5 m, 8-12 m, 22-24 m, 28-38 m, 50-62 m and 80-85 m above the river bottom, respectively. The dating results of the alluvium sediments suggest that these terraces were formed during Holocene, 20-23 ka B.P., 110-120 ka B.P., 200-240 ka B.P., 840-1200 ka B.P. or ~450 ka B.P. and 1600-1800 ka B.P. or -1100 ka B.P., respectively. These results indicate that episodic incision of the river, which controls the formation of the scenery in the Yuntaishan World Geopark, was mainly influenced by the periodic dry-wet climate change during late Cenozoic mountain uplift.

Seismic geomorphology of buried channel systems in the western South Huanghai Sea:retrodiction for paleo-environments

Quantitative morphologic analysis of shallowly buried, dendritic channel systems in the continental shelf off the abandoned Huanghe River （Yellow River） mouth has been made based on interpretation of high resolution seismic profiles, with the attempt to estimate the paleo-hydrologic parameters when the incised-channels formed, then assess the paleoenvironment. The results indicate that the buried channel systems were formed about 44 cal ka BP when the shelf was subaerially exposed and subsequently drowned and filled during the Holocene transgression with the sea level rise continuously. The study area has experienced the processes from fluvial and estuarine to fully marine.

A STUDY ON FLUVIAL DYNAMIC GEOMORPHOLOGY AND ITS EXPERIMENT AND SIMULATION

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.

Tectonic Geomorphology of Atrak River, NE Iran

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.

Reconstruction and petroleum geological significance of lithofacies paleogeography and paleokarst geomorphology of the Middle Permian Maokou Formation in northwestern Sichuan Basin,SW China

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.

The impact of geomorphology of marsh creeks on fish assemblage in Changjiang River estuary

Tidal marshes are an important habitat and nursery area for fi sh.In the past few decades,rapid economic development in the coastal areas of China has led to the interruption and destruction of an increasing number of tidal marshes.The growing interest in tidal marsh restoration has increased the need to understand the relationship between geomorphological features and fi sh assemblages in the design of marsh restoration projects.We studied temporal variations in,and the effects of creek geomorphological features on,the estuarine tidal creek fi sh community.Using modifi ed channel nets,we sampled fi sh monthly from March 2007 to February 2008 from seven tidal creeks along an intertidal channel system in Chongming Dongtan National Nature Reserve.Fourteen creek geomorphological variables were measured or derived to characterize intertidal creek geomorphological features.The Gobiidae,with 10 species,was the most speciesrich family.The most abundant fi sh species were Liza affi nis,Chelon haematocheilus,and Lateolabrax maculatus.The fi sh community was dominated by juvenile marine transients,which comprised about 80% of the total catch.The highest abundance of fi sh occurred in June and July,and the highest biomass occurred in December.Canonical redundancy analyses demonstrated that depth,steepness,cross-sectional area,and volume signifi cantly affected the fi sh species assemblage.L.affi nis favored small creeks with high elevations.Synechogobius ommaturus,Acanthogobius luridus,and Carassius auratus preferred deep,steep creeks with a large cross-sectional area and volume.These fi ndings indicate that the geomorphological features of tidal creeks should be considered in the conservation and sustainable management of fi sh species and in the restoration of salt marshes.

Analysis of the Geomorphology and Environmental Geological Problems of Huzhou on the Yangtze River Delta

Geomorphically, Huzhou, which is on the Yangtze River delta is characterized mainly by plains, with small hills. This paper presents a detailed analysis of the environmental geological hazards both natural and those incurred by human activities in different morphologic units. The authors point out that most of the regional environmental geological problems in the natural geologic-morphologic conditions, such as crustal stability, foundation of soft soil, soil waterlogging and soil erosion, have insignificant effects to the society, or related countermeasures of prevention and control have been adopted. But environmental geological problems incurred by human being's economic activities become more and more severe, for example, water and soil pollution and land subsidence in plain areas resulting from overexploitation of groundwater, and landslides, karst collapses and water and soil loss etc. caused by quarrying in hilly areas.

The application of geographic information technology to coastal geomorphology

With the development of modern oceanic observation technologies, coastal survey data have been experiencing a substantial growth. The integration management of the data from different disciplines, different sources and different formats has become a major research field in coastal geomorphology by using Geographic Information System （GIS）. This paper puts forward a new methodology framework of GIS techniques in coastal ocean geomorphology, including data acquisition, process, analysis, and representation. It focuses on some major GIS techniques to study the land-ocean interaction mechanism, such as spatial analysis, submarine topography model and three-dimension （3D） visualization, and apply its result to coastal urban planning, harbor site selection and geomorphology environment about coral reef and islands on the continental shelf. The case studies cover the whole coastal ocean to serve the social community, economical development and diplomatic rights for decision-making all round in the coastal zone. The research shows clearly that the application of coastal multi-source geospatial platform has changed the traditional coastal geomorphology science dramatically from its research scope, fields and methods, however, as made clear in this paper, extracting accurate information from remote sensing data and GIS databases for coastal geomorphological applications is a nontrivial challenge that requires the combined knowledge and skills of information scientists and geomorphologists.

Geomorphology Processes of Channel Planform Migration on Meandering Rivers

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 the

Holocene Biostratigraphic Zones Corresponding Litho-Chronostratigraphy, Environment of Deposition and Successive Changes in the Geomorphology of Bengal Basin, India during Last 10,000 Years

Biostratigraphic Zones Bb. Bz. H. I-V distinguished in C14 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.

CHARACTERISTICS OF PERIGLACIAL GEOMORPHOLOGY IN THE SOURCE AREA OF THE HUANGHE RIVER

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.

DISTRIBUTION OF PERIGLACIAL GEOMORPHOLOGY AND THE RELATIONSHIP BETWEEN PERIGLACIAL GEOMORPHOLOGY AND GLACIATED HISTORY ON FILDES PENINSULA, KING GEORGE ISLAND,ANTARCTICA

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.

AN APPROACH TO THEORY AND METHODS OF URBAN GEOMORPHOLOGY

Urban geomorphology is a new subject,and its theory and practice need approaching and substantiating.This paper deals with the utilization and transformation of landforms in the process urbanization,and the evolvement and unique character of an urban geomorphological environment.Taking an evaluation about catastroability of the urban geomorphological environment in Chongqing as an example,the author introduces a researching method in the urban geomorphology,including selection and quantification of evaluation parameters,a grid method used in mapping and a mathematical synthesizing method to evaluate on a fixed position.

Digital regionalization of geomorphology in Xinjiang

This paper presents a method of geomorphologic regionalization for Xinjiang, with the use of Srtm-DEM (resolution 90 m) and TM images for 1990 (resolution 30 m). After interpretation and classification of geomorphologic types, the present research focuses on the qualitative and quantitative distribution of different geomorphologic types based on geographical grid analysis. Then, by using system clustering analysis method, geomorphologic types are grouped into divisions. The resulting geomorphologic regionalization hierarchy of Xinjiang includes three levels, i.e., macro-landform divisions, medium-landform divisions, and micro-landform divisions, containing 6, 23 and 200 types, respectively. This method makes it possible to digitally delimit geomorphologic regions. Comparison and verification show that the spatial precision of the boundaries of geomorphologic subareas in Xinjiang is very high.

Detailed seafloor geomorphology of the western region of the North Yellow Sea,China:The result of Holocene erosional and depositional processes sculpting the offshore continental shelf

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.

Correlation between seismicity and geomorphology in Dingxi Basin,Gansu Province,China

A M6.6 earthquake occurred on July 22, 2013 at Dingxi Basin in Gansu Province within the tectonially expanding northeastern margin of the Qinghai-Tibet Plateau. We analyzed the geomorphological features of the Dingxi Basin by using remote sensing technology and compared them with local seismic activity. We found that most of the river basins are at the robust stage of development and that the major local rivers and the development of some basins boundaries are controlled by the seismic faults. Among four zones identified to have significant tectonic activities, the northwestly-oriented one located in the south has the highest seismic activity, and it is where the M6.6 earthquake occurrred.