Geomorphological evidence inconvenient for the antecedent rivers of the Arun and Tista across the Himalayan range

The Arun and Tista Rivers,which flow across the Himalayas,are commonly known as antecedent valleys that overcame the rapid uplift of the Higher Himalayan ranges.To clarify whether the idea of antecedent rivers is acceptable,we investigated the geomorphology of the Himalayas between eastern Nepal and Bhutan Himalayas.The southern part of Tibetan Plateau,extending across the Himalayas as tectonically un-deformed glaciated terrain named as'Tibetan Corridor,'does not suggest the regional uplift of the Higher Himalayas.The 8,000-m class mountains of Everest,Makalu,and Kanchenjunga are isolated residual peaks on the glaciated terrain composed of mountain peaks of 4,000–6,000 m high.The Tibetan glaciers commonly beheaded by Himalayan glaciers along the great watershed of the Himalayas suggest the expansion of Himalayan river drainage by glaciation.For the narrow upstream regions of the Arun and Tista Rivers with less precipitation behind the range,it is hard to collect enough water for the power of down-cutting their channels against the uplifting Himalayas.The fission track ages of the Higher Himalayan Crystalline Nappe suggest that the Himalayas attained their present altitude by 11–10 Ma,and the Arun and Tista Rivers formed deep gorges across the Himalayas by headward erosion.

A process-oriented approach for identifying potential landslides considering time-dependent behaviors beyond geomorphological features

Geomorphological features are commonly used to identify potential landslides.Nevertheless,overemphasis on these features could lead to misjudgment.This research proposes a process-oriented approach for potential landslide identification that considers time-dependent behaviors.The method integrates comprehensive remote sensing and geological analysis to qualitatively assess slope stability,and employs numerical analysis to quantitatively calculate aging stability.Specifically,a time-dependent stability calculation method for anticlinal slopes is developed and implemented in discrete element software,incorporating time-dependent mechanical and strength reduction calculations.By considering the time-dependent evolution of slopes,this method highlights the importance of both geomorphological features and time-dependent behaviors in landslide identification.This method has been applied to the Jiarishan slope(JRS)on the Qinghai-Tibet Plateau as a case study.The results show that the JRS,despite having landslide geomorphology,is a stable slope,highlighting the risk of misjudgment when relying solely on geomorphological features.This work provides insights into the geomorphological characterization and evolution history of the JRS and offers valuable guidance for studying slopes with similar landslide geomorphology.Furthermore,the process-oriented method incorporating timedependent evolution provides a means to evaluate potential landslides,reducing misjudgment due to excessive reliance on geomorphological features.

Geochemical-geomorphological Evidence for the Provenance of Aeolian Sands and Sedimentary Environments in the Hunshandake Sandy Land, Eastern Inner Mongolia, China

Identifying the provenance of aeolian sediments in the Hunshandake Sandy Land is of great importance for understanding the formation of the dune fields in the mid-latitudes and for deciphering information about desert＇s responses to global change. By determining the major and trace elements concentrations of aeolian sands in three grain size fractions from the central and western parts of the Hunshandake Sandy Land, we systematically study the provenance and the depositional history of aeolian sands in this desert environment. Our results show that aeolian sands from the Hunshandake Sandy Land are enriched in SiO2 and are depleted in many other elements compared to those of the Upper Continent Crust （UCC）. Variations of the immobile elements ratios like Zr/Hf, La/Yb, Th/Nb, La/Nb, LaN/YbN, GdN/YbN are relatively large in the coarse and medium fractions but minor in the fine fractions. Eu anomalies are quite different in the coarse fractions, but mostly positive in the medium fractions and all negative in the fine fractions. Decreasing tendency of Zr concentrations from the west to the east in the Hunshandake Sandy Land is evident in the coarse sands but rather weak in the fine grain size fractions. Our geochemical data indicate that the sources for the coarse and medium fractions of aeolian sands are diverse, influenced by local geology and geomorphology, while the fine sand fractions are more homogenous due to intensive mixture mainly by aeolian processes. Various ratios of immobile elements suggest that these sands should be sourced primarily from the surrounding mountains by fluvial/alluvial processes rather than from any remote territories. Aeolian sands with Ce negative anomalies are widely distributed in the Hunshandake Sandy Land, indicating that aquatic environments have occurred extensively prior to the occurrence of the dune field.

A geomorphological response of beaches to Typhoon Meari in the eastern Shandong Peninsula in China

Eight representative beach profiles on the eastern coast of the Shandong Peninsula are observed and measured in 2011 and 2012 to determine the coastal processes under the lower tropical wind speed condition and the beach response to and recovery from the tropical storm Meari in a rare typhoon region. The results show that it is the enhancement and directional change of cross-shore and longshore sediment transports caused by Meari that leads to the beach morphological changes, and most of the sediment transports occur during the pre-Meari landing phase. The erosional scarp formation and the berm or beach face erosion are the main geomorphological responses of the beaches to the storm. The storm characteristics are more important than the beach shapes in the storm response process of the beaches on Shandong Peninsula. The typhoon is a fortuitous strong dynamic event, and the effect on the dissipative beach is more obvious than it is on the reflective beach in the study region. Furthermore, the beach trend is the main factor that controlls the storm effect intensity, and it is also closely related to the recovery of the beach profiles.

Precision estimation and geomorphological analysis based on the DEM generated by InSAR: Taking Damxung-Yangbajain area as an example

Digital elevation model （DEM） can be generated by interferometric synthetic aperture radar （InSAR）. In this paper, the interferometric processing and analyses are carried out for Damxung-Yangbajain area in Tibet, using a pair of Europe remote-sensing satellite （ERS）-1/2 tandem SAR images acquired on 6 and 7 April 1996. A portion of the In- SAR-derived DEM is selected and compared with the 1：50 000 DEM to determine the precision of the InSAR-derived DEM. The comparison indicates that the root mean squared errors （RMSE）, which are used to evaluate error, are about 35, 60, 10, and 15 m in the studied area, mountainous area, basin area and near-fault area, respectively, suggesting that obvious errors are mainly in mountainous area. Besides, the limitation of InSAR technology to generate DEM is analyzed. Our investigation shows that InSAR is an effective tool in geodesy and an important complement to field surveying in some dangerous areas.

Understanding of Earthquake Damage Pattern through Geomorphological Approach: A Case Study of 2006 Earthquake in Bantul, Yogyakarta, Indonesia

The last major earthquake in Bantul causing severe damage occurred on May 27th, 2006. The damages in the flat area of Bantul had a certain pattern. The damages pattern controlled the subsurface characteristic below the flat area. Understanding earthquake damage pattern through geo-morphological approach is important for earthquake hazard analysis. The techniques of remote sensing and Geographical Information Systems were applied to analyze earthquake damage pattern and geomorphological characteristics. Gravity analysis was used to identify the subsurface structure and the basement depth while geoelectric analysis was used to identify sediment depth. Moreover, spatial correlation analysis was used to identify the relationship between the earthquake damage, geomorphological characteristics, and subsurface characteristics. The results show that fluvial, marine, and aeolian landforms have low rock density value based on gravity analysis. These indicate that they were composed by thick unconsolidated material of quaternary alluvium. While denudational, structural, and solutional landforms composed by material of tertiary rocks have high rock density value. The severe damage occurred in the area that has a lower value of local gravity and deeper basement. In contrast, the slight damage occurred in the area that has higher values of local gravity and shallower basement. Moreover, the severe damage occurred in areas of thicker sediment that consist of unconsolidated material. Consequently, the area of unconsolidated material that has deeper basement and thicker sediment is prone to earthquake. They were located on fluvial, marine, and aeolian landforms.

Dasht-e Lut in Iran, the Most Complete Collection of Beautiful Geomorphological Phenomena of Desert

Given special tectonic and climatic conditions, Iran has the most diverse land-forms and beautiful geological phenomena, which could attract many scientific, adventurous tourists and geological researchers. The present study aims at studying and introducing wonderful geomorphological attractions and numerous geotourism potentials of very hot paradise of the earth, e.g. Dasht-e Lut of Iran, a desert which contains a collection of exclusive desert relieves and geological and geomorphological records of the world. Such unique perspectives as the biggest Nebkhas of the world, the largest Yardangs or Kaluts of the world, the hottest point of the earth, as well as rare species of desert structures such as salt marshes and salt polygons, Gandom Beryan Hill, massive sand dunes, Barchans, clay zones in pretty shapes, saline river , etc., present a vast and diverse extension of geographical beauties and phenomena of the desert. Using library studies, interpretation of satellite images and field studies, this study has been conducted. The results of the studies show that Lut Desert has considerable capability for carrying out complementary studies as well as effect on economic development process in national and international levels. In addition, geotourism development obstacles in Lut Desert are identified, and such solutions as development of ways for access to attractions, erection of geotourism development centers, advertisement and introduction of the desert's attractions, dispatch of guides with tourists, promotion of the region security, extension of accommodations and… for better use of the potentials of the desert, are provided. Furthermore, towards developing the region geotourism, some other fun and exciting activities such as sand skiing, racings and desert rallies, endurance cycling, sun bath, star observation, camel riding and so on, are suggested. Obviously, having various desert attractions and multiple geotourism potentials, Dasht-e Lut has the capability of being considered among global geoparks of UNESCO.

Topographic and geomorphological features and tectogenesis of the southern section of the Kyushu-Palau Ridge(KPR)and its adjacent areas

The Philippine Sea is the largest marginal sea in the Western Pacific Ocean and is divided into two parts by the Kyushu-Palau Ridge(KPR).The western part is the West Philippine Basin,and the eastern part consists of the Shikoku and Parece Vela basins.Based on surveyed data of massive high-resolution multibeam bathymetric data and sub-bottom profiles data collected from the southern section of the KPR from 2018 to 2021,this paper analyzes the topographic and geomorphological features,shallow sedimentary features,and tectonic genesis of the southern section of the KPR,obtaining the following conclusions.The southern section of the KPR has complex and rugged topography,with positive and negative topography alternatingly distributed and a maximum height difference of 4086 m.The slope of seamounts in this section generally exceeds 10°and is up to a maximum of 59°.All these contribute noticeably discontinuous topography.There are primarily nine geomorphological types in the southern section of the KPR,including seamounts,ridges,and intermontane valleys,etc.Among them,seven independent seamount groups are divided by five large troughs,forming an overall geomorphological pattern of seven abyssal seamount groups and five troughs.This reflects the geomorphological features of a deep oceanic ridge.Intramontane basins and intermontane valleys in the southern section of the KPR are covered by evenly thick sediments.In contrast,sediments in ridges and seamounts in this section are thin or even missing,with slumps developing locally.Therefore,the sediments are discontinuous and unevenly developed.The KPR formed under the control of tectonism such as volcanic activities and plate movements.In addition,exogenic forces such as underflow scouring and sedimentation also play a certain role in shaping seafloor landforms in the KPR.

Geomorphological mapping for the valorization of the alpine environment. A methodological proposal tested in the Loana Valley(Sesia Val Grande Geopark, Western Italian Alps)

Geomorphological mapping plays a key role in landscape representation: it is the starting point for many applications and for the realization of thematic maps, such as hazard and risk maps, geoheritage and geotourism maps. Traditional geomorphological maps are useful for scientific purposes but they need to be simplified for different aims as management and education. In tourism valorization, mapping of geomorphological resources(i.e., geosites, and geomorphosites), and of geomorphic evidences of past hazardous geomorphological events, is important for increasing knowledge about landscape evolution and active processes, potentially involving geomorphosites and hiking trails. Active geomorphosites, as those widespread in mountain regions, testify the high dynamicity of geomorphic processes and their link with climatic conditions. In the present paper, we propose a method to produce and to update cartographic supports(Geomorphological Boxes)realized starting from a traditional geomorphological survey and mapping. The Geomorphological Boxes are geomorphological representation of single, composed or complex landforms drawn on satellite images, using the official Italian geomorphological legend(ISPRA symbols). Such cartographic representation is also addressed to the analysis(identification, evaluation and selection) of Potential Geomorphosites and Geotrails. The method has been tested in the upper portion of the Loana Valley(Western Italian Alps), located within the borders of the Sesia Val Grande Geopark, recognized by UNESCO in 2013. The area has a good potential for geotourism and for educational purposes. We identified 15 Potential Geomorphosites located along 2 Geotrails; they were ranked according to specific attributes also in relation with a Reference Geomorphosite located in the Loana hydrographic basin and inserted in official national and regional databases of geosites(ISPRA; Regione Piemonte). Finally, the ranking of Potential Geomorphosites allowed to select the most valuable ones for valorization or geoconservation purposes. In thisframework, examples of Geomorphological Boxes are proposed as supports to geo-risk education practices.

Geomorphological Structures of Jashak Salt Dome

Salt domes have always been attractive because of special attribute due to chemical and physical properties of salt.Jashak salt dome is one of Hormoz series domes,which is appeared in the southeast part of Zagros Mountains and has a great potential for being a geotourism zone in that region as a result of amazing geomorphological structures which made it

Geomorphological effects of plate movement during Quaternary in China' s tropics

The eastern and western fronts of plate movement in Taiwan Island and Tibetan Plateau respectively are the two major sources of tectonic force for the morphogensis during Quaternary in China's tropics. Seven examples of geomorphological effects of plate movement are enumerated to discuss the differentiation of tectonic landforms in space and time during Quaternary. The tectonic movement tends to be more active since middle Pleistocene. Some phenomena such as the arc-shape mountain systems, volcanism and crustal deformation imply that the juncture zone of eastern and western tectonic forces is located at about 110 o E.

The Role of Geomorphological Studies in Development of Coastal Cities

Natural and unnatural factors would develop coastal areas. Coastal area is a region that takes materials and substances from land surface then transfers them to sea and the remained and cumulative substances of them would deform under the effect of erosion forming the coasts appearance. Geomorphology is the study of land and process leading to formation and development of it. Coastal geomorphology emphasizes on formation of coastal areas and some processes such as waves, tides, and stream leading to formation of boulders, coral reefs and sandy beaches. The base of this study is on analytical comparison method of affecting variables on periodic change of shoreline in river estuary in which statistical and image data were analyzed. This research was conducted within three time intervals including 1955-1988, 2000-2006, and 2006-2013. Wind hourly data of Meteorological Organization of Iran was used to study waves. The fluctuation in level of Caspian Sea is an important factor in changes in shoreline of Caspian Sea besides the role of river and providing sediment output into the sea. The most area was belonged to 1995 along with declining trend of seal level of Caspian Sea and the lowest area was belonged to 2000 with a rising trend of sea level within three studied intervals. This point indicates the effect of seal level factor on change in area of studied intervals.

Geomorphological Evolution and Fluvial System Development during the Holocene: The Case of Vouraikos River Evolution in Kalavrita Plain, Northern Peloponnese, Greece

Fluvial geomorphology is affected by physical conditions which allow its adaptation due to high dynamics and environmental influences. Fluvial morphological changes are manifested as a result of tendency of the river system to maintain its physical balance. Our study area is the upper and middle flow part of Vouraikos river and surrounding area, near the NW border of Chelmos mountain in Northern Peloponnese, near the town of Kalavrita, at an altitude of 800 m. The area is part of the Skepasto basin, constituting of a graben with a general E-W direction that was developed NW of Kalavrita. The area comprises of Mesozoic, Upper Triassic-Jurassic limestone and dolomite of the Tripolitsa unit External Hellenides and Plio-Pleistocene fluvio-lacustrine sequences, while its tectonic structure is characterized mainly by normal faults. The geomorphological landscape is characterized by alluvial deposits and important geomorphological features including fluvial terraces, alluvial fans, fluvial scarps and their main rill washes. This area has been a place of major human activity as shown by the findings of many uncovered artifacts and a settlement. Through a paleographic reconstruction, detailed field investigations, in combination with the compilation of geomorphological maps using GIS software and archaeological evidence found in the area, we attempted to reconstruct the fluvial evolution of Vouraikos river and identify the major geomorphological factors that led to, and influenced it. Finally, the link between cultural activities and sedimentary processes is also studied. The recorded environmental variations had a great impact on the geomorphological shaping and instability of Kalavrita plain and Vouraikos river and are being reflected on the buried settlement. Sediment fluxes were high enough to form strath terraces, while local tectonics aided in the strath and fill terrace creation. Smaller and younger strath terraces, formed during increased sediment supply periods, when the valley was at a higher level.

Geomorphological processes and landforms of glacier forelands in the upper Aktru River basin(Gornyi Altai), Russia: evidence for rapid recent retreat and paraglacial adjustment

The glaciers in the Aktru River basin of Gornyi Altai, Russia currently represent some of the fastest receding glaciers in the world. Formation of the morainic complexes closest to the contemporary glaciers in the Aktru River basin took place during the 17^th-18^th centuries with recession commencing at the end of the 18 th century. Coupled with this glacial retreat, earth surface processes and vegetation succession are responding to shape the glacier forelands. This article presents the first geomorphological maps for the upper reaches of the Aktru River basin and focuses on the geomorphological landforms that occur in the rapidly changing glacier forelands. Geomorphological mapping is difficult in steep mountainous regions and, thus, mapping was completed using satellite imagery, field mapping and observations coupled with highresolution aerial photography obtained from Unmanned Aerial Vehicles(UAVs). Critical steps of the procedure used to process UAV imagery and difficulties encountered in this mountainous terrain are noted. The acquired spatial data enable the mapping and classification of small-scale transient geomorphological features such as talus, glacial and glaciofluvial landforms. Their dynamics provide insights into supraglacial and subglacial processes of the glaciers of the Aktru River basin and subsequent paraglacial adjustment. The presented highresolution spatial data, which can also be obtained at high temporal resolutions in the future, can act as a reference frame for geomorphologists and ecologists studying the temporal evolution of glacier forelands of the Aktru River basin during paraglacial adjustment and subsequent colonisation and stabilisation by biota.

Geomorphological Zoning of Racha Region for Geopark Planning

Geomorphological zoning and complex relief research were conducted in the Racha region, which is located In the Caucasus, in the northwestern part of Georgia, south of the Greater Caucasus, in the central part of which there are Precambrian and Paleozoic crystalline substrates (gneisses, migmatites, crystalline shales) and granitoid intrusions of different ages. The Caucasus axis and higher massifs are built of granitoid, gneiss, and metamorphic shales. The oldest rocks (600 million years old) are found at the highest points and the age of the rocks decreases in the vicinity of the hypsometry steps (70 - 30 million rocks). The geological structure of the region has made a significant contribution to the formation of relief landscapes. Karst, erosion-denudation, volcanic, periglacial relief, and various interesting forms are formed here: caves, valleys, canyons, glacial and rocky lakes, waterfalls, deep valleys, mineral waters, and more. The peculiarity of the relief also influenced the mining geological history (5000 AD) and the creation of ancient settlements. Here, still in ancient Racha, at the head of the main river, Rioni, ancient settlements were formed due to iron, gold, and copper metal, which is confirmed by archeological monuments.

Structural traits of woody plants and geomorphological conditions to the vegetation recovery at Ksudach caldera(Southern Kamchatka) since the explosive eruption in 1907

This study considers the restoration of the plant cover destroyed by a catastrophic volcano eruption in the south of Kamchatka Peninsula(the Ksudach caldera,Shtyubel cone),with a particular attention to the role of woody plants.It aims to qualitatively estimate(at a qualitative level)the rate of the primary succession development depending on the microrelief and the modern relief-forming processes.The vegetation recovery in the caldera after the Shtyubel cone eruption 109 years ago proceeds slowly and irregularly.It proceeds most slowly on a thick tephra mantle continuously disturbed by water and wind erosion,lahars,debris flows,landslides,etc.Such conditions are most typical of the western part of the caldera dominated by pumice fields with occasional patches of pioneer herbs and dwarf shrubs.Alpine tundra communities with gradually expanding patches of shrub alder develop in the southern,eastern and northeastern parts of the Ksudach caldera.Since 1997 the area of the shrub alder communities has increased by 1.9 times,while the alpine tundra–by 1.3 times only.The woody plants(dwarf shrubs and prostrate shrubs)are of particular importance in the process of the vegetation recovery on pumice fields.We suggest that the bark thickness of woody plants is an integrated indicator,which may serve for estimating the state of ecosystem in the course of the primary succession development on juvenile sediments.The extremely inhospitable environments cause changes in physiological processes in the plant body and in its bark in particular.The results show that woody plants have a"thin"bark and develop some structural-functional arrangements for keeping bark tissues at their minimum.So,the woody plant structure and the rate of changes in plant communities are under control of the geomorphic conditions and primarily–of physicochemical features of the pyroclastic cover.

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.

Gravity tectonics controls on reservoir-scale sandbodies:Insights from 3D seismic geomorphology of the canyons buried in the upper slope of the Eastern Niger delta basin

High-resolution 3D seismic data analysis was integrated with a calibrated well and biostratigraphy data to present the first overview of a buried Pleistocene canyon system on the upper slope of the eastern Niger Delta,the Galabor Canyon.Attribute maps of specific horizons allow documenting the changing morphologies and infill lithologies of two main branches of the canyon through two stages of activity separated by a reference horizon dated at 0.99 Ma based on well calibration.At the upper slope,growth faults dissect the canyon heads,the catchment of which encroaches a network of valleys incised on the outer shelf.The canyon fill is composed of muddy channels and mass-transport deposits,largely derived from the collapse of canyon walls and sand-rich bodies forming a tract sourced by shelf-edge deltas at the outlet of the incised valleys.High-density turbiditic processes likely control the distribution of sand bodies along the canyon,ranging from tributary fans on the upper slope to 6 km-wide meander belts on the middle slope.The sandy deposits accumulate in minibasins formed along the canyon path,downstream of the subsiding hanging wall of the growth faults and upstream of shale ridges that damp the flow in the canyon.These results show that canyons can be major targets for sand reservoir exploration on the upper slope of large muddy deltas.

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.

试评地表形态研究的趋势——以Geomorphology为例

地貌学杂志(Geomorphology)1987年以来刊印的1479篇科技论文,反映了地表形态研究面临着复杂的形势。选取10个主题对这些论文进行不重复的类型划分,初步反映出地表形态研究的概况,即地表形态的空间结构关系、地表过程及环境灾害影响等主题明显占有较高的比例,大多数研究内容注重与实际案例的紧密结合,地貌学研究范围的基本格局变化不大。但是近些年来地貌学重视新技术的应用,因而在研究方法上已经发生了一些变化,主要表现在地表形态的信息探测、测试技术所占的比例急剧升高,传统方法则呈现相对下降的趋势。