scholarly journals Recent glacier variations in Mongolia

2007 ◽  
Vol 46 ◽  
pp. 185-188 ◽  
Author(s):  
Kadota Tsutomu ◽  
Davaa Gombo

AbstractGlacier monitoring enables us to detect influences of global warming in high mountain regions. To initiate the establishment of a glacier-monitoring network in northern Eurasia, we studied recent glacier variations in Mongolia using topographical maps, aerial photographs and satellite images (Corona and Landsat). Glaciers in Mongolia exist in the Altai mountains which span approximately 1400 km within Russia, China and Mongolia. Four regions were selected to form the study area: Tavan Bogd region, Turgen massif, Kharkhiraa massif and Tsambagarav massif. During the period from the 1940s to 2000 or from 1968 to 2000, the glaciers in these regions lost 10.2%, 19.3%, 28.0% and 28.8% of their area respectively. The glaciers in the Tavan Bogd, Kharkhiraa and Turgen regions were found to have been almost stationary since 1987/88, while those in Tsambagarav massif showed no significant change in area since 1963. Shrinkage of the glaciers occurred between 1945/68 and 1987/88 in the former regions and between 1948 and 1963 in the latter. Mongolian glaciers seem to behave differently from other glaciers which have been experiencing steady shrinkage recently.

1996 ◽  
pp. 64-67 ◽  
Author(s):  
Nguen Nghia Thin ◽  
Nguen Ba Thu ◽  
Tran Van Thuy

The tropical seasonal rainy evergreen broad-leaved forest vegetation of the Cucphoung National Park has been classified and the distribution of plant communities has been shown on the map using the relations of vegetation to geology, geomorphology and pedology. The method of vegetation mapping includes: 1) the identifying of vegetation types in the remote-sensed materials (aerial photographs and satellite images); 2) field work to compile the interpretation keys and to characterize all the communities of a study area; 3) compilation of the final vegetation map using the combined information. In the classification presented a number of different level vegetation units have been identified: formation classes (3), formation sub-classes (3), formation groups (3), formations (4), subformations (10) and communities (19). Communities have been taken as mapping units. So in the vegetation map of the National Park 19 vegetation categories has been shown altogether, among them 13 are natural primary communities, and 6 are the secondary, anthropogenic ones. The secondary succession goes through 3 main stages: grassland herbaceous xerophytic vegetation, xerophytic scrub, dense forest.


Author(s):  
Homayoun Khoshravan ◽  
Homayoun Khoshravan

The main goal of the research is to analyze the global warming impact on Urmia lake vulnerabiliy and hazard. By the study of topographic maps, satellite images and field research, the various types of coasts were identified: mud flats, salt marshes, sandy or cliffed coasts, and islands. Moreover the interpretation of seismic profiles, has led to recognize so important morphological features in the lake bed, such as: erosive channels, colos, mud volcanoes, the raised sandy masses and under water mounts. The main results illustrate the variable morphological behavior of Urmia Lake in different parts of the lake.


Planet ◽  
2012 ◽  
Vol 26 (1) ◽  
pp. 31-35
Author(s):  
Dennis Edler ◽  
Nils Lammert-Siepmann ◽  
Carsten Jürgens

Diversity ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 22
Author(s):  
George Kazakis ◽  
Dany Ghosn ◽  
Ilektra Remoundou ◽  
Panagiotis Nyktas ◽  
Michael A. Talias ◽  
...  

High mountain zones in the Mediterranean area are considered more vulnerable in comparison to lower altitudes zones. Lefka Ori massif, a global biodiversity hotspot on the island of Crete is part of the Global Observation Research Initiative in Alpine Environments (GLORIA) monitoring network. The paper examines species and vegetation changes with respect to climate and altitude over a seven-year period (2001–2008) at a range of spatial scales (10 m Summit Area Section-SAS, 5 m SAS, 1 m2) using the GLORIA protocol in a re-survey of four mountain summits (1664 m–2339 m). The absolute species loss between 2001–2008 was 4, among which were 2 endemics. At the scale of individual summits, the highest changes were recorded at the lower summits with absolute species loss 4 in both cases. Paired t-tests for the total species richness at 1 m2 between 2001–2008, showed no significant differences. No significant differences were found at the individual summit level neither at the 5 m SAS or the 10 m SAS. Time series analysis reveals that soil mean annual temperature is increasing at all summits. Linear regressions with the climatic variables show a positive effect on species richness at the 5 m and 10 m SAS as well as species changes at the 5 m SAS. In particular, June mean temperature has the highest predictive power for species changes at the 5 m SAS. Recorded changes in species richness point more towards fluctuations within a plant community’s normal range, although there seem to be more significant diversity changes in higher summits related to aspects. Our work provides additional evidence to assess the effects of climate change on plant diversity in Mediterranean mountains and particularly those of islands which remain understudied.


1892 ◽  
Vol 9 (2) ◽  
pp. 54-64
Author(s):  
Henry H. Howorth

In some papers which you have done me the favour to print in the GEOLOGICAL MAGAZINE, I have endeavoured to apply a new touchstone to test the age of high mountain chains and of land of high elevation, namely, the presence or absence of distinct and prominent traces of former glaciation, and I have argued that where such traces are not forthcoming in a very unmistakable manner, we are justified in concluding that these highlands have been elevated since the so-called Glacial Period. I have endeavoured to apply the touchstone in question to the Ural and Altai Mountains, to the Thian Shan and Himalaya ranges in Asia, and to the great Cordillera which binds together the two continents forming the New World. I wish to make my survey more complete by an examination of an interesting area comprising Eastern Europe and South Western Asia.


Author(s):  
С.А. Мамаев ◽  
А.Р. Юсупов ◽  
А.С. Мамаев ◽  
З.А. Юсупов

В данной статье даны особенности геологического строения района газопроявления «Цущар» в Кулинском районе на отложениях среднеюрского возраста, предлагается геолого-структурная схема возможного формирования залежи нефти и газа. Незначительные проявления газоносности, связанные обычно с минеральными источниками и подчиненные мощной толще юрских сланцев, развитых на значительных площадях нагорного Дагестана, начали обращать на себя внимание с 1931 г., в связи с поисками месторождений легких редких газов. Анализы газов показывают повышенное содержание легких редких газов в целом ряде месторождений нагорного Дагестана. Кроме группы месторождений Южного Дагестана известен пока только один выход горючего газа в Центральном Дагестане – Кулинском районе. На него указывает в своем рукописном отчете Дагестанскому Совнархозу геолог Н. М. Леднев. Этот выход подчинен юрским сланцам, связан с нарушениями неотектонического характера, образованными в результате сейсмической активизации региона. Цель исследования. Целью наших исследований является обоснование перспектив газоносности Горного Дагестана. На изучаемой территории отмечается наличие неправильных куполовидных складок с неожиданными направлениями их осей, пересекающими основное направление складчатости, частичными местными уклонениями в залегании пластов. Методы исследования. Основными методами исследования при изучении перспектив газоносности Горного Дагестана являлись геолого-структурный, стратиграфический, морфологический, тектонический и дешифрирование аэрофотоснимков. Результаты исследования. По сравнению с Предгорным Дагестаном и Прикумским районом, Горный Дагестан был подвержен более интенсивным геотектоническим движениям, неоднократно подвергался складчатости, испытал инверсию, со значительно большей амплитудой, что привело к усиленной денудации, развитию трещиноватости и разрывов, метаморфизму пород и органических образований. Все это отрицательно влияло на сохранение нефти и газа. Можно предполагать, что многие залежи, сформировавшиеся при прохождении продуцирующими толщами главной фазы нефтеобразования, были разрушены в периоды активизации тектонической деятельности на рубеже юры и мела, мела и палеогена. В дальнейшем шла генерация, преимущественно, газообразных углеводородов, которые при особенно благоприятных условиях могли сохраниться до настоящего времени. По результатам исследований можно утверждать, что газовое проявление Цущар могло проявиться в 1622, 1652 гг. в результате сильных землетрясений, эпицентр которых располагался в пределахисследуемого района This article describes the features of the geological structure of the Tsushar gas show area in the Kulinsky region on the Middle Jurassic deposits, and proposes a geological-structural diagram of the possible formation of oil and gas deposits. Minor manifestations of gas content, usually associated with mineral springs and subordinate to a thick stratum of Jurassic shales, developed over large areas of highland Dagestan, began to attract attention from 1931, in connection with the search for deposits of light rare gases. Gas analyzes show an increased content of light rare gases in a number of fields in highland Dagestan. In addition to the group of fields in Southern Dagestan, only one outlet of combustible gas in Central Dagestan is known – the Kulinsky region. It is pointed out in his handwritten report to the Dagestan Economic Council by the geologist N. M. Lednev. This outlet is subordinate to the Jurassic shale and is associated with neotectonic disturbances formed as a result of seismic activation of the region. Aim. The purpose of our research is to substantiate the prospects for gas content in Gorny Dagestan. In the study area, there are irregular dome-shaped folds with unexpected directions of their axes crossing the main direction of folding, partial local deviations in bedding. Methods. The main research methods in the study of the prospects for the gas content of Mountainous Dagestan were geological-structural, stratigraphic, morphological, tectonic and additional aerial photographs. Research results. Compared to Piedmont Dagestan and Prikumskiy region, Gorny Dagestan was subject to more intense geotectonic movements, repeatedly underwent folding, experienced inversion, with a much higher amplitude, which led to increased denudation, the development of fracturing and fractures, metamorphism of rocks and organic formations. All of this negatively affected the conservation of oil and gas. It can be assumed that many deposits, formed during the passage of the producing strata of the main phase of oil formation, were destroyed during periods of intensified tectonic activity at the boundary between the Jurassic and Cretaceous, Cretaceous and Paleogene. In the future, there was the generation of mainly gaseous hydrocarbons, which, under especially favorable conditions, could persist to the present day. According to the research results, it can be argued that the gas manifestation of Tsushar could have manifested itself in 1622, 1652. as a result of strong earthquakes, the epicenter, which was located within the study area


2020 ◽  
pp. 034
Author(s):  
Ludovic Ravanel ◽  
Florence Magnin ◽  
Xavi Gallach ◽  
Philip Deline

Avec le réchauffement du climat, la dégradation du permafrost est à l'origine d'une intensification des processus géomorphologiques sur les versants de haute montagne. Dans les parois rocheuses, les écroulements se multiplient et leur volume augmente, posant des problèmes de sécurité non seulement à haute altitude (infrastructures, alpinistes), mais également pour les fonds de vallée. Cet article présente les travaux récemment menés dans le massif du Mont-Blanc sur la relation entre climat et écroulements à différentes échelles de temps, les effets des épisodes caniculaires et la répartition et l'évolution du permafrost de paroi. Under global warming, permafrost degradation tends to intensify geomorphological processes on high mountain slopes. In the perennially frozen rock walls, the number and volume of rockfalls is increasing, causing safety problems not only at high altitude (infrastructure, mountaineers) but also for the valleys. This article summarizes recent work carried out in the Mont-Blanc massif on the climate-rockfall relationship at different time scales, the effects of heat waves, and the distribution/evolution of rock wall permafrost.


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