New perspectives of geomorphological risk conception founded in the early 1990th are shown. Active faults are considered to be a factor of risk. Some of tectonic geomorphology postulates were adjusted to the conception of geomorphological risk. Author suggests to consider landforms of faults' zones as a new type of relief, to distinguish geomorphological risk from geomorphological danger, to divide the latter into hidden and obvious, localized/sudden and dispersed/continuous, dangerous for people, technology or environment. Aims and purposes of geomorphological risk investigations are determined.
Systematic is considered to be the stage of methodological development in geomorphology that goes after classification. At the same time it is the first stage of systems approach in this field. Morphological system proposed by author earlier has been modified without changes of its axiomatic system and language. Forth parameter was added into its parametric form - plane curvature of land surface. Morphologically ulterior lines of maximum and minimum gradients were excluded from the set of linear elements while the ridge and keel lines within the slope relief with negative anisotropy was added. Therefore some significant corrections were made in the complete groups and in the systematic of points and area elements.
Геоморфология и россыпи
Applications of paleogeomorphological analysis are reviewed. Investigations of origin and reformation of the placers as well as stages of relief development were predominant during last decades. Among them morphostructural researches, study of river network and slope evolution is of great importance. Principles of prognostic-evaluation maps have been developed. While studying ancient placers which origin dates to pre-geomorphological epoch the tectonic movements of that time may be revealed.
During Oligocene stage of regional planation the releasing of minerals from the host rock took place. During Neogene stage of dissection the transportation of metal from crust of weathering and its concentrating in alluvial deposits happened. Repeated interchanges of planation and dissection of land surface in Late Pliocene as Quaternary time led to rise and enrichment of placers. Early-Pleistocene epoch of cutting has more productive alluvium than later epochs, maximum ore concentration exists in the areas where placers of different age are overlapped. Morphology of gold in the recent placers indicates that significant part of metal have migrated long distance after the primary source had been destroyed.
Paleogeomoiphological analysis of gold fields in the Southern and Central Mongolia has proved the areas of overlapping of MZ and KZ placers to be quite productive. The sites of recent valleys and Cretaceous red pudding rock intersection belong to this type. The pattern of recent drainage network significantly differs from that of Mezosoic time.
Научные сообщения
Morphological differences of landforms created by ephemeral streams of different epochs are under consideration. Three generations of these forms are distinguished: Late Pleistocene, Early Holocene and recent. Zone of recent forms is the narrowest, zone of Late Pleistocene forms in the closest to watersheds.
The analyzed part of Alpine active belt includes the Great Caucasus, the Small Caucasus, and the highlands of East Anatolia and of North-Western Iran. The main faults of this region were distinguished by the landscape- geomorphological deciphering of remote sensing map. The new scheme of lineaments was compiled. Transversal lineaments with "anticaucasus" strikes are of special interest because they play significant role in the recent geodynamic of the region.
Mass-movement on the low-grade slopes made of supracolloidal icy grounds in running layer by layer with different rate. On the different parts of slope (zones of outflow, transit, accumulation) the movement of the under layer may outrun the movement of upper one (zone of outflow) or even became negative (zone of transit). It leads to the formation of hillocks alike the solifluction terraces. Their origin is determined not due to desiccation of ground and drag of the lower layers but due to circulation of material at those parts of slope where the depth of thaw is large. The rate of mass movements depends to a much extent on short-period oscillations of temperature and precipitation in warm period.
The mapping principles and legend of the map are discussed. Authors describe new types of technogenic deposits: "technoground" and "technoalluvium". The impact of technogenic deposits into geological, geomorphological and geochemical ribs is shown.
Gullies occur in different climatic zones. In each zone gully erosion process has its own particularity: both in the channel component and in the slope one. Eventually it effects geomorphological structure of gullies. These particularities were investigated in tundra, forest, forest-steppe, steppe, and desert zones. Zonal features need special approaches in field researches as well as in the development of the computative prognostic methods.
The formation of coastal arcs - the largest landforms indicating the embayment of the coast is analyzed from the new point of view. Their location ~doesn't thoroughly depend on the structural pattern of the coast as it was supposed earlier and their size to a large extent depends on wave parameters.
A small impact of selective denudation on the relief evolution of Gorny Altai has been established on the basis of geomorphological structure analysis and its relation to geological composition. New model for relief development has been put forward. According to this model vertical movements which have caused the formation of Altai Mts. have taken place due to regional contraction of this area. At first a system of swells separated by troughs appeared during the contraction, and then it was broken by faults, of which shears and thrusts were predominant.
The structure and origin of the outer part of Taman peninsular programming shelf are analyzed. This sedimentary prismatic body was formed due to alluvial and deltaic accumulation in periods of the pleistocene transgression.
Results of ten years field researches in tundra regions of Taimyr and West Siberia are presented. Field experiments, modeling of spots' formation, mapping of cryogenic microrelief, were fulfilled. The main causes of central bald spot formation are the lack of nutrient stuff washed away down the soil profile and the excessive iciness in the near-surface soil. The main factors of this process - ground temperature zero crossing, snowmelt, freezing-thawing of the near surface ground. The peculiarities of formation and development of different types of microrelief have zonal character and depend on humidification of surface.
By means of remote sensing data analysis and morphometric method the local centers of the last Putorana glaciation were reconstructed as well as boundaries of main glacier basins and flow directions.
Different variations of interaction between industrial projects and geomorphological environment are considered. Examples of their effects on geomorphological resources and impacts of geomorphological processes on engineering structures are given. Techniques of measuring the dynamics of geomorphological processes needed for predicting their impacts on industrial projects are discussed.
Юбилеи
17 февраля 1998 г. исполнилось 70 лет одному из ведущих отечественных геоморфологов, Лауреату Государственной премии СССР, Почетному члену Азербайджанского, Болгарского, Кубинского и Сербского географических обществ, автору около 500 научных работ, ведущему научному сотруднику Института географии РАН - Д.А. Лилиенбергу.
Рецензии
О генезисе гипсовых пещер Подолии - о статье Л. Якута, Г. Мезеши «Генетические особенности гипсовых пещер Подолий»
Хроника
15-19 сентября 1997 г. в Дубне в помещении Международного Университета Природы, Общества и Человека "Дубна" проходило совещание "Важнейшие промышленные типы россыпей и месторождений кор выветривания, технология оценки и освоения". Это было второе международное совещание, в нем приняли участие 9 специалистов стран дальнего зарубежья - США, Канады, Франции, Германии, Турции, Алжира, Бразилии, Индии, Китая, Вьетнама (опубликованы тезисы 29 авторов). Россыпники бывшего Союза были представлены геологами не только из бывших республик, но и из удаленных регионов России. Всего на совещании присутствовало около 200 человек. Традиционно организаторами и основными исполнителями выступили Совет по рудообразованию и металлогении РАН, ИГЕМ РАН, Министерство природных ресурсов РФ. Оргкомитет базировался в И ГЕМе, и вся работа координировалась и возглавлялась ученым секретарем оргкомитета д.г-м.н. Н.Г. Патык-Кара и ученым секретарем Совета по рудообразованию и металлогении РАН Е.М. Камшилиной. Оргвзнос составил 350 т.р. (45 на предыдущем совещании, 1994 г.)
ISSN 2949-1797 (Online)