Some types of small clinoforms in latest continental deposits

Some rare types of small clinoforms found in the latest continental deposits of lowland platform and mountain regions are described. The clinoforms are represented by prodelta deposits of mountain lakes, oblique-bedded horizons of floodplain alluvium of strongly meandering rivers, thick and short lenses of mountain alluvium, and alluvium horizons of great lowland rivers with oblique bedding grading into horizontal bedding. Such structures bear information on paleogeographic, morphological, and lithodynamic features of continental sedimentation.     

Morphotectonics of the Mongolia-Siberian mountain belt

The mountains of north-eastern Inner Asia comprise the Mongolia-Siberian orogenic belt which has a complex structure. The southern flank of the belt consists of a chain of large domal uplifts. The Baikal rift zone is located on the northern flank. The central segment is composed of zones of linear warping. The tectonic landforms rest on a large domal basement uplift. The morphology of the latter is paragenetically connected with the shape of the asthenolith underlying the belt. The neotectonic zones are also connected with the deep structure elements.The Mongolia-Siberian mountain belt is a group of orogenic forms typical of intracontinental mountain areas.     

A discussion of terms for the description of the space-time of relief

The leading role of water and its interactions with other key environmental elements was well understood already in Antique time. Due to the later fragmentarization of science, this leading role seems to have become hidden, if not neglected. Today, both life-support systems and the productivity of land and water systems are increasingly threatened by human pressure, influencing water availability, water-related land productivity, water quality and productivity of aquatic ecosystems. The world may in fact be approaching or even overshooting its carrying capacity in certain regions, producing quite dangerous conditions. Basically, the anthropogenic influences from a rapidly growing world population with rising demands will produce a reshaped landscape with altered ways of functioning, and a growing water crowding.Paying due attention to water phenomena and functions, this modified landscape has to be analyzed to identify the new strategies by which life support can be managed in the future. A conceptual base is urgently needed, addressing both natural and anthropogenic conditions and phenomena. In follow up of Agenda 21, the paper focuses on landscape analysis for the integration of land and water. It analyzes the main natural components of landscape systems and the ways in which the determinants are being influenced by human activities. A multitude of different interactions between land characteristics and water phenomena are identified. Due to the integrity of the water cycle, these interactions will have to be synthesized and integrated. When the natural funtions of a particular landscape are known, together with the anthropogenic pressure and the various influences from which it is composed, the landscape analysis in this paper may be useful in support of planning, projection and conceptualization of landscape management and spatial organization of land.     

Rockfall-Dammed Lakes in the Baikal Region: Evidence from the Past and Prospects for the Future

The mountain province of East Siberia, which includes the Baikal Rift system, is a zone of high tectonic and seismic hazard. Earthquakes and coseismic faulting are dangerous not only by themselves but also as far as they initiate rock collapse and downslope movement of unconsolidated deposits, which may block river valleys and produce rockfall-dammed lakes. Within some rifts of the rift system, evidence of past dammed lakes was discovered that arose instantly, in a geological sense, and flooded large areas of forest. In mountains around some rift basins, small living dammed lakes were encountered, as well as traces of catastrophic debris flows that may have accompanied breaching of earlier collapse-produced dams. Analysis of geomorphological setting in the region, especially in the Muya Rift Basin, revealed conditions favourable to hazardous origination of rockfall-dammed lakes. A large dammed lake may come into existence due to the collapse of bedrock over the narrow antecedent valley of Vitim in the Muya Rift. Preliminary estimates based upon data on the Vitim River discharge showed that the lake might form in as short as 27 days, though the rapidity of its formation, and hence the degree of the risk, can vary as a function of the highly variable amount of summer discharge of the river. Rockfall-dammed lakes may also originate in the floors of Chara and Tunka Rift Basins. Due to their rapid formation, lakes will bring about extensive flooding and cause danger to the taiga, railways and constructions in this populated developing area, and will cause degradation of the permafrost.     

Morphotectonics of the Lower Amur region

The morphotectonics of the Lower Amur region is controlled by the marginal-continental areal rifting and its interaction with the general uplifting and moderate tectonic stacking on the margin of the “stable” continent. The marginal-continental rifts represent an element of the general evolutionary system of forms in the continent-toocean transition zone and morphotectonically reflect the initial stage of the thinning and transformation of the continental lithosphere. The rim of the stable continent in the southern Far East is characterized by a complex configuration bordered by large continuous or composite scarps, which coincide spatially with high-gradient gravity zones.     

Deep Geodynamics of the Himalaya Orogeny

DEEP GEODYNAMICS OF THE HIMALAYA OROGENYRFBR( grant 990 56 56 38)     

Latest erosional incision in river valleys of southern East Siberia

Examples of the geological and geomorphic framework of river valleys in the Tunka rift basin (Baikal rift system) and in the Irkutsk amphitheater (Siberian craton) have been used to show that horizontal and vertical motions of tectonic units in southern East Siberia are superposed with periodic movements. In the latter, the waves of slow uplift are attendant with erosional incision events, whereas during the subsidence cycles the incised valleys become filled with mainly alluvial sediments. The latest incision events in the area occurred in the past 70 kyr.     

Coastal tropical morphogenesis of the Islands in the Andaman Sea (Thailand)

The characteristics of topography of the coastal zones composed of carbonate and crystalline rocks are considered. In the coastal zones there occur outcropping tropical karst, rock ledges shaped like greywethers or coastal balls having a subaerial origin. An outer resemblance of these convergent formations with abrasion landforms is highlighted.     

Under-ice mountains

The morphological structure of mountains forming under conditions of extensive continental and mountain glaciation is described. They are characterized by a general hummocky profile with alternating dome-shaped summits, steps, valley-shaped depressions, and microrelief represented by roche moutonées, greywethers, and nunataks with isolated peaks in the form of high cones and prisms. The under-ice mountains are represented by a step morphological landscape with glacial steps and leveling surfaces. The step pattern of their morphological landscape is assumed to be related to successive layering of ice according to its movement velocity and the formation of a jet current against the background of general dominant displacements of ice masses. This makes under-ice mountains morphologically similar to medium-height and low mountainous relief of the temperate humid belt in the Northern Hemisphere with dominant landslides on their slopes.     

Structure of relief of continents in the river network pattern

The hydrographic network structure of continents conveys the chief peculiarities of relief of mainland at the planetary level of organization. In eastern Eurasia, it is a general northward ramp occupying the entire Siberian part of Russia and the central elevation of the Tibetan Plateau and extending further in the form of Arctic shelves. The other continents are characterized by some elevation of their marginal parts, and by the presence of central basins with hydrographic nodes and rivers, or catchments.