Development and dolomitization of Anisian isolated carbonate platforms in the Transdanubian Range, Hungary

In the Middle Anisian, extensional tectonic movements led to the development of isolated carbonate platforms in the area of the southwestern part of the Transdanubian Range. The platforms are made up of meter-scale peritidal–lagoonal cycles bounded by subaerial exposure surfaces. One of the platform successions (Tagyon Platform) consists predominantly of limestone that contains partially and completely dolomitized intervals, whereas the other one (Kádárta Platform) is completely dolomitized. Drowning of the platforms took place in the latest Pelsonian to the early Illyrian interval when submarine highs came into existence and then condensed pelagic carbonate successions with volcanic tuff interbeds were deposited on the top of the drowned platforms from the late Illyrian up to the late Ladinian. The comparative study of dolomitization of the coeval platforms, affected by different diagenetic histories, is discussed in the current paper. Traces of probably microbially-mediated early dolomitization were preserved in the slightly dolomitized successions of the Tagyon Platform. This might also have been present in the successions of the Kádárta Platform, but was overprinted by geothermal dolomitization along the basinward platform margin and by pervasive reflux dolomitization in the internal parts of the platform. The Carnian evolution of the two submarine highs was different, and this may have significantly influenced the grade of the shallow to deeper burial dolomitization.

New geodynamics: geosyncline plate tectonics

For the first time, on the basis of the data set of the Taimyr geophysical site, the processes that cause vertical oscillatory movements of large blocks of the continental crust and largely determine its deep structure are confidently recorded. In this regard, the conceptual apparatus of plate tectonics is being expanded due to terms that were not originally used for it, previously used within the framework of geosyncline theory. Modern geodynamics combines concepts opposed in the past, thereby forming a conceptually new geosyncline plate tectonics. Under the new paradigm, the oil and gas prospects of an area are determined not so much by its confinement to a geostructure of any age, as by the current stage of the geosyncline cycle, characterized by subsidence, active sedimentation processes and formation of a sedimentary basin or, conversely, orogenesis and dominant erosion of sediments. Thus, one or another scenario will cause a different inflow of hydrocarbons from the generation area, which means that regional tectonic movements largely predetermine the realization of the hydrocarbon potential, making them one of the most important criteria for its assessment.

The results of a complex study of the Turchu limestone hollow (polje). Western Georgia, Caucasus

Based on the complex studies (geographical-geological, karst-speleological, and geophysical studies), conducted by the authors in the study area, karst forms such as sinkholes and ponors were identified, the width (2-17 m) of the Quaternary deposits located on the limestones were determined, the average and maximum discharges of the streams flowing on the bottom of the hollow were calculated. Studies have also shown that relatively heavy rains and snowmelt periodically flood the relatively low, western part of the hollow and create a temporary lake that soon dries up through the ponors at the bottom of the hollow, where the water stream are discharged. The closed shape of the Turchu hollow the limestone bottom covered with Quaternary deposits and the events described above indicate the corrosive origin of the hollow, which has been practically confirmed by our georadiological and electrometric studies. It is notable that the role of tectonic movements in the origin of the hollow along with the corrosive processes, which had a periodic character, and together with the uplifting of the area caused the lowering of the levels of underground waters and, consequently, the activation of karst processes.

Soils of mountain floodplains in the zone of tectonic joints of Mongol-Okhotsk Orogenic Belt (Mongolia)

New data on the soils of mountain floodplains in the tectonic joints zone of the Mongol-Okhotsk Orogenic Belt on the example of the Upper Kerulen Basin are presented. Soil diversity is mostly determined by sedimentation conditions and drainage of the parent rocks. There are alluvial–humus (Fluvisol (Humic)), mucky–humus (Folic Fluvisol), dark–humus (Fluvisol (Mollic)), dark–humus gley (Gleyic Fluvisol) and dark–humus saline soils (Sodic Gleyic Fluvisol (Mollic)) were diagnosed. Tectonic movements of the earth’s crust lead to the appearance of shaftlike linear dams, blocking river flow through the valley. So, the Kerulen river changed the direction of the channel and go beyond the depression, embedding into its mountain frame. Current seismicity impact on soils appears locally at tectonically active positions of epigenetic areas, close to outputs of saline underground deep waters, in the form of surface soil salinity and hydrometamorphism.

The krathis lake, one century of evolution.

A riverbed swamp in the Krathis River, N. Peloponnese, is studied and analyzed geomorphologicaly. Our analysis is also based on sedimentological, geochemical, palaeontological and radiometric dating data which enabled the investigation of the possible relationship between the studied swamp and the 1913 Tsivlos landslide. Sedimentological analysis showed that the current sedimentation is dominated by fine grain material and occasional coarse-grained beds. Micropalaeontological analysis indicated that the deeper layers of the core are barren, while the upper ones contain fresh water ostracods suggesting hydrodynamically a progressively more stable environment. In accordance, radiocarbon C14 and 137Cs dating showed a progressively decreasing sedimentation rate over the last fifty years. The results of this study show that the Tsivlos landslide is not the only cause for the formation of the modern swamp. Tectonic movements in the area seem to play a decisive role causing uplift and subsidence in the area near an active fault.

HISTORY OF THE SOLOTVYNO HOLLOW OF TRANSCARPATHIA RELIEF DEVELOPMENT

The analysis of four stages of relief development is done, which created the corresponding complexes within the Solotvyno hollow. The main attention is paid to the morphostructural and morphosculptural features. The morphostructures of the third and fourth orders are distinguished. Among the elements of morphosculpture the main attention is paid to denudation and denudation-accumulative surfaces (Kycherska, Skrydeyska, Boronyavska). The role of the new technological movements in the formation of these surfaces and river valleys was rated. The second stage of the upper baden is associated with the retreat of the sea basin and the division of the land into mountains. The main features of the modern relief were formed in the Pliocene Pleistocene stage - a river network with a complex of terraces, denudation and denudation-accumulative surfaces, quest forms in the marginal zone. Age of the Kicherska denudation surface is pannon-pont. According to the palynological analysis, the estimated age of the Skrydei denudation-accumulative surface is upper pliocene-lower pleistocene. The age of the Boronyava surface is considered to be Eopleistocene, and pebbles of metamorphic rocks are present in its alluvium (up to 5%). In the modern period, newer differentiated tectonic movements have become more active, which have contributed to the active manifestation of exogenous processes: erosion, landslides, and halogen karst. Key words: denudation and denudation-accumulative surfaces; power of ancient alluvium; modern morphodynamic processes.

Statistics and Formation Mechanism Analysis on the Basin-Range Patterns of Granite Bodies in Hunan Province, China

This paper presents the results of statistical analysis on the basin-range relations between the granite rock bodies and surrounding rocks in Hunan Province of China. Among the 44 granitoids in Hunan Province, 28 are basins, 14 are ranges, and only 2 cannot be directly classified. The basin-range properties of granite bodies are closely related to the lithology of surrounding rocks. Among the 28 granite basins, 24 are surrounded by slate, 3 by sandstone, and only 1 by glutenite, while 11 of 14 ranges are surrounded by carbonate rocks. From the perspective of endodynamic process, tectonic movements played an important role in the evolution of the terrain in the granite areas. Firstly, tectonism shaped the large-scale tectonic framework which deter-mined the distribution of some granite mountains in Hunan Province. In addition, tectonic compression or extension formed some granite compressional uplifts or horsts, which present as ranges now. From the perspective of differential weathering, the difference of resistance to weathering between granite and their surrounding rocks is an essential factor for the development of granite basin or range. When their surrounding rocks are carbonate rocks, the granite areas mostly present as ranges for the high solubility of carbonate minerals. When their surrounding rocks are slate rocks, the granite areas are mostly basins for their lower resistance to weathering than slate rocks determined by their more unstable minerals to weathering and more conductive soils to rainfall infiltration.

К вопросу о режиме водных объектов Охотско-Колымского водораздела

The article discusses previously unexplored hydrological and hydrogeological manifestations of smallscale tectonics on a number of lakes and streams in the North-East of Russia. The research involves the results of the author's own observations, analysis of cartographic and aerospace materials of different years as well as published and interrogation data. Regime and evolution of the investigated objects display significant (to several years) variability within short time intervals, manifested in intense fluctuations of water levels in lakes, including their complete draining, absorption of rivers flow, and a number of other effects. The most unusual of them are: 1) counter-directed underground and surface water flows at one of the lakes' extremity; 2) an underground reservoir existence in low reaches of a stream. Most of the time, it drains the surface flow but occasionally it generates volleys of water many times exceeding the extreme floods on streams of comparable sizes. In high-water periods, it functions as a low-debit spring whose output oscillates daily under the influence of tidal force. Many of the studied objects are situated in localities of low-contrast relief without distinct features of tectonic activity. Undoubtedly, the presence of such features does not exclude the processes similar to the abovementioned, though in areas with intense and high-amplitude tectonic movements they are mostly obscure. Probably, in mountainous parts, including foothills, they are widespread. The results presented indicate the need for searching unconventional approaches to interpreting similar observations and using the maximum possible amount of available information. Practical importance of such studies is implied by the necessity to consider the possibility of local tectonic movements when designing industrial and civil objects. The leading inventory in this case should be the study of hydrological and hydrogeological peculiarities of regimes at the sites proposed and the retrospective analysis of cartographic and aerospace materials, examples of which are presented in this paper.

Carbonate shelf development and early Paleozoic benthic diversity in Baltica: a hierarchical diversity partitioning approach using brachiopod data

The Ordovician–Silurian (~485–419 Ma) was a time of considerable evolutionary upheaval, encompassing both great evolutionary diversification and one of the first major mass extinctions. The Ordovician diversification coincided with global climatic cooling and paleocontinental collision, the ecological impacts of which were mediated by region-specific processes including substrate changes, biotic invasions, and tectonic movements. From the Sandbian–Katian (~453 Ma) onward, an extensive carbonate shelf developed in the eastern Baltic paleobasin in response to a tectonic shift to tropical latitudes and an increase in the abundance of calcareous macroorganisms. We quantify the contributions of environmental differentiation and temporal turnover to regional diversity through the Ordovician and Silurian, using brachiopod occurrences from the more shallow-water facies belts of the eastern Baltic paleobasin, an epicontinental sea on the Baltica paleocontinent. The results are consistent with carbonate shelf development as a driver of Ordovician regional diversification, both by enhancing broadscale differentiation between shallow- and deep-marine environments and by generating heterogeneous carbonate environments that allowed increasing numbers of brachiopod genera to coexist. However, temporal turnover also contributed significantly to apparent regional diversity, particularly in the Middle–Late Ordovician.