Neotectonic Stage Research Articles

“THE RELIEF OF EUROPE” AND THE PARADIGM OF GEOMORPHOLOGY OF THE FUTURE (CONCLUSIONS TO THE FIRST TRAINING MANUAL ON THE RELIEF OF CONTINENTS WRITTEN IN THE UKRAINIAN LANGUAGE)

The article emphasizes the need to prepare training manuals on the geomorphology of large land areas. The relief of continents (their parts) and parts of the world is an object of regional geomorphology. The author substantiates the structure and content of the textbook "The relief of Europe", the first written in Ukrainian on the geomorphology of the continents. The manual consists of an introduction, 2 chapters, conclusions and a list of references. The manual uses 6 schematic maps, 9 digital maps, 2 tables, and 28 color photos. The first section of the manual is devoted to issues of planetary geomorphology – the main regularities of Earth's relief forms. Geotexture, morphostructure and morphosculpture are the categories of their are considered as parts of their size-genetic classification and its critical assessment is given (1.1). In 1.2 the planetary features of the Earth's relief at the level of the largest geotextures – continental ridges and ocean depressions are considered (the time of formation and the main trends in the process of the Earth's evolution - the increase in the area of the oceans at the expense of the continents; the sequence of the appearance of the main types of the Earth's crust in the process of the geological evolution of the Earth; the scheme of the geological evolution of the Earth's lithosphere: oceanic-type crust > transition-type crust > continental crust). In 1.3 the considered geomorphological stage of the Earth's development (the beginning of the end of the Paleozoic – the beginning of the Mesozoic – the breakup of Pangea), during which the main features of the modern relief were formed. It is characterized by the following trends: oceanization (expansion and deepening of ocean depressions through the destruction of ancient platforms; increasing the area of continents due to the joining of young platforms (plates); tectonic activation of continents (epiplatform orogeny and the formation of reborn mountains). In 1.4 general regularities of the Earth's morphostructure are considered – 14 types of main morphostructures of plain-platform areas, mountain (orogenic) areas, high platforms and revived mountains, the age and history of the development of land morphostructures, the role of the neotectonic stage, the importance of studying alignment surfaces and hydrographic basins in the study of morphostructure. General regularities of the morphosculpture of the Earth – modern zonal and ancient and the influence of the latter on the development of modern, azonal types of morphosculpture are considered (1.5). The second section consists of general and regional parts. The main regularities of geotexture, morphostructure and morphosculpture of Europe are considered in the general part. In the regional part, modern and ancient geomorphological formations of the author's accepted taxonomic units of geomorphological zoning of Europe (4 zones and 13 countries) are considered. In the conclusions, the author, using data from geology, geomorphology, planetology, substantiates, in his opinion, the content of the future paradigm of geomorphology. Key words: relief of Europe, geotecture; morphostructure; morphosculpture; morphochronodynamic concept; thermodynamic evolution of the Earth.

Morphotectonics, Seismicity, and Exogenous Processes of the Kola Peninsula

Abstract—The purpose of this study is to determine a morphologically pronounced fault–block structure identified with the neotectonic stage and compare it with sites with manifested exogenous processes, as well as modern and historical paleoseismicity in order to establish faults activated in the postglacial time. Based on the analysis of space images (Landsat-ETM+) and a digital elevation model (GTOPO-30), the territory of the Kola Peninsula and the adjacent part of North Karelia is subjected to morphostructural interpretation with identifying morpholineaments and an elementary block structure. It is shown by the analyzing the directions and extent of elementary, single (simple), and complex (echeloned, parallel conjugated, and imbricated) linear structures and their zones that both linear (fault) and areal (block) structures are characterized by a predominance of a single system of northwestern and northeastern differences with a clear dominance of the former and unimodal distribution of the extent of faults and the area of blocks, depending on their number. This indicates a single (recent) stage in the formation of the morphotectonic appearance of the territory and no discrete hierarchy of the morphostructures. The degree of fragmentation of the territory at different depths is calculated depending on the number and extent of morpholineaments. It is determined that morpholineaments have a high degree of inheritance from Archean–Proterozoic structures (≈50%). Elementary morphotectonic blocks are grouped into composite blocks bounded by linear zones of great extent (100–600 km) having individual physiognomic features determined by fault patterns, which indicates the nature of the neotectonic dynamics and the degree of inheritance or reformation of the structural plan. The localization of manifestations of exogenous processes, epicenters of paleo-, historical, and modern earthquakes is determined on the basis of the analysis of topographic maps scaled at 1:100,000, catalogs of historical and paleoearthquakes, and the consolidated literature (including the data obtained by the authors of this study) on paleoseismic deformations. A geoinformation base is compiled, which is used to simulate the spatial distribution of endo- and exogenous signs of tectonic activity and compare it with the neotectonic fault–block structure. The spatial similarity of endogenous and exogenous activation zones and their confinement to faults, defined as activated in the postglacial time, are revealed. It is revealed that the following elements are most active in the postglacial–Holocene. First, flank elements on the Kola Peninsula along the Barents Sea coast, the Kandalaksha Bay shores, and the Gorlo Strait of the White Sea. Second, the central (nodal) part with the Khibiny and Lovozero massifs. Third, submeridional (transverse) secant structures separating the eastern part of the peninsula from the western part (Khibiny–Kola and Khibiny–Niva). The spatial parameters of the activated zones indicate a range of earthquake magnitudes M ≈ 6.5–7.5 generated by these structures both in the postglacial period and in the Neopleistocene as a whole.

Two Distinct Back-Arc Closure Phases of the East Sea: Stratigraphic Evidence From the SW Ulleung Basin Margin

This study focuses on revisiting the tectostratigraphic framework of the Ulleung Basin and conceptualizing neotectonics around the western East Sea margin. Based on the analysis of 2D and 3D multi-channel seismic reflection data and offshore drill wells, we divided the entire sedimentary successions of the Ulleung Basin into four tectostratigraphic sequences, named TS1 (c. 23–16 Ma), TS2 (c. 16–9 Ma), TS3 (c. 9–4 Ma), and TS4 (c. 4 Ma–present), in ascending order. The results show that each sequence has been deformed once or multiple times in different periods by juxtaposing two major compressional structures named the Dolgorae Thrust-Fold Belt and the Gorae Anticline. Interpretation of the stratal deformation and termination patterns of the syn- and post-deformational sequences of each structures suggests that the thrusting and folding of the Dolgorae Thrust-Fold Belt was active from c. 16 Ma to c. 9 Ma under the NNW–SSE compressional stress regime (Stage-2), whereas the Gorae Anticline was active from 4 Ma to the present under the ENE–WSW compressional stress regime (Stage-4). Between these two compressional events, there was an intervening period of regional slow subsidence driven by thermal contraction of the back-arc lithosphere and isostatic sedimentary loading (Stage-3). Based on the stratigraphic and structural reconstruction, we propose a 4-stage tectonic model: Stage-1) back-arc opening stage associated with the southward drift of the Japanese islands (c. 23–16 Ma), Stage-2) tectonic-inversion stage in association with the reorganization of the Pacific and Philippine Sea plates and clockwise rotation of SW Japan (c. 16–9 Ma), Stage-3) post-inversion stage with regional thermal and isostatic subsidence (c. 9–4 Ma), and Stage-4) neotectonic stage in which embryonic subduction is nucleating on the East Sea margins under the E–W compressional stress regime (c. 4 Ma–present).

Neotectonic vertical movements of Northern Sikhote-Alin and adjacent territories and its relationship with the characteristics of the stream network

Morphostructural analysis of the relief and the analysis of the self-similarity characteristics of stream network of the Northern Sikhote-Alin and adjacent territories were carried out. The relief of the studied territory has an inherited character; it was formed in several stages during the neotectonic stage. The most intense vertical movements occurred at the early phases of the neotectonic stage. At Pleistocene time the intensity of vertical movements decreased significantly. At this time, the modern erosion-denudation forms of relief was formed. At the final stages of neotectonic development (at the end of the Pleistocene — Holocene), there was a slight activation of vertical movements with a changes in the structural plan and the manifestation of NNE stretched structures in the relief, which was reflected in the features of the residual relief. The boundaries of areas with increased residual relief coincide with areas of increased seismicity in the region. A modification of the complex self-similarity parameter PRNS was proposed, the use application of which allowed us to improve the correlation of this parameter with the latest (youngest) movements detected by the morphostructural method. Zones of maximum PRNS values correlate with the areas of greatest relief increment, and zones of it’s minimum correlate with areas the smallest relief increment, or areas of most significant erosion. The results of the analysis of the characteristics of self-similarity of the stream network are mainly comparable with the manifestations of vertical tectonic movements at the final stages of neotectonic development.

Neotectonic Fault Pattern of the Salair Area (Southern West Siberia): Relation with the Pre-Cenozoic Tectonic Framework

Abstract —Neotectonic activity in the area of the Salair Ridge (southern West Siberia) rejuvenated a system of large arc-shaped faults separating the Salair tectonic arc from the adjacent tectonic units. These regional faults, which make up the general tectonic framework of the Altai–Sayan Folded Area, originated in the late Paleozoic and were repeatedly reactivated in the Mesozoic. The deformation within the major Salair thrust sheet is mainly brittle and follows small fault planes that crosscut the margins of Paleozoic thrusts. The neotectonic faulting has controlled the erosion pattern of the territory and produced a reticulate drainage system. The Salair tectonic unit is a single 80 × 250 km block consisting of multiple neotectonic blocks, with relative vertical offset no more than 100 m in the block interior and 100–200 m in its southern, northern, and eastern borders. The northwestern and southeastern border faults have reverse slip geometry, while the motions on the en-echelon northeastern fault boundary include reverse and right-lateral strike-slip components. The thickness of the Salair thrust sheet estimated from magnetotelluric (MT) data increases in the western direction from 5 to 15 km in the northern block part and from 10 to >20 km in the south. The allochthon base is delineated by a low-resistivity zone interpreted as a horizontal detachment. This boundary formed in the Mesozoic and was rejuvenated at the neotectonic stage. The lithology and deformation of Jurassic sediments filling piedmont basins around the Salair Ridge indicate that the Cenozoic fault pattern generally inherits the Mesozoic framework but differs in about ten times smaller vertical offset.

Deep structure of the Salair fold-nappe terrane (NW CAOB) according to magnetotelluric sounding

The Salair fold-nappe terrane (a.k.a. Salair orogen, Salair) is the northwestern part of the Altai-Sayan folded area of the Central Asian Orogenic Belt. It is composed of Cambrian – Early Ordovician volcanic rocks and island-arc sedimentary deposits. In plan, Salair is a horseshoe-shaped structure with the northeast-facing convex side, which is formed by the outcrops of the Early Paleozoic folded basement. Its inner part is the Khmelev basin composed of Upper Devonian – Lower Carboniferous sandstones and siltstones. The Early Paleozoic volcanic rocks and sediments of Salair are overthrusted onto the Devonian-Permian sediments of the Kuznetsk basin. The Paleozoic thrusts, that were reactivated at the neotectonic stage, are observed in the modern relief as tectonic steps. Our study of the Salair deep structure was based on the data from two profiles of magnetotelluric sounding. These 175-km and 125-km long profiles go across the strike of the Salair structure and the western part of the Kuznetsk basin. Profile 1 detects a subhorizontal zone of increased conductivity (100–500 Ohm·m) at the depths of 8–15 km. At the eastern part of Profile 1, this zone gently continues upward, towards a shallow conducting zone that corresponds to the sediments of the Kuznetsk basin. Two high-resistance bodies (1000–7000 Ohm⋅m) are detected at the depths of 0–6 km in the middle of the section. They are separated by a subvertical conducting zone corresponding to the Kinterep thrust. The main features are the subhorizontal positions and the flattened forms of crustal conductivity anomalies. At the central part of Profile 2, there is a high-resistance block (above 150000 Ohm⋅m) over the entire depth range of the section, from the surface to the depths of about 20 km. In the eastern part of Profile 2, a shallow zone of increased conductivity corresponds to the sediments of the Kuznetsk basin. The subhorizontal mid-crust layer of increased conductivity, which is detected in the Salair crust, is typical of intracontinental orogens. The distribution pattern of electrical conductivity anomalies confirms the Salair thrust onto the Kuznetsk basin. The northern part of the Khmelev basin is characterized by high resistivity, which can be explained by abundant covered Late Permian granite massifs in that part of the Khmelev basin. The Kinterep thrust located in the northeastern part of the Khmelev basin is manifested in the deep geoelectric crust structure as a conducting zone, which can be considered as an evidence of the activity of this fault.

Structural characteristics of central depression belt in deep-water area of the Qiongdongnan Basin and the hydrocarbon discovery of Songnan low bulge

The Qiongdongnan Basin has the first proprietary high-yield gas field in deep-water areas of China and makes the significant breakthroughs in oil and gas exploration. The central depression belt of deep-water area in the Qiongdongnan Basin is constituted by five sags, i.e. Ledong Sag, Lingshui Sag, Songnan Sag, Baodao Sag and Changchang Sag. It is a Cenozoic extensional basin with the basement of pre-Paleogene as a whole. The structural research in central depression belt of deep-water area in the Qiongdongnan Basin has the important meaning in solving the basic geological problems, and improving the exploration of oil and gas of this basin. The seismic interpretation and structural analysis in this article was operated with the 3D seismic of about 1.5×104 km2 and the 2D seismic of about 1×104 km. Eighteen sampling points were selected to calculate the fault activity rates of the No.2 Fault. The deposition rate was calculated by the ratio of residual formation thickness to deposition time scale. The paleo-geomorphic restoration was obtained by residual thickness method and impression method. The faults in the central depression belt of deep-water area of this basin were mainly developed during Paleogene, and chiefly trend in NE-SW, E-W and NW-SE directions. The architectures of these sags change regularly from east to west: the asymmetric grabens are developed in the Ledong Sag, western Lingshui Sag, eastern Baodao Sag, and western Changchang Sag; half-grabens are developed in the Songnan Sag, eastern Lingshui Sag, and eastern Changchang Sag. The tectonic evolution history in deep-water area of this basin can be divided into three stages, i.e. faulted-depression stage, thermal subsidence stage, and neotectonic stage. The Ledong-Lingshui sags, near the Red River Fault, developed large-scale sedimentary and subsidence by the uplift of Qinghai-Tibet Plateau during neotectonic stage. The Baodao-Changchang sags, near the northwest oceanic sub-basin, developed the large-scale magmatic activities and the transition of stress direction by the expansion of the South China Sea. The east sag belt and west sag belt of the deep-water area in the Qiongdongnan Basin, separated by the ancient Songnan bulge, present prominent differences in deposition filling, diaper genesis, and sag connectivity. The west sag belt has the advantages in high maturity, well-developed fluid diapirs and channel sand bodies, thus it has superior conditions for oil and gas migration and accumulation. The east sag belt is qualified by the abundant resources of oil and gas. The Paleogene of Songnan low bulge, located between the west sag belt and the east sag belt, is the exploration potential. The YL 8 area, located in the southwestern high part of the Songnan low bulge, is a favorable target for the future gas exploration. The Well 8-1-1 was drilled in August 2018 and obtained potential business discovery, and the Well YL8-3-1 was drilled in July 2019 and obtained the business discovery.

Geological structure of the northern part of the Kara Shelf near the Severnaya Zemlya archipelago according to recent studies

Until recently, the North of the Kara Shelf was completely unexplored by seismic methods. Seismic and seismo-acoustic data that have appeared in recent years have made it possible to decipher features of the regional geological structure. This study solves the urgent problem of determining the prospects for the oil and gas potential of the North Kara sedimentary basin. The relevance of the research is associated with determining the prospects of the oil and gas potential of the North Kara sedimentary basin. The aim of the study is to clarify the age of the reflecting horizons using data on the geology of the island, as well as to determine the tectonic position of the sedimentary cover and basement structures in the north of the Kara shelf. The sedimentary cover is divided into three structural levels: Cambrian-Devonian, Middle Carboniferous-Cretaceous, Miocene-Quarter. The Cambrian-Devonian complex fills the deep troughs of the North Kara shelf. The most noticeable discontinuity is the base of Carboniferous-Permian rocks, lying on the eroded surface of folded Silurian-Devonian seismic complexes. The blanket-like plate part of the cover is composed of thin Carbon-Quarter complexes. The authors came to the conclusion that the fold structures of the Taimyr-Severozemelskiy fold belt gradually degenerate towards the Kara sedimentary basin and towards the continental slope of the Eurasian basin of the Arctic Ocean. A chain of narrow uplifts within the seabed relief, which correspond to narrow anticlines is traced to the West of the Severnaya Zemlya islands. Paleozoic rocks have subhorizontal bedding further to the West, within the Kara shelf. Mesozoic folding in the North of the Kara Sea is expressed exclusively in a weak activation of movements along faults. At the neotectonic stage, the shelf near Severnaya Zemlya was raised and the Mesozoic complexes were eroded. The modern seismic activity of the North Zemlya shelf is associated with the ongoing formation of the continental margin.

МАРМАРОСЬКА ЗОНА СКЕЛЬ У СТРУКТУРІ УКРАЇНСЬКИХ КАРПАТ Стаття 2. Тектоно-магматична позиція і погляди на структуру зони

The paper describes the tectonic position of Marmarosh zone of rocks and determine its place in the structure of the Ukrainian Carpathians. Shown is the history of the study of igneous rocks. The comparative analysis of the views on the structure and position of the Marmarosh klippen belt in the structure of the Carpathians processed by the literature was carried out. At the end of the article the researchers compared views on the structure of Foreign Affairs, highlighted the main features of the geological structure and tectonic zoning area. Some similar features of rocks composed of Marmarosh klippen belt, namely formational, to a lesser extent, the morphology of the folded and dislocations with a break of continuity history of even-aged species of complexes the Marmarosh zone of rocks is considered as NW continuation of Marmarosh massif that was torn from its substratum in the tectonic evolution of the region. These tectonic elements of different times and different phases of folding, but the final phase of tectonogenesis was manifested are almost simultaneously during the Miocene. MKB is a special category of tectonic structures associated with faults, of considerable length and long stage of development, is so-called near-fracture or suture structures and delineates two different areas with sharply different geological development history, geodynamic conditions of formation, stratified formations, independent tectonic regime. The structure is characteristed by the set of formations – sedimentary, igneous, metamorphic. As a result of structural and tectonic studies the Marmarosh klippen belt is a consequence of Albian movements where appeared blocky dislocation and Post-Oligocene folding and formation of small intrusive bodies. Modern look of the band was formed in Oligocene time at neotectonic stage of development of the Carpathians. MKB is not correlated with any of the Carpathians area, although it has similarities with some elements, such as Marmarosh massif, but it different by a character of section and especially by peculiarity of the section of the Lower Cretaceous. One of the conditions for further study of Marmarosh klippen belt is integrated research, including the study of facies changes of the nature of the thickness, more mapping of folded and discontinuous structures, further development of stratigraphic scheme of the area, the analogy of even-aged sediments and similar genesis formations of adjorning the territories both on the – territory and abroad of Ukraine. In this comprehensive analysis the Marmarosh klippen belt may get a proper understanding of its nature and place in the structure of folded Carpathians.

Геохимические особенности микробиолитов миоцена (Юго-Западный Крым) по результатам ICP-MS исследований

Background. In this paper, we provide new data on the morphology and geochemistry of heraclites, which are represented by specific products formed by degradation of the carbonate paleostructures of prokaryotes around the degassing zones of the Miocene age. The heraclites exhibiting siltstone and sandstone structures are referred to as micrometanolites. An analysis of literature data showed that heraclites had formed in the upper sedimentary strata under the conditions of increased methane levels in the affinity of the stream exits. Methods. The geochemical examination of heraclites of a different colour and morphology was carried out using ICP-MS at the facilities of the Geoanalytik centre, UB RAS Institute of Geology and Geochemistry, Ekaterinburg. Results. According to lithological characteristics and morphology, the following heraclite types were distinguished: slag-like, banded, angular and сementation slabs. Morphologically, the heraclites under study were characterized by high concentrations of Sr, Ba, Co, Ni, Bi, Ce, Nd and Yb, which significantly exceed those in carbonate rocks. The concentrations of Rb, Cs, Nb, Th, Cu, Tl, As, Sc, Sb, Eu, Gd, Tb, Dy and Er in some morphological differences were above the Clarke values, while others demonstrated their deficit. The samples under study showed low concentrations of some heavy REE. A high content of lithophilic, chalcophile, siderophilic and REE elements indicate paleo-fluids of a deep mantle-derived character. The data on the oxide environment during construction material formation was obtained, which is confirmed by low concentrations of U (0.579 to 2.096 ppm) and Bi (0.014-0.084 ppm), as well as the ratios of U/Th (0.4-2.1), V/Cr (0.3-0.9) and Mo/Mn (less than 0.0014). Such conditions existed near or within the cellular organism of prokaryotes. Low concentrations of U, Ti, Mn and Zr confirm a significant growth rate of heraclite carbonate substances. Minor differences in the concentrations of chemical elements in heraclites of a different morphology are believed to have resulted from the physic-geographical and chemical conditions of their formation across the areas of regional faults with an active tectonic regime. Conclusions. Our results have confirmed the assumption that the carbonate material of heraclites formed by processing of deep fluids. In the South-Western Crimea, heraclites constitute a geological phenomenon of the Miocene hydrocarbon paleo-degassing, which was associated with the neotectonic stage of the uplift of the Crimean Mountains. The presence of methane, ethane, propane and petroleum products in the composition of heraclites allows an assumption to be made about the presence of oil and gas deposits in the Sevastopol region.

About the structure of the Kama-Kinel trough system

Kama-Kinel Trough System (KKTS) — the structure formed in the Frasnian of the Late Devonian in the vast territory of the Volga-Ural province, is distinguished by the Upper Devonian — Lower Carboniferous deposits. The new interpretation of forming conditions of carbonate deposits in the KKTS has been given. The troughs of the KKST were formed in the Late Devonian as basin with gently sloping shelf zones. The deposits of the middle shelf (ramp), gently sinking into the side of the pool, where the layered accumulated precipitation are presented by bioclastic and intraclastic (lumpy) limestones and carbonate breccia, formed under the influence of storms. Three structural-facial zones, central, border and arched, allocated in the structure of deflections of the KKTS, reflect the structure of troughs formed as a result of tectonic restructuring at the beginning of the Visean and reactivated at the neotectonic stage. The uplift of the side zone considered as the reef buildups seem to be horst-shaped structures in fault zones. These features allow us to consider the structure of the KKTS as formed as a result of paleotectonic processes with the appropriate distribution of shallow and deep-water facies, subsequently changed as a result of reactivation of the basement faults.

Seismotectonic Activation of Modern Structures of the Siberian Craton

Our research of the modern structures of Siberian Craton aims to reveal regional regularities in the seismotectonic destruction of the Earth’s crust and to clarify the dynamics of the formation of the focal zones of strong earthquakes. Analysis of activated structures and marginal suture zones located in the study area was based on structural and geophysical data, the modern structural plan, and the quantitative characteristics of modern and recent tectonic movements, active faults, and tectonic stress fields identified by tectonophysical analysis of deformation and seismological parameters. Unambiguous correlation between the seismic activity level of modern structures and the rates of modern and recent tectonic movements were not determined in our study. The most active structures of the Siberian Craton located in zones of the dynamic influence of marginal sutures are contrasted against the gradient field of modern vertical tectonic movements and characterized by the mosaic field of the mean and low rates of modern movements. The kinematics of seismotectonic deformation and levels of seismic activation of suture zones of the Siberian Craton are governed by global geodynamic processes taking place at the boundaries between the Eurasian, North American and Amur lithospheric plates. The activated structures in the northern regions of Siberian platform, which are characterized by the highest rates of modern movements, are heterogeneous. Both fluid processes and glacioisostatic movements may have influenced the dynamics of the formation of these high-gradient deformation zones. In seismotectonic studies aimed at determining levels of the potential seismic hazard of modern structures, we find it important to take into account errors in geodetic data and ensure more correct reference to the rates of tectonic movements at the neotectonic stage. In order to correctly assess the degree of geodynamic activity of modern structures, special consideration should be given to the fluid-geodynamic factor that controls most geodynamic processes, including tectonic stress accumulation, the formation of earthquake focal zones, and the intensity of seismic events.

Geodynamic conditions for Cenozoic activation of tectonic structures in Southeastern Mongolia

The knowledge of the neotectonic structures inSoutheastern Mongolia, that is considerably distant from the active plate boundaries, is important for determining a source of tectonic deformation and regular features of activation in the intracontinental setting. Our research was focused on the East Gobi and South Gobi depressions located inSoutheastern Mongolia, which developed since the Mesozoic and were activated to various degrees in the neotectonic stage. The study aimed to assess the paleostress state of the crust inSoutheastern Mongolia, identify the stages, factors and mechanisms of the Cenozoic activation of the regional structures of different strike, and determine the sources of activation. The analysis of the available literature suggests a similar history of their development in the Late Jurassic – Early Cretaceous (rifting) and Late Cretaceous – Paleogene (tectonic quiescence). In the Cenozoic stage, the depressions experienced activation of completely different styles. In theEast Gobidepression, left-lateral strike-slip faults were activated in the Tertiary, and the post-Late Cretaceous thrusting took place along the northeastern faults on the northern slope of the Totoshan uplift. In the Early Cenozoic, the N-S and N-W compression was dominant as evidenced by the deformed Late Cretaceous sediments and the reconstructed stress tensors typical of the compression and transpression regimes. An overview of the published data suggests that the most probable cause of such deformation was the impact of the Western Pacific zone of plate interaction. However, a potential influence of compression at the early stages of the Indo-Asian collision cannot be completely excluded. TheEast Gobidepression was low active in the second half of the Cenozoic. In contrast to the East Gobi depression, theSouth Gobiactivation began in the Late Cenozoic (Late Miocene – Early Pliocene). Young uplifts and forbergs (Gobi Altai eastern termination) developed actively and ‘cut’ the sediments of the basins originating from the Mesozoic. The W-E and N-W strike-slip and thrust faults were active in the Pliocene–Quaternary. The stress field reconstructions show compression, transpression and strike-slip regimes with the NE-trending axis of compression. Deformation in the East Goby Altay (as well as in Western andSouthwestern Mongolia) is driven by the India-Eurasia collision.

Neotectonic and Geomorphological Characteristics of the Ma Pi Leng Area (Ha Giang Province, North Vietnam): Implications for Improving the Worth of Vietnamese Geological Heritage

Ma Pi Leng area is the core part of Dong Van karst plateau geopark, and is a region of high diversity of geology and tectonics in Vietnam. This region has experienced strong uplift motions that have created three grades of regional relief: 1400–1600 m; 1100–1200 m and 500–600 m. This geomorphology is in turn strongly eroded by the stream systems and divided into different structural blocks controlled by the faults. During the neotectonic stage, several modes of faulting have occurred in Ma Pi Leng such as strikeslip, normal, extension, riverse faults. The NW–SE fault system had a decisive role in determining the structural pattern of the region. The tectonic fractures, at the largest scale, are hundreds of meters high and up to a kilometer long. Tectonic activities, together with exogenic processes, have made regional relief strongly diverse with strips of horsts and grabens as well as laddersteps-shaped escarpments, inverse topography, high cliffs and deep canyons. Besides that there are also the caves at varying levels of height, chains of sinkholes, and pyramidal mountainous peaks. Ma Pi Leng area is truly majestic and worthy of tourist attractions both in terms of scientific value and natural landscape.

Reconstruction of the Cenozoic History of Hydrocarbon Fluids from Rifting Stage to Passive Continental Margin Stage in the Huizhou Sag, the Pearl River Mouth Basin

The Eocene lacustrine sediments are the primary source rocks in the Huizhou Sag of the Pear River Mouth Basin. This study employs basin modeling for four representative wells and two profiles in the Huizhou Sag to reconstruct the process of generation, expulsion, migration, and accumulation of hydrocarbon fluids. The Eocene source rocks started to generate hydrocarbon at 33.9 Ma and are currently in a mid-mature and postmature stage. Hydrocarbons are mainly expelled from the Eocene Wenchang Fm, and the contribution of the Eocene Enping formation is minor. Under the driving forces of buoyancy and excess pressure, major hydrocarbons sourced from the Eocene source rocks firstly migrated laterally to the adjacent Eocene reservoirs during the postrift stage, then vertically via faults to Oligo-Miocene carrier beds, and finally laterally to the structural highs over a long distance during the Pliocene-Quaternary Neotectonic stage, which is controlled by both structural morphology and heterogeneity of carrier beds. Fault is the most important conduit for hydrocarbon fluid migration during the Neotectonic stage. Reactivation of previous faults and new-formed faults caused by the Dongsha Movement (9.8–4.4 Ma) served as vertical migration pathways after 10.0 Ma, which significantly influenced the timing of hydrocarbon accumulation in the postrift traps.

Characteristics of the Thakhet - Sepon active fault zone

Thakhet - Sepon active fault zone is one of fault zones of the Lao PDR in particular, and of Indochina block, in general. This fault zone was longer than 550km, extending into Vietnam with nearly 80km in length and with a name Dakrong - Hue. In Laos fault zone consists of three major faults, running nearly parallel in direction NW-SE. During the neotectonic stage it operate under two main phases: the early phase (Late Miocene - early Pliocene) - with left-lateral slip; the late phase (Late Pliocene-Quaternary)- with right-lateral slip. The largest amplitude of the left-lateral slip in the Pleistocen reach 2880m and the rate approximately 9.6 mm / year; the vertical displacement amplitude of about 400m with a rate approximately 1.33 mm/year.Related to fault zones were instrumentally recored earthquakes with 5<Ms<6. Thakhet-Sepon zone can generate earthquakes Msmax³ 6.5.ReferencesDonald L. Wells and Kevin J.Copersmith,1994: New Empirical Relationships among Magnitude, Rupture Length, Rupture Width, Rupture Area, and Surface Displacement. Bl.of SSA. Vol.84, No4, pp 974-1002. Santi Pailoplee, Yuichi Sugiyanna, Punya Charusin, 2010: Deterministic and probabilistic seismic hazard analyses in Thailand and adjust areas using fault data online. Phan Cự Tiến (chủ biên), 1988: Bản đồ địa chất Campuchia, Lào và Việt Nam 1: 1 000 000. Tổng cục Địa chất Hà Nội - Việt Nam. Bùi Văn Thơm, 2001: Đặc điểm hoạt động Tân kiến tạo đới đứt gãy Đakrông - Huế. TC Địa chất, số 267, 64-75. Bùi Văn Thơm, 2002: Một số đặc điểm đứt gãy Tân kiến tạo khu vực Bắc Trung bộ. Luận án Tiến sỹ. Viện Địa chất. Cao Đình Triều, 2010: Seismic hazads in Vietnam. S&T Publ. House-Hanoi. Lê Thạc Xính (chủ biên), 1969: Bản đồ địa chất Lào 1: 500 000. Cục Địa chất Lào - Vientiane. Nguyễn Đình Xuyên (chủ nhiệm), 1985: Động đất trên lãnh thổ Việt Nam. Lưu trữ tại Viện khoa học Việt Nam, Hà Nội. Nguyễn Trọng Yêm (chủ nhiệm), 2005: Nghiên cứu thiên tai nứt đất lãnh thổ Việt Nam và các giải pháp phòng tránh, giảm nhẹ thiệt hại - Đề tài điều tra cơ bản. Lưu trữ tại Viện Địa chất.

THE RECENT DENUDATION RATE AND UPLIFT VELOCITY OF EPIGEOSYNCLINAL MOUNTAINS OF EURASIA

Recent mechanical denudation rate in Alps, Carpathians, West and East Caucasus, and Himalayas was estimated by the sediment discharge data. The values obtained were compared with tectonic uplift velocities. Everywhere within the axial zone of the mountains the tectonic uplift predominates denudation in ratio 1.8:1 - 6.4:1. This indicates the continuous upward evolution of mountains. Recent rates of mountains uplift are higher than average rates for the whole neotectonic stage.

THEORETICAL OUTLINES OF MORPHOTECTONIC RESEARCHES. PAPER 1. GEOMORPHOLOGIC STAGE AND GENERAL MODEL OF SUBMARINE-SUBGLACIAL ANTARCTIC RELIEF DEVELOPMENT

The duration of neotectonic stage, of which the earth's crust movements formed the main features of present-day relief, is comparable with the lifetime of the ice cover. The landforms were developed under peculiar condition of inhibiting the lithodynamic processes of relief formation and thence are the most objective indicators of concurrent tectonic movements.

Neotectonic stage in the formation of the Khokhlovskoe uranium deposit, eastern Transural region: Structural, hydrochemical, mineralogical, and geochemical formation conditions

The structural, hydrochemical, mineralogical, and geochemical features of the Khokhlovskoe uranium deposit related to neotectonic processes are considered. The structural feature is expressed in neotectonic dislocations in the form of overall intense fragmentation of host rocks and widespread low-amplitude strike-slip faulting. The hydrochemical specificity is determined by the appearance of thermal carbonated formation water in ore-bearing aquifers. This water is similar in chemical and gas composition to hydrothermal solutions in fluid inclusions and mineral waters abundant in this district. The mineralogical and geochemical features comprise the occurrence of newly formed ferroan carbonates and late iron hydroxides in altered (bleached) pelitic rocks; the formation of silicic opal segregations in ore-bearing sand and sandstone; late sulfides, arsenides, and selenides of iron and other metals; and multiphase gel-pitchblende enriched in Zr especially typical of high-grade uranium ore. The age of high-grade ore determined by a precision uranium-ionium method coincides with the time when thermal carbonated water appeared in the host rocks. This time was estimated from a mathematical model of heat transfer and regional dynamics of underground water. This coincidence clearly indicates that the aforementioned processes are related to the late Quaternary neotectonic reactivation of the eastern Transural region.

Modern geodynamically active zones in the Central East European Craton

To identify the modern geodynamic processes in the structures of the East European Craton (EEC), the complex approach is used. The results of visual and automated deciphering of the LANDSAT satellite images are analyzed combined with the data of preci� sion measurements for horizontal components of motion rates of GPS reference points. The approach used allowed us to consider the modern activity of geo� logical structures and to distinguish the zones of higher geodynamic instability. To analyze the morphostructures and geodynamic setting of the studied territory, we constructed a space� tectonic scheme of the central EEC using the LESSA software packet [1] and data on the deep structure of the Earth’s crust [2] (Fig. 1). In the scheme, the sys� tems of extended lineaments of different directions are marked; these lineaments shape the integrated struc� tural pattern describing the complex geological evolu� tion of the region. Deep faults in the basement are often expressed on the surface as localized deforma� tions and clustered cracking zones. The rheological properties of sedimentary rocks predetermine the “scatter” of boundaries (faults) between the basement blocks [3]. The orientation of extended lineaments and linea� ment forms in the central EEC reflects the block struc� ture of the basement and partially reveals the buried structures that were activated at the neotectonic stage. Figure 1 shows that the major lineaments are oriented in the SW–NE and SE–NW directions and are related with the primary regmatic division of the crust trans� formed by tectonic processes. Sublatitudinal and sub� meridional lineaments are of secondary value [4]. The distinguished extended Moscow–Ryazan lineament zone of SE–NW strike consists of a series of subparal� lel extended lineaments and corresponds to the transi� tion zone boundary at the layer of sedimentary cover