Дэлгэрэнгүй мэдээлэл

The age of Jargalant Formation in western Mongolia is changed to the middle Jurassic by Quadraeculina, Uvaesporites, main types of palynomorph group of middle Jurassic. The dominance of pollen Coniferalis (Inaperturopollenites, Quadraeculina), Cycadales (Cycadopites, Ginkgocycadoptes), Shpagnaceae (Leiotriletes), and Zygnematacea (Ovoides) in palynomorph groups indicates a warm-temperate, relatively humid seasonal climate during the deposition of Jargalant formation. Four palynomorph groups have defined as upland, lowland, riverside and aquatic conditions. Based on the palynomorph group definition of ancient plants accumulated in intracontinental, intermontane lowland along banks of river lake system in seasonally dry-humid climate, we reconstruct the flattened paleolandscape. Western Mongolia had a humid and warm environment during the Mesozoic (until the early Cretaceous), therefore fluvial erosion and accumulation were predominantly responsible for basin sedimentation

Multiple lava flows have profoundly shaped the landscape of Terkhiin Tsagaan Lake (TTL) in central Mongolia, influencing its level and extent over the Quaternary. Optically Stimulated Luminescence (OSL) dating of terraces unveils ages ranging from 65 to 59 ka at 2073 m, 54–51 ka at 2069 m, and approximately 46 ka at 2065 m. Additionally, cosmogenic 36Cl dating of a lava flow provides insights into the timing of the most recent volcanic eruption, dating it to 7.2 ka ago. The integration of geomorphic and geochronological evidence, along with observations of Lava-Water-Interaction features, suggests the presence of a paleolake preceding the last Holocene eruption of Khorgo Volcano. The geomorphic evolution unfolds in three stages: (i) A Pleistocene lava flow formed multiple dams across the Tariat Basin, creating temporally successive lava-dammed lakes. (ii) The paleolakes underwent fluctuations, leaving lacustrine terraces, and experiencing lower levels. (iii) Holocene eruption of Khorgo, which is one of the youngest in Central Asia, shaped the current TTL by releasing lavas over the eastern margin of the paleolake. The study contributes valuable insights into the paleoenvironmental dynamics, shedding light on the interplay between volcanic activity, climate, and landscape evolution.

The lake depressions in the Mongolian Altai Mountains, and the issues related to their formation have yet to be thoroughly examined in previous research. Previous studies primarily focused on the paleogeographical evolution and glaciation dynamics of the Altai Mountains. This study presents relationships between tectonic and glacial processes that have formed the lake depressions, such as Khoton, Khurgan, Dayan, Khar (western), and Khar (eastern) in the Mongolian Altai Mountains. The depressions of Khoton, Khurgan, and Dayan lakes are situated along regional fault zones, extending in an nortwest -southeast direction, forming intermontane depressions directly connected to the Mongolian Altai Mountains. However, the depressions of Dayan, Khar (western), and Khar (eastern) lakes have been dammed by moraine deposits in the near portion of the depression. The compliance matrix of tectonic geomorphological criteria indicates that the Khoton, Khurgan, Dayan Lake, and Khar (western) Lake depressions are more than 50% compatible. Similarly, the compliance matrix for glacial geomorphological criteria indicates more than 60% compliance for all lake depressions. The Mongolian Altai intermontane depressions are thus of tectonic origin, whereas the lakes have a glacial origin, resulting from dammed moraine sediments. The significance of this work lies in demonstrating how geomorphological research can be employed to provide a detailed understanding of the pattern of lake depressions.

Studies of paleoclimate change based on the sediments of Lake Telmen have been conducted. We present the morphometric characteristics, depression origin of the Telmen Lake, Western Mongolia. In the study, the morphometric analysis, spatial improvement method, hypsometric curve method, Geophysical magnetic mapping, and AWEI index were used to determine the pattern of lake depressions. The depression of the Telmen Lake formed as a block-subsidence by faults. Lake water is likely to relate to underground water, which level cutted by fault. Climate change and permafrost studies show that water area and volume of the Telmen Lake are not changed through Central Asia warming and drying in last two decades.

The newly discovered Shuvuutai Molybdenum (Mo) porphyry deposit located in central-east Mongolian volcanic pluton belt within the southern Altaids, is characterized by quartz vein- and veinlet-disseminated-type Mo ore bodies mainly hosted in the Late Permian-Early Triassic granitic intrusion. In this study, we provide an elaborate study that integrates detailed geology, petrographic, mineragraphic, geochemistry, geochronology, tectonic setting and fluid inclusions (FIs) to reconstruct the fluid evolution history of the Shuvuutai Mo mineralization system and to bridge the aforementioned knowledge gap. The ore bodies occur mainly as veins, lens, pods in the positions from inner intrusions through contact zones to the host rocks distal to causative intrusions. The host rocks are variable in lithologies, including granites, porphyries, volcanic breccias and tuffs, and sedimentary rocks. Outward from ore bodies to host rocks, the wall rock alteration is zoning from potassic (K-feldspar-quartz-mica), through phyllic (quartz-sericite-chlorite-epidote), to propylitic or argillic alterations. Two samples, including early phase monzodiorite porphyry and main phase quartz syenite intrusions porphyry stock body at Shuvuutai, were selected for U–Pb zircon geochronology. Here, this study targeted ore-hosting monzodiorite porphyry and quartz syenite porphyry from the Shuvuutai Mo deposit to conduct in situ U-Pb dating and trace element composition studies with major views to determine the timing and magma evolution and to provide new insights into Mo porphyry metallogeny. Which are consistent or slightly postdate with the published zircon U-Pb ages of early phases monzodiorite porphyry (268–232 Ma) and mainly phases quartz syenite porphyry (251.6±1.7Ma). Hydrothermal mineralization generally includes four stages, from early to late, represented by (1) potassic feldspar-quartz veins or veinlets, (2) quartz-molybdenite stockworks, (3) quartz-sulfide stockworks, and (4) quartz ± carbonate veins or veinlets. The ore-forming fluids were initially magmatic in origin and shew high-temperature and high-salinity, containing daughter mineral-and/or CO2-bearing fluid inclusions; and eventually evolved to low-temperature, low-pressure, low-salinity and CO2-poor meteoric water. The Central-Eastern Mongolian volcanic-plutonic belt continues from Mongolia into northeast China, where similar Mo deposits are not yet recognized, suggesting that a new exploration strategy, based on the characteristics and history of the Shuvuutai discovery, is needed for the Chinese segment of the Altaids.

In Mongolia, engineering geological study is developed as much when constructing urban settlement areas, but engineering geomorphological concerns have been not used in practice. In this study, we focused on the aufeis formation to influence to urban and land planning, a part of engineering geomorphological study. Our results of study are occurred by relevant methods, and based on geomorphological, geological, tectonic, hydrogeological, and engineering-geological base maps of the Eg River valley. According to our results, near of Erdenebulgan soum has consistent by geomorphological and tectonic indicators and non-consistent by geological, hydrogeological, engineering geological and permafrost indicators. Correlation between aufeis square, volume and precipitation is in average r=0.60, r²=0.35 and p=0.05. This result shows that 35% of aufeis square and volume is related to precipitation, and 65% is likely related to other geo-spatial conditions. We concluded that in the next step engineering geomorphological indicators would include necessarily in the land and settlement planning, and waste management of Erdenebulgan soum. In the future, following this criterion, it will eventually be feasible to test, compare, and ascertain the engineering geomorphological conditions in different study areas.

In this study, the reasons for the formation of Aufeis in the settlement area of Erdenebulgan Soum, Khuvsgul Province, located in the Eg River valley, were clarified. In addition to the analysis of geomorphology and permafrost survey materials, the research was based on satellite image data and calculated using the methods of normalized snow index (NDSI) and snow water index (SWI). In the Eg River valley, the normative depth of seasonal freezing and thawing of subsoil ranges from 2.2-3.7 meters. Depending on the freezing of the winter season, there were long, short, and straight rows of cracks and fractures in the vicinity of river diversions, floodplains, terraces, or along the settlement zone. Over the past 10 years, the average size of the Aufeis area was 5555.8 m², and the average Aufeis volume was 5000.2 m³. In 2022, the Aufeis area increased sharply to 6,381.3 m², which can be related to that year's precipitation and soil temperature fluctuations. According to the area and volume classification of Aufeis in Mongolia, the research area belongs to the III class of medium-sized category, but it is exposed to the space of Aufeis distribution due to the improper expansion of the settlement area and wrong planning. According to the changes in the satellite map over the last 30 years, the diversion of the Eg River has caused the spatial distribution of the Aufeis to move towards the settlement area.

Аккрецийн бүсийн меланжийн бүрдэлд серпентинит, перидотит, габбро, тоналит, трондьемит, яшма болон гүн усны цахиурлаг чулуулгийн блокууд тогтоогдох боловч аккрецийн төрлөөс хамаарч эдгээр чулуулгийн гарал үүсэл өөр өөр байх төдийгүй цахиурлаг чулуулаг нь бүх тохиолдолд меланжийн бүрдэлийг илэрхийлэхгүй болно. Монгол орны террейн тектоникийн ангилалаар Гурвансайханы нуруу нь арлан нумын, Зөөлөнгийн нуруу нь аккрецийн бүсэд ялгагдсан ч эдгээр нуруудад ижил настай формацууд зураглагдсан төдийгүй, аль аль нь меланжийн бүрдэлтэй байна. Зүүн Гурвансайханы нуруунд далайн царцдасын гаралтай чулуулгууд янзын бүрийн чиглэлтэй дайк хэлбэртэй илэрсэн нь меланжийн бүрдэл нь зөвхөн аккрецилагдаж буй арал талын бүрдэл бус, өөр гарал үүсэлтэйг харуулна. Энэ нуруунуудад тархсан тунамал хурдас хуримтлалд доод палеозойгоос дээд палеозойн фауны олдворууд тогтоогддог ч чулуулгийн бүтэц, бүрдэл ижил төстэйн улмаас судлаачдын санал зөрөлдөх шалтгаан болж байв. Ялангуяа Гурвансайхан серийн хурдсыг дунд дээд девонд ангилдаг ч залуу хурдсууд мөн энэ серийн хурдастай ижил төстэй харагддаг байна. Гурвансайханы нуруун дахь нэгэн хуримтлалын 283 ± 3 с.ж. настай хэмхдэслэг цирконы насыг Гурвансайхан серийн хурдсын нас мэт эндүүрэх ойлголтыг залруулах үүднээс энэ абстрактыг бичив.

Монгол орны геологийн хөгжлийг үндсэнд нь: кембрийн өмнөх, палеозойн эхэн, палеозойн дунд ба сүүл, мезозойн, кайнозойн гэсэн таван үе шатанд хуваах боловч үе шатуудын ялгаа болон одоогийн хотгор гүдгэрт нөлөөлөх байдлыг тодорхой болгохын үүднээс кембрийн өмнө ба палеозойн эхэн үе шат, палеозойн дунд ба сүүл үе шат, мезозойн ба кайнозойн үе шат, дөрөвдөгч галавын үе шат гэж ялган үзэж болох юм. Кембрийн өмнө ба палеозойн эхэн үе шатанд Монгол орны нутаг дэвсгэрт Завханы эх газар, түүний баруун болон зүүн талаар Палео-Азийн ба Палео-Номхон далай хөгжиж байсан бол палеозойн дунд ба сүүл үе шатанд эдгээр далайнууд хаагдаж эх газрын горимд шилжсэний сацуу Монгол орны өмнө талд Палео-Тетисын далай хөгжиж эхэлжээ. Палео-Тетисын далай хаагдсанаар мезозой ба кайнозойн үе шатанд Монгол орны газар нутаг эх газрын хөгжлөөр хөгжиж өнөөг хүрч байгаа ба энэ хооронд дөрөвдөгч галавын үе шатанд их мөстлөгийн нөлөөнд автсан нь гадаргын хөгжлийн өөрчлөлтөнд томоохон нөлөөг үзүүлсэн ажээ. Монголын нутаг дэвсгэр ирээдүй хойчдоо ямар хөгжлийг дамжин ямар болох, хэрхэн орших, яаж өөрчлөгдөх асуудал цаашдын судалгааны гол сэдвүүдийн нэг юм.

Aufeis formation in the winter season in settlements located in continuous, discontinuous, and isolated permafrost regions of Mongolia has become one of the urgent problems that must be solved in the settlement areas. In this study, the reasons for the formation of Aufeis in the settlement area of Erdenebulgan Soum, Khuvsgul Province, located in the Eg River valley, were clarified. In addition to the analysis of geomorphology and permafrost survey materials, the research was based on satellite image data and calculated using the methods of normalized snow index (NDSI) and snow water index (SWI). In the Eg River valley, the normative depth of seasonal freezing and thawing of subsoil ranges from 2.2-3.7 meters. Depending on the freezing of the winter season, there were long, short, and straight rows of cracks and fractures in the vicinity of river diversions, floodplains, terraces, or along the settlement zone. Over the past 10 years, the average size of the Aufeis area was 5555.8 m², and the average Aufeis volume was 5000.2 m³. In 2022, the Aufeis area increased sharply to 6,381.3 m², which can be related to that year's precipitation and soil temperature fluctuations. According to the area and volume classification of Aufeis in Mongolia, the research area belongs to the III class of medium-sized category, but it is exposed to the space of Aufeis distribution due to the improper expansion of the settlement area and wrong planning. According to the changes in the satellite map over the last 30 years, the diversion of the Eg River has caused the spatial distribution of the Aufeis to move towards the settlement area. This study is important for the planning of the spatial location of towns to determine the methods of pre-research and prevention of permafrost-related phenomena and engineering geomorphological problems.

Data on the origin and morphology of lake depressions in Mongolia are relatively poor, with 2% based on lake total studies. The morphological patterns of the lake depressions caused by volcanic activity have not been well studied in Mongolia. We present a result of existing reconstructions of lake depression development and changes in the hydrology system during the Khorgo volcanic activation and the Holocene environmental change. The morphometric analysis and field measurements indicate that the derivation of the Terkhiin Tsagaan Lake depression and Khorgo volcano may have evolved from movement on a sinistral strike-slip fault, which is about 70 km long. The southern mountains and rivers were displaced from northwest to southeast along the Terkh Fault. The offset along Terkh Fault is 4.02-5.28 km in the depression of the Terkhiin Tsagaan Lake. After movement, a wide valley of the Terkh River developed in the present landscape. The active Khorgo Volcano formed along the Khorgo Fault. The Terkhiin Tsagaan Lake is formed by blocked water from the Paleo-Terkh River after lava damming from the Khorgo Volcano. Our estimation area of the lava plateau was 30.4 km²; volume is consistent with 11.13 km³ of the lava plateau. Based on high-resolution satellite maps and field morphometric estimation is 22.1-51.2 m in thickness. The height of the terraces and lava plateau that show a Paleo-lake is about 2068 m above sea level. Paleo-lake area was about 195.7 km², which is calculated much larger than the modern Terkhiin Tsagaan Lake (60-62 km²) and Khuduu Lake (11-12 km²) using satellite maps. The water volume of the Terkhiin Tsagaan Lake is 0.351 km³, and the volume of the Paleo-lake was 2.248 km³. Based on this volume indicator the paleo-lake was 6.4 times larger than the current lake. Changes in the water volume of Terkhiin Tsagaan Lake and the erosion of the Suman River canyon are inversely related. The main result indicates that the mountains moved along the sinistral strike-slip fault from the northwest to the southeast direction. We suggest that the Khorgo Volcano formed in a lithosphere along an extensional bend in the fault. The fault is related to the active tectonics of Asia, and may represent a distant effect of the India-Asia collision.

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Монгол Улсад 20-р зууны хагасаас эхлэн геологи шинжилгээний ажил эрчимтэй өрнөж эхэлснээр өсөн нэмэгдэж байгаа мэргэжилтний хэрэгцээг дотоодын боловсон хүчнээр хангах шаардлага гарч ирсэн бөгөөд үндэсний геологийн сургалтыг зохион байгуулсан нь Монголын геологийн салбарын хөгжилд томоохон түлхэц болсон байна. 1960 оны 4-р сарын 11-ний өдрийн БНМАУ-ын Сайд нарын зөвлөлийн ба МАХН-ын Төв хорооны 171/112-р тогтоолын дагуу тухайн ондоо МУИС-ийн Байгалийн ухааны факультет (БУФ)-д Геологийн анги нээн хичээллүүлж эхэлснээр Монгол улсад Геологийн дээд мэргэжилтэй боловсон хүчин бэлтгэж эхлэв. 1982 онд МУИС-ийн харьяа Политехникийн дээд сургууль салснаар МУИС Геологийн ангигүй болжээ. Монгол Улсын ууган их сургууль МУИС-д Геологийн анги зайлшгүй байх шаардлагаар 1991 онд МУИС-ийн Ректорын тушаал гарч, тухайн оны 4-р сарын 1-нд БУФ-ийн дэргэд Геологийн тэнхим байгуулагдаж сургалтын ажлыг эхлүүлснээр МУИС-д геологийн мэргэжилтэн бэлтгэх хоёр дахь үе шат эхэлсэн юм. 1992 оноос Геологийн салбарын багшлах боловсон хүчин, сургалт-эрдэм шинжилгээний үйл ажиллагааг өргөжүүлэн хөгжүүлэх зорилгоор өргөн мэдлэг боловсрол, үйлдвэрлэлийн дадлага туршлагатай эрдэмтэд, судлаачдыг багшаар ажиллуулж эхэлсэн ба тэнхимийн багш нар Монголын геологи, геодинамик, тектоник, геоморфологи, ашигт малтмалын геологи, петрографийн судалгаа, палеонтологи, палеогеограф, ашигт малтмалын ордын эдийн засгийн үнэлгээ, мөн газрын доорх усны экологи, нүүрсний геологи, шатах ашигт малтмалын геохимийн чиглэлүүдээр ажиллаж, олон арван бүтээл туурвисан нь Монголын геологийн шинжлэх ухааны хөгжилд томоохон үүргийг гүйцэтгэж хөгжүүлсэн билээ.

Data on the origin and morphology of lake depressions caused by volcanism are scarce in Mongolia. Previous studies focused on climate change patterns based on Terkhiin Tsagaan Lake sediment. We present a result of existing reconstructions of lake depression development and changes in the hydrology system during the Khorgo volcanic activation and the Holocene environmental change. A depression of the Terkhiin Tsagaan Lake is formed by a lava flow barrier from the Khorgo volcano. However, the Khorgo volcanic eruption and the lake depression that could shape a large lake have arisen instead from a fault. The morphometric analysis and field measurements indicate that the derivation of the Terkhiin Tsagaan Lake depression and Khorgo volcano may have evolved from movement on a sinistral strike-slip fault, which is about 70 km long. The southern mountains and rivers were displaced from northwest to southeast along the Terkh Fault. The offset along Terkh Fault is 4.02–5.28 km in the depression of the Terkhiin Tsagaan Lake. After movement, a wide valley of the Terkh River developed in the present landscape. The active Khorgo Volcano formed along the Khorgo Fault. The Terkhiin Tsagaan Lake is formed by blocked water from the Paleo-Terkh River after lava damming from the Khorgo Volcano. The initial paleo-lake area was about 195.7 km2, which was three times larger than the modern lake. The current water volume of the Terkhiin Tsagaan Lake is 0.351 km3 while the volume of the paleo-lake was 2.248 km3. Based on this volume indicator the paleo-lake was 6.4 times larger than the current lake. Overflowing water from the lake depression formed the Suman River by a drying canyon through the lava plateau, but the canyon is along the Terkh Fault. Changes in the water volume of Terkhiin Tsagaan Lake and erosion of Suman River canyon are inversely related to each other. We present the morphometric relationships between the lava plateau of Khorgo Volcano and development of Terkhiin Tsagaan Lake depression.

There is the need to divide Mongolia's lake research into trends of development stages and to provide a detailed analysis of modern lake research. The aim of this study is to identify the development stages of lake research in Mongolia and to analyse lake research development. This study provides a comparative analysis of the development trends of lake research carried out in the country. The historical development of lake research in Mongolia was divided into 4 stages in chronological order, highlighting the current research direction, scope, and contribution to geography. Since 1990, researchers from many countries have been able to conduct extensive research in Mongolia, and especially since the 2000s, lake research intensified owing to global warming and environmental change. Studies, in particular, focus on paleogeography, paleoclimate changes, lake water regimes and water level fluctuation. Mongolian lake-based studies have tended to identify environmental evolution from the Pleistocene to the Holocene. The investigated areas were primarily Khuvsgul Lake and Darkhad Basin, Lakes Valley and Gobi Lakes, the Great Lake Depression, Mongolian Altai and Khangai Mountain lakes. Since 1990, scientists from Russia, Mongolia, Germany, China, Japan, USA and South Korea have been increasingly focusing on research into lakes in Mongolia. Paleogeographic and paleoclimatic reconstruction, based on the lakes of Central Asia, is being conducted in an innovative manner. Dividing Mongolia's lake research into development stages and identifying research trends will help determine which areas of research can be developed in the future.

There is a need to divide Mongolia's lake research into stages of development and to provide a detailed analysis of modern lake research. The purpose of this study is to identify the stages of development of lake research in Mongolia and to analyze thematic research areas published at the modern international level. The comparative analysis method was used in this study. The comparative research method is the process of comparing two or more data to compared one or more items. This study provides an overview of the development trends of lake research in Mongolia and a comparative analysis of thematic studies. The main result of the direction and scope of the lake survey were summarized and divided into 4 stages of development, highlighting the specifics of each stage of the study. Based on the lakes research since 1990 has focused on palaeogeography, paleoclimate changes, lake water regimes, and water level fluctuations. Mongolian lake-based studies have tended to identify changes from the Pleistocene to the Holocene. The studies area was dominated by the Khuvsgul-Darkhad basin, Lakes Valley and Gobi Lakes, Great Lakes Depression, Mongol Altay and Khangay Mountain lakes. Recent scientists from Russia, Germany, Mongolia, China and Japan tend to do more research on lakes in Mongolia.

This study focuses on the impact of faults on the origin and depression morphology of Bayan Nuur in North-West Mongolia. The relationships of Nuur and faults have been studied using morphometric analysis, spatially-improved remote sensing and magnetic survey. According to the results, the main fault formed in the western part of the Bayan Nuur depression influenced the origin of the lake depression SW -NE oriented. The length of the Bayan Nuur main fault is 147.1 km; 4 lakes have been formed along this fault, of which, the Bayan Nuur is the largest one. This study suggests that the Bayan Nuur origin is different from that suggested by previous studies and we conclude that the depressions hosting lakes in Mongolia need to be further investigated. This study represents a new contribution to better understand both the origin of the depressions hosting the Mongolian lakes and the impact of neotectonic activity, through morphometric analysis integrated with remote sensing analysis and geophysical surveys.

Lake depressions are intracontinental basins formed by endogenous or exogenous processes. Mongolia has a distinctive location that has a comparatively high topography in the inland of Central Asia, which extends along the latitude. Lakes and lake depressions of Mongolia are located with a lot of features in their formation. Some lake depressions are related to faults. Faults in Mongolia have been well studied, but the study of lake depressions along faults and development is scarce. The purpose of this study was to clarify the impact of the Bulnay fault on the lake depression types. The main factor causing the Bulnay fault is the effect of convergent tectonic movements of the Indo-Eurasian plate. In this study, the morphometric analysis, satellite and geophysical mapping analysis methods were used. This study presents results on the lakes along Bulnay faults and their development, including the Bust, Oigon, Sangyn Dalay Lakes in the Khuvsgul and Zavkhan provinces, respectively. The depressions of lakes such as Oigon, Bust, and Sangyn Dalai lakes were differentiated into fault subtypes of the main tectonic type. This study could represent an integrating mapping analysis to a better definition of the Mongolian lakes depression and the impact of tectonic processes.

Data on the origin and morphology of lake depressions in Mongolia is poor and only 2 percent of total studies. The morphological patterns of the lake depressions caused by volcanic activity have not been well studied in Mongolia. The morphometric indicators of Khorgo volcanic lava plateau, its effect on the morphological changes of the lake depression, and the relationship between them are not studied in detail. The Khorgo volcanic lava is analyzed to clarify how it formed and compare it to the origin of the neighbouring Terkhiin Tsagaan Lake depression. This paper is defined the effect of Khorgo volcanic lava plateau on the origin of the Terkhiin Tsagaan Lake depression, based on morphometric analysis, remote sensing and geological mapping. Also study is checked by field measurements as identifying fault lengths, locations and morphology. Upon the Khorgo volcano activation, the valley of the Terkh River was dammed by a lava plateau. Lava damming formed the Terkhiin Tsagaan Lake depression, blocking the Terkh River valley. Another evidence is the age of the lava plateau and lake sediment. Terkhiin Tsagaan Lake area was three times larger than it is now (9000 years ago), comparing the terraces on the shoreline of the lake. The lake water outflows via the Suman River. The Suman River diversion has created a large canyon along fault. Changes in the water volume of Terkhiin Tsagaan Lake and the erosion of the Suman Gol canyon are inversely related. This study is concerned that the effect of the youngest volcano in Central Asia is achieved a role in the development of lake depression, and presents a basis for integrating morphometric analysis to define the main phases of volcanic activity and lake depression evolution. Current lake area and volume is under influences of climate and environmental changes and human activities.

Abstract Following the breakup of Rodinia and the opening of the Paleo-Asian ocean the relative positions of geological units (now in Mongolia) remain uncertain, and in consequence relevant paleogeographic reconstructions are poorly construed. In this paper, we apply an integrated approach to the reconstruction of the Paleo-Asian ocean using preserved ophiolites and ocean plate stratigraphy (OPS) in the Mongolian Lake and Altay zones in western Mongolia, which surround the Precambrian Central Mongolian Microcontinent (CMM) in the center of Central Asia. The Lake Zone of Mongolia contains many sediments of Ocean Plate Stratigraphy (OPS) and their underlying basalt-dominated ophiolites, which occur in three main zones along the western margin of the Precambrian crystalline basement of the CMM. The ophiolites in all zones have similar isotopic ages of ca. 570 Ma. The sections of OPS, together with serpentinite mélanges and other volcanogenic-sedimentary assemblages, have been thrust in nappe sheets over the Zavkhan block of the CMM. In the Neoproterozoic microcontinents derived from Rodinia drifted towards Siberia, and a passive margin developed on the Zavkhan block on the eastern margin of the Paleo-Asian ocean. In mid-upper Neoproterozoic times the eastern side of the Paleo-Asian oceanic plate was thrust over the CMM, and in the early Cambrian the Khasagt and Tas Khairkhan ophiolites were obducted and a mid-ocean ridge (?) reached the CMM, preventing further obduction. In the Neoproterozoic the western margin of the Paleo-Asian ocean was subducted under the Rodinia-derived microcontinent and evolved into an active continental margin. In mid-Cambrian–early Ordovician times thick turbidites were deposited in the Altay. Marine sediments, which had accumulated in the Devonian to Carboniferous in the Paleo-Asian ocean are preserved in a remnant ocean in the Lake Zone. Locally in the Devonian, terrigenous – volcanogenic sequences were deposited in the Ulgey extensional superimposed basin, and later in Meso-Cenozoic time (?) some ophiolitic and OPS fragments (Tsagaan Nuur, Ulaankhus and Bodonch) were exposed along fault escarpments that were possibly re-activated during transpression related to the India-Eurasia collision. Our analysis of the Neoproterozoic–Middle Paleozoic tectonic development of western Mongolia leads to a new holistic model for the evolution of the western Altaids, according to which the ophiolites and OPS formed in the Mongolian Lake and Altay zones between two microcontinents within a new tectonic framework of the western Altaids.

Нуурын геоморфологнйн судалгаа нуурын эрэг, дэнжийн морфологи хэлбэрийг зонхилон авч үздэг, нуурын хурдасын онцлог, ус зүйн горим дээр тулгуурлан эртний газарзүйн орчин, уур амьсгалын өөрчлөлтийн сэргээн босголт дээр төвлөрч ирсэн бол нуурын хотгорын асуудал морфологийн үүднээс дэвшүүлэгдсэн асуудал харьцангуй бага байсан байна. Бид энэ өгүүлэлд нуурын геоморфологийн судалгаанд хотгорын морфологи хэлбэрийг авч үзэхийг дэвшүүлж байна. Үүний тулд, элсэн хаагдлаар үүссэн нуур хэмээн үзэж байсан Завхан аймгийн Баян нуурыг сонгон авч, геоморфологийн ба бусад уялдааг аргуудаар шалган үзсэний үндсэн дээр элсний хаагдлаар үүссэн бус тектоникийн гаралтай хоггорт хуримтлагдсан нуур болохыг батлан гаргалаа. Улмаар, Монгол орны хэмжээнд өмнөх судлаачдын боловсруулсан нуурын хоггорын хэв шинжийн ангиллуудад харьцуулалт хийн шинэчилж, Мошолын нуурын хоггоруудад 8 үндсэн хэв шинж, 20 дэд хэв шинж ялгарч байгааг дэвшүүлж байна.

An improved classification of the origin of lake depressions due to geological, geomorphological factors and climate change is a requirement of the day in Mongolia. We present a new holistic classification using comparative analysis method. This study suggests a two-tier classification in terms of origin and morphological feature of the lakes, which replaces the previous one-tier classification. Mongolia has identified 11 main and 26 subtypes of origin, and 8 main types of morphology, based on the features of 32 lake depressions. The result of the study shows that the lakes of Mongolia developed in 3 stages, first, affected by tectonic movement, followed by glacial and finally, owing to other exogenic factors. This morphological classification study will create the basic conditions for preserving and using these lakes more efficiently and ecologically in the future by making the classification of the origin of lake depression.

The appearances of the lake depression, area of the lakes, and its geographical location have changed over time due to some influences. Lake depressions are an intracontinental basins formed by endogenous or exogenous processes. An area and volume of lake depression may have changed by dynamic processes, if depression is exogenic in origin. Some lake depressions are related with faults. Faults in Mongolia have been well studied, but study of lake depressions along faults and development is poorly. This study presents a results on the lakes along faults and their development, including the Bayan Lakes in the Uvs and Zavkhan provinces, respectively, and Ulaagchiny Khar Lake. We highlight that we revealed to make a new genetic classification of lakes in the western Mongolia and to identify a changes of water regime, and of lake area and volume, based on study results.

Data on the origin and morphology of lake depressions in Mongolia are relatively poor. Bayan Lake in Zavkhan Province, Western Mongolia, has freshwater, supplied by groundwater emanating from a tectonic fault-oriented northeast to southwest, defining the southeastern side of the Bayan Lake. The depression of Bayan Lake has a tectonic origin, related with the fault which on its southern side, which is covered by sand dunes. The results of morphometric analysis, satellite mapping, geomagnetic anomaly assessment, and other relevant methods all support that the southern margin of the lake is defined by a large fault. The depression morphology of Bayan Lake shows that it was formed by subsidence accommodated by the fault along the southwestern side of the lake. Bayan Lake depression has the origin tectonic, but the recent barrier in the south is the dunefield on the bedrock.

Lake depression and its volume and area have been changed around the earth due to geological, geomorphological processes and climate change. Data on the origin and morphology of the lakes in Mongolia is relatively poor. This study presents the research results related to several lakes of Mongolia, including Khoton, Khurgan, Dayan, Tolbo and Tal lake depression of the Mongol Altay mountains which were formed along tectonic and glacier. Analysis of Topography, Spatial Improvement method of remote Sensing have been implemented for this study. The present morphological patterns of lake depression were defined by coherent research methods. The formations and evolution of the lakes depend on climate conditions, precipitation, and humidity changes, but their depressions have a different origin and morphology. We are seeking the possibilities to make a new genetic classification of the Mongolian lakes and to identify factors that changes in water regime, volume and area of lakes, relating with lake depression formed along in detail as well.

The study of the origin of lake depressions is very important. The origin of lake depressions has always attracted researchers. Historically, due to geological, geomorphological and climate change, the volume and area water in the lakes around the world has changed. The processes are reflected in the depressions of the lake. That is why it is difficult to determine the origin of depression in the lakes. Researchers have classified the lake depression into different origins. Comparative analysis method were used in this study. An updated classification has been developed by comparing these categories. For the present, the classification of the origin of the lake depression in Mongolia is lacking. In the future, there have required to renew and re-define the origin of lakes depression in Mongolia. There is need international lake depression classification of Mongolian lakes.

Data on the origin and morphology of the lakes in Mongolia is relatively scarce. This study represents the relationship between lake depression and faults of Uvsyn Bayan Lake, Uvs province, in Mongolia. Lake, volume, and area have changed around the earth due to geological and geomorphological processes and climate change. Geological faults may relate to the lake depression. Whereas, to the best of our knowledge, lake depressions along faults have not been studied yet according to the previous studies. The methods have been used in this study are morphometric methods (Analysis of topography, geomorphological criteria, hypsometric integral (HI) and Relief Slope (RSl) analysis), Spatial improvement method of remote sensing and, geophysical magnetic survey. The present morphological patterns of lake depression were defined by coherent research methods. Our result suggests that a fault has a significant impact on the origin of lake depression. According to study results, main fault was formed in the western part of the Uvsyn Bayan Lake depression. In our field investigation and based on coherent methods, we clarified that the fault influenced the origin of the lake depression, directed by the fault SW to NE. The length of the main fault is 82, 5 km; 4 lakes have been formed along this fault. The largest of the Uvsyn Bayan Lake. The current research suggests that the Uvsyn Bayan Lake origin is different from the previous explanation, and the depressions of the lakes in Mongolia need to be redefined further.

The wetland ecosystem and its driving mechanism are significance impact on the ecological environment and the sustainable development of semi-arid regional economy. Agricultural and industrial land use/land cover change (LUCC) is also important for wetland system. The Daihai wetland (DW) in Inner Mongolia has been suffering from severe environmental problems such as water resource shortages and wetland areas decrease. We analyzed spatiotemporal LUCC at the catchment scale of Daihai Lake, which has recently exhibited a dramatic loss of water area, and investigated the potential role of climatic changes and human activities in the wetland loss. From 1976 to 2015, the arable land and construction land increased by 71.72 and 15.81 km2, with ranges of 18.72% and 39.61%, respectively. Meanwhile, the wetland area decreased by 84.47 km2, accounting for 29.07% of the area in 1976. From 1960 to 2015, the area of Daihai Lake decreased by 100.73 km2, diminishing to 37.09% of the area in 1960, and the lake storage accordingly shrank from 12.9 × 108 to approximately 3.9 × 108 m3. The lake level also rapidly declined. From 1962 to 2014, the lake water mineralization, total nitrogen (TN), and total phosphorus (TP) increased by 2410, 7.86, and 0.182 mg L-1, respectively. The pollution sources included not only mineral fertilizers and pesticides, but also livestock, poultry breeding, aquaculture, and rural household waste. The lake area decreased with increasing agricultural development, Daihai power plant (DHPP) water consumption, and catchment climatic dryness. Thus, the urgent implementation of effective restoration and mitigation measures are needed.

Родиниа тивийн задрал, Палео-Азийн далайн нээгдлийн үед Монголын структуруудын байрлал ямар байсан нь маргаантай, тэдгээрийн сэргээн босголт сул байна. Энэ өгүүлэлд бид ТАОБ ба Палео-Азийн далайн хувьсалтай уялдуулан Баруун Монгол дахь Нуур, Монгол Алтайн бүс, тэдгээртэй зэргэлдээ Тува-Монголын ба Төв Монголын бичил тивүүдийн тусгаар структуруудыг нэгтгэн авч үзлээ. Бид Баруун Монгол, улмаар ТАОБ-ийн Неопротерозой – түрүү Палеозойн тектоник хөгжлийн тоймыг харуулж, хувьслын шинэ загварыг дэвшүүлж байгаа юм. Нуурын бүс бол ТАОБ доторх офиолит, нумын бүрдлийн гол бүс юм. Офиолитын үндсэн зүсэлт Төв Монголын бичил тивийн кембрийн өмнөх талст суурьтай хиллэж байгаа зүүн захын дагуу байршсан байна. Офиолитууд хойноос өмнө тийш тархсан, нас нь төсөөтэй тогтоогдсон байна. Нуурын бүсэд сонгодог ДПС-ийн зүсэлт хадгалагдан үлдсэн байна. Нуурын бүсийн гаралтай серпентинитын меланж, бусад вулканоген-терриген зузаалаг Төв Монголын бичил тив (ТМБТ)-ийн Завханы блок дээгүүр тохролын систем байдалтай байдаг онцлогтой. Алтай-Нуурын бүсийн өмнө талыг дагасан структур Гондванаас гаралтай бичил тив, Палео-Азийн далайн хоорондох хөгжлийг тайлбарлах боломжийг олгож байгаа юм. Неопротерозойгоос өмнө, Сибирь, ТМБТ хоорондын аккрецын улмаас Тува-Монголын бүс үүссэн нь сүүлд Алтай-Нуурын бүсийн зүүн захын тохролоор холбогдсон коллизын бүс болжээ. Баруун Монголын сайтар мэдэгдэж байгаа бүх офиолитууд (Агардаг, Хантайшир, Дарив), мөн Эрдэнэ Уулын офиолит 655-540 сая жилийн хооронд буюу Неопротерозойд хөгжиж байсан бичил тивүүдийн хоорондох задгай далайн үе шаттай илүү холбогдоно. Түрүү Неопротерозойд зүүн Гондваны рифтээс тасарсан Алтайн хойг маягтай бичил тив аажмаар Сибирь рүү хөдөлсөн. Энэ үед Палео-Азийн далайн зүүн зах Завханы блоктой идэвхигүй зах байдалтай хөгжиж байжээ. Алтайн бичил тив Сибирь – ТМБТ рүү хөдлөхтэй зэрэгцэн Палео-Азийн далайн плит ТМБТ рүү мөн шахаж хөдөлсөн. Дунд-хожуу Неопротерозойн үед Палео-Азийн далайн плитийн зүүн зах ТМБТ дээгүүр тохорч, офиолитын обдукц үүсгэсэн (Тас хайрхан зэрэг) бол түрүү Кембрийн үед Палео-Азийн далайн спредингийн төв (?) ТМБТ хүрч, обдукц зогссон байх боломжтой байна. Неопротерозойд Палео-Азийн далайн баруун зах Гондванаас гаралтай бичил тивийн доогуур шургасан субдукц бүхий эх газрын идэвхитэй зах байдлаар хөгжиж байсан. Түрүү Кембрид субдукцын ухралт, симаунтын аккрец (Түргэн) голлох ач холбогдолтой болсон. Үүний дараа, дунд Кембри – түрүү Ордовикийн үед Алтайд томоохон турбидит хурдас хуралдсан. Девоноос карбон хүртэл Палео-Азийн далай үлдэгдэл далай буюу томоохон тэнгис (Нуурын бүс) байдалтайгаар хадгалагдаж байсан тул тэнгисийн хурдас хуралдсаар байжээ.

Cenozoic basalt, which is widespread in Mongolia, has been attracting the attention of Central Asian researchers since the beginning of the last century. This study identified the geomorphological shape of the Khorgo volcano. The main purpose of the study is to determine the origin and morphological form of Khorgo volcano, a key representative of Cenozoic volcanism. In general, there are several types of morphological forms associated with lava overflow, and it is important to determine which types are the most common and also to establish a link between them. Geomorphological studies in this area have not been conducted in Mongolia. Spatial improvement and morphometric methods satellite imagery had identified Khorgo volcanic faults. Khangai magmatism had thinned its crust to 45 km during the Tariat-Chuluut volcanic activity. It can be concluded that this was due to the thinning of the continental crust in the Khangai Mountains because of mantle plume. During this time, tectonic faults formed were formed, which had broken through the earth's crust. Part of this fault was formed in the vicinity of Khorgo Mountain from northwest to southeast, and lava flowed with the basic composition, which led to the formation of the current morphological form of Khorgo volcano. The lava flow was less than 45% silica and potassium-dominated, which blocked the Suman River valley and formed the present-day Terkhiin Tsagaan Lake. The morphometric analysis compared the morphology of a typical volcano, which showed that the mouth of the crater of the Khorgo volcano has a slope slanting about 45 degrees, it is about 100 meters in depth, with a diameter of about 500 meters. By comparing the basalt composition of the Khorgo volcano and its morphometric characteristics with other standard volcanoes, it has been determined that it is in the form of a lava dome.

The position of structures of Mongolia during Rodinia break-up and Paleo-Asian ocean opening is debatable, and reconstructions between them is poorly known. In this paper, we apply an integrated approach to the not widely known yet distinctive structure (ribbon-like) of the Lake and Mongolian Altay zones in Western Mongolia, relating these with the surrounding Tuva-Mongolian and Central Mongolian microcontinents development within the CAOB and Paleo-Asian ocean evolution. We present a summary of the Neoproterozoic – Early Paleozoic tectonic development of Western Mongolia, and the CAOB and suggest a new comprehensive model for its evolution. The Lake zone of Mongolia is a major zone of ophiolite and arc complexes within the CAOB. The main sections of ophiolites are located along the east margin, bordering with pre-Cambrian crystalline basement of the Central Mongolian Microcontinent. The ophiolites are distributed from north to south and have been dated to have similar ages. A classic OPS section is preserved in the Lake zone. Serpentinite mélange and other volcanogenic-terrigenous assemblages from the Lake zone is characterized by a system of nappe sheets thrust over the Dzavkhan block of the Central Mongolian Microcontinent (CMM). The ribbon-like structure which the southern part of the Altay – Lake zone preserves at present provides an explanation for the development between the Gondwana-derived microcontinent and Paleo-Asian ocean. During the pre-Neoproterozoic, convergence accretion between Siberia and the CMM formed the Tuva-Mongolian belt, which later converted to the Altay – Lake collision zone associated with the thrusting of its eastern margin. All well-known ophiolites of western Mongolia (Agardag, Khantayshir, Dariv) as well as ophiolites of the Erdene-Uul area mostly correspond to an “open-ocean” phase with drifting microcontinents between 655–540 Ma or Neoproterozoic. In the Early Neoproterozoic, the Altay peninsula-like ribbon microcontinent after rifting of East Gondwana gradually drifted to Siberia. In this time, the east margin of the Paleo-Asian ocean was developed as a passive margin with the Dzavkhan block. The Paleo-Asian ocean plate simultaneously drifted to the CMM, while the Altay microcontinent moved into Siberia-CMM. In Middle-Upper Neoproterozoic times, the eastern part of the Paleo-Asian ocean plate was thrusted over the CMM, obducting ophiolites (e.g., Tas Khairkhan), in the Early Cambrian time, an oceanic spreading center (?) of the Paleo-Asian ocean reached the CMM and stopped obduction. In the Neoproterozoic, the west margin of the Paleo-Asian ocean was developed as an active continental margin, with subduction under the Gondwana-derived microcontinent. In the Early Cambrian, there was significant subduction roll-back and accretion of seamounts (Turgen). Later, in Middle Cambrian – Early Ordovician times, a large turbidite sequence was deposited in Altay. During the Devonian to Carboniferous, the Paleo-Asian ocean was preserved as a remnant ocean or big sea (Lake zone), accumulating marine deposits after collision of Siberia and the Gondwana-derived microcontinent by Late Cambrian.

Information about the depression origin of some lakes is out in previous studies on the genetics and morphology of lakes in Mongolia. One example of these is the genetics of Ulaagchinii Kharnuur. The site research was done by using the morpho-structural method and integrated the results in topographic and satellite images implementing the software such as remote sensing, etc. Ulaagchinii Kharnuur is a freshwater lake supplied with the deepwater due to tectonic faults. In other words, thaw depression in the middle of Ulaagchinii Kharnuur basin is may be related to the tectonic fault from northwest to the southeast. The Ulaagchinii Kharnuur is very much defined as the lakes which are large, deep and with the steep bed are inequalities in the tectonic fault lakes, and the lake's depression is narrow and heavily shaped. It proposes the tectonic origin for Ulaagchinii Kharnuur which origin was recorded as having an Aeolus.

Our research aim is to define beneficiary way that what methodology can use be for educating and geomorphology in order to make the students with full of theory and practical knowledge gained during class or courses. In order to organizing such field practice, The field workshops are designed to be more effective for students in obtaining newer methods, its uses, taking account into their own unique structure of learning, engaging knowledge with the practic that gained through classroom training, testing, adaptable to the fieldwork and research tools using methodologies for both pedagogy and geomorphology. For this research, we managed research methods for learning from scientific basics and applied research for motivation, creative thinking and activation as well as surface morphology, age, relief parameters and their uses in practices based on geomorphological research methods such as morphometric and morph structure, morph geography. All students would learn taking measurements, observation, writing and mapping in the field using this training methodology. We concluded some result about methodology for lecturers and students in organizing their implemented tasks under preparation and practice stages in the field situation. Besides that, we attached noting patterns for geomorphological field measurement record sheet and training field practice report.

ABSTRACT The book, Cenozoic alkaline basalts of Mongolia and their deep inclusion, volcano existing during Cenozoic was firstly written by V.V.Kepejenskas in 1979 was the first comprehensive monograph including integration of results in many years. The aim of my paper is to define volcanic origin of the Khorgo as the one representative and its morphology or landscape based on such monograph. In Mongolia, there is nothing about study on morphological features by volcanic activity. There are much morphology formed due to effusive effect of lava with basic content in which it’s very crucial to find out which type of morphology had been distributed and relation between origin preferring Khorgo volcanic issues. Thickness of crust of Tariat volcano was 45 km during its activity (Stoch, Kopylova 1995; Ionov 2002). Harris (2009) Due to the ground hot spot, continent became thinner resulted as Khangai magmatic activity. Many intermissive breakdowns through earth crust were formed here. Therefore, due to such formation of intermissive breakdown or one of the main breakdown extending from north-west to south east became stream for basic lava resulted in formation of Khorgo volcano. Lava stream consisting of silicon oxide less than 45% and predominant kali content with fluidity formed as barrier blocking the Suman river valley which led to the formation of Terkhiin Tsagaan lake. Research showed that it was lava elevation among morphologies formed by lava with basic content. The steepness of crater of Khorgo volcano is around 45 degrees while its depth and diameters are 100 m and 500 m respectively. Scientists have predicted that the age. Khorgo volcano as approximately 1.8-2.0 million years in quaternary. Therefore, it’s needed to precise the age of its rocks. Keywords: Khorgo, Fracture, Lava elevation

Information about the origin of some lakes is out in previous studies on the genetics and morphology of lakes in Mongolia. One example of these is the genetics of Bayan nuur. If we look at the morphology of the lake basin using a morpho-structure method based on previous studies, it is seen that it matches with the orthogonal fault of the Bayan nuur basin. Bayan nuur originated by tectonic fault is a freshwater lake supplied with the deep water. In other words, thaw depression at the southwest coast of Bayan nuur basin is related to the tectonic fault from northwest to the southeast (non-barrier). It leads to a condition that water resource of the lake is supplied with the deep water which is contained in sediment for the Quaternary Glacial Period. Cross section between main fault and crustal fault at the east coast of Bayan nuur basin from northeast to the southwest presents the orthogonal compound fault. If we look at overlaying depth of the lake with its area, volume, and isobath, it is seen that the origin of the lake is related to transfer of sands at the south side of the lake without a sand barrier. Thus it confirms that Bayan nuur originated in depression along tectonic fault

The book, Cenozoic alkaline basalts of Mongolia and their deep inclusion, volcano existing during Cenozoic was firstly written by V.V.Kepejenskas in 1979 was the first comprehensive monograph including integration of results in many years. The aim of my paper is to define volcanic origin of the Khorgo as the one representative and its morphology or landscape based on such monograph. In Mongolia, there is nothing about study on morphological features by volcanic activity. There are much morphology formed due to effusive effect of lava with basic content in which it’s very crucial to find out which type of morphology had been distributed and relation between origin preferring Khorgo volcanic issues. Thickness of crust of Tariat volcano was 45 km during its activity (Stoch, Kopylova 1995; Ionov 2002). Harris (2009) Due to the ground hot spot, continent became thinner resulted as Khangai magmatic activity. Many intermissive breakdowns through earth crust were formed here. Therefore, due to such formation of intermissive breakdown or one of the main breakdown extending from north-west to south east became stream for basic lava resulted in formation of Khorgo volcano. Lava stream consisting of silicon oxide less than 45% and predominant kali content with fluidity formed as barrier blocking the Suman river valley which led to the formation of Terkhiin Tsagaan lake. Research showed that it was lava elevation among morphologies formed by lava with basic content. The steepness of crater of Khorgo volcano is around 45 degrees while its depth and diameters are 100 m and 500 m respectively. Scientists have predicted that the age. Khorgo volcano as approximately 1.8-2.0 million years in quaternary. Therefore, it’s needed to precise the age of its rocks. Keywords: Khorgo, Fracture, Lava elevation