{"title":"Uranium deposits of Mongolia, their exploration and mine development","authors":"Dorjyunden Altankhuyag, Baldorj Baatartsogt, Batbold Munkhtur","doi":"10.5564/mgs.v0i49.1227","DOIUrl":"https://doi.org/10.5564/mgs.v0i49.1227","url":null,"abstract":"Most of the known uranium deposits in Mongolia are related to volcano-tectonic structures of the Late Mesozoic and permeable sandstone aquifers of terrigenous sedimentary rocks in Late Mesozoic-Cenozoic basins. A young uranium deposit has been recently discovered at the surface in Quaternary alluvial sediments. Uranium deposits are classified here according to the International Atomic Energy Agency (IAEA) classification scheme. Beside of supergene and hydrothermal uranium discoveries, uranium mineralization can also be found in the Lower Cretaceous lignite seams, in Mesozoic alkaline intrusive rock related REE, Th, U enriched mineral systems and in metasomatic rocks, as well as in migmatites and pegmatites localized in Precambrian metamorphic rocks. Currently, no uranium can be produced in Mongolian facilities except pilot testing being done first. A pilot test was carried out at the Khairhan and Kharaat deposits in Mongolia and these experiments have demonstrated the ore to be amenable to acid leach (sulphuric acid) with the addition of an oxidizing agent. These tests confirmed that hydraulic control can be maintained and that the uranium solubilization and mobilization can be controlled. The results of the test were encouraging, with the well production rate, uranium concentration in produced solutions, chemical usage, and estimated uranium recovery all within ranges expected for normal commercial operations. There are a number of Mongolian uranium deposits are in the stage of mine development. The Government of Mongolia has approved the agreement of mine development of the Zuuvch ovoo and Dulaan uul deposits. Pilot testing on these deposits is underway and uranium will be extracted by in-situ leaching soon.","PeriodicalId":52647,"journal":{"name":"Mongolian Geoscientist","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43166191","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
B. Tumenbayar, R. Grayson, V. Petrova, Rentsendorj Enkhsaikhan
{"title":"Natural zeolite formation in Mongolia","authors":"B. Tumenbayar, R. Grayson, V. Petrova, Rentsendorj Enkhsaikhan","doi":"10.5564/mgs.v0i49.1225","DOIUrl":"https://doi.org/10.5564/mgs.v0i49.1225","url":null,"abstract":"The genesis of natural zeolite in Mongolia is attributable to the late Mesozoic tectonic-magmatism activity in East Mongolia - Dornod. The numerous volcanoes formed during this activation process were surrounded by Cretaceous depressions with mineralized waters (Na+, K+, Ca+, Мg+, Al+, H+, SO42-, CO32- ,Cl-, O2- etc.). The huge amount of ash (glass) emanating from volcanic eruptions fell into the mineralized waters; the hydrolysis of amorphous (silicon-oxygen) structure of the glassy ash was dispersed by the effects of acid and alkaline in the water and became colloids. With the water composition transformation, the silicon and oxygen ions bonded together to form tetrahedral radicals, so forming a structure built up through low-pressure silicon-oxygen chains to become the spongy, web-like structural “skeletons” of zeolite minerals. This silicon-oxygen net structure has hollow spaces of varying sizes, which generates strong charges inside, capable of pulling in and out ions and molecules of various dimensions. These naturally occurred rocks (zeolite) are referred to as “molecular sieves” functioning as a sort of colander for radicals. In other words, it breathes. By this means, a vast region developed rich in natural zeolites of many different types under the influence of the geological, paleogeographic and crystallographic factors noted above and have the volcanic sediments’ origin. Among these, clinoptilolite, chabazite and mordenite deposits have, according to our research, a strategic significance for our country’s possible chemical pollution and nuclear poisoning (reflected in the next article). Also, it is now very obvious that Mongolia's natural zeolites can be used in many branches like heavy industries, construction, agriculture, livestock and household needs.","PeriodicalId":52647,"journal":{"name":"Mongolian Geoscientist","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42344227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"New scientific direction of the bacterial paleontology in Mongolia","authors":"D. Dorjnamjaa, G. Altanshagai, B. Enkhbaatar","doi":"10.5564/mgs.v0i49.1226","DOIUrl":"https://doi.org/10.5564/mgs.v0i49.1226","url":null,"abstract":"We review the initial development of Bacterial Paleontology in Mongolia and present some electron microscopic images of fossil bacteria in different stages of preservation in sedimentary rocks. Indeed bacterial paleontology is one the youngest branches of paleontology. It has began in the end of 20th century and has developed rapidly in recent years. The main tasks of bacterial paleontology are detailed investigation of fossil microorganisms, in particular their morphology and sizes, conditions of burial and products of habitation that are reflected in lithological and geochemical features of rocks. Bacterial paleontology deals with fossil materials and is useful in analysis of the genesis of sedimentary rocks, and sedimentary mineral resources including oil and gas. The traditional paleontology is especially significant for evolution theory, biostratigraphy, biogeography and paleoecology; however bacterial paleontology is an essential first of all for sedimentology and for theories sedimentary ore genesis or biometallogeny","PeriodicalId":52647,"journal":{"name":"Mongolian Geoscientist","volume":"407 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41263186","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Baatar Gendenjamts, B. Munkhtsengel, D. Odgerel, Dorjgochoo Sanchir, B. Ganbat
{"title":"Age, origin and tectonic setting of Dulaankhan granitic pluton in northern Mongolia","authors":"Baatar Gendenjamts, B. Munkhtsengel, D. Odgerel, Dorjgochoo Sanchir, B. Ganbat","doi":"10.5564/mgs.v0i49.1224","DOIUrl":"https://doi.org/10.5564/mgs.v0i49.1224","url":null,"abstract":"Dulaankhan granitic pluton, which is situated in northern Mongolia, the southern portion of the Mongolian-Transbaikalian belt (MTB), is petrographically composed of fine to medium-grained peralkaline granite and is intruded by a small body of quartz syenite. Geochemical data show the Dulaankhan granite and the intruding quartz syenite are both slightly peraluminous and high-K calc-alkaline, and are enriched in LREEs relative to the HREEs, with negative Eu anomaly, and in large ion lithophile elements (LILEs; such as K, Cs and Rb) with respect to high field strength elements (HFSEs; e.g., Nb, Ta and Ti). In terms of relations of Nb, Zr and Y to Ga/Al, however, the Dulaankhan granite and quartz syenite show geochemical features of A-type granites and can be classified into the A2-sub type granite, implying that the pluton formed in an post-collision extensional environment. LA-ICPMS zircon U-Pb dating results suggest that the Dulaankhan granite crystallized at 198±1 Ma, whereas the intruding quartz syenite at 180±1 Ma, consistent with our field observation that the quartz syenite intrudes the granite, attesting that the two granitic bodies were emplaced at different times although both of them formed during the Early Jurassic period. According to these new data, as well as regional ones, we propose that the Dulaankhan granitic pluton was likely generated in the post-collision setting related to the orogenesis of the Mongol-Okhotsk belt that seems to occur prior to Early Jurassic in the northern Mongolian segment.","PeriodicalId":52647,"journal":{"name":"Mongolian Geoscientist","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44584581","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Togtokh Khasmaral, Bars Amarjargal, L. Miao, B. Munkhtsengel, A. Chimedtseren
{"title":"Geochemical comparison of late Mesozoic and early Cenozoic volcanic rocks in South Mongolia","authors":"Togtokh Khasmaral, Bars Amarjargal, L. Miao, B. Munkhtsengel, A. Chimedtseren","doi":"10.5564/mgs.v0i49.1223","DOIUrl":"https://doi.org/10.5564/mgs.v0i49.1223","url":null,"abstract":"The Mesozoic-Cenozoic volcanic rocks are widely distributed in the interior of the East Asia and document the tectonic transition of East Asia. We present new geochronology and geochemistry data of late Cretaceous-early Cenozoic basalts in Bayantsagaan and Han-Uul volcanic provinces in South Mongolia, in order to explore their petrogenesis and geodynamic settings. The volcanic rocks in the Bayantsagaan and Han-Uul field yielded K-Ar ages of 90.55±1.93 Ma and 55.49±1.49 Ma, respectively. The volcanic rocks in South Mongolia can be subdivided into to alkaline basalts and tholeiitic series, and are characterized by ocean island basalts (OIB) trace elements features, such as enrichment of light REE relative to heavy REE and enrichment in large ion lithophile elements (LILE) with positive K anomaly. Compared with the late Cretaceous, the early Cenozoic basalts show a decrease in the contents of HREE and an increase of Nb and Ta. Crustal contamination and fractional crystallization are insignificant in the genesis of late Cretaceous-early Cenozoic basalts South Mongolia. The available Sr-Nd isotope results indicate that a mixing depleted (DM) and enriched mantle (EM) signature characterize in late Cretaceous volcanic rocks, which derived from magmas from the asthenosphere with some contributions of metasomatized subcontinent lithospheric mantle, whereas the early Cenozoic basalts are ascribed to contributions from the asthenospheric mantle. We propose that the generation of the late Cretaceous-early Cenozoic volcanism (90-40 Ma) in Mongolia is probably related to the shallow mantle upwelling (asthenosphere) induced by the edge convection along the northern margin of the North China Craton (NCC), triggered by a far-field effect of Indo-Asian collision.","PeriodicalId":52647,"journal":{"name":"Mongolian Geoscientist","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45018592","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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