Mongolian Geoscientist最新文献_第3页

Investigation of the electrical resistivity structure of the subsurface at Mogod valley in central Mongolia: Insight is using 1D Magnetotelluric inversion 蒙古中部莫戈德山谷地下电阻率结构研究:Insight利用一维大地电磁反演

Mongolian Geoscientist Pub Date : 2022-07-16 DOI: 10.5564/mgs.v26i54.1810

Bayartogtokh Enkhzul, E. Batmagnai, S. Tserendug, G. Bayanjargal

{"title":"Investigation of the electrical resistivity structure of the subsurface at Mogod valley in central Mongolia: Insight is using 1D Magnetotelluric inversion","authors":"Bayartogtokh Enkhzul, E. Batmagnai, S. Tserendug, G. Bayanjargal","doi":"10.5564/mgs.v26i54.1810","DOIUrl":"https://doi.org/10.5564/mgs.v26i54.1810","url":null,"abstract":"In this paper, we report a preliminary result of the Magnetotelluric investigation of the Mogod area. The Mogod region is one of the most prominent fields for geophysical study since the region includes young and active faults and geothermal activities. We conducted magnetotelluric measurements at 20 sites during geophysical field seasons in 2018-2021 as a pilot survey to understand data property and the electromagnetic noise level for the detailed electromagnetic studies. During the fieldwork, we used Lemi Magnetotelluric instruments and measured all three orthogonal components of the magnetic field and the horizontal components of the electric field. For the data processing, we used Matlab code by using the M-estimate regression method, and estimated the magnetotelluric transfer function with a lownoise level. The electrical resistivity model of the subsurface of survey layout shows us the existing resistivity anomalies at shallow-depth, and thickness of the upper crust approximately 11-17 km. Here, suggest that the thickness of the upper crust is 17 km and crust is 40 km with local magnetotelluric measurements. Additionally, the electric conductor appears in the southwest of Mogod region, we interpret that conductor play as a source of geological activity of Mogod region, and it might be the signature of a remanent fluid.","PeriodicalId":52647,"journal":{"name":"Mongolian Geoscientist","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41876512","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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A critical issue 关键问题

Mongolian Geoscientist Pub Date : 2022-03-01 DOI: 10.1144/geosci2022-006

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The Society and the climate summit 社会与气候峰会

Mongolian Geoscientist Pub Date : 2022-03-01 DOI: 10.1144/geosci2022-002

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The geoscience time machine 地球科学时间机器

Mongolian Geoscientist Pub Date : 2022-03-01 DOI: 10.1144/geosci2022-007

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From dirt to pay dirt 从肮脏到肮脏

Mongolian Geoscientist Pub Date : 2022-03-01 DOI: 10.1144/geosci2022-003

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I have a passion for wild places 我酷爱荒野

Mongolian Geoscientist Pub Date : 2022-03-01 DOI: 10.1144/geosci2022-008

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Natural hydrogen: the new frontier 天然氢:新前沿

Mongolian Geoscientist Pub Date : 2022-03-01 DOI: 10.1144/geosci2022-005

引用次数: 1

Critical policies 重要的政策

Mongolian Geoscientist Pub Date : 2022-03-01 DOI: 10.1144/geosci2022-001

引用次数: 0

Multi-stage serpentinization of ultramafic rocks in the Manlay Ophiolite, southern Mongolia 蒙古南部曼莱蛇绿岩中超镁铁质岩石的多期蛇纹岩化

Mongolian Geoscientist Pub Date : 2021-12-30 DOI: 10.5564/mgs.v26i53.1787

Nomuulin Amarbayar, N. Tsuchiya, Otgonbayar Dandar, A. Okamoto, M. Uno, Undarmaa Batsaikhan, Jiajie Wang

{"title":"Multi-stage serpentinization of ultramafic rocks in the Manlay Ophiolite, southern Mongolia","authors":"Nomuulin Amarbayar, N. Tsuchiya, Otgonbayar Dandar, A. Okamoto, M. Uno, Undarmaa Batsaikhan, Jiajie Wang","doi":"10.5564/mgs.v26i53.1787","DOIUrl":"https://doi.org/10.5564/mgs.v26i53.1787","url":null,"abstract":"Serpentinization of ultramafic rocks in ophiolites is key to understanding the global cycle of elements and changes in the physical properties of lithospheric mantle. Mongolia, a central part of the Central Asian Orogenic Belt (CAOB), contains numerous ophiolite complexes, but the metamorphism of ultramafic rocks in these ophiolites has been little studied. Here we present the results of our study of the serpentinization of an ultramafic body in the Manlay Ophiolite, southern Mongolia. The ultramafic rocks were completely serpentinized, and no relics of olivine or orthopyroxene were found. The composition of Cr-spinels [Mg# = Mg/(Mg + Fe2+) = 0.54 and Cr# = Cr/(Cr + Al) = 0.56] and the bulk rock chemistry (Mg/Si = 1.21–1.24 and Al/Si < 0.018) of the serpentinites indicate their origin from a fore-arc setting. Lizardite occurs in the cores and rims of mesh texture (Mg# = 0.97) and chrysotile is found in various occurrences, including in bastite (Mg# = 0.95), mesh cores (Mg# = 0.92), mesh rims (Mg# = 0.96), and later-stage large veins (Mg# = 0.94). The presence of lizardite and chrysotile and the absence of antigorite suggests low-temperature serpentinization (<300 °C). The lack of brucite in the serpentinites implies infiltration of the ultramafic rocks of the Manlay Ophiolite by Si-rich fluids. Based on microtextures and mineral chemistry, the serpentinization of the ultramafic rocks in the Manlay Ophiolite took place in three stages: (1) replacement of olivine by lizardite, (2) chrysotile formation (bastite) after orthopyroxene and as a replacement of relics of olivine, and (3) the development of veins of chrysotile that cut across all previous textures. The complex texture of the serpentinites in the Manlay Ophiolite indicates multiple stages of fluid infiltration into the ultramafic parts of these ophiolites in southern Mongolia and the CAOB.","PeriodicalId":52647,"journal":{"name":"Mongolian Geoscientist","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46498939","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}

引用次数: 1

Geochemistry and geochronology of granitoid rocks of the Taatsiin Gol pluton of the Khangai Complex, Central Mongolia 蒙古中部康艾杂岩塔扎欣岩体花岗岩类岩石地球化学及年代学

Mongolian Geoscientist Pub Date : 2021-12-30 DOI: 10.5564/mgs.v26i53.1788

Tsogoo Bayasgalan, B. Munkhtsengel, S. Khishigsuren, B. Khurelbaatar

{"title":"Geochemistry and geochronology of granitoid rocks of the Taatsiin Gol pluton of the Khangai Complex, Central Mongolia","authors":"Tsogoo Bayasgalan, B. Munkhtsengel, S. Khishigsuren, B. Khurelbaatar","doi":"10.5564/mgs.v26i53.1788","DOIUrl":"https://doi.org/10.5564/mgs.v26i53.1788","url":null,"abstract":"The Taatsiin Gol pluton is one of the major constitute the intrusive body of the Khangai Complex, and is composed the first phase of diorite, the second phase of porphyritic granite, biotite-hornblende granite, and granodiorite, and the third phase of biotite granite and alkali granite. This paper presents new geochemical and U-Pb zircon age data from intrusive rocks of the Taatsiin Gol pluton. Geochemical analyses show that the granitoid rocks of the pluton are high-K calc-alkaline, and metaluminous to weakly peraluminous I-type granites, depleted in HFSE such as Nb, Ta, Ti and Y and enriched in LILE such as Rb, Cs, Th, K and LREE, where some variations from early to later phases rock. Zircon U-Pb dating on the biotite granite of the third phase yielded weighted mean ages of 241.4±1.2 Ma and 236.7±1.4 Ma. Based on the new and previous researchers’ age results, the age of the Taatsiin Gol pluton of the Khangai Complex is 256-230 Ma consistent with the late Permian to mid-Triassic time. Although showing variated geochemical features, the rocks of the three phases are all suggested to form at an active continental margin setting, probably related to the southwestward subduction of the Mongol-Okhotsk Ocean plate during the late Permian to mid-Triassic period.","PeriodicalId":52647,"journal":{"name":"Mongolian Geoscientist","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44396100","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}

引用次数: 0