Composition and Formation Conditions of Lower Eocene Shallow-Marine Carbonates in Southern Armenia     

Fokin  P. A.  Zakrevskaya  E. Yu.  Sahakyan  L. G.  Grigoryan  T. E. 《Lithology and Mineral Resources》2021,56(5):438-459

Lithology and Mineral Resources - Nummulite facies are known to be a good indicator of Eocene shallow-water paleoenvironments. Nummulitic limestones are widespread in the Lower Eocene of...  相似文献   

Geological Conditions of the Formation and Dissociation of Gas Hydrates in the Sea of Okhotsk: Tectonic and Genetic Aspects     

Obzhirov  A. I.  Sokolova  N. L.  Telegin  Yu. A. 《Lithology and Mineral Resources》2021,56(4):333-342

Lithology and Mineral Resources - The paper is dedicated to gas hydrate fields and active underwater gas seeps found in the Sea of Okhotsk. The study of geological conditions of the generation and...  相似文献   

Mud Volcanic Fluids of the Kerch–Taman Region: Geochemical Reconstructions and Regional Trends. Communication 1: Geochemical Features and Genesis of Mud-Volcanic Waters     

Lavrushin  V. Yu.  Aydarkozhina  A. S.  Sokol  E. V.  Chelnokov  G. A.  Petrov  O. L. 《Lithology and Mineral Resources》2021,56(6):461-486

Lithology and Mineral Resources - The chemical and isotopic characteristics (δ18O and δ2H) of water from 42 mud volcanoes of the Kerch–Taman region (Crimean–Caucasus district)...  相似文献   

Neotectonics and the Upper Mantle Structure of Central Asia     

Trifonov  V. G.  Sokolov  S. Yu.  Bachmanov  D. M.  Sokolov  S. A.  Trikhunkov  Ya. I. 《Geotectonics》2021,55(3):334-360

Geotectonics - Studies carried out by the authors show that the uplift of Central Asia situated between the eastern Alpine–Himalayan and western Altai–Stanovoy orogenic belts formed in...  相似文献   

2010—2020年黄河下游河南典型灌区浅层地下水中砷和氟的演化特征及变化机制     

任宇  曹文庚  潘登  王帅  李泽岩  李谨丞 《岩矿测试》2021,(6):846-859

黄河下游典型灌区河南段是豫北平原重要的农业种植区。该地区浅层水质整体较差,因常用于作物灌溉或家畜饮用,会对人体健康产生风险,因此对该地区地下水中砷与氟浓度变化特征和机制的研究将有助于提高对该地区地下水污染的认识水平。本文基于2010年和2020年在灌区范围内采集的327组浅层地下水样品,研究区内地下水砷和氟分布情况,并在此基础上对比研究十年间灌区浅层地下水中砷、氟的演化特征,探索分析砷与氟浓度及空间变化机制。研究结果表明：该地区浅层地下水中存在砷与氟超标问题,2020年浅层地下水中高砷（砷浓度大于10μg/L）和高氟（氟浓度大于1mg/L）的样品数量分别占总数的26.1%和26.06%。高砷水分布在太行山前洼地与黄河冲积平原等泥沙互层结构的沉积环境中,还原性较强,同时地下水径流不畅,较强的阳离子交换作用使得其所处环境中Ca²⁺浓度较高。近十年间砷浓度增加的水样占总数31.8%,砷浓度减少的水样占36.7%。砷浓度的增长（减少）是地下水还原性增强（减弱）使得锰氧化物溶解释放（吸附）导致。近十年间不同地区农业灌溉和水源置换等用水方式导致水位变化是引起砷浓度变化的潜在因素。高氟水主要分布在河南新乡与濮阳的黄河沿线,氟离子浓度受到沉积物中萤石等钙质矿物溶解影响,使得高氟地下水出现在低钙环境中。近十年间研究区中氟离子浓度减少的占总数60.2%,氟离子浓度增加的占32.1%,整体变化趋势向好,但是高氟区中氟离子浓度继续增加。氟浓度的变化同样受到Ca²⁺变化影响,在Ca²⁺浓度降低（升高）时氟浓度进一步升高（降低）。地下水中氟升高地区分布在黄河沿线,因此受到黄河水补给影响较大,地下水径流条件较好,阳离子交换作用减弱,使得Ca²⁺浓度降低,此时地下水中砷浓度受到环境影响而降低,因此研究区氟增加地区中砷与氟的分布和演化呈现反向关系。  相似文献   

Assessment of regional drought vulnerability and risk using principal component analysis and a Gaussian mixture model     

Kim  Ji Eun  Yu  Jisoo  Ryu  Jae-Hee  Lee  Joo-Heon  Kim  Tae-Woong 《Natural Hazards》2021,109(1):707-724

Due to the complex characteristics of drought, drought risk needs to be quantified by combining drought vulnerability and drought hazard. Recently, the major focus in drought vulnerability has been on how to calculate the weights of indicators to comprehensively quantify drought risk. In this study, principal component analysis (PCA), a Gaussian mixture model (GMM), and the equal-weighting method (EWM) were applied to objectively determine the weights for drought vulnerability assessment in Chungcheong Province, located in the west-central part of South Korea. The PCA provided larger weights for agricultural and industrial factors, whereas the GMM computed larger weights for agricultural factors than did the EWM. The drought risk was assessed by combining the drought vulnerability index (DVI) and the drought hazard index (DHI). Based on the DVI, the most vulnerable region was CCN9 in the northwestern part of the province, whereas the most drought-prone region based on the DHI was CCN12 in the southwest. Considering both DVI and DHI, the regions with the highest risk were CCN12 and CCN10 in the southern part of the province. Using the proposed PCA and GMM, we validated drought vulnerability using objective weighting methods and assessed comprehensive drought risk considering both meteorological hazard and socioeconomic vulnerability.

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Comprehensive analysis control effect of faults on the height of fractured water-conducting zone in longwall mining     

Wang  Xianhui  Zhu  Shuyun  Yu  Haitao  Liu  Yanxin 《Natural Hazards》2021,108(2):2143-2165

Natural Hazards - In order to examine the height of a fractured water-conducting zone due to the presence of a fault, a typical working face in the Baodian Coal Mine which is located in the Yanzhou...  相似文献   

Physical Model Tests on the Effect of Anchoring on the Splitting Failure of Deep Large-Scale Underground Rock Cavern     

Yu  Guangyuan  Zhang  Qiangyong  Li  Fan  Cheng  Lei  Guo  Xin 《Geotechnical and Geological Engineering》2021,39(6):4545-4562

Geotechnical and Geological Engineering - A set of splitting cracks often occur in the high side wall of the deep underground hydropower station due to the excavation-induced unloading during the...  相似文献   

New Systematic Method to Determine Elastic Constants and Crack Propagation Thresholds of Brittle Rocks Under Triaxial Compression     

Yu  Hua  Ng  Kam 《Geotechnical and Geological Engineering》2021,39(5):3931-3945

Geotechnical and Geological Engineering - Elastic constants and crack propagation stress thresholds of brittle rocks are important mechanical properties for engineering applications. However, these...  相似文献   

Destressing Mechanics Effect of Surrounding Rock Induced by Blasting Precondition at Deep Drift Development     

Yu  Shibo  Yang  Xiaocong  Zhu  Chun  Yuan  Ye  Wang  Zhixiu 《Geotechnical and Geological Engineering》2021,39(6):4113-4125

Geotechnical and Geological Engineering - Using a detailed modeling simulation technology, a mechanics simulation model was constructed, including multiple development rounds, stress relief holes...  相似文献