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<正>Ophiolites are the best archives of the evolutionary history of ocean basins from their rift–drift and seafloor spreading stages to subduction initiation and final closure(Dilek and Furnes,2014).Mongolia,the major domain of the Central Asian Orogenic Belt,represent the accretionsubduction belts with remnants of ophiolites.Ophiolites are distributed in the Northern,Western,South and 相似文献
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Ochir Gerel 《大地构造与成矿学(英文版)》2001,25(1)
1 Introduction
Petrogenesis of Mesozoic granitoids in Mongolia that comprise the Mongol-Okhotsk foldbelt was studied during more than 40 years.This belt is well known province of the Mesozoic magmatism and mineralization including gold,copper and molybdenum,tin and tungsten,lead and zinc,and fluorite.In the middle of the 1950's Chen Guoda proposed the diwa theory to explain tectonic activity in Chinese platform.In Russian Far East for similar processes the activization (revivation) theory was proposed which explained intracontinental events in the Mongol-okhotsk foldbwlt. 相似文献
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蒙古高原地处干旱半干旱地区,河流水系对该区域的资源环境格局及其生态环境影响重大。发源于蒙古国的色楞格河是蒙古高原最主要的水资源来源,准确掌握该流域的水体信息对东北亚地区生态环境问题及资源保护具有重要意义。本文以蒙古高原色楞格河流域为研究对象,基于谷歌地球引擎（Google Earth Engine,GEE）云平台,使用 Sentinel-2 多光谱卫星遥感影像,利用深度神经网络（Deep Neural Network, DNN）方法对色楞格河流域的水体信息进行提取,并与支持向量机方法进行对比;利用全球30 m SRTM数据生成水系分布矢量图,通过空间分析形成河流提取目标区,结合深度神经网络分类结果,绘制蒙古国色楞格河流域2019年河流分布图。研究结果表明：① 该方法能够准确地完成大流域范围内的水体制图,提取结果能够体现色楞格河流域河流的空间分布,且能够减少河流断流、空洞现象;② 深度神经网络模型中批量大小设置为8时,在处理数据速度与精度中达到最优,而神经网络结构中隐含层数达到4层时,在精度评价指标测试数据集上达到0.9666,保证了模型特征挖掘能力;③ 经样本点的验证,结果总体精度达到97.65%,可以满足实际应用需求。本研究预期可以为蒙古高原的水体提取提供方法支持和相关数据支持。 相似文献
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Benjamin S. Linhoff Philip C. Bennett Tamir Puntsag Ochir Gerel 《Environmental Earth Sciences》2011,62(1):171-183
Extremely high concentrations of uranium (U) were discovered in shallow, groundwater-fed hyperalkaline soda lakes in Eastern
Mongolia. A representative groundwater sample in this area is dilute and alkaline, pH = 7.9, with 10 mM TIC and 5 mM Cl−. In contrast, a representative lake water sample is pH ~ 10 with TIC and Cl− each more than 1,000 mM. Groundwater concentrations of U range from 0.03 to 0.43 μM L−1. Lake water U ranges from 0.24 to >62.5 μM, possibly the highest naturally occurring U concentrations ever reported in surface
water. Strontium isotopes 87Sr/86Sr varied in groundwaters from 0.706192 to 0.709776 and in lakes 87Sr/86Sr varied from 0.708702 to 0.709432. High concentrations of U, Na, Cl−, and K correlate to radiogenic Sr in lake waters suggesting that U is sourced from local Cretaceous alkaline rhyolites. Uranium-rich
groundwaters are concentrated by evaporation and U(VI) is chelated by CO3−2 to form the highly soluble UO2(CO3)3−4. Modeled evaporation of lakes suggests that a U-mineral phase is likely to precipitate during evaporation. 相似文献
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Altansukh Ochir Munkhtsetseg Zorigt Solongo Tsetsgee John Lodewijk van Genderen 《国际地球制图》2018,33(7):699-712
The purpose of this research was to identify suitable sites for water harvesting ponds using spatial multi-criteria analysis (SMCA). In total, 12 spatial data-sets were used for this research, 14 criteria have been selected for defining a proper sink, and each of these criteria is converted into the common scale differently based on whether one is a constraint or a factor. The defined sinks were evaluated by nine constraints and five factors analysis, sequentially. At the end of the factor analysis, the proper sinks were divided into four classes, namely: unsuitable, marginally, moderately and highly suitable. Ground truth observation was carried at randomly selected 13 proper sinks. Overall accuracy of site selection for water harvesting ponds using SMCA was 92.3%. Due to the very different natural zones and fluctuating climate of Mongolia, spatial factors for SMCA were standardized instead of using interval divisions. 相似文献
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王艳杰 王卷乐 魏海硕 Altansukh Ochir Davaadorj Davaasuren Sonomdagva Chonokhuu 《地球信息科学学报》2020,22(9):1814-1822
产草量是衡量草原生产力和诊断草原健康状况的指标,是草地资源管理的重要依据。近年来,遥感数据结合地面实测数据建模已成为产草量估算的重要手段。充足的实测样点信息是产草量遥感建模估算的基础。受境外采样多重因素的制约,蒙古国产草量估算研究中无法获取足够且分布均匀的实测样点,估产模型的精度受到影响,这一问题目前尚未发现有好的解决方法。本研究选取中蒙铁路沿线（蒙古段）两侧200 km缓冲区作为研究区,针对产草量遥感估算中野外样点稀少且分布不均的问题,引入P-BSHADE方法,基于多年NDVI数据和获取的少量地面实测样点数据,考虑草地分布的非均匀性以及样点之间的相关性,对均匀分布的模拟样点处的产草量数据进行插值实验。结果显示,P-BSHADE法的插值效果优于Kriging法,可得到均匀分布于研究区的样点。基于以上实测样点和插值样点,结合NDVI、EVI、PsnNet 3种植被指数进行遥感建模,最优模型精度达到80%,精度优于已有相关研究。选取其中最优的基于NDVI的指数模型对研究区2000—2019年产草量进行反演,获得的产草量空间格局与年际变化与已有研究结果趋势吻合,进一步印证了结果的可靠性和插值方法的可行性。本研究通过插值的方式改善数据源从而提高估算模型精度是一种全新的思路与尝试,对于“一带一路”等境外区域资源环境监测具有借鉴意义。 相似文献
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A. Bischoff O. Gerel V. F. Buchwald B. Spettel T. Loeken L. Schultz H. W. Weber J. Schlüter L. Bauinnyam D. Borchuluun C. Byambaa D. Garamjav 《Meteoritics & planetary science》1996,31(1):152-157
Abstract— The mineralogy and composition of six Mongolian meteorites were studied in some detail. Previously, only limited information existed about these rocks, and some were still unclassified. The six meteorites include three ordinary chondrites and three irons. The ordinary chondrite Adzhi-Bogdo (stone) is a regolith breccia (LL3–6) containing various types of clasts (some of foreign origin) embedded within a fine-grained clastic matrix. Tugalin Bulen (H6) and Noyan Bogdo (L6) meteorites are typical, well-metamorphosed ordinary chondrites. Adzhi-Bogdo (iron) has to be regarded as an IA iron meteorite like Campo del Cielo or Canyon Diablo; although the sample studied had been heated to about 900 °C–950 °C some time in the past, thus eradicating all original structural elements. Manlai is structurally closely related to the IIC iron meteorites; but based on its chemistry, which does not fit into this group, it is suggested that Manlai is an anomalous iron meteorite. The third iron, Sargiin Gobi, is certainly a normal member of the IA iron meteorites. The concentrations and isotopic compositions of He, Ne, and Ar were measured for all meteorites and their gas retention ages and exposure ages are discussed. 相似文献
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