排序方式： 共有4条查询结果，搜索用时 15 毫秒
1
1.
Abstract. Scanning electron microscopy-cathodoluminescence (SEM-CL) imaging of vein quartz in the Cu-mineralised, Shuteen Complex (South Gobi, Mongolia) has revealed a complex history of crystal growth, dissolution and microfracture healing, associated with several hydrothermal events that could not be detected using other observational techniques (e.g. transmitted/reflected light microscopy, back-scattered electron imaging, or secondary electron imaging).
The quartz initially grew as CL-bright/grey crystals in a 345±30C liquid reservoir, as inferred by the analysis of primary liquid fluid inclusions (average Th of 343C; 6.6∼7.7 wt% NaCleq ). Quartz precipitation occurred at the edge of the crystals as reservoir fluids cooled to 260±25C, as indicated by micron-scale CL-dark/CL-bright quartz growth bands containing abundant fluid inclusions (with an average Th values of 261C). Pressure fluctuations were the likely cause of dissolution, as SEM-CL imaging reveals the quartz have corroded or rounded crystal edges, and precipitation of later quartz into open space. SEM-CL imaging shows the quartz contains healed microfractures that trapped low salinity fluids (3.9 wt% NaC1eq ) with Th values of 173±15C.
SEM-CL imaging provides a means of deciphering the thermal and chemical evolution of the fossil Shuteen hydrothermal system, and the nature of hydrothermal quartz vein-forming processes, by facilitating the correlation of distinct fluid inclusion populations and their relative chronology, with specific hydrothermal events. 相似文献
The quartz initially grew as CL-bright/grey crystals in a 345±30C liquid reservoir, as inferred by the analysis of primary liquid fluid inclusions (average Th of 343C; 6.6∼7.7 wt% NaCl
SEM-CL imaging provides a means of deciphering the thermal and chemical evolution of the fossil Shuteen hydrothermal system, and the nature of hydrothermal quartz vein-forming processes, by facilitating the correlation of distinct fluid inclusion populations and their relative chronology, with specific hydrothermal events. 相似文献
2.
Investigating internal structure of permafrost using conventional methods and ground-penetrating radar at Honhor basin, Mongolia 总被引：1，自引：1，他引：0
Tonghua Wu Qinxue Wang Lin Zhao Erji Du Wu Wang Ochirbat Batkhishig Dorjgotov Battogtokh Masataka Watanabe 《Environmental Earth Sciences》2012,67(7):1869-1876
A ground-penetrating radar (GPR) survey was conducted at the end of August 2009 in the suburb region of Ulaanbaatar, Honhor basin, Mongolia, in combination with conventional methods such as borehole drilling and measurement of ground temperatures. The interface of frozen and unfrozen sediment was distinctly resolved in the interpreted GPR images, verified by the borehole drilling records and 6-month measurement of ground temperatures. The location of the permafrost table was assessed to be at the depth of 2?C4?m in the study region. A conspicuous ice-saturated soil layer (massive ground ice) was detected in the interpreted GPR images with a thickness of 2?C5?m. The GPR investigation results were consistent with the borehole drilling records and ground temperatures observation. The borehole logs and ground temperatures profile in the borehole indicates that permafrost at Honhor basin is characterized by high ground temperature and high ice content, which implies that ongoing climatic warming would have great influence on permafrost dynamics. The research results are of great importance to further assess permafrost dynamics to climatic change in the boundary of discontinuous and sporadic permafrost regions in Mongolia in the future. 相似文献
3.
Cross-boundary and cross-level dynamics increase vulnerability to severe winter disasters (dzud) in Mongolia 总被引：1，自引：0，他引：1
María E. Fernández-Giménez B. Batkhishig B. Batbuyan 《Global Environmental Change》2012,22(4):836-851
Dzud is the Mongolian term for a severe winter weather disaster. With global change dzud may increase in frequency and intensity, placing livestock and livelihoods at risk. We conducted in-depth case studies of dzud impacts and responses in two mountain-steppe and two Gobi desert-steppe districts in Mongolia. We used focus groups, key informant interviews, a household survey and photovoice to document individual and community experiences with dzud and identify the factors that make some households and communities more vulnerable to dzud and others less so. We found that dzud is a complex social–ecological phenomenon and vulnerability to dzud is a function of interacting physical, biological, socio-economic and institutional factors. Vulnerability was affected by factors within and interactions between communities as well as cross-level dynamics. Communities that are well prepared for dzud at the household level may suffer disproportionate losses if exposure is increased by in-migrating livestock from other districts. Relief aid that helps prevent loss of life, suffering and impoverishment in the short-term may contribute to long-term dependence syndromes, social disparities, and lack of initiative on the part of both herders and local government. Based on our findings, we recommend that dzud policies and programs promote: (1) increased individual responsibility for disaster preparedness; (2) greater cooperation and communication on disaster planning and response among different actors within communities and across governance levels; (3) sustained and scaled out investment in building local capacity for collective action through formal herder organizations; and (4) effective cross-level institutions to manage pastoral movements and pastures. 相似文献
4.
蒙古高原中部气候变化及影响因素比较研究 总被引：4，自引：0，他引：4
利用蒙古国中部6个气象站1940~2004年和中国内蒙古自治区中部6个气象站1951~2004年的温度和降水资料,对两地的气候变化及其影响因素作了对比研究。结果表明:20世纪90年代与60年代相比,中国内蒙古6站平均升温1.35℃,蒙古国6站上升1.13℃,2000~2004年与60年代相比:中国内蒙古6站上升1.89℃,蒙古国则为1.37℃,中国内蒙古6站的升温速率高于蒙古国6站。对温度变化趋势作突变性检验,结果表明:温度发生突变时间是纬度较高地区早于纬度较低的地区,大城市早于中小城镇,城市化对温度变化影响比较明显。相对于温度变化,降水变化没有显著性的突变,但有周期变化,中国内蒙古降水变化有2.8年周期,蒙古国有4年、8年的周期,这可能因为中国内蒙古降水水汽主要来源于太平洋,而蒙古国降水的水汽主要来源于北冰洋。 相似文献
1