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81.
Hogbomite,a rare exotic mineral,is found to be associated with the vanadiferous-titaniferous (V-Ti) bearing magnetite bands at Bhakatarhalli,Nuggihaifi greenstone belt,western Dharwar Craton,India.We report on a second occurrence of hogbomite from the Dharwar craton in Karnataka,which is the sixth documented occurrence of this mineral from India.We evaluate the chemical characteristics of hogbomite and associated Fe-Ti-minerals in an attempt to identify its formation as a primary hydrothermal mineral in a metamorphosed magnetite layer.We report here the presence of hogbomite as a complex oxide of Fe,Mg,Al and Ti with accessory of Zn,V and Sn.Petrographic studies suggest the (V-Ti) bearing magnetite (Mt) contain spinel,hogbomite,chlorite,martite,ilmenite (Ⅱ) and minor amounts of diaspore.The hogbomite displays euhedral to subhedral textures,and is up to 250 μm along the grain boundaries of magnetite and ilmenite.In the samples studied,hogbomite is prismatic,irregular and elongated in shape.The genesis of hogbomite in veins between magnetite and ilmenite implies its precipitation from fluids without involving complicated reactions.Several models were proposed for the formation of hogbomite; however,the subject is still debatable. 相似文献
82.
DING Xiaozhong HAN Kunying PANG Jianfeng WANG Liang HAN Tonglin JU Yuanjing DING Weicui 《《地质学报》英文版》2013,87(6):1643-1657
Based on the CCD images,IIM data and DEM data of China's lunar exploration project (Chang'E-Ⅰ) and related processed and analytic results,an integrated study of regional geology of Sinus Iridum and its adjacent area was conducted,and a series of relevant researches and analyses were carried out,including analysis of impact craters and their extrusive and accumulative materials,division of stratigraphic and tectonic units and classification of rock types,integrated analysis of chronology and lunar evolution history.In consideration of crater's shape features,quantity and preserving status of filling materials,the lunar impact craters can be divided into 7 types and 11 subtypes,and the accumulative materials of craters are divided into 6 types and 9 accumulative groups.According to the content and distribution of TiO2 and image characteristics,the basalts are divided into high-TiO2,medium-TiO2 and low-TiO2 basalts.Discussion was made on division of tectonic units and evolution features in the study area.The geological map of the Sinus Iridum Quadrangle (LQ-4) at a scale of 1∶2.5 M was preliminarily compiled with the ArcGIS system,and the spatial database of the map was established.Related technical specification,procedure and method for lunar geological mapping have been worked out,so as to lay a foundation for the forthcoming geological mapping of the global Moon in China by using the data of Chang'E-Ⅱ and also for comprehensive study and geological mapping of other celestial bodies in the future. 相似文献
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84.
XIAO Xuchang LIU Xun GAO Rui Houn KAO LUO Zhaohua Institute of Geology Chinese Academy of Geological Sciences Beijing China Institute of Earth Sciences Academia Sini Taipei China China University of Geosciences Beijing China 《《地质学报》英文版》2001,75(2):126-132
New results from deep seismic reflection profiling, wide-angle reflection-refraction profiling and broadband seismic experiments reveal that a series of south-dipping reflectors occur on the southern margin of the Tarim block (basin). However, it is these south-dipping structures that are intercepted by another series of north-dipping reflectors at depths from 30 to about 150 km beneath the foreland of the W Kunlun Mountains. No evidence from the above geophysical data as well as geochemical and surface geological data indicate the southward subduction of the Tarim block beneath the W Kunlun Mountains (NW Tibet plateau), forming the so-called "two-sided subduction" model for the Tibet plateau as proposed by previous studies. So the authors infer that the tectonic interaction between the Tarim block and the W Kunlun block was chiefly affected by a "horizontal compression in opposite directions", which brought about "face-to-face contact" between these two lithospheric blocks and led to the thickening, sh 相似文献
85.
本文论述了矿物材料的定义、类型,矿物材料学的概念、研究内容和任务;介绍并分析了我国非金属材料的发展现状与趋势;指出发展我省非金属矿物材料产业,对振兴湖南经济有重要意义。 相似文献
86.
利用高分辨电子显微术观察了球粒陨石中的顽火辉石和斜长岩中的紫苏辉石,发现沿a轴方向有周期为13.5?和22.5?两种多形体与单斜辉石及斜方辉石紧密连生。这些新多形体的产生与高温相向低温相转变过程中Si—O链的错排有关。利用高分辨像推测了Si—O链在两种多形体中的排列方式。同时,还观察和讨论了新多形结构向单斜和斜方辉石的转变。 相似文献
87.
中国科学院地质研究所 《地质科学》1991,(4):307-308
这是中国科学院地质研究所所长王思敬教授在祝贺我国著名地质学家刘鸿允教授从事地质科学研究五十年纪念会上敬献的贺诗。他高度概括和赞颂了刘鸿允先生在从事地质科学研究中,对地质所的发展和对我国地层学、古地理学、前塞武纪地质学(尤其在震旦纪)研究领域中作出的重要贡献。 相似文献
88.
The research indicates that there is a positive correlation between the negative CG flash rate and the area of radarecho with its reflectivity being equal to or greater than 30 dBz in the mesoscale convective system in Beijing area.A max-imum of the positive CG flash rate exists at both the initial and the dissipating stages.The CG flashes are usually locatednear but not within the high reflectivity center.The negative flashes are associated with.the positions of the updraft re-gion,and with the regions of wind convergence and wind shear.Generally,the negative CG flashes are concentrative andthe positive ones are dispersive. 相似文献
89.
A PRELIMINARY STUDY OF SNOW MASS VARIATIONS IN CHINA OVER THE PAST 30 YEARS 总被引:1,自引:0,他引:1
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李培基 《Acta Meteorologica Sinica》1992,(2)
Daily snow data for 2300 climate stations covering the period from 1951 through 1980 have been used to monitorand diagnose secular variations,year-to-year fluctuations,and the spatial characteristics of snow variation trends inChina.An examination of time series reveals that there is a strong teleconnction to ENSO,to major volcanic eruptions,as well as to the CO_2-induced warming.The country-wide snow mass variations are positively correlated with globalmean temperature,increasing during the current warming period and decreasing during the recent cooling period priorto the mid 1960s.A synchronous relationship exists between El Nino/Southern Oscillation and snowy winter in China.The year-to-year snow fluctuations seem to be generally out of phase with volcanic activity.The anomaly map showsthat snow mass increased in high altitudes and moist regions,while it decreased in arid lowland and the southern bounda-ry zone during the warming period.The potential CO_2-induced changes in snow mass will further aggravate the regionaldifferentiation between high mountains and lowlands,between moist and arid regions.The number of snow cover dayswill decrease in the northern lowlands,and snowfall will increase in the Qinghai-Xizang Plateau,high mountains,andthe lower reaches of the Changjiang(Yangtze)River. 相似文献
90.