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981.
S-wave velocity and Poisson''''s ratio structure of crust in Yunnan and its implication 总被引:13,自引:2,他引:11
HU Jiafu SU Youjin ZHU Xiongguan & CHEN Yun Geophysical Department of Yunnan University Kunming China Seismological Bureau of Yunnan Province Kunming China Institute of Geology Geophysics Chinese Academy of Sciences Beijing China 《中国科学D辑(英文版)》2005,48(2):210-218
Receiver function of body wave under the 23 stations in Yunnan was extracted from 3-component broadband digital recording of teleseismic event. Thus, the S-wave velocity structure and distribution characteristics of Poisson's ratio in crust of Yunnan are obtained by inversion. The results show that the crustal thickness is gradually thinned from north to south. The crustal thickness in Zhongdian of northwest reaches as many as 62.0 km and the one in Jinghong of further south end is only 30.2 km. What should be especially noted is that there exists a Moho upheaval running in NS in the Chuxiong region and a Moho concave is generally parallel to it in Dongchuan. In addition, there exists an obvious transversal inhomogeneity for the S-wave velocity structure in upper mantle and crust in the Yunnan region. The low velocity layer exists not only in 10.0-15.0 km in upper crust in some regions, but also in 30.0-40.0 km in lower crust. Generally, the Poisson's ratio is on the high side, however it has a better co 相似文献
982.
Hu Xing 《Astrophysics and Space Science》1992,190(1):145-148
On the basis of the model properties of the expansive nondecelerative universe, present temperature of cosmic microwave background and specific entropy in the era of matter, the present parameters of our Universe may be exactly determined. 相似文献
983.
Liu Rui-yuan Hu Hong-qiao Liu Yong-hua Xu Zhong-hua Sato N. Fraser B.J. 《Solar physics》2001,204(1-2):305-313
Simultaneous observations at Zhongshan Station, Antarctica, are presented for the interval of 13–17 July 2000 to show responses
of the polar ionosphere to the Bastille Day (14 July 2000) solar event. The polar ionosphere was highly disturbed, as shown
by frequently large deviations of the geomagnetic H-component, large riometer absorption events and strong ULF waves. Associated
with the huge solar proton event produced by the X5/3B flare, a polar cap absorption (PCA) was observed. It began at ∼ 10:40 UT
on 14 July and ended at ∼ 19:40 UT on 17 July. Superposed on it, there was a large absorption event with a peak of 26 dB,
starting at ∼ 03:00 UT and ending at ∼ 11:10 UT on 15 July. This kind of absorption was probably produced by an intense `cloud
of energetic electrons' during an auroral substorm. The ULF waves were very intense during the main phase and the recovery
phase of the severe magnetic storm on 15 and 16 July. The ionospheric absorption was so strong that the digisonde signal was
blacked out most of the time. The ionosphere returned to normal in the afternoon on 17 July. 相似文献
984.
FENG Xionghan LIU Fan TAN Wenfeng LIU Xiangwen & HU Hongqing . College of Resources Environment Huazhong Agricultural University Wuhan China . Testing Center China University of Geosciences Wuhan China 《中国科学D辑(英文版)》2004,47(8):760-768
Todorokite is one of the common manganese ox-ides in manganese ore deposits, weathering product of manganese-bearing rocks, soils and sediments. It is also an important component in the abundant marine manganese nodules. Since todorokite was firstly found in Japanese Todoroki mine in 1934, its properties and origination have appeared to be very interesting to many researchers[1—3]. It has a stable structure similar to porous molecular sieves, constructed of triple MnO6 octahedral chains. Th… 相似文献
985.
Investigations and assessment of the landslide hazards of Fengdu county in the reservoir region of the Three Gorges project on the Yangtze River 总被引:12,自引:0,他引:12
Shuren?WuEmail author Yimin?Jin Yongshuang?Zhang Jusong?Shi Chen?Dong Weizhi?Lei Ling?Shi Chengxuan?Tan Daogong?Hu 《Environmental Geology》2004,45(4):560-566
The spatial database of landslides in Fengdu County of the reservoir region of the Three Gorges project (TGP) on the Yangtze River was compiled from a variety of different sources including field investigations on landslides, existing catalogues and archives on landslides, reports of meteorological events and human engineering activities that triggered slope failures. The major factors that are found to have affected the slope stabilities are outlined, and an assessment and zonation of landslide hazards of the region is made using an integrated information model, which is divided into destructive, disastrous, likely disastrous and essentially non-disastrous areas from the assessment of landslide hazards. The destructive and disastrous areas are respectively 1.9 and 13.8% of the total region, mostly being nearby townships, highways along the south bank of the Yangtze River and residential quarters along two flanks of the Yangtze River and its distributaries, that will impose direct impact to highway transportation and residential lives, and may effect to some degree the navigation of the Yangtze River, reservoir banks, and building of cities and towns. 相似文献
986.
Jianping?Zheng W.?L.?GriffinEmail author Suzanne?Y.?O’Reilly Fengxiang?Lu Chunmei?Yu Ming?Zhang Huimin?Li 《Contributions to Mineralogy and Petrology》2004,148(1):79-103
Mafic xenoliths from the Paleozoic Fuxian kimberlites in the North China craton include garnet granulite, and minor pyroxene amphibolite, metagabbro, anorthosite and pyroxenite. The formation conditions of the amphibolites are estimated at 745–820 °C and 7.6–8.8 Kb (25–30 km); the granulites probably are derived from greater depths in the lower crust. LAM-ICPMS U–Pb dating of zircons from four granulites reveals multiple age populations, recording episodes of magmatic intrusion and metamorphic recrystallisation. Concordant ages and upper intercept ages, interpreted as minimum estimates for the time of magmatic crystallisation, range from 2,620 to 2,430 Ma in three granulites, two amphibolites and two metagabbros. Lower intercept ages, represented by near-concordant zircons, are interpreted as reflecting metamorphic recrystallisation, and range from 1,927 to 1,852 Ma. One granulite contains two metamorphic zircon populations, dated at 1,927±55 Ma and 600–700 Ma. Separated minerals from one granulite and one amphibolite yield Sm–Nd isochron ages of 1,619±48 Ma (143Nd/144Nd)i=0.51078), and 1,716±120 Ma (143Nd/144Nd)i=0.51006), respectively. These ages are interpreted as recording cooling following metamorphic resetting; model ages for both samples are in the range 2.40–2.66 Ga. LAM-MC-ICPMS analyses of zircon show a range in 176Hf/177Hf from 0.28116 to 0.28214, corresponding to a range of Hf from –34 to +12. The relationships between 207Pb/206Pb age and Hf show that: (1) the granulites, amphibolites and metagabbro were derived from a depleted mantle source at 2.6–2.75 Ga; (2) zircons in most samples underwent recrystallisation and Pb loss for 100–200 Ma after magmatic crystallisation, consistent with a residence in the lower crust; (3) metamorphic zircons in several samples represent new zircon growth, incorporating Hf liberated from breakdown of silicates with high Lu/Hf; (4) in other samples metamorphic and magmatic zircons have identical 176Hf/177Hf, and the younger ages reflect complete resetting of U–Pb systems in older zircons. The Fuxian mafic xenoliths are interpreted as the products of basaltic underplating, derived from a depleted mantle source in Neoarchean time, an important period of continental growth in the North China craton. Paleoproterozoic metamorphic ages indicate an important tectonic thermal event in the lower crust at 1.8–1.9 Ga, corresponding to the timing of collision between the Eastern and Western Blocks that led to the final assembly of the North China craton. The growth of metamorphic zircon at 600–700 Ma may record an asthenospheric upwelling in Neoproterozoic time, related to uplift and a regional disconformity in the North China craton. 相似文献
987.
Preliminary study on PAH degradation by bacteria from contaminated sediments in Xiamen Western Sea,Fujian, China 总被引:1,自引:0,他引:1
In order to estimate the biodegradation of three polycyclic aromatic hydrocarbons (PAHs) compounds, bacterial strains were isolated from marine sediments in three heavily contaminated sites (Yuandang Lake, Dongdu Port and Aquacultural zones in Maluan Bay) in Xiamen Western Sea. The results show three bacterial strains, which used pyrene as the sole carbon source, were identified as strains of Aureobacterium sp.,Arthrobacter sp., Rhodococcus sp. The PAH-degrading bacteria isolated had a strong ability to degrade phenanhrene, fluoranthene and pyrene at different degradation rates. The highest degradation rate was observed when three PAH compounds were mixed with an individual strain in the medium. The three PAHs were degraded after one week with a degradation rate of 89.94 % for phenanthrene and 93.4 % for both of fluoranthene and pyrene.In addition, after 25 days of incubation, the degradation rate was 99.98 % for phenanthrene and 99.97 % for both of fluoranthene and pyrene. Optical density was measured to estimate bacterial growth during the degradation of PAHs. Highest levels of bacterial growth were observed with a three PAH mixture in the culture, suggesting that the concentration of PAHs influenced bacterial growth and the highest levels of degradation for most series were detected after one week of incubation. 相似文献
988.
Fluid evolution in the Rushan lode gold deposit of Jiaodong Peninsula, eastern China 总被引:2,自引:0,他引:2
Fang-Fang Hu Hong-Rui Fan Ming-Guo Zhai Cheng-Wei Jin 《Journal of Geochemical Exploration》2006,89(1-3):161
The Rushan gold deposit in the Jiaodong Peninsula is currently the largest lode gold in China. Gold occurs mainly in pyrite- and polymetallic sulfide–quartz vein/veinlet stockworks. Fluid inclusions in the deposit are divided into three main types, namely CO2–H2O, H2O–CO2 ± CH4 and aqueous ones. Microthermometric data show that the pre-gold fluids were CO2-dominant (XCO2 up to 0.53), and the total homogenization temperatures fall in the range of 298377 °C. These fluids, modified by fluid/wallrock reactions, gradually evolved into fluids with less CO2 (XCO2 = 0.010.19) in the main ore-forming stage, and the total homogenization temperatures range from 170 to 324 °C. Hydrogen and oxygen stable isotope data suggest that ore-forming fluids were mixture of magmatic and meteoritic origin. Co-occurrence of gold and sulfides implies that gold was most likely transported in the form of gold–sulfide complexes. The wide distribution of CO2 inclusions means that the pH variation during gold transportation was controlled by CO2 buffering. 相似文献
989.
990.