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41.
Abstract: From the southernmost part of Jiangsu province to the northeastern part of Jiangxi province, China, the Northeast Jiangxi Deep Fault runs for about 400 km length with a width of 30 to 40 km. This fault marks the suture zone of two ter-ranes of Proterozoic age. At the both sides of the fault, Yanshanian granitic activity is recognized. That is, the Dexing-Wuyuan porphyry belt on the NW side of the fault, and the Damaoshan-Lingshan granite belt on the SE side. The former activity is characterized by the occurrence of small stocks of granodioritic composition, rich in siderophile elements but poor in LIL elements. No distinct Eu anomaly is recognized in the REE pattern, and a low initial 87Sr/86Sr ratio is reported. Magnetite, sphene and apatite are observed as accessory minerals. On the contrary, granitic activity on the SE side of the fault is characterized by the occurrence of composite batholiths, in general of granitic to monzogranitic composition, rich in LIL and alkali elements but poor in siderophile and alkali earth elements. A strong Eu anamaly is recognized in the REE pattern, and initial 87Sr/86Sr ratios are as high as 0. 716. Fluorite, zircon and REE minerals are observed as accessory minerals. These two contrasting granitic activities are refered to as syntexis– and transformation–types, respectively, following the classification commonly used in China, and have similar petrochemical characteristics to those defined for the magnetite– and ilmenite–series, and I– and S-type granitoids. Considering that the above igneous activity occurred far from the supposed subduction zone along the East Coast of China, intracontinental A-type (continent to continent) subduction is proposed to have occurred northwestwards along the NE Jiangxi Deep Fault during Yanshanian time due to a strong compressional stress from SE to NW. A-type subduction introduced the continental slab to some depth, and resulted in the production of the paired granitic activity observed on both sides of the fault. Many mineral deposits are associated with both granitic belts. In the Dexing-Wuyuan porphyry belt, the Dexing porphyry Cu and Yinshan polymetallic deposits are representative, whereas in the Damaoshan-Lingshan granite belt, several tens of rare metal deposits are known such as the Geyuan Nb–Ta–W–Sn deposits. Metal assemblages of those deposits reflect the source materials of magmas in both granitic belts. 相似文献
42.
43.
Nobumichi Shimizu 《Geochimica et cosmochimica acta》1974,38(12):1789-1798
The partition coefficients of K, Rb, Cs, Sr and Ba between clinopyroxene and liquid were experimentally determined in the system diopside-albite-anorthite-water at 15–30 kb and 1100–1200°C. Clinopyroxene and liquid (glass) were separated by a new technique (differential dissolution technique—DDT) and analyzed by isotope dilution. The partition coefficients lie in the range 0.054–0.081 for Sr, 0.0014–0.0026 for K, 0.00078–0.0023 for Ba, 0.0010–0.0041 for Rb, 0.00035–0.0036 for Cs. Variations of the partition coefficients with pressure, temperature and composition of the phases are relatively small, though no systematic study of these parameters was attempted. 相似文献
44.
Japanese early-warning for debris flows and slope failures using rainfall indices with Radial Basis Function Network 总被引:3,自引:1,他引:2
Nobutomo Osanai Takeshi Shimizu Kazumasa Kuramoto Shinichi Kojima Tomoyuki Noro 《Landslides》2010,7(3):325-338
Early-warning systems for natural disasters are important tools for disaster risk reduction and for achieving sustainable
development and livelihoods. In 2005, the Japanese government initiated a new nationwide early-warning system for landslides
disasters. The main methodology of the system is to set a criterion for occurrences of debris flows and slope failures based
on several rainfall indices (60-min cumulative rainfall and soil–water index) in each 5-km grid mesh covering all of Japan.
Because many of the records of mass movements are lacking in scientific precision on timing and location, the system applies
Radial Basis Function Network methods to set the criterion based primarily on rainfall data recorded as not triggering disasters.
Since the end of March 2007, under torrential rainfall conditions, early-warning information has been disseminated as part
of weather news using TV, radio, and the Internet. Because of the increasing worldwide recognition of the importance of early-warning
systems for natural disaster reduction, the aim of this article is to introduce the new Japanese early-warning system to the
international landslide community. In this article, the method, the system, and the result of its application to landslide
disasters in 2009 are presented. 相似文献
45.
When load acts on a circular foundation on or in a dense sand, average contact pressure on the lower surface of the foundation is q and settlement of the foundation is s. Diameter and depth of the foundation are B and Df. When the sand, B and Df are given, we can know the relation between q and s/B by, e.g. a loading test, i.e. the relation is determined by B and Df for the sand. Using the results of numerical analyses, we express a relation between q and s/B up to s=0.1B by functions of a single variable which is a linear combination of B and Df. Consequently when two foundations have different B's and different Df's but have the same value of the variable, the relations are the same. Then we examine whether the functions can express the results of eleven tests of model foundations of wide range of B and/or Df. In all the tests, the relations are expressed with sufficient accuracy. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
46.
The South American Monsoon System (SAMS) is a major climatic feature of South America, and its domain extends from Amazon to La Plata basin. The SAMS region is vulnerable to variations of climate and precipitation patterns, which could impact economic activities and lead to potential societal consequences. In the face of a warming future scenario, the importance of the study of the past climate with numerical simulations is to evaluate the climate models and to assure the reliability of future projections. Here we investigate the Mid-Holocene SAMS, evaluating changes in strength, life cycle and associated dynamical mechanisms in ten Earth System Models simulations. Our results show that the SAMS was weaker in the Mid-Holocene than in the pre-industrial climate in December–January–February (DJF), but stronger in September–October–November (SON). This is probably a consequence of insolation variations in the Mid-Holocene, which contributed to changes in the moisture flux from the Atlantic Ocean to the continent, the strength of the upper-level atmospheric circulation, and the amount of precipitation over the SAMS region. Moreover, we suggest that the life cycle of the SAMS was altered during the Mid-Holocene, with an earlier onset and demise. Our results also indicate that Mid-Holocene SAMS changes are connected to precipitation variations near Northeast Brazil, in a dipole configuration of precipitation between western Amazon and Northeast Brazil, due to the influence of the Walker cell. Finally, this study highlights a need for improvement of the numerical models to better simulate the amount of precipitation over South America and the upper-level circulation over western Amazon in SON, which are crucial factors for a more realistic representation of the SAMS. 相似文献
47.
Mitsugu Makita Shigeo Hamana Keizo Nishi Minoru Shimizu Takashi Sakurai Kiyoto Shibasaki 《Astrophysics and Space Science》1986,118(1-2):163-167
The title instrument is mounted on the 65 cm solar Coudé telescope at the Okayama observatory. Observation is usually of the Fei 5250 Å line. The data obtained are briefly described.Paper presented at the IAU Third Asian-Pacific Regional Meeting, held in Kyoto, Japan, between 30 September–6 October, 1984. 相似文献
48.
Mikio Shimizu 《Astrophysics and Space Science》1977,51(2):497-499
Some absorption features in the ultraviolet spectrum of Venus observed by the OAO-2 cannot be interpreted in terms of H2SO4. Carbon suboxide polymer has a yellow colour and absorption at 2000 Å. Fine graphite grains have an absorption band at about 2175 Å as is well known in the case of the interstellar extinction curves. A mixture of these substances which is inevitably formed in the Venus atmosphere by photochemical reactions is the best candidate for explaining the Venus absorption features in the ultraviolet. 相似文献
49.
Masahiro Endoh 《Journal of Oceanography》1971,27(3):116-120
Response of an unbounded two-layer ocean to traveling atmospheric disturbances is analytically investigated. Under the assumption that (1) lower layer is motionless, (2) each layer is homogeneous and in hydrostatic balance, (3) the Coriolis parameter is constant, and (4) the density difference between the two layers is small compared to the density itself, the one-dimensional Klein-Gordon's equation is solved analytically for both the divergent and rotational wind stress. Numerical examples of the wake pattern of the upwelling behind the regional divergent and rotational wind fields are also represented.The results may be summarized as follows: (1) the effect of the divergent wind stress is dominant when the forced Rossby numberR
0 (the ratio of the frequency of the wind stress to the Coriolis parameter) is larger than unity unless the Mach numberM (the ratio of the traveling velocity of the wind stress to the internal gravitational velocity) is far less than unity, (2) the effect of the rotational wind stress is important, when the forced Rossby numberR
0 is less than unity. 相似文献
50.
Mikio Shimizu 《Astrophysics and Space Science》1975,36(2):353-361
Dirty ice of a second kind (major components, H2O, CO, and N2; minor components less than several percents, NH3, CH4, and other organic substances such as HCN, CH3CN etc.) is assumed for the composition of volatiles in the cometary nucleus. The consistency with the observations of molecular ions and daughter molecules in the cometary atmosphere is argued by taking into account various ion-molecular reactions and dissociative recombinations. There is a satisfactory agreement for the second kind of dirty-ice model, but the presence of large amounts of CH4 and NH3 is found to be rather in contradiction with observational evidence. A velocity of 8 km s?1 for the hydrogen atoms, derived from analysis of the hydrogen Lyman-alpha corona around comets, is found from the dissociative recombination of H3O+, the dominant constituent of cometary ionosphere, in accordance with H3O++e ?→OH+H+H. 相似文献