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41.
This study has reviewed recent studies about impact of the Rossby wave propagation on the weather of East Asia.Then,we have focused on the northward progression of the subtropical high affected by the propagations and their interaction.The following results are obtained:(1) The two kinds of meridional Rossby wave propagations often affect the East Asian weather in summer,which propagate in two conflicting directions(northwest-southeastward and southwest-northeast-ward).This is considered as the interaction of the large-scale systems between high and low latitudes with wave propagation,especially to the circulation systems around East Asia.(2) The northward progression of the subtropical high is largely restrained,aecompanied by the southward shift of the convective activity in middle latitudes,under the strong and persistent Rossby wave propagation from high to low latitudes.And the opposite role could be found in the Rossby wave propagation from low to high latitudes. 相似文献
42.
江西永平铜矿花岗质岩石的岩石结构、地球化学特征及其成矿意义 总被引:2,自引:7,他引:2
江西永平铜矿位于华南怀玉山—北武夷山铜铅锌多金属成矿带内,是赣东北地区除了德兴铜矿外的另一个大型铜矿基地。该矿区存在两种类型的花岗质岩石,一种是花岗岩;另一种是英安斑岩。英安斑岩具有典型斑状结构和石英眼结构,而花岗岩则具有单向固结结构。在化学成分上,两者属于高钾的钙碱性系列岩石,英安斑岩贫硅、富Al、Fe、Mg、Ca,以及具有较大的Na_2O/K_2O(0.02~0.64)等特点;而花岗岩富硅、贫Al、Ca,以及富碱和具有较小的Na_2O/K_2O(0.02~0.03)等特点。两种类型的岩石具有一致的REE配分曲线。它们均富集大离子亲石元素(Ba、Rb、K),亏损高场强元素(Th、Nd、Ta、Ti)以及元素Sr和P,显示了与俯冲作用有关的岩浆作用。在结构和化学成分上,花岗岩则类似于美国Climax斑岩钼(铜)矿成矿斑岩的性质(如具有单向固结结构、较高的分异指数、富Si、贫Al、Ca、富Na_2O K_2O以及K_2O>Na_2O)。与英安斑岩有关的蚀变作用主要有夕卡岩化、黑云母化、白云母化、绿泥石化和萤石化,而与花岗岩有关的蚀变作用主要是白云母化和萤石化;相应地,与英安斑岩有关的成矿作用主要为铜,而与花岗岩有关的成矿作用则主要为钼。2件辉钼矿样品的Re-Os年龄分别为156.7±2.8Ma和155.7±3.6Ma,表明与花岗岩有关的钼成矿作用发生在156Ma左右。本文认为,永平铜钼矿的成矿地球动力学背景应是由挤压向伸展的转换环境。 相似文献
43.
Kenichi HOSHINO Yuki YAMAMOTO Xiangping GU Su Young LEE Makoto WATANABE 《Resource Geology》2000,50(3):185-190
Abstract: Possible ore deposition by fluid mixing was preliminarily examined using MIX 99, a FORTRAN program developed for simulating water-rock interactions. We consider mixing of two fluids, the low fO2 and high temperature source fluid and the high fO2 and low temperature seawater. Oxygen fugacity of a mixed fluid formed by titration of seawater into the source fluid gradually decreases with decreasing temperature (model A). Sequential precipitation of ore-forming minerals was examined in this model. On the other hand, simultaneous precipitation of the minerals could be followed by simulation of instantaneous overall mixing of the two fluids (model B). Results of simulation of the both models revealed that a temporal sequence of mineralization observed in the Karuizawa mine, NE Japan, can be formed by model A, while model B is suitable for the mineralization of an active chimney found in the Rainbow hydrothermal area of the Mid-Atlantic Ridge. 相似文献
44.
Takeshi Ohba Yasushi Daita Takeshi Sawa Noriyasu Taira Yusuke Kakuage 《Bulletin of Volcanology》2011,73(4):457-469
The chemical and isotopic compositions of volcanic gases at a borehole and a natural fumarole in the Owakudani geothermal
area, Hakone volcano, Japan, have been repeatedly measured since 2001, when a seismic swarm occurred in the area. The CO2/H2O and CO2/H2S ratios were high in 2001. It increased in 2006 and again in 2008 when seismic swarms occurred beneath the geothermal area.
The observed increases suggest the injection of CO2- and SO2-rich magmatic gas into the underlying hydrothermal reservoir, implying that the magmatic gas was episodically supplied to
the hydrothermal system in 2006 and 2008. The earthquake swarms probably resulted from the injection of gas through the shallow
crust accompanying the break of the sealing zone. 相似文献
45.
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47.
Geothermometry and geobarometry of 10 garnet–oligoclase zone schists in the Franz Josef–Fox Glacier area, Southern Alps, New Zealand, give temperatures ranging from 415 to 625°C and pressures from 5.2 to 9.2 kbar, indicating a T–P array of about 50°C/kbar and inferred peak temperature conditions over a c. 15-km-thick section at depths between c. 20 and 34 km. The present-day distribution of the schist samples implies that only about one-third of the original crustal section is now exposed.
The garnet–oligoclase zone schists represent the deeper part of a metamorphosed and deformed accretionary complex that was associated with late Palaeozoic–early Mesozoic subduction along the Gondwana continental margin. Partial uplift ( c. 0.2 m/Ma) and erosion of the complex during Jurassic–Cretaceous times (Rangitata uplift) was synchronous with D2 deformation and recrystallization, as recorded by the P–T array. Cenozoic (Kaikoura) uplift and exhumation of the schist since c. 30 Ma to form the Southern Alps was associated with oblique-slip movement on the Alpine Fault. The present-day position and steep eastward dip of isograds and D2 structures suggest considerable clockwise rotation during uplift associated with ductile attenuation and tectonic thinning by over two-thirds of the original schist sequence, largely due to simple shear along schistosity planes. As the schist generally shows only incipient greenschist facies retrograde recrystallization, an apparently complete (although contracted) prograde mineral sequence has been preserved by rapid uplift (>5 km/Ma) of hot rock and the effects of limited shear heating near the Alpine Fault. 相似文献
The garnet–oligoclase zone schists represent the deeper part of a metamorphosed and deformed accretionary complex that was associated with late Palaeozoic–early Mesozoic subduction along the Gondwana continental margin. Partial uplift ( c. 0.2 m/Ma) and erosion of the complex during Jurassic–Cretaceous times (Rangitata uplift) was synchronous with D2 deformation and recrystallization, as recorded by the P–T array. Cenozoic (Kaikoura) uplift and exhumation of the schist since c. 30 Ma to form the Southern Alps was associated with oblique-slip movement on the Alpine Fault. The present-day position and steep eastward dip of isograds and D2 structures suggest considerable clockwise rotation during uplift associated with ductile attenuation and tectonic thinning by over two-thirds of the original schist sequence, largely due to simple shear along schistosity planes. As the schist generally shows only incipient greenschist facies retrograde recrystallization, an apparently complete (although contracted) prograde mineral sequence has been preserved by rapid uplift (>5 km/Ma) of hot rock and the effects of limited shear heating near the Alpine Fault. 相似文献
48.
Ken T. Murata Praphan Pavarangkoon Atsushi Higuchi Koichi Toyoshima Kazunori Yamamoto Kazuya Muranaga Yoshiaki Nagaya Yasushi Izumikawa Eizen Kimura Takamichi Mizuhara 《Earth Science Informatics》2018,11(2):217-237
It has been almost four decades since the first launch of geostationary meteorological satellite by Japan Meteorological Agency (JMA). The specifications of the geostationary meteorological satellites have shown tremendous progresses along with the generations, which are now entering their third generation. The third-generation geostationary meteorological satellites not only yield basic data for weather monitoring, but also globally observe the Earth’s environment. The development of multi-band imagers with improved spatial resolution onboard the third-generation geostationary meteorological satellites brings us meteorological data in larger size than those of the second-generation ones. Thus, new techniques for domestic and world-wide dissemination of the observational big data are needed. In this paper, we develop a web-based data visualization for Himawari-8 satellite sensed images in real time and with full resolution. This data visualization is supported by the ecosystems, which uses a tiled pyramid representation and parallel processing technique for terrain on an academic cloud system. We evaluate the performance of our techniques for domestic and international users on laboratory experiments. The results show that our data visualization is suitable for practical use on a temporal preview of observation image data for the domestic users. 相似文献
49.
A CASE STUDY ON THE RELATIONSHIP BETWEEN A PRECEDING LA NINA EVENT AND EAST ASIAN SUMMER ATMOSPHERIC CIRCULATION* 下载免费PDF全文
This study examined the relationship between mature phase of the cold event in 1999 and the East Asian summer atmosphere circulation in 2000.The cold event reaches its mature phase in the autumn and winter of 1999,which is the strongest La Nina episode in recent 11 years.There is a clear anomalous pattern of the atmosphere circulation around East Asia in the summer of 2000, i.e.the negative anomaly centers around the Cherski Mountains and 20°N,170°E at 500 hPa,the main body of the subtropical high keeps in further northern position than usual and the negative anomaly of precipitation located in southern central China.This pattern is thought as the response to the preceding strong cold event in autumn of 1999.It is also identified that the response of the East Asian atmosphere circulation in summer of 2000 to the strong La Nina event in 1999 belongs to the top rank in recent 43 years.On the other hand,the inactive blocking anticyclone around East Asia in summer of 2000 is associated with the positive SST anomaly and the 850 hPa temperature anomaly around the Bering Sea simultaneously.Nevertheless,although the impact on the summer atmosphere circulation around East Asia from La Nina events could not rank with that from E1 Nino,the impact could not be neglected especially in a strong La Nina case. 相似文献
50.
Shoko Oshigami Shinya Okuno Yasushi Yamaguchi Makiko Ohtake Junichi Haruyama Takao Kobayashi Atsushi Kumamoto Takayuki Ono 《Icarus》2012,218(1):506-512
Comparison of the Lunar Radar Sounder (LRS) data to the Multiband Imager (MI) data is performed to identify the subsurface reflectors in Mare Serenitatis. The LRS is FM-CW radar (4–6 MHz) and the 2 MHz bandwidth leads to the range resolution of 75 m in a vacuum, whereas the sampling interval in the flight direction is about 75 m when an altitude of the spacecraft with polar orbit is nominal (100 km). Horizontally continuous reflectors were clearly detected by LRS in limited areas that consist of about 9% of the whole maria. The typical depth of the reflectors is estimated to be a few hundred meters. Layered structures of mare basalts are also discernible on some crater walls in the MI data of the visible bands (VIS). The VIS range has nine wavelengths of 415, 750, 900, 950, and 1000 nm, and their spatial resolution is 20 m/pixel at a nominal altitude. The stratigraphies around Bessel and Bessel-H craters in Mare Serenitatis are examined in this paper. It was revealed that the subsurface reflectors lie on the boundaries between basalt units with different chemical compositions. In addition, model calculations using the simplified radar equation indicate that the subsurface reflectors are not compositional interfaces but layer boundaries with a high-porosity contrast. These results suggest that the detected reflectors in Mare Serenitatis are regolith accumulated during so long hiatus of mare volcanisms enough for chemical composition of magma to change, not instantaneously. Therefore combination of the LRS and MI data has a potential to reveal characteristics of a series of magmatism forming each lithostratigraphic unit in Mare Serenitatis and other maria. 相似文献