湘南荷花坪锡多金属矿床稀有气体同位素特征及其地质意义   总被引：3，自引：1，他引：2  

蔡明海  王显彬  长尾敬介  彭振安  郭腾飞  刘虎  谭泽模 《矿床地质》2012,31(6):1163-1170

荷花坪锡多金属矿床是南岭中段湘南地区新发现的一个大型矿床,发育有印支期和燕山期2期成岩、成矿作用。文章对不同期矿石中的黄铁矿分别进行了稀有气体同位素研究。测试结果表明,印支期矽卡岩型矿石中的黄铁矿:³He/⁴He=0.15～2.49 Ra,³⁸Ar/³⁶Ar=0.18733～0.18902,⁴⁰Ar/³⁶Ar=310.45～523.98,²⁰Ne/²²Ne=9.727～9.830,²¹Ne/²²Ne=0.0286～0.0310;燕山期蚀变碎裂岩型矿石中的黄铁矿:³He/⁴He=0.15～4.33 Ra,³⁸Ar/³⁶Ar=0.18750～0.18843,⁴⁰Ar/³⁶Ar=331.78～602.62,²⁰Ne/²²Ne=9.736～9.858,²¹Ne/²²Ne=0.0286～0.0305,显示区内两期成矿流体均为大气饱和水、地壳流体和地幔流体的混合流体。印支期矽卡岩型矿石中地幔He所占比例为2.34%～41.40%,平均18.16%;燕山期蚀变碎裂岩型矿石中地幔He所占比例为2.34%～72.12%,平均27.41%,燕山期幔源流体的作用强度略高于印支期。湘南地区印支期基性岩浆活动及荷花坪矿床印支期成矿过程中有幔源物质的参与,二者共同指示南岭地区中生代构造体制的转换或岩石圈伸展减薄可能始于印支主期(244～230 Ma)之后的224 Ma左右,即晚三叠世。  相似文献   

An integrated analysis platform merging SuperDARN data within the THEMIS tool developed by ERG-Science Center (ERG-SC)     

Tomoaki Hori  Nozomu Nishitani  Yoshizumi Miyoshi  Yukinaga Miyashita  Kanako Seki  Tomonori Segawa  Keisuke Hosokawa 《极地研究(英文版)》2013,24(1)

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Fifteen years progress of the TRITON array in the Western Pacific and Eastern Indian Oceans     

Kentaro Ando  Yoshifumi Kuroda  Yosuke Fujii  Tatsuya Fukuda  Takuya Hasegawa  Takanori Horii  Yasuhisa Ishihara  Yuji Kashino  Yukio Masumoto  Keisuke Mizuno  Motoki Nagura  Iwao Ueki 《Journal of Oceanography》2017,73(4):403-426

The Triangle Trans‐Ocean Buoy Network (TRITON) project by the Japan Agency for Marine-Earth Science and Technology began with deployment in the western tropical Pacific Ocean in 1998 and has shifted to steady, long-term observations since 1999. After on-site inter-comparison with the Autonomous Temperature Line Acquisition System mooring system of the Tropical Atmosphere and Ocean (TAO) array by the National Oceanic and Atmospheric Administration, the TRITON array became the international TAO/TRITON array in 2000 as a key component of the Global Ocean and Climate Observing Systems. The TAO/TRITON array took over from the TAO array, which was developed during the Tropical Ocean and Global Atmosphere program (1985–1994), and replaced the western part of TAO with new additional real-time measurements of salinity and ocean currents. In 2001, two TRITON moorings were deployed in the eastern Indian Ocean for capturing the eastern pole of the Indian Ocean Dipole. From this initiative, the Indian Ocean Observing System (IndOOS) was designed, and the Indian Ocean mooring array (Research Moored Array for Africa–Asian–Australian Monsoon Analysis and Prediction) was developed as a key component of IndOOS. In this paper, 15 years of progress in the TRITON project in the western Pacific and eastern Indian Oceans is reviewed with regards to scientific outcomes, technological development, and collaborations with international and domestic partners. Future directions for sustainable observation in the Pacific and Indian Oceans are also discussed.  相似文献   

Influence of interaction between small asperities on various types of slow earthquakes in a 3-D simulation for a subduction plate boundary   总被引：3，自引：1，他引：2  

Keisuke Ariyoshi  Takane Hori  Jean-Paul Ampuero  Yoshiyuki Kaneda  Toru Matsuzawa  Ryota Hino  Akira Hasegawa 《Gondwana Research》2009,16(3-4):534-544

Recently, the occurrence of slow earthquakes such as low-frequency earthquakes and very low-frequency earthquakes have been recognized at depths of about 30 km in southwest Japan and Cascadia. These slow earthquakes occur sometimes in isolation and sometimes break into chain-reaction, producing tremor that migrates at a speed of about 5–15 km/day and suggesting a strong interaction among nearby small asperities. In this study, we formulate a 3-D subduction plate boundary model with two types of small asperities chained along the trench at the depth of 30 km. Our simulation succeeds in representing various types of slow earthquakes including low-frequency earthquakes and rapid slip velocity in the same asperity, and indicates that interaction between asperities may cause the very low-frequency earthquakes. Our simulation also shows chain reaction along trench with propagation speed that can be made consistent with observations by adjusting model parameters, which suggests that the interactions also explain the observed migration of slow earthquakes.  相似文献   

He, Sr and Nd isotopes of mantle-derived xenoliths in volcanic rocks of NE China     

Sheng Xu  Keisuke Nagao  Kozo Uto  Hiroshi Wakita  Shun&#x;ichi Nakai  Congqian Liu 《Journal of Asian Earth Sciences》1998,16(5-6)

Abundances and isotopic ratios of He and isotopic ratios of Sr and Nd have been measured for 18 mantle-derived xenoliths from three Cenozoic volcanic provinces in NE China. The xenoliths are characterized by low He concentrations (2.3×10⁻⁹–2.5×10⁻⁷ cm³ STP g⁻¹) and large variations of ³He/⁴He ratios (1.6×10⁻⁷–15.8×10⁻⁶ or R/Ra=0.1–11). ³He/⁴He, ⁸⁷Sr/⁸⁶Sr and ¹⁴³Nd/¹⁴⁴Nd ratios in xenoliths from Kuandian Holocene volcanic provinces are consistent with those observed in mid-oceanic ridge basalt (MORB), indicating that the source of He–Sr–Nd in the lithospheric mantle is chemically and isotopically identical to that of MORB reservoir. However, xenoliths in Huinan Pleisteocene–Holocene volcanic province are characterized by slightly low ³He/⁴He ratios (R/Ra=4.3–6.5) and more radiogenic Sr and Nd. The age-corrected ³He/⁴He ratios suggest that their time-integrated ratio of (U+Th)/³He is slightly elevated compared to the depleted upper mantle. The Hannuoba xenoliths in the Miocene volcanic province show much lower and wider variable ³He/⁴He ratios, which is most likely caused by in situ radiogenic ⁴He accumulation since it erupted on to the surface. The He–Sr–Nd results suggest chemical and isotopical heterogeneity in the subcontinental mantle beneath NE China.  相似文献   

Heat-Mitigation Effects of Irrigated Rice-Paddy Fields Under Changing Atmospheric Carbon Dioxide Based on a Coupled Atmosphere and Crop Energy-Balance Model     

Ikawa  Hiroki  Kuwagata  Tsuneo  Haginoya  Shigenori  Ishigooka  Yasushi  Ono  Keisuke  Maruyama  Atsushi  Sakai  Hidemitsu  Fukuoka  Minehiko  Yoshimoto  Mayumi  Ishida  Sachinobu  Chen  Charles P.  Hasegawa  Toshihiro  Watanabe  Tsutomu 《Boundary-Layer Meteorology》2021,179(3):447-476

Boundary-Layer Meteorology - Known as the heat-mitigation effect, irrigated rice-paddy fields distribute a large fraction of their received energy to the latent heat during the growing season. The...  相似文献   

P - V - T equation of state of stishovite to the mantle transition zone conditions     

Yu Nishihara  Keisuke Nakayama  Eiichi Takahashi  Tomohiro Iguchi  Ken-ìchi Funakoshi 《Physics and Chemistry of Minerals》2005,31(10):660-670

In-situ synchrotron X-ray diffraction experiments were conducted using the SPEED-1500 multi-anvil press of SPring-8 on stishovite SiO₂ and pressure-volume-temperature data were collected at up to 22.5 GPa and 1,073 K, which corresponds to the pressure conditions of the base of the mantle transition zone. The analysis of room-temperature data yielded V₀=46.56(1) ų, K_{T 0}=296(5) GPa and K _T =4.2(4), and these properties were consistent with the subsequent thermal equation of state (EOS) analyses. A fit of the present data to high-temperature Birch-Murnaghan EOS yielded (K_T /T) _P =–0.046(5) GPa K^–1 and = a + bT with values of a =1.26(11)×10^–5 K^–1 and b =1.29(17)×10^–8 K^–2. A fit to the thermal pressure EOS gives ₀=1.62(9)×10^–5 K^–1, ( K _T / T) _V =–0.027(4) GPa K^–1 and (²P /T ²) _V =27(5)×10^–7 GPa K^–2. The lattice dynamical approach by Mie-Grüneisen-Debye EOS yielded ₀=1.33(6), q =6.1(8) and ₀=1160(120) K. The strong volume dependence of the thermal pressure of stishovite was revealed by the analysis of present data, which was not detectable by the previous high-temperature data at lower pressures, and this yields ( K _T / T) _V 0 and q 1. The analyses for the fictive volume for a and c axes show that relative stiffness of c axis to a axis is similar both on compression and thermal expansion. Present EOS enables the accurate estimate of density of SiO₂ in the deep mantle conditions.  相似文献   

PSP-toxicification of the carnivorous gastropod Rapana venosa inhabiting the estuary of Nikoh River, Hiroshima Bay, Hiroshima Prefecture, Japan     

Ito K  Asakawa M  Beppu R  Takayama H  Miyazawa K 《Marine pollution bulletin》2004,48(11-12):1116-1121

During surveillance on the toxicity of invertebrates such as bivalves inhabiting the coasts of Hiroshima Bay in 2001 and 2002, the carnivorous gastropod rapa whelk Rapana venosa collected in the estuary of Nikoh River, was found to contain toxins which showed paralytic actions in mice; the maximum toxicities (as paralytic shellfish poison, PSP) were 4.2 MU/g (May 2001) and 11.4 MU/g (April 2002). Their total toxicities were 224 and 206 MU/viscera of one specimen throughout the monitoring period. Attempts were made to identify the toxic principle in the gastropod. The viscera were extracted with 80% ethanol acidified with acetic acid, followed by defatting with dichloromethane. The aqueous layer obtained was treated with activated charcoal and then applied to a Sep-Pak C18 cartridge. The unbound toxic fraction was analyzed by high-performance liquid chromatography techniques. The gastropod toxin was rather unexpectedly identified as PSP. It was comprised of high toxic component (gonyautoxin-3; GTX3, GTX2, saxitoxin; STX) as the major components, which accounted for approximately 91 mol% of all components along with C1 and C2, which are N-sulfocarbamoyl derivatives. Judging from their toxin patterns, it is suggested that the PSP toxification mechanism of the gastropod that PSP toxins produced by phytoplankton such as Alexandrium tamarense, are transferred to and accumulated in plankton feeders such as the short-necked clam, and then transferred to this carnivorous rapa whelk R. venosa through predation.  相似文献   

Deep and Bottom Currents in the Challenger Deep,Mariana Trench,Measured with Super-Deep Current Meters   总被引：3，自引：0，他引：3  

Keisuke?TairaEmail author  Shoji?Kitagawa  Toru?Yamashiro  Daigo?Yanagimoto 《Journal of Oceanography》2004,60(6):919-926

The bottom currents in the Challenger Deep, the deepest in the world, were measured with super-deep current meters moored at 11°22′ N and 142°35′ E, where the depth is 10915 m. Three current meters were set at 9687 m, 10489 m and 10890 m at the station in the center of the Challenger Deep for 442 days from 1 August 1995 to 16 October 1996. Although rotor revolutions in 60 minutes of recording interval were zero for 37.5% of the time, the maximum current at the deepest layer of 10890 m was 8.1 cm s⁻¹, being composed of tidal currents, inertia motion and long period variations. Two current meters were set at 6608 m and 7009 m at a station 24.9 km north of the center for 443 days from 31 July 1995 to 16 October 1996, and two current meters at 6214 m and 6615 m at a station 40.9 km south of the center for 441 days from 2 August 1995 to 16 October 1996. The mean flow at 7009 m depth at the northern station was 0.7 cm s⁻¹ to 240°T, and that at 6615 m depth at the southern station was 0.5 cm s⁻¹ to 267°T. A westward mean flow prevailed at the stations, and no cyclonic circulation with mean flows of the opposite directions was observed in the Mariana Trench at a longitude of 142°35′ E. Power spectra of daily mean currents showed three spectral peaks at periods of 100 days, 28–32 days and 14–15 days. The peak at 100 day period was common to the power spectra.  相似文献   

Southward intrusion of the intermediate Oyashio water along the east coast of the Boso Peninsula,Japan II. Intrusion events into Sagami Bay     

Sung-Kee Yang  Yutaka Nagata  Keisuke Taira  Masaki Kawabe 《Journal of Oceanography》1993,49(2):173-191

In the previous paper (Yanget al., 1993), it was shown that there always exists the coastal salinity-minimum-layer (SML) water just off the Boso Peninsula. The coastal SML water is bounded by the current zone of the Kuroshio, and a relatively high salinity domain separates it from the offshore SML water which would be a continum of the North Pacific Intermediate Water. We suggested that the coastal SML water region indicates the pathway along which the Intermediate Oyashio Water intrudes into Sagami Bay. In this paper, by selecting seven cases where we found the coastal SML water having abnormally high oxygen content and low salinity, we try to follow the intrusion manner of the Intermediate Oyashio Water into Sagami Bay by using available hydrographic data taken routinely by various organizations in the period from 1973 to 1986. Some of these water can be traced from the observation line near the cape of Inubo to the central part of Sagami Bay, and its propagation speed along the coast is shown to be of order of 1 cm/s. The intruding intermediate Oyashio water usually has a complicated layered structure in it, and its time scale of persistence is shown to be only a few months.  相似文献