Horizontal distribution of calanoid copepods in the western Arctic Ocean during the summer of 2008

The horizontal distribution of the epipelagic zooplankton communities in the western Arctic Ocean was studied during August–October 2008. Zooplankton abundance and biomass were higher in the Chukchi Sea, and ranged from 3,000 to 274,000 ind. m^?2 and 5–678 g WM m^?2, respectively. Copepods were the most dominant taxa and comprised 37?94% of zooplankton abundance. For calanoid copepods, 30 species belonging to 20 genera were identified. Based on the copepod abundance, their communities were classified into three groups using a cluster analysis. The horizontal distribution of each group was well synchronized with depth zones, defined here as Shelf, Slope and Basin. Neritic Pacific copepods were the dominant species in the Shelf zone. Arctic copepods were substantially greater in the Slope zone than the other regions. Mesopelagic copepods were greater in the Basin zone than the other regions. Stage compositions of large-sized Arctic copepods (Calanus glacialis and Metridia longa) were characterized by the dominance of late copepodid stages in the Basin. Both the abundance and stage compositions of large copepods corresponded well with Chl. a concentrations in each region, with high Chl. a in the Shelf and Slope supporting reproduction of copepods resulting in high abundance dominated by early copepodid stages.     

Geology and Skarn Cu–Bi–Au Mineralization at Shwe Min Bon Area,Kalaw Township,Southern Shan State,Myanmar

The Shwe Min Bon Cu–Au skarn deposit lies within one of the largest Au–Cu belts in Myanmar. The deposit is situated along the Shan scarp zone, which marks the boundary between the Myanmar central basin to the west and the Shan plateau to the east. The Shwe Min Bon deposit comprises skarn‐type metasomatic alteration, and the Cu–Au mineralization occurs along the contact face between the Nwabangyi Dolomite and Shweminbon Formation and the Cretaceous dioritic rocks. The metasomatic process resulted in pro‐ and retrograde mineral assemblages in exoskarn. Hydrothermal activities in the Shwe Min Bon deposit are classified into prograde, retrograde stage I, and retrograde stage II. The prograde skarn is classified into a proximal garnet skarn with minor clinopyroxene and a distal wollastonite skarn. Chlorite, epidote, and tremolite–actinolite were formed during the retrograde stage I. Cu–Au mineralization mainly occurred in retrograde stage I, which was characterized by moderate temperatures (260–320 °C) and fluid with a moderate salinity (5.0–6.0% NaCl equiv.). Low temperature (180–200 °C) and low salinity (2.0–3.0% NaCl equiv.) were responsible for retrograde stage II. Au mineralization is mainly associated with chalcopyrite and tennantite in retrograde stage I and with tellurobismuthite in retrograde stage II.     

Monitoring of DSP toxins in small-sized plankton fraction of seawater collected in Mutsu Bay,Japan, by ELISA method: relation with toxin contamination of scallop

Monitorings were conducted on DSP toxins in mid-gut gland of scallop (mouse assay), cell numbers of toxic dinoflagellate species of Dinophysis, and diarrhetic shellfish poisoning (DSP) toxins in small-sized (0.7-5 microm) plankton fraction of seawater collected from surface (0 m) and 20 m depth at a station in Mutsu Bay, Aomori Prefecture, Japan, in 2000. A specific enzyme-linked immunosorbent assay (ELISA) was employed for the analysis of DSP toxins in small-sized plankton fraction using a mouse monoclonal anti-okadaic acid antibody which recognizes okadaic acid, dinophysistoxin-1, and dinophysistoxin-3. DSP toxins were detected twice in the mid-gut gland of scallops at 1.1-2.3 MU (mouse units) g(-1) on 26 June and at 0.6-1.2 MU g(-1) on 3 July, respectively. Relatively high cell densities of D. fortii were observed on 26 June and 11 September, and may only contribute to the bivalve toxicity during late June to early July. D. acuminata did not appear to be responsible for the toxicity of scallops in Mutsu Bay in 2000. ELISA monitoring of small-sized plankton fraction in seawater could detect DSP toxins two weeks before the detection of the toxin in scallops, and could do so two weeks after the loss of the bivalve toxicity by mouse assay. On 17 July, toxic D. fortii was detected at only small number, <10 cells l(-1), but DSP toxins were detected by the ELISA assay, suggesting a presence of other toxic small-sized plankton in seawater. For the purpose of reducing negative impacts of DSP occurrences, monitorings have been carried out hitherto on DSP toxins of bivalve tissues by mouse assay and on cell densities of "toxic" species of Dinophysis. Here we propose a usefulness of ELISA monitoring of plankton toxicity, especially in small-sized fraction, which are possible foods of mixotrophic Dinophysis, as a practical tool for detecting and predicting DSPs in coastal areas of fisheries grounds of bivalve aquaculture.     

DATABASE ON INTERNET FOR GEOLOGICAL SURVEY OF JAPAN GEOCHEMICAL REFERENCE SAMPLES

A database on thirty-one Geological Survey of Japan (GSJ) geochemical reference samples has been set up on Internet which allows the retrieval of recommended or preferable values, compiled data, location, sample preparation and other relevant information. The URL location on WWW server is: http://www.aist.go.jp./RIODB/geostand/welcome.html     

An interpretation of the 1883 cataclysmic eruption of Krakatau from geochemical studies on the partial melting of granite

Pumice flow from the 1883 Krakatau eruption significantly differs in both mineral and chemical compositions from any other volcanic rocks or ejecta of the Krakatau group, which belong to the tholeiitic series. Lithic fragments of granitic Rock, discovered in the pumice flow, are similar to West Malayan granitic rocks. No other granitic rock occurs throughout the Krakatau group, therefore, we consider that the granitic fragments came from the underlying complex at depths, where they were captured as foreign materials by the magma.It is possible that sialic crustal materials plunged into depths along a peculiar tectonic structure located at the Sunda Strait, which appears to be a sheared portion caused by deformation of the Sunda arc due to differential movement between the Indo-Australian oceanic plate and the Eurasian continental crust. The crustal materials were partially melted and produced a magma of granitic composition. The magma was mixed with or assimilated by an ascending basaltic magma originating probably from the upper mantle. This resulted in a dacitic magma distinctly dominant in silica, alkalis and volatile components, and the 1883 Krakatau eruption, characterized by the pumice flow of dacitic composition, took place.     

Geochronological Constraints Using 40Ar/39Ar Dating on the Mineralization of the Hishikari Epithermal Gold Deposit, Japan

Abstract. Ages for thirty adularia samples collected from various veins were in the Hishikari gold deposit determined by ⁴⁰Ar/³⁹Ar dating to constrain the timing of adularia‐quartz vein formation and to determine the temporal change in temperature of hydrothermal fluid. Plateau ages were obtained from all adularia samples, and significant excess ⁴⁰Ar is not recognized from inverse isochrones. The duration of mineralization within individual veins was determined by adularia ages from the early and late stages of mineralization within the same vein. The durations of mineralization in the Daisen‐1, Daisen‐3, Hosen‐2 and Keisen‐3 veins in the Honko‐Sanjin zone were 7,000, 140,000, 160,000 and 170,000 years, respectively. The durations of mineralization in the Seisen‐2 and Yusen‐1–2 veins in the Yamada zones were 360,000 and 320,000 years, respectively. Mineralization lasted for a relatively longer period in individual veins at the Yamada zone. Mineralization ages from the Honko‐Sanjin zone range from 1.04 to 0.75 Ma, and most mineralization ages are concentrated in a short period from 1.01 to 0.88 Ma. In contrast, mineralization ages for the Yamada zone range from 1.21 to 0.64 Ma. These results indicate that fracturing and subsequent vein formation lasted for a longer period in the Yamada zone (about 570,000 years) compared with those events in the Honko‐Sanjin zone (about 290,000 years). The homogenization temperatures of liquid‐rich fluid inclusions in columnar adularia used for age determination were determined to be 223°C on average, and most of these temperatures range from 180 to 258d?C. No significant temporal change in homogenization temperature is recognized in this study. However, adularia in the Keisen veins indicated higher homogenization temperatures compared with elsewhere in the deposit, suggesting that the principal ascent of mineralizing hydrothermal fluid was via the Keisen veins.     

利用MODIS数据计算陆地植被指数VIUPD

介绍了利用MODIS卫星数据计算VIUPD的步骤,将计算结果与NDVI和EVI进行了比较,验证了本文方法的正确性。     

1994 COMPILATION OF ANALYTICAL DATA FOR MINOR AND TRACE ELEMENTS IN SEVENTEEN GSJ GEOCHEMICAL REFERENCE SAMPLES, "IGNEOUS ROCK SERIES"

Analytical data for minor and trace elements published or communicated to us, on seventeen GSJ (Geological Survey of Japan) reference samples, "Igneous rock series" received up to April 1994 are compiled. The data were evaluated statistically in consideration of analytical methods. Based on the selected available data, 1994 recommended and proposed values for 65 minor and trace elements are presented.