Trans-boundary and in-country transport of air pollutants observed in Kobe,Japan by high frequent filter pack sampling method

The seasonal intensive sampling of gases and particulate matter in ambient air was conducted at the site established in urban area of Japan to study the seasonal difference of the temporal variation of gases and particulate matter concentrations in urban atmosphere as well as to illustrate the different transport regimes that impacts air pollutants. The sample was collected by the four-stage filter-pack method with 6-h interval for one week in four seasons (spring, summer, autumn and winter). The trans-boundary transport of air pollutants with high concentration was characteristically observed in the spring sampling. On the other hand, we could successfully detect the in-country transports of air pollutants in the summer sampling. Four-season’s intensive survey considered, we could show the characteristic transport of air pollutants to provide the episodic high concentration for ambient air in the urban area of Japan, and successfully illustrate the seasonal-dependent transport regimes to impact on air pollutants.     

High-temperature thermal expansion and elasticity of calcium-rich garnets

We present new high temperature elasticity data on two grossular garnet specimens. One specimen is single-crystal, of nearly endmember grossular, the other is polycrystalline with about 22% molar andradite. Our data extend the high temperature regime for which any garnet elasticity data are available from 1000 to 1350 K and the compositional range of temperature data to near endmember grossular. We also present new data on the thermal expansivity of calcium-rich garnet. We find virtually no discernable differences in the temperatureT derivatives at ambient conditions of the isotropic bulkK _S and shearμ moduli when comparing our results between these two specimens. These calcium-rich garnets have the lowest values of ¦(?K _S /?T) _P ¦ = (1.47,1.49) x 10^-2GPa/K, and among the highest values of ¦(?μ/?T) _P ¦ = 1.25 x 10^-2GPa/K, when compared with other garnets. Small, but measurable, nonlinear temperature dependences of most of the elastic moduli are observed. Several dimensionless parameters are computed with the new data and used to illustrate the effects of different assumptions on elastic equations of state extra-polated to high temperatures. We discuss how dimensionless parameters and other systematic considerations can be useful in estimating the temperature dependence of some properties of garnet phases for which temperature data are not yet available. While we believe it is premature to quantitatively predict the temperature variation ofK _S andμ for majorite garnets, our results have bearing on the amount of diopside required to explain the shear velocity gradients in Earth's transition zone.     

Particle dynamics in the deep water column of Sagami Bay, Japan. I: origins of apparent flux of sinking particles

Temporal variations of sinking particle flux, together with their organic chemical properties, were monitored in the deep basin of Sagami Bay, Japan, using sediment traps with very high time resolutions from March 1997 to August 1998. At a height of 350 m above the bottom (about 1200 m water depth), the averaged total mass flux was more than 1000 mg/m²/day, which is about 10 times higher than those obtained for open ocean regions near Sagami Bay. While large amounts of phytodetritus, derived from phytoplankton blooms in the surface water, were transported downward in spring, the following extraordinary patterns in the temporal variability of sinking particle flux were also observed: (1) A sustained large flux of sinking particles during low productive periods from summer to winter in 1997. (2) An episodic increase of sinking particle flux in June 1998. (3) A difference in the temporal variability of sinking particles between the spring bloom periods of 1997 and 1998. The content of total organic carbon (TOC) and the stable carbon isotopic ratio (δ¹³C) of TOC demonstrated that the large fluxes observed in (1) and (2) could be attributed to the resuspension of phytodetritus deposited on the sea floor during the spring bloom period, and the abrupt erosion of surface sediment on the continental slope, respectively. The concentration of suspended particles in the deep water column affect the apparent flux of sinking particles. At the same time, sinking particles exported from surface waters during the spring bloom both decrease and increase suspended particle concentration through scavenging and rebound processes, respectively. Finally, the apparent difference in sinking particle flux between 1997 and 1998, (3), could be explained by differences in the extent of the scavenging process, which depend on the flux and quality of exported particles from the surface waters.     

Acetylene reducing activity at a tropical seagrass bed in Papua New Guinea

Acetylene reduction activity at a tropical seagrass bed in Papua New Guinea was studied. Blades of every species of seagrass studied (Enhalus acoroides, Thalassia hemprichii, Halodule uninervis, Syringodium isoetifolium) at the bed showed active acetylene reduction in the rage of 0.025–0.050 mol cm^–2d^–1. It is suggested that epiphytic blue-green algae would be responsible for active acetylene reduction. Acetylene reducing activity was observed also at rhizosphere of seagrasses, microbial communities on the detritus and periphyton on snail shells. It is estimated that total nitrogen fixed at the seagrass bed will be equivalent to 6.7% of that required for the growth of seagrasses.     

Spatial and temporal variations in free polyamine distributions in Uranouchi Inlet, Japan

Polyamines are an essential component of living organisms that influence normal cell growth and development. Despite the possible importance of polyamines for marine microbial ecology, concentrations of polyamines in seawater are not well known.Using HPLC analysis with a cation exchange column and OPA reagent, we determined polyamine concentrations in seawater without carrying out desalting, concentration or derivatization steps prior to chromatography.In seawater collected from Uranouchi Inlet, putrescine and spermidine were the predominant polyamines, ranging from undetectable (N.D.) to 4.4 nM and N.D. to 2.8 nM, respectively. Though other polyamines were detected, the frequency of detection was much lower than that of putrescine and spermidine; concentrations ranged from N.D. to 0.9 nM for cadaverine, and N.D. to 3.2 nM for norspermidine. Norspermine and spermine were detected in only a few samples; their concentrations varied from N.D. to 3.2 nM and N.D. to 0.5 nM, respectively. These concentrations were higher in the summer.     

AFM study on surface nanotopography of matrix olivines in Allende carbonaceous chondrite

By means of nanoscale surface observation, we have proposed a new approach for investigating fine crystals of cosmic materials to reveal their origin and growth conditions. Several different morphologies of polyhedral fine olivines with faceted faces have been found in Allende carbonaceous chondrite (4.5 byr in geochronological age). In the present work, molecular level topography of the faceted matrix olivine by Atomic Force Microscopy (AFM) has successfully been performed. The matrix olivine found to have preserved growth step pattern on its surface even though quite long time has passed since they formed in the early Solar System. The surface pattern suggests that the faceted matrix olivine could have been condensed from the gas phase, and possibly that these olivine crystals had continued to grow under a rapid cooling condition (0.1-1 K s⁻¹). The estimated cooling rate agrees well with predictions based on hypothetical rapid heating and cooling events such as shock wave heating.     

Thermochronology for the Granitic Pluton Related to Lead-Zinc Mineralization in Tsushima, Japan

Abstract: K–Ar datings and oxygen isotope analyses revealed a cooling history of the Uchiyama granitic pluton, which is genetically related to the Pb-Zn deposits (Taishu mine) in the Tsushima Islands, Japan. The pluton intrudes into the Paleogene Taishu Group to form the biotite-hornfels zone, while the Taishu vein-type Pb–Zn deposits occur in fissures developed in the non-hornfels zone about 1 to 3 km westward from the contact. Amphibole and biotite K-Ar ages of the pluton have a wide range from 19 to 13 Ma. Oxygen isotopes of the biotite and coexisting quartz grains indicate that isotopic exchange reactions have occurred under subsolidus conditions, and that the K-Ar ages are affected by various cooling rates in the pluton. The mineralization age of the Taishu ore deposits is obtained for the first time to be 15.40.8 Ma by a K-Ar age of 2 M ₁–muscovite in a calcite–quartz–muscovite–chlorite veinlet of the Shintomi orebody. Whole rock K-Ar ages of biotite-hornfels near the pluton represent similar ages to the ore deposits. Using blocking temperature calculated from reported diffusivity for argon, the pluton was cooled from 560 to 350C in the period of 17 to 14 Ma. The vein formation took place after the time when temperature in wall rocks of the pluton had dropped below the brittle-plastic transition (about 400C). These results imply that the cooling of the pluton has caused injection of magmatic fluids into meteoric hydrothermal systems, and the Pb-Zn mineralization has occurred due to this mixing at the age of about 15 Ma.     

A trial for monitoring temporal variation of seismic velocity using an ACROSS system

Abstract The temporal variation of seismic velocity near the Nojima Fault, which ruptured during the 1995 Kobe earthquake (Hyogo-ken Nanbu earthquake), was detected using an accurately controlled routine-operated seismic source (ACROSS). The source generates elastic waves by a centrifugal force of an eccentric mass rotating around an axis. The mass is driven with an AC servomotor whose angular position is accurately controlled with reference to a very accurate global positioning system (GPS) clock. The error of the mass' position is less than 0.002 radian and does not accumulate. As a result, the source generates sinusoidal waves of very narrow spectral peaks enabling their detection with an excellent signal-to-noise ratio. Although the stability of the rotation is quite excellent, a large daily variation was found, which seems to be caused by changes in atmospheric temperature. The daily variation was 10% in amplitude and 0.1 radian in phase of the signal observed at the 800 m borehole seismometer. A significant variation was found to be due to that of coupling between the rotational source and the foundation made of reinforced concrete in which the source was situated. In order to make a correction on the signal of the 800 m borehole seismometer, the vibration of the foundation was measured and modeled assuming a rigid body movement. The correction successfully reduced the daily variation by approximately 90%, resulting in a variation of 1% in amplitude and 0.01 radian in phase. The phase variation of 0.01 radian corresponds to 100 μs and less than 0.1% in velocity over 1000 m between the source and the receiver.     

THREE NEW GSJ ROCK REFERENCE SAMPLES: RHYOLITE JR-3, GABBRO JGB-2 AND HORNBLENDITE JH-1

Three new rock reference samples, Rhyolite JR-3, Gabbro JGb-2 and Hornblendite JH-1 have been prepared by the Geological Survey of Japan for collaborative studies on their chemical composition. Twenty-eight major, minor and trace elements were determined and presented. The results of homogeneity tests showed that all elements are considered to be distributed homogeneously in each reference sample. Geological and mineralogical characteristics are also described.     

A thermodynamic theory of the Grüneisen ratio at extreme conditions: MgO as an example

The Grüneisen ratio, γ, is defined as γy=αK _TV/C_v. The volume dependence of γ(V) is solved for a wide range in temperature. The volume dependence of αK _T is solved from the identity (? ln(αK _T)/? ln V)T ≡ δ _T-K′. α is the thermal expansivity; K _T is the bulk modulus; C _V is specific heat; and δ _Tand K′ are dimensionless thermoelastic constants. The approach is to find values of δ _T and K′, each as functions of T and V. We also solve for q=(? ln γ/? ln V) where q=δ _T -K′+ 1-(? ln C _V/? ln V)T. Calculations are taken down to a compression of 0.6, thus covering all possible values pertaining to the earth's mantle, q=? ln γ/? ln V; δ _T=? ln α/? ln V; and K′= (?K _T/?P)T. New experimental information related to the volume dependence of δ _T, q, K′ and C _V was used. For MgO, as the compression, η=V/V ₀, drops from 1.0 to 0.7 at 2000 K, the results show that q drops from 1.2 to about 0.8; δ _T drops from 5.0 to 3.2; δ _T becomes slightly less than K′; ? ln C _V/? In V→0; and γ drops from 1.5 to about 1. These observations are all in accord with recent laboratory data, seismic observations, and theoretical results.