The degree of Cl-loss for the particulate matter (PM) and fog water sampled at the same air mass at the Hachimantai mountain range in northern Japan

It is well known that sea-salt aerosols in particulate matter (PM) react with acids such as H₂SO₄ and HNO₃ during transportation and thereby lose chloride ions (Cl-loss). The PM and fog were sampled concurrently at different altitudes in the Hachimantai mountain range, northern Japan. The PM and fog sampled at different altitudes had nearly identical properties for the ion components. However, the PM was in a Cl-depleted state (more than 80% of all samples), but the fog water was not in so Cl-depleted state (less than 29%). As a result, it could be explained that this phenomenon caused because the fog droplets took up the gaseous state HCl other than sea-salt PM. After all Cl^- in the fog water recovered and was rather rich compared with the sea-salt or the PM by the uptake of the gaseous state HCl. Moreover, it was found that for PM_coarse(2.5 < D < 10), 86% of the acid (H₂SO₄ and HNO₃) was consumed for Cl-loss reactions and/or for dissolution of Ca and Mg in soil particles.     

Identifying spatial heterogeneity of coal resource quality in a multilayer coal deposit by multivariate geostatistics

This study presents a new geostatistical approach to characterization of the geometry and quality of a multilayer coal deposit using the data of seam thickness as a geometric property and the contents of ash, sodium, total sulphur, and the heating value as quality properties. A coal deposit in East Kalimantan (Borneo), Indonesia, which has a synclinal geological structure, was chosen as the study site. Semivariogram analysis clarified the strong dependence of heating value on ash content in the top and bottom parts of each seam and the existence of a strong correlation with sodium content over the sub-seams in the same location. The correlations between the geometry and quality of the seams were generally weak. A linear coregionalization model was used to derive the spatial correlation coefficients of two variables at each scale component from the single- and cross-semivariogram matrices. Because the data were correlated spatially in the same seam or over different seams, multivariate techniques (ordinary cokriging and factorial cokriging) were mainly used and the resultant spatial estimates were compared to those derived using a univariate technique (ordinary kriging). A factorial cokriging was effective to decompose the spatial correlation structures with different scales. Another important characteristic was that the sodium content shows distinct segregation: the low zones are concentrated near the boundary of the sedimentary basin, while the high zones are concentrated in the central part. The main component of sodium originates from the abundance of saline water. Therefore, it can be inferred that seawater had stronger effects on the coal depositional process in the central basin than in the border part. The geostatistical modeling results suggest that the thicknesses of all the major seams were controlled by the syncline structure, while the coal qualities chiefly were originated from the coal depositional and diagenetic processes.     

Two contrasting magmatic types coexist after the cessation of back-arc spreading

Amongst island arcs, Izu–Bonin is remarkable as it has widespread, voluminous and long-lived volcanism behind the volcanic front. In the central part of the arc this volcanism is represented by a series of seamount chains which extend nearly 300 km into the back-arc from the volcanic front. These back-arc seamount chains were active between 17 and 3 Ma, which is the period between the cessation of spreading in the Shikoku Basin and the initiation of currently active rifting just behind the Quaternary volcanic front. In this paper we present new age, chemical and isotopic data from the hitherto unexplored seamounts which formed furthest from the active volcanic front. Some of the samples come from volcanoes at the western limit of the back-arc seamount chains. Others are collected from seamounts of various sizes which lie on the Shikoku Basin crust (East Shikoku Basin seamounts). The westernmost magmatism we have sampled is manifested as a series of volcanic edifices that trace the extinct spreading centre of the Shikoku Basin known as the Kinan Seamount Chain (KSC).Chemically, enrichment in fluid-mobile elements and depletion in HFSE relative to MORB indicates that the back-arc seamount chains and the East Shikoku Basin seamounts have a significant contribution of slab-derived material. In this context these volcanoes can be regarded as a manifestation of arc magmatism and distinct from the MORB-like lavas of the Shikoku back-arc basin. ⁴⁰Ar/³⁹Ar ages range from 15.7 to 9.6 Ma for the East Shikoku Basin seamounts, indicating this arc magmatism started immediately after the Shikoku Basin stopped spreading.Although the KSC volcanoes are found to be contemporaneous with the seamount chains and East Shikoku Basin seamounts, their chemical characteristics are very different. Unlike the calc-alkaline seamount chains, the KSC lavas range from medium-K to shoshonitic alkaline basalt. Their trace element characteristics indicate the absence of a subduction influence and their radiogenic isotope systematics reflect a mantle source combining a Philippine Sea MORB composition and an enriched mantle component (EM-1). One of the most remarkable features of the KSC is that their geochemistry has a distinct temporal variation. Element ratios such as Nb/Zr and concentrations of incompatible elements such as K₂O increase with decreasing age and reach a maximum at ca. 7 Ma when the KSC ceased activity.Based on the chemical and temporal information from all the data across the back-arc region, we have identified two contrasting yet contemporaneous magmatic provinces. These share a tectonic platform, but have separate magmatic roots; one stemming from subduction flux and the other from post-spreading asthenospheric melting.     

Low-temperature single crystal reflection spectra of forsterite

The infrared reflectivities of crystalline forsterite (Mg₂SiO₄) were measured for the temperature range 295–50 K for each crystal axis, between wavenumber 5000 and 100 cm⁻¹. The reflection spectra show clear dependence of temperature; most of the bands become more intense, sharper and their peak positions shift to higher wavenumber with decreasing temperature. Reflection spectra were fitted with dispersion formula of damped oscillator model of the dielectric constants and the oscillator parameters in the model were derived. The absorption spectra of forsterite particle are calculated with the derived dielectric constants to show that the forsterite features are good thermal indicator for cold temperature range below 295 K.