Experimental determination of partition coefficients of ten rare earth elements and barium between clinopyroxene and liquid in the synthetic silicate system at 20 kilobar pressure

Two experiments were carried out at 20 kb pressure for the measurement of partition coefficients of ten lanthanides and barium between diopside clinopyroxene and liquid in the synthetic system diopside-enstatite-silica-H₂O. Starting materials are glass of two different compositions CaMgSi₂O₆ 56, MgSiO₃ 14, SiO₂ 30 weight % and CaMgSi₂O₆ 80, MgSiO₃ 20 weight %.In the experiment on the former composition, the partition coefficient increases regularly with decrease of ionic radii from La to Dy and decreases also regularly from Dy to Lu. In the experiment on the latter composition, stepwise shift of partition coefficient was observed between Dy and Er.The results suggest that the lanthanide cations occupy the site of 8-fold coordination in the clinopyroxene and that the partition coefficients depend on the ionic radii of lanthanide elements and also on the chemical composition of the starting material or heating process during the run.     

An ultimate steady-state pattern of c-axis fabric of quartz in metamorphic tectonites

The c-axis fabrics of quartz grains at the hinge zones of the orthorhombic buckle folds of quartz-rich layers which were collected from the Sambagawa crystalline schists of Shikoku, Japan, have been described and discussed. Especially, attempt to correlate the pattern of the quartz fabric with the strain picture has been made. It has been pointed out that the high concentration of quartz axes on two positions which are symmetrically placed on the plane of the longest principal axis and the shortest principal axis of the strain ellipsoid and at an angle of ca. 30 to the latter axis may be regarded as an ultimate steady-state pattern of preferred orientation of quartz axes developed under non-rotational two dimensional strain.

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Zusammenfassung Untersucht wurden die Quarzachsen-Gefüge in den Scheiteln der orthorhombischen Biegefalten der quarzreichen Lagen aus dem Sambagawa-Schiefer von Shikoku, Japan. Besonders wurde es versucht, die Quarzachsen-Orientierung mit dem Verformungsbild zu vergleichen. Zwei Quarzachsen-Maxima in der Ebene von der lÄngsten Hauptachse und der kürzesten Hauptachse des Verformungsellipsoides, die symmetrisch zur kürzesten Hauptachse im Abstand von etwa 30 liegen, wurden als bevorzugte Endlagenorientierung der Quarzachsen angesprochen, die durch die zweidimensionale Verformung ohne Rotation erzeugt wurden.

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Résumé La fabrique c-axiale des grains de quartz dans les charnières de plis, collectionnés dans les schistes cristallins de Sambagawa prés de Shikoku (Japon) sont décrits et interprétés dans cette étude. Il a été essayé spécialement de comparer le type de la fabrique du quartz au type de la déformation. Enfin il a été prouvé que la forte concentration des axes de quartz en deux lieux fixes des diagrammes, qui sont situés symétriquement aux deux axes principaux (long et petit) de l ellipsoide de déformation et qui forment un angle de 30 avec le petit axe, sont les positions définitives et stables de l'orientation préférée des axes de quartz qui à été produite par une déformation bi-dimensionelle sans rotation.

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Holocene climate and environmental changes inferred from sediment characteristics and diatom assemblages in a core from Hwajinpo Lagoon,Korea

Hwajinpo is the largest lagoon in Korea and is located along the east coast of the country. It possesses Holocene sediments that provide an important record of past climate change. We studied the evolution of Hwajinpo Lagoon using grain size data and diatom assemblages in an 11.0-m core (HJ02), which was obtained at the mouth of a small river that drains into the lagoon. Core chronology was established with accelerator mass spectrometry ¹⁴C dates and optically stimulated luminescence dates. Diatom assemblages and grain size analysis revealed that estuarine conditions in the inner lagoon area transitioned to an open embayment ca. 8 ka as a result of sea-level rise. Around 7.8 ka, the open bay became a semi-closed bay as a consequence of development of a sand barrier. After the bay was semi-closed, marine water inflow was increasingly restricted as the sand barrier developed, and the semi-closed bay became a completely enclosed, low-salinity, brackish lagoon around 6 ka. There was an erosional hiatus between 5.5 and 1.7 ka (7.0 m depth), likely caused by river flooding and a switch in the location of drainage along the delta. The lagoon became oligohaline around 1.6 ka, likely because of increasing precipitation associated with an intensified Asian summer monsoon. This increase in precipitation resulted in expansion of the sand bar by sediment inflow, driven by agricultural development in the area. About 1000 years ago, the diatom assemblage was similar to the modern assemblage, suggesting the lagoon’s current geomorphic conditions had been established.     

Evaluating Hyperspectral Imager for the Coastal Ocean (HICO) data for seagrass mapping in Indian River Lagoon,FL

Differentiation between benthic habitats, particularly seagrass and macroalgae, using satellite data is complicated because of water column effects plus the presence of chlorophyll-a in both seagrass and algae that result in similar spectral patterns. Hyperspectral imager for the coastal ocean data over the Indian River Lagoon, Florida, USA, was used to develop two benthic classification models, Slope_RED and Slope_NIR. Their performance was compared with iterative self-organizing data analysis technique and spectral angle mapping classification methods. The slope models provided greater overall accuracies (63–64%) and were able to distinguish between seagrass and macroalgae substrates more accurately compared to the results obtained using the other classifications methods.     

Marine environmental impact assessment of abalone,Haliotis discus hannai,cage farm in Wan-do,Republic of Korea

To assess the marine environmental impacts of abalone, Haliotis discus hannai, cage farms in Wan-do, we monitored the benthic environment on top of the sediment underneath cage farm stations and reference stations. We applied two methods for this assessment. One was the A- and B-investigation of the MOM system (Modeling–On fish farm–Monitoring) developed in Norway. The other was a general environmental monitoring method which is widely used. In this study, we found benthic animals in all samples that belonged to condition 1 which were based on group 1(presence of macrofauna) of the B-investigation method. The values of redox potential (group 2–pH, redox potential) in all samples were above +65 mV belonging to condition 1. Based on sensory results (group 3–gas, color, odor, thickness of deposits), five out of seven experiment samples showed condition 1 while stations 2 and 7 showed condition 2, which have been cultured for 10 years in semi-closed waters. As group 2 takes precedence over group 3, the level of the conditions for B-investigation results consequently showed condition 1 in all stations. We found that pollutants and trace metals in the sediment underneath cage farms were lower than the pollution standard. This led us to conclude that the environmental impacts of the cage farms in this study were not significant.     

Long-term comparison of satellite and in-situ sea surface temperatures around the Korean Peninsula

Ocean Science Journal - Satellite remotely sensed sea surface temperature (SST) was compared with in-situ SST in the seas around the Korean Peninsula from 1984 to 2013. A matchup dataset between...     

Global spectral energy distributions of the Large Magellanic Cloud with interstellar dust

The effects of dust on infrared emission vary among galaxies of different morphological types. We investigated integrated spectral energy distributions (SEDs) in infrared and submillimeter/millimeter emissions from the Large Magellanic Cloud (LMC) based on observations from the Herschel Space Observatory (HSO) and near- to mid-infrared observations from the Spitzer Space Telescope (SST). We also used IRAS and WMAP observations to constrain the SEDs and present the results of radiative transfer calculations using the spectrophotometric galaxy model. We explain the observations by using dust models with different grain size distributions in the interstellar medium of the LMC, noting that the LMC has undergone processes that differ from those in the Milky Way. We determined a spectral index and a normalization factor in the range of ?3.5 to ?3.45 with grain radii in the range of 1 nm–300 nm for the silicate grain and 2 nm–1 μm for the graphite grain. The best fit to the observed SED was obtained with a spectral index of ?3.47, similar to the value derived by Piovan et al. (Mon. Not. R. Astron. Soc. 366(3):923, 2006a). The grain size distribution is described using a power law but with a break that is introduced below a _b , where a larger exponent is used. Changing the graphite grain size distribution significantly changed the SED pattern within the observational uncertainties. Based on the SED fits to the observations from submillimeter wavelengths to infrared radiation from the LMC using GRASIL (Silva et al., Astrophys. J. 509(1):103, 1998), we obtained a reasonable set of parameter values in chemical and geometric space together with the grain size distributions (Weingartner and Draine, Astrophys. J. 548(1):296, 2001) and a modified MRN model with the LMC extinction curve (Piovan et al., Mon. Not. R. Astron. Soc. 366(3):923, 2006a). For a given set of parameters including the disc scale height, synthesis of the starlight spectrum, optical depth, escape time scale, dust model, and star formation efficiency, the adopted dust-to-gas ratio for modeling the observed SEDs, ～1/300 (from the literature) yields a reasonable fit to the observed SEDs and similar results with the metallicity of the LMC as those reported in Russell and Bessell (Astrophys. J. Suppl. Ser. 70:865, 1989). The dust-to-gas ratios that are given as the metallicity caused the variation in the model fits. The difference mainly appears at the wavelengths near 100 μm.     

A massif‐type (~1.86 Ga) anorthosite complex in the Yeongnam Massif,Korea: late‐orogenic emplacement associated with the mantle delamination in the North China Craton

To unravel the petrogenesis of a massif‐type anorthosite in terms of the crust‐mantle geodynamics, we dated zircons separated from six samples from the Sancheong‐Hadong (SH) complex, Korea, using a sensitive high‐resolution ion microprobe. The weighted mean ²⁰⁷Pb/²⁰⁶Pb age of two anorthosites is 1862 ± 2 Ma, whereas the ages of the hornblende gabbro and granitic gneiss are 1873 ± 4 Ma and 1875 ± 5 Ma respectively. Zircon rims from mafic granulite and migmatitic gneiss yielded ages of 1860 ± 5 Ma and 1858 ± 4 Ma, respectively, implying that the granulite facies metamorphism and anatexis are associated with anorthosite emplacement. Our results, together with available Re–Os data, are compatible with the ~1.9–1.86 Ga collisional orogeny prevalent in the North China Craton and the Korean Peninsula, and suggest that orogenesis was accompanied by mantle delamination beneath the craton. It is thus likely that the SH anorthositic rocks are a product of late‐orogenic magmatism during the post‐collisional extension‐dominated phase of orogeny.     

Evaluation of the applicability of pier local scour formulae using laboratory and field data

The reliable estimation of the local scour depth at a bridge pier is essential for proper design and maintenance of bridge piers. Most local scour formulae have been developed based on the results of laboratory experiments. The formulae based on laboratory data do not often produce reasonable predictions for field piers because laboratory investigations are apt to oversimplify or ignore many of the complexities of the flow fields around the bridge piers. Validation of the formulae is necessary in order to ascertain which of the formulae are able to provide reasonable estimates of the local scour depth. In this study, six commonly cited formulae based on laboratory data or field data were selected for validation using 180 laboratory data sets gathered from the literature and 446 field data sets collected from four countries. The six formulae validated in this paper are the Colorado State University (CSU), Neill, Froehlich, Breuser, Laursen, and simplified Chinese formulae. Comparisons between the predicted and measured depths were performed using scour from the laboratory and field data. An artificial neural network technique was also applied in order to compare the tendencies between the field and laboratory data sets.     

Characterization of alluvium soil using geophysical and sounding methods

The alluvial deposits are highly heterogeneous and thus special techniques for investigating the subsurface have been required to obtain high quality data. The objective of this study is to apply two geophysical methods to alluvial deposits: a seismic survey method and the electrical resistivity method. The one-dimensional sounding method known as the standard penetration test is also applied to investigate subsurface properties and to compare these results with those measured by the geophysical methods. In seismic survey method, the seismic impulse source system shotgun is used to strongly propagate the elastic wave through the soil. The nonpolarizable electrode is selected to obtain the most reliable result by reducing the contact resistance. The application test is performed at Nakdong River in the southern part of Korean Peninsula where the area consists of alluvial deposits. The four profiles are selected for conducting the geophysical methods and the ranges of profiles are 115 ～ 205 m with interval distance of 5 m. The six one-dimensional soundings are performed in the intersection of geophysical profiles. Even though the measured results based on the geophysical method and one-dimensional sounding show slight difference, every result is applied to estimate subsurface characterization as the complementary data.