Petrogenesis and Solidification Depth of the Jurassic Daebo and Cretaceous Bulguksa Granitic Rocks in South Korea     

Etsuo UCHIDA  Seon‐Gyu CHOI  Daisuke BABA  Yusuke WAKISAKA 《Resource Geology》2012,62(3):281-295

We investigated the Jurassic Daebo and Cretaceous Bulguksa granitic rocks in South Korea. The former are distributed mainly in the Gyeonggi and Yeongnam massifs and the latter are present in the Gyeongsan basin and Ogcheon belt. The Daebo granitic rocks generally are of ilmenite series and I to S type. These rocks are associated with Au–Ag hydrothermal deposits, whereas the Bulguksa granitic rocks are of magnetite series and I type, and are associated with Pb–Zn, Cu and Mo–W hydrothermal deposits, as well as Au–Ag hydrothermal deposits. The Daebo granitic rocks show adakitic signatures in their chemical compositions. They are considered to have been derived from partial melting of the thick lower continental crust. Conversely, the Bulguksa granitic rocks in the Gyeongsan basin are non‐adakitic and are considered to have been derived from partial melting of a mantle wedge. Magmas of the Daebo granitic rocks formed at relatively shallow levels, but solidified at deep levels compared with those of the Bulguksa granitic rocks. The Bulguksa granitic rocks in the central to western Ogcheon belt are considered to have been formed by fractionation of magmas derived from partial melting of continental crust. The total Al contents of biotite and hornblende in the granitic rocks increased, with the Bulguksa granitic rocks in the Gyeongsan basin < the Bulguksa granitic rocks in the Ogcheon belt and Gyeonggi and Yeongnam massifs and the Daebo granitic rocks in the Ogcheon belt < the Daebo granitic rocks in the Gyeonggi and Yeongnam massifs. This order corresponds to an increase in solidification depth.  相似文献   

Reaction of forsterite with hydrogen molecules at high pressure and temperature     

Ayako?ShinozakiEmail author  Hisako?Hirai  Hiroyuki?Kagi  Tadashi?Kondo  Taku?Okada  Daisuke?Nishio-Hamane  Shin-ichi?Machida  Tetsuo?Irifune  Takumi?Kikegawa  Takehiko?Yagi 《Physics and Chemistry of Minerals》2012,39(2):123-129

High pressure and temperature reactions of a mixture of forsterite and hydrogen molecules have been carried out using a laser heated diamond anvil cell at 9.8–13.2 GPa and ~1,000 K. In situ X-ray diffraction measurements showed no sign of decomposition or phase transitions of the forsterite under these experimental conditions, indicating that the olivine structure was maintained throughout all runs. However, a substantial expansion of the unit cell volume of the forsterite was observed for samples down to ~3 GPa upon quenching to ambient pressure at room temperature. The Raman spectroscopy measurements under pressure showed significant shifts of the Raman peaks of the Si–O vibration modes for forsterite and of the intramolecular vibration mode for H₂ molecules toward a lower frequency after heating. Additionally, no OH vibration modes were observed by Raman and FT-IR spectroscopic measurements. These lines of evidence show that the observed volume expansion in forsterite is not explained by the incorporation of hydrogen atoms as hydroxyl, but suggest the presence of hydrogen as molecules in the forsterite structure under these high pressure and temperature conditions.  相似文献   

Ion microprobe analyses of oxygen three‐isotope ratios of chondrules from the Sayh al Uhaymir 290 CH chondrite using a multiple‐hole disk     

Daisuke NAKASHIMA  Takayuki USHIKUBO  Rudraswami N. GOWDA  Noriko T. KITA  John W. VALLEY  Keisuke NAGAO 《Meteoritics & planetary science》2011,46(6):857-874

Abstract– The ion microprobe is the only technique capable of determining high‐precision stable isotope ratios in individual tiny extraterrestrial particles (≤100 μm in diameter), but these small samples present special analytical challenges. We produced a new sample holder disk with multiple holes (three holes and seven holes), in which epoxy disks containing a single unknown sample and a standard grain are cast and polished. Performance tests for oxygen two‐isotope analyses using San Carlos olivine standard grains show that the new multiple‐hole disks allow accurate analysis of tiny particles if the particles are located within the 500 μm and 1 mm radius of the center of holes for seven‐hole and three‐hole disks, respectively. Using the new seven‐hole disk, oxygen three‐isotope ratios of eight magnesian cryptocrystalline chondrules (approximately 100 μm in diameter) from the Sayh al Uhaymir (SaU) 290 CH chondrite were analyzed by ion microprobe at the University of Wisconsin. Five out of eight chondrules have nearly identical oxygen isotope ratios (Δ¹⁷O = ?2.2 ± 0.6‰; 2SD), which is consistent with those of magnesian cryptocrystalline chondrules in CH/CB and CB chondrites, suggesting a genetic relationship, i.e., formation by a common (possibly impact) heating event. The other three chondrules have distinct oxygen isotope ratios (Δ¹⁷O values from ?6.4‰ to +2.2‰). Given that similar variation in Δ¹⁷O values was observed in type I porphyritic chondrules in a CH/CB chondrite, the three chondrules may have formed in the solar nebula, similar to the type I porphyritic chondrules.  相似文献   

Lithium and strontium isotopic systematics in playas in Nevada,USA: constraints on the origin of lithium   总被引：1，自引：0，他引：1  

Daisuke Araoka  Hodaka Kawahata  Tetsuichi Takagi  Yasushi Watanabe  Koshi Nishimura  Yoshiro Nishio 《Mineralium Deposita》2014,49(3):371-379

Lithium-rich brine in playas is a major raw material for lithium production. Recently, lithium isotopic ratios (δ⁷Li) have been identified as a tool for investigating water–rock interactions. Thus, to constrain the origin of lithium in playas by the use of its isotopes, we conducted leaching experiments on various lacustrine sediment and evaporite deposit samples collected from playas in Nevada, USA. We determined lithium and strontium isotopic ratios and contents and trace element contents of the leachate, estimated the initial δ⁷Li values in the water flowing into the playas, and examined the origin of lithium in playas by comparison with δ⁷Li values of the possible sources. In samples from the playas, δ⁷Li values show some variation, reflecting differences both in isotopic fractionation during mineral formation and in initial δ⁷Li value in water flowing into each playa. However, all δ⁷Li values in this study are much lower than those in river water and groundwater samples from around the world, but they are close to those of volcanic rocks. Considering the temperature dependence of lithium isotopic fractionation between solid and fluid, these results indicate that the lithium concentrated in playas in Nevada was supplied mainly through high-temperature water–rock interaction associated with local hydrothermal activity and not directly by low-temperature weathering of surface materials. This study, which is the first to report lithium isotopic compositions in playas, demonstrates that δ⁷Li may be a useful tracer for determining the origin of lithium and evaluating its accumulation processes in playas.  相似文献   

Tsunamis from the Arica-Tocopilla source region and their effects on ports of Central Chile     

Rafael Aránguiz  Tomoya Shibayama  Yoshiki Yamazaki 《Natural Hazards》2014,71(1):175-202

The last great earthquake in northern Chile took place in 1877, and the ensuing tsunami affected not only that region but also Central Chile. For example, the Bay of Concepción, which is located 1,500 km south of the tsunami source, experienced an inundation height of around 3 m. Ports are important in the Chilean economy, due to the fact that a large percentage of Chilean exports (excluding copper) use ports located in Central Chile. With this in mind, the authors investigated the potential effect of an 1877-like tsunami on the main ports of Central Chile. To do this, the dispersive wave model Non-hydrostatic Evolution of Ocean WAVEs was used. In addition, the first tsunami forecast model for Talcahuano, inside the Bay of Concepción, was developed by means of numerical simulation of several events of different moment magnitudes. The results showed that most of the important ports (Valparaiso, San Antonio, San Vicente and Coronel) had inundation heights on the order of just 1 m, while inundation levels in Talcahuano reached up to 3.5 m. The forecast model for Talcahuano uses only earthquake magnitude, focal depth and tide level to determine tsunami inundation heights. In addition, the tsunami arrival time was computed to be 3 h, and the maximum tsunami amplitude takes place at 4 h and 45 min after the earthquake.  相似文献   

Nanoindentation approach characterizing strain rate sensitivity of compressive response of asphalt concrete     

Daisuke Katsuki  Marte Gutierrez 《Acta Geotechnica》2014,9(5):887-901

This paper presents the results of a study on the use of nanoindentation test to characterize the strain rate-dependent compressive response of asphalt concrete. Nanoindentation is now widely used for characterization and testing of composite as well as single-phase materials. Using a small piece of sample, nanoindentation tests can evaluate material behavior and structure in terms of the elasticity, time-dependent response, yield strength, damage, crack advance, debonding, and fatigues. In this study, a mixture of asphalt and calcium carbonate filler powder filling the intergranular void space of the asphalt concrete was characterized in terms of strain rate sensitivity at room temperature. The indentation hardness is observed to continuously decrease during constant indentation strain rates, but the hardness response clearly indicates positive strain rate dependency when compared at the same indentation depths. Following the constant strain rate tests, indentation creep response of the asphalt–filler mixture was tested at constant load conditions. The strain rate sensitivity values characterized from double logarithmic relationships between indentation hardness and strain rate during constant strain rate and constant load tests are comparable with that determined from uniaxial compression test of cylindrical asphalt concrete samples. The observed indentation size effect on hardness value was analyzed based on an existing size effect model. The size effect in the asphalt–filler mixture, which is stronger than that defined by the model, could be attributed to a plastically graded surface of asphalt–filler sample.  相似文献   

History matching for exploring and reducing climate model parameter space using observations and a large perturbed physics ensemble     

Daniel Williamson  Michael Goldstein  Lesley Allison  Adam Blaker  Peter Challenor  Laura Jackson  Kuniko Yamazaki 《Climate Dynamics》2013,41(7-8):1703-1729

We apply an established statistical methodology called history matching to constrain the parameter space of a coupled non-flux-adjusted climate model (the third Hadley Centre Climate Model; HadCM3) by using a 10,000-member perturbed physics ensemble and observational metrics. History matching uses emulators (fast statistical representations of climate models that include a measure of uncertainty in the prediction of climate model output) to rule out regions of the parameter space of the climate model that are inconsistent with physical observations given the relevant uncertainties. Our methods rule out about half of the parameter space of the climate model even though we only use a small number of historical observations. We explore 2 dimensional projections of the remaining space and observe a region whose shape mainly depends on parameters controlling cloud processes and one ocean mixing parameter. We find that global mean surface air temperature (SAT) is the dominant constraint of those used, and that the others provide little further constraint after matching to SAT. The Atlantic meridional overturning circulation (AMOC) has a non linear relationship with SAT and is not a good proxy for the meridional heat transport in the unconstrained parameter space, but these relationships are linear in our reduced space. We find that the transient response of the AMOC to idealised CO₂ forcing at 1 and 2 % per year shows a greater average reduction in strength in the constrained parameter space than in the unconstrained space. We test extended ranges of a number of parameters of HadCM3 and discover that no part of the extended ranges can by ruled out using any of our constraints. Constraining parameter space using easy to emulate observational metrics prior to analysis of more complex processes is an important and powerful tool. It can remove complex and irrelevant behaviour in unrealistic parts of parameter space, allowing the processes in question to be more easily studied or emulated, perhaps as a precursor to the application of further relevant constraints.  相似文献   

The spatial and temporal distributions of spheroidal carbonaceous particles from sediment core samples from industrial cities in Japan and China     

Eri Hirakawa  Akiko Murakami-Kitase  Takamoto Okudaira  Jun Inoue  Hideo Yamazaki  Shusaku Yoshikawa 《Environmental Earth Sciences》2011,64(3):833-840

Spheroidal carbonaceous particles (SCPs) are produced by the high-temperature combustion of fossil fuels and emitted in to the atmosphere. The distribution and concentration of SCPs in sediments have been used as a proxy for the distribution of pollutants emitted to the atmosphere. However, the effect on the distribution of SCPs due to industrial activity at nearby industrial cities is yet to be quantified. To clarify the origin of SCPs of ~20 μm in size that are preserved in sediments, we evaluated the abundance, surface morphology, and chemical composition of SCPs in sediment core samples recovered from industrial cities in Japan (Tokyo, Osaka, and Nagasaki) and China (Beijing), with the cities being located at least ~500 km away from each other. Vertical profiles of SCP concentration in sediment cores from the Japanese cities and Beijing are different, reflecting the contrasting industrial histories of the two countries. The SCPs from different cities show contrasting morphological and chemical characteristics, suggesting that ~20 μm SCPs in sediments from the industrial cities could represent the local combustion history in detail, as the influx of local SCPs is dominant at such sites.  相似文献   

Spectroscopic properties of Cr-doped and Cr,Li-doped synthetic forsterite crystals     

Akiko Sugimoto  Yukio Nobe  Takafumi Yamazaki  Yasuhide Yamaguchi  Kiyoshi Yamagishi  Yusaburo Segawa  Humihiko Takei 《Physics and Chemistry of Minerals》1997,24(5):333-339

Cr-droped and Cr,Li-doped forsterite crystals were grown and their optical properties were investigated. It was shown that when only Cr is doped, Cr³⁺ is substituted at the site of low crystal field, and the energy level ²E lie above the ⁴T₂ level, while ⁴T₂ is just above ²E when Cr and Li are codoped. The difference was rationalized by a deformation of the Cr substituted site with the introduction of Li.  相似文献   

Tectonic setting and formation of the Setouchi volcanic rocks in the western Seto Inland Sea,Japan     

Daisuke Sato  Toshiki Haji 《Island Arc》2021,30(1):e12405

The Setouchi volcanic rocks include high-Mg andesites (HMAs) and garnet-bearing dacite–rhyolite, and are sporadically distributed along the Median Tectonic Line, Japan. New U–Pb zircon ages and geological and geochemical data are presented for those rocks in the Western Setouchi region (W-Setouchi). Previous studies referred to the altered andesite in the W-Setouchi as “pre-Setouchi volcanic rocks.” However, on the basis of the new U–Pb age (14.4 Ma ± 0.3 Ma) and geochemical characteristics, we redefine it as the Jikamuro Formation, part of the Setouchi volcanic rocks. Incompatible elements are more enriched in the Jikamuro Formation rocks than in the Setouchi HMAs. The characteristic element compositions may be explained by mixing of compositionally different magmas, including subducted sediment melts, plus a contribution from crustal contamination. A stress-inversion technique with Bingham distribution method was applied to the orientations of felsic and mafic dikes within the Setouchi volcanic rocks, and indicates paleo-stress conditions during the period of Setouchi volcanism in the W-Setouchi. The analysis reveals NNW-extensional stresses and a strike-slip stress. We infer that the former represents extensional conditions during the main period of volcanism and the latter represents a stress transition during the most recent period of volcanism (after 12 Ma).  相似文献