Sequential Chemical Separation of Cr and Ti from a Single Digest for High‐Precision Isotope Measurements of Planetary Materials     

Yuki Hibiya  Tsuyoshi Iizuka  Katsuyuki Yamashita  Shigekazu Yoneda  Akane Yamakawa 《Geostandards and Geoanalytical Research》2019,43(1):133-145

Combined determination of Cr and Ti isotopes of planetary materials offers a means with which to investigate their genetic relationship and the evolution of the protoplanetary disk. Here, we report the new sequential chemical separation procedure for combined Cr and Ti isotope ratio measurements. It comprises three steps: (a) Fe removal using AG1‐X8 anion exchange resin, (b) Ti separation using TODGA resin and (c) Cr separation using AG50W‐X8 cation exchange resin (with one additional step of Ti purification using AG1‐X8 anion exchange resin for samples having high Cr/Ti and Ca/Ti ratios). We applied the proposed procedure to terrestrial and meteorite samples with various compositions. Typical recovery rates of 90–100% were achieved with total procedural Cr and Ti blanks of 3–5 and 2–3 ng, respectively. We measured the Cr and Ti isotope compositions of the separated samples using thermal ionisation mass spectrometry and multiple collector‐inductively coupled plasma‐mass spectrometry, respectively. Our Cr and Ti isotope data were found to be consistent with those of previous studies of individual Cr and Ti isotopic compositions of the meteorites. These results demonstrate the capability of our separation method when applied to combined high‐precision Cr and Ti isotope analyses for single digests of planetary materials.  相似文献   

The Antarctic achondrite ALHA 76005: a polymict eucrite     

Lawrence Grossman  Edward Olsen  Andrew M. Davis  Tsuyoshi Tanaka  Glenn J. MacPherson 《Geochimica et cosmochimica acta》1981,45(8):1267-1279

ALHA 76005 is a basaltic achondrite containing few. if any, orthopyroxenes. Its bulk major and trace element composition is like that of a non-cumulate eucrite, and unlike that of a howardite. It contains a variety of igneous clasts which differ in their textures, pyroxene/plagioclase ratios and pyroxene and plagioclase compositions. One clast, No. 4, was found to have the REE pattern of a cumulate eucrite and an oxygen isotopic composition different from that of the bulk meteorite. Both the chemical and oxygen isotopic composition of clast No. 4 suggest that it was derived from a source different from its host. These observations lead to the conclusion that ALHA 76005 is a polymict eucrite.  相似文献   

Compressibility of the calcium aluminosilicate, CAS, phase to 44 GPa     

Shigeaki Ono  Tsuyoshi Iizuka  Takumi Kikegawa 《Physics of the Earth and Planetary Interiors》2005,150(4):331-338

In situ X-ray diffraction measurements on a calcium aluminosilicate (CAS) phase have been carried out using a laser-heated diamond anvil cell up to a pressure of 44 GPa, employing a synchrotron radiation source. CAS is the major mineral formed from sediments subducted into the Earth's mantle. The sample was heated using a YAG laser after each pressure increment to relax the deviatoric stress in the sample. X-ray diffraction measurements were carried out at T = 300 K using an angle-dispersive technique. The pressure was calculated using an internal platinum metal pressure calibrant. The Birch–Murnaghan equation of state for the CAS phase obtained from the experimental unit cell parameters showed a density of ρ₀ = 3.888 g/cm³ and a bulk modulus of K₀ = 229 ± 9 GPa for K^′₀ = 4.7 ± 0.7. When the first pressure derivative of the bulk modulus was fixed at K^′₀ = 4, then the value of K₀ = 239 ± 2 GPa. From the experimental compressibility, the density of the CAS phase was observed to be lower than the density of co-existing Al-bearing stishovite, calcium perovskite, calcium ferrite-type phases, and (Fe,Al)-bearing Mg-perovskite in subducted sediments in the lower mantle. Therefore, the density of subducted sediments in the lower mantle decreases with increasing mineral proportion of the CAS phase.  相似文献   

Resource depletion calculated by the ratio of the reserve plus cumulative consumption to the crustal abundance for gold   总被引：1，自引：0，他引：1  

Takashi Nishiyama  Tsuyoshi Adachi 《Natural Resources Research》1995,4(3):253-261

The magnitude of the world's mineral consumption has increased sharply, and there is no sign that growth is likely to stop in the near future. Currently, new discoveries and technology add to the reserves of varous mineral commodities at a rate that has exceeded depletion. As a result, life expectancies have remained nearly constant. However, it is questionable whether this condition is sustainable in the future. Therefore, most of our attention to the future has been focused on potentially recoverable resources. The potentially recoverable resources for 35 minerals in the Earth's crust were estimated based on the relationship between crustal abundance and the reserve of currently recoverable gold. The ratio of the reserve plus cumulative consumption to the abundance of gold is appropriate for calculating reserves of other mineral resources because gold has the highest profit margin for exploration of reserves. From an economic perspective, the price of gold is 350 times the mean value of 33 other resources for calculating production versus price. New mining technologies and new processing methods have been developed during the last 20 years as a response to high prices. As a result, five times the reserves available in 1970 have now been discovered, and two times the reserves available in 1970 were consumed during the past two decades. It is questionable whether other mineral commodities can reach the ratio of reserve plus cumulative consumption to abundance that gold does. Using this concept, the limit of the Earth's resources under present technology was calculated for 35 mineral resources, based on the ratio of the reserve plus cumulative consumption to abundance for gold. Even though recoverable tonnage of lead, silver, tin, boron, copper, and mercury from ore deposits in the Earth's crust is relatively low, the abundance of these metals is apparently sufficient for future supplies. However, considering the special situation of gold created by its very high price compared to world production, there is anxiety concerning steep increases in the price or depletion of these metals, which have a shorter lifetime from a geochemical point of view.  相似文献   

Os, Nd, and Sr isotopic and chemical compositions of ultramafic xenoliths from Kurose, SW Japan: Implications for contribution of slab-derived material to wedge mantle     

Ryoko Senda  Tsuyoshi Tanaka  Katsuhiko Suzuki 《Lithos》2007,95(3-4):229-242

We examined seven ultramafic xenoliths from 1~3 Ma alkali olivine basalt reefs near the Eurasian continent and one sample of the host alkali basalt to identify the mantle wedge material and to constrain the origin and evolution of mantle beneath SW Japan. Six xenoliths are from Kurose and one xenolith is from Takashima, northern part of the Kyushu islands, SW Japan. The Sr and Nd isotopic ratios vary from 0.70416 to 0.70773 and from 0.51228 to 0.51283, respectively. The Kurose and Takashima xenoliths have higher Sr isotopic ratios and lower Nd isotopic ratios than those of the peridotite xenoliths from the other arc settings such as Simcoe and NE Japan.

The Kurose xenoliths have less radiogenic Os isotopic ratios (¹⁸⁷Os/¹⁸⁸Os = 0.123–0.129) than the primitive upper mantle (PUM) estimate and limited variation compared to the other arc xenoliths. Their Os isotope compositions are rather similar to the ultramafic xenoliths from NE and east China. In addition, the samples of the Kurose and Takashima xenoliths plot along a mixing line between ultramafic xenoliths from SE and NE China and a slab component in Sr–Nd–Os isotopic space. Our results suggest that fragments of continental lithospheric mantle from the China craton may exist beneath Kurose and Takashima after the Sea of Japan expansion when the Japanese islands were rifted away from the Eurasian continent during Miocene. Later magmatism due to subduction of the Philippine Sea Plate beneath the SW Japan arc around 15 Ma ago may have introduced fluids or melts derived from slab component, interpreted to be oceanic sediments rather than altered oceanic crust, that possibly modified the original composition of the lithospheric mantle sampled by the peridotite xenoliths from Kurose and Takashima.  相似文献   

Progressive metamorphism of the Taitao ophiolite; evidence for axial and off-axis hydrothermal alterations     

Takazo Shibuya  Tsuyoshi Komiya  Ryo Anma  Tsutomu Ota  Soichi Omori  Yoshiaki Kon  Shinji Yamamoto  Shigenori Maruyama 《Lithos》2007,98(1-4):233-260

We estimated metamorphic conditions for the  6 Ma Taitao ophiolite, associated with the Chile triple junction. The metamorphic grade of the ophiolite, estimated from secondary matrix minerals, changes stratigraphically downwards from the zeolite facies, through the prehnite–actinolite facies, greenschist facies and the greenschist–amphibolite transition, to the amphibolite facies. The metamorphic facies series corresponds to the low-pressure type. The metamorphic zone boundaries are subparallel to the internal lithological boundaries of the ophiolite, indicating that the metamorphism was due to axial hydrothermal alteration at a mid-ocean ridge.

Mineral assemblages and the compositions of veins systematically change from quartz-dominated, through epidote-dominated, to prehnite-dominated with increasing depth. Temperatures estimated from the vein assemblages range from  230 °C in the volcanic unit to  380 °C at the bottom of the gabbro unit, systematically  200 °C lower than estimates from the adjoining matrix minerals. The late development of veins and the systematically lower temperatures suggest that the vein-forming alteration was due to off-axis hydrothermal alteration.

Comparison between the Taitao ophiolite with its mid-ocean ridge (MOR) affinity, and other ophiolites and MOR crusts, suggests that the Taitao ophiolite has many hydrothermal alteration features similar to those of MOR crusts. This is consistent with the tectonic history that the Taitao ophiolite was formed at the South Chile ridge system near the South American continent (Anma, R., Armstrong, R., Danhara, T., Orihashi, Y. and Iwano, H., 2006. Zircon sensitive high mass-resolution ion microprobe U–Pb and fission-track ages for gabbros and sheeted dykes of the Taitao ophiolite, Southern Chile, and their tectonic implications. The Island Arc, 15(1): 130–142).  相似文献   

Geochemical mapping in Aichi prefecture,Japan: Its significance as a useful dataset for geological mapping     

Koshi Yamamoto  Tsuyoshi Tanaka  Masayo Minami  Koichi Mimura  Yoshihiro Asahara  Hidekazu Yoshida  Setsuo Yogo  Makoto Takeuchi  Masami Inayoshi 《Applied Geochemistry》2007

  相似文献   

Distributed object‐based software environment for urban system integrated simulation under urban‐scale hazard—Part II: Application     

M. Hassanien Serror  Junya Inoue  Muneo Hori  Yozo Fujino  Tsuyoshi Ichimura 《地震工程与结构动力学》2007,36(11):1561-1579

A software prototype of a simulation service software environment, called DOSE (distributed object‐based software environment), is developed to realize the integrated simulation of an urban system under the risk of urban‐scale hazards such as earthquakes. DOSE infrastructure is built on three basic building blocks, namely: modularity, scalability, and interoperability. In this paper, the application of DOSE to real‐world urban systems is described in order to provide an evidence for DOSE modularity and scalability. An overview of DOSE is presented and then followed by a beverage application to simulate earthquake hazard in an urban system. The urban system is developed for the city of Kobe (Kobe district) with dimensions of 700 × 500 (m) and Bunkyo ward (Tokyo district) with dimensions of 800 × 600 (m) where DOSE simulation participants are identified for each district. The effectiveness of data exchange among different participants through a distributed service exchange network is described as an evidence for DOSE modularity that facilitates the integration process. On the other hand, the effectiveness of processing time when applying the simulation to different urban system sizes and/or using different third‐party applications is described as an evidence for DOSE scalability. The details of the underlying infrastructure of DOSE are beyond the scope of this paper and are presented in an accompanying paper work. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

A very hydrous mantle under the western Pacific region: Implications for formation of marginal basins and style of Archean plate tectonics   总被引：7，自引：6，他引：1  

Tsuyoshi Komiya  Shigenori Maruyama 《Gondwana Research》2007,11(1-2):132

The western Pacific region has been refrigerated by the subducting cold oceanic plates since 450 Ma. However, the region is also characterized by the presence of many oceanic microplates less than 1300 km across, as well as active magmatism; the Philippine Sea plate is representative. We have compiled and examined petrochemical characters of drilled basalts of DSDP from the Philippine Sea plate, and conclude that the source mantle for oceanic basalts is rich in water ca. 0.2 wt.%, and is 50–60 °C lower than that for MORB. The extensive melting is due to the high water content in the source mantle.It is well known that some marginal basins apparently have greater depths than the major oceans. We calculated the age–depth correlation based on a model of transient half-space cooling at given parameters of temperatures of mantle and surface, 1280 and 0 °C, and the thermal diffusivity, 1 mm² s^− 1. The calculation shows the correlation of age-residual depth from a mid-oceanic ridge is 367 for the Philippine Sea, consistent with the bathymetric data. Moreover, the mid-oceanic ridge may be relatively deep because this region is underlain by the cooler mantle.Addition of water to the mantle peridotite lowers the solidus temperature and viscosity. Melting experiments of hydrous peridotite show that addition of 0.2 wt.% H₂O content lowers the solidus temperature by 150 °C. As a result, the mantle under the region may practically correspond to a ca. 90 °C hotter mantle than normal MORB-source mantle in terms of magmatism and rheology. Numerical simulation for a hotter mantle suggests that many small plates should be formed because of extensive heat release by active magmatism, consistent with many microplates in this region. The presence of many oceanic microplates may be analogous to Archean plate tectonics, characterized by a hotter mantle.  相似文献   

Depositional and diagenetic history of limestones and dolostones of the Oligo‐Miocene Kujung Formation in the Northeast Java Basin,Indonesia     

Muhlash Hada Firman Syah  Akihiro Kano  Tsuyoshi Iizuka  Yoshihiro Kakizaki 《Island Arc》2019,28(6)

Lithological and geochemical features of platformal carbonates record the signatures of the global climates and the regional environmental settings and also reconstruct the diagenetic history and porosity evolution, which are essential to evaluate the potential of hydrocarbon reservoirs. This study investigates the platformal carbonates of the Oligo‐Miocene Krunji Formation of North East Java Basin, which are potentially significant hydrocarbon reservoirs. The carbonate sequence in a 283 m thick section at Kranji in East Java is subdivided into three lithological units: limestone unit 1, dolostone unit 2, and limestone unit 3, in ascending order. The strontium‐isotope ratios of well‐preserved calcite samples indicate the depositional period from Chattian (late Oligocene) to Burdigalian (early Miocene), which is consistent with ages of the foraminifer assemblages. Unit 1 consists of low‐porosity limestone, in which two horizons of subaerial exposure are recognized by the occurrence of red‐colored matrix and lower δ¹³C values. Unit 2 consists of dolomitic rock and exhibits coarse‐grained calcitic grains and cross‐stratified structure. Considering that this unit has been subject to dolomitization, the sediment of unit 2 was initially permeable and was likely deposited in a shoal setting. The overlying unit 3 of Aquitanian–Burdigalian age is characterized by a highly granular texture. High porosity and uniformly low δ¹³C and δ¹⁸O values indicate that Unit 3 was subjected to more intense meteoric diagenesis than the Chattian unit 1. This was likely a consequence of the Antarctic ice‐sheet expansion during the Oligocene/Miocene transition, which amplified sea level change. The unit 2 dolomite has high δ¹³C and δ¹⁸O values and a high ⁸⁷Sr/⁸⁶Sr ratio which resulted from the reflux of seawater into permeable the sediment body in middle‐late Miocene (Burdigalian Tortonian) following the deposition of unit 3. The porosity and permeability of the Kujung Formation were initially controlled by sedimentological processes, but largely modified by later diagenetic processes.  相似文献