Formation age of the lunar crater Giordano Bruno     

Tomokatsu Morota  Junichi Haruyama  Hideaki Miyamoto  Chikatoshi Honda  Makiko Ohtake  Yasuhiro Yokota  Tsuneo Matsunaga  Naru Hirata  Hirohide Demura  Hiroshi Takeda  Yoshiko Ogawa  Jun Kimura 《Meteoritics & planetary science》2009,44(8):1115-1120

Abstract— Using the Terrain Camera onboard the Japanese lunar explorer, SELENE (Kaguya), we obtained new high‐resolution images of the 22‐kilometer‐diameter lunar crater Giordano Bruno. Based on crater size‐frequency measurements of small craters (<200 m in diameter) superposed on its continuous ejecta, the formation age of Giordano Bruno is estimated to be 1 to 10 Ma. This is constructive evidence against the crater's medieval age formation hypothesis.  相似文献   

Reconstruction of historical pressure patterns over Japan using two-point pressure–temperature datasets since the nineteenth century     

Masumi Zaiki  Gunther P. Können  Keiji Kimura  Takehiko Mikami  Togo Tsukahara 《Climatic change》2009,95(1-2):231-248

The temperature and pressure differences between Tokyo and Nagasaki were used to reconstruct past climate conditions. January and July in each available year since the 1820s were classified into several types with characteristic sea level atmospheric pressure patterns. This results in 18 years of pre-1881 data and a continuous series thereafter. The series indicate that the warming after 1900 (after the end of the so-called Little Ice Age) and again after 1960 can at least partly be attributed to an increase in the frequency of warm circulation pattern types at the expense of cold types. The difference in nature of the shifts in circulation types that occurred in the late nineteenth century compared with that in the late twentieth centuries suggests that the mechanism behind the warming in the late nineteenth century differs from that in the late twentieth century.  相似文献   

Basanite–nephelinite suite from early Kilauea: carbonated melts of phlogopite–garnet peridotite at Hawaii’s leading magmatic edge     

T. W. Sisson  J.-I. Kimura  M. L. Coombs 《Contributions to Mineralogy and Petrology》2009,158(6):803-829

A basanite–nephelinite glass suite from early submarine Kilauea defines a continuous compositional array marked by increasing concentrations of incompatible components with decreasing SiO₂, MgO, and Al₂O₃. Like peripheral and post-shield strongly alkalic Hawaiian localities (Clague et al. in J Volcanol Geotherm Res 151:279–307, 2006; Dixon et al. in J Pet 38:911–939, 1997), the early Kilauea basanite–nephelinite glasses are interpreted as olivine fractionation products from primary magnesian alkalic liquids. For early Kilauea, these were saturated with a garnet–phlogopite–sulfide peridotite assemblage, with elevated dissolved CO₂ contents responsible for the liquids’ distinctly low-SiO₂ concentrations. Reconstructed primitive liquids for early Kilauea and other Hawaiian strongly alkalic localities are similar to experimental 3 GPa low-degree melts of moderately carbonated garnet lherzolite, and estimated parent magma temperatures of 1,350–1,400°C (olivine–liquid geothermometry) match the ambient upper mantle geotherm shortly beneath the base of the lithosphere. The ~3 GPa source regions were too hot for stable crystalline carbonate and may have consisted of ambient upper mantle peridotite containing interstitial carbonate–silicate or carbonatitic liquid, possibly (Dixon et al. in Geochem Geophys Geosyst 9(9):Q09005, 2008), although not necessarily, from the Hawaiian mantle plume. Carbonate-enriched domains were particularly susceptible to further melting upon modest decompression during upward lithospheric flexure beneath the advancing Hawaiian Arch, or by conductive heating or upward drag by the Hawaiian mantle plume. The early Kilauea basanite–nephelinite suite has a HIMU-influenced isotopic character unlike other Hawaiian magmas (Shimizu et al. in EOS Tran Amer Geophys Union 82(47): abstr V12B-0962, 2001; Shimizu et al. in Geochim Cosmochim Acta 66(15A):710, 2002) but consistent with oceanic carbonatite involvement (Hoernle et al. in Contrib Mineral Petrol 142:520–542, 2002). It may represent the melting products of a fertile domain in the ambient upper mantle impinged upon and perturbed by the sustained plume source that feeds later shield-stage magmatism.  相似文献   

The Apparent Polar Wander Path For the North China Block Since the Jurassic   总被引：7，自引：0，他引：7  

Zhong Zheng  Masaru Kono  Hideo Tsunakawa  Gaku Kimura  Qingyun Wei  Xiangyuan Zhu  Tianyao Hao 《Geophysical Journal International》1991,104(1):29-40

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Palaeomagnetism of Neogene Ocros dyke swarm, the Peruvian Andes: implication for the Bolivian orocline     

Kosuke Heki  YOZO Hamano  Masaru Kono  Tadahide Ui 《Geophysical Journal International》1985,80(2):527-534

Summary. Remanent magnetization directions of 32 dykes and lava flows sampled near Ayacucho, the Peruvian Andes revealed 14.2°± 5.5° counterclockwise rotation after the Neogene intrusion of this dyke swarm. Palaeo-magnetic results of these rocks and other palaeomagnetic evidences from the Central Andean Mesozoic rocks suggest relatively recent occurrence of the Andean oroclinal bending around the axis at the Peru-Chile border.  相似文献   

Orogeny of the Japanese Islands     

G. Kimura  Y Isozaki  S. Maruyama 《Island Arc》1996,5(3):215-215

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A deep section of accretionary complex: Susunai Complex in Sakhalin Island, Northwest Pacific Margin     

Gaku  Kimura Masayuki  Sakakibara Hisashi  Ofuka Hideo  Ishizuka Sumio  Miyashita Makoto  Okamura Olex A.  Melinikov Vilera  Lushchenko 《Island Arc》1992,1(1):166-175

Abstract A deep section of accretionary complex, the metamorphosed Susunai Complex, is observed on Sakhalin Is., Russia. High pressure part of pumpellyite-actinolite facies metavolcanics, metacherts and metapelites are well exposed and constitute a tectonic pile preserving primary structures related to underplating of the oceanic crust. Three stages of deformation, D₁ through D₃, suggest successive deformation during subduction, underplating and exhumation of the complex. Oceanic material in the complex is more abundant than other well documented ancient accretionary complexes (e.g. the Shimanto Belt in southwest Japan and the Ghost Rocks Formation in Alaska), which were shallowly underplated. At Susunai, deep down-stepping of a décollément has scraped off the upper part of the oceanic crust, primarily the pillowed basalt horizon. This down-stepping results from crustal weakening as overpressured water is released from the fractured oceanic crust during metamorphism.  相似文献   

The solubility of alumina in enstatite and the phase equilibria in the join MgSiO3-MgAl2SiO6 at 10–25 kbar     

Makoto Arima  Kosuke Onuma 《Contributions to Mineralogy and Petrology》1977,61(3):251-265

The solubility of alumina in enstatite was determined in the range of 1100–1500° C and 10–25 kbar. The alumina content in enstatite coexisting with sapphirine and quartz increases with increasing temperature and pressure, while that in enstatite coexisting with sapphirine and sillimanite or with pyrope decreases with increasing pressure and decreasing temperature. Two univariant lines, pyrope = enstatite_ss + sillimanite + sapphirine_ss and enstatite_ss + sillimanite =sapphirine_ss + quartz were confirmed. The invariant point involving these phases is metastable. The alumina content of orthopyroxene can not be used either as a pressure indicator or as a temperature indicator without taking the mineral assemblage into account.  相似文献   

High-pressure phase transition and behavior of protons in brucite Mg(OH)2: a high-pressure–temperature study using IR synchrotron radiation     

K. Shinoda  M. Yamakata  T. Nanba  H. Kimura  T. Moriwaki  Y. Kondo  T. Kawamoto  N. Niimi  N. Miyoshi  N. Aikawa 《Physics and Chemistry of Minerals》2002,29(6):396-402

 Infrared absorption spectra of brucite Mg (OH)₂ were measured under high pressure and high temperature from 0.1 MPa 25 °C to 16 GPa 360 °C using infrared synchrotron radiation at BL43IR of Spring-8 and a high-temperature diamond-anvil cell. Brucite originally has an absorption peak at 3700 cm⁻¹, which is due to the OH dipole at ambient pressure. Over 3 GPa, brucite shows a pressure-induced absorption peak at 3650 cm⁻¹. The pressure-induced peak can be assigned to a new OH dipole under pressure. The new peak indicates that brucite has a new proton site under pressure and undergoes a high-pressure phase transition. From observations of the pressure-induced peak under various P–T condition, a stable region of the high-pressure phase was determined. The original peak shifts to lower wavenumber at −0.25 cm⁻¹ GPa⁻¹, while the pressure-induced peak shifts at −5.1 cm⁻¹ GPa⁻¹. These negative dependences of original and pressure-induced peak shifts against pressure result from enhanced hydrogen bond by shortened O–H···O distance, and the two dependences must result from the differences of hydrogen bond types of the original and pressure-induced peaks, most likely from trifurcated and bent types, respectively. Under high pressure and high temperature, the pressure-induced peak disappears, but a broad absorption band between 3300 and 3500 cm⁻¹ was observed. The broad absorption band may suggest free proton, and the possibility of proton conduction in brucite under high pressure and temperature. Received: 16 July 2001 / Accepted: 25 December 2001  相似文献   

Geology and geochemistry of Karasugasen lava dome, Daisen–Hiruzen Volcano Group, southwest Japan     

Jun-Ichi  Kimura  Mamiko  Tateno  Isaku  Osaka 《Island Arc》2005,14(2):115-136

Abstract   The geology and geochemistry of pyroclastic flows and fallout tephras formed during the Karasugasen dome eruption in the Daisen–Hiruzen Volcano Group in southwest Japan have been examined in detail. The Karasugasen lava dome erupted at about 26 ka. The eruption began with a vulcanian ash fall, and this was followed by at least eight block and ash flows and a pumice flow. The block and ash flows were produced by the successive collapses of a growing lava dome. This main eruption phase was followed by an eruption of vulcanian ash falls, and finally ended with a sub-Plinian pumice fall. This eruption sequence is typical of the Daisen Volcano during the last three eruption events, which occurred at 58, 26 and 17 ka. The magma produced during the Karasugasen eruption was a typical adakite, with extremely high Sr/Y ratios and low HREE/LREE ratios compared to normal arc lavas. The chemistry of the Karasugasen lavas is almost identical to other Daisen–Hiruzen lavas that were produced from eruptions over an interval of a million years. The continuous supply of a huge amount of adakitic magma (>100 km³) for such a long period suggests a massive homogeneous source material, such as molten Philippine Sea Plate slab. Slab melting is a plausible mechanism for the production of the adakitic lavas at Karasugasen, and hence the Daisen–Hiruzen Volcano Group.  相似文献