Petrogenesis of lunar impact melt rock meteorite Oued Awlitis 001     

Axel Wittmann  Randy L. Korotev  Bradley L. Jolliff  Kunihiko Nishiizumi  A. J. Timothy Jull  Marc W. Caffee  Michael Zanetti  Anthony J. Irving 《Meteoritics & planetary science》2019,54(10):2167-2188

Oued Awlitis 001 is a highly feldspathic, moderately equilibrated, clast‐rich, poikilitic impact melt rock lunar meteorite that was recovered in 2014. Its poikilitic texture formed due to moderately slow cooling, which judging from textures of rocks in melt sheets of terrestrial impact structures, is observed in impact melt volumes at least 100 m thick. Such coherent impact melt volumes occur in lunar craters larger than ~50 km in diameter. The composition of Oued Awlitis 001 points toward a crustal origin distant from incompatible‐element‐rich regions. Comparison of the bulk composition of Oued Awlitis 001 with Lunar Prospector 5° γ‐ray spectrometer data indicates a limited region of matches on the lunar farside. After its initial formation in an impact crater larger than ~50 km in diameter, Oued Awlitis 001 was excavated from a depth greater than ~50 m. The cosmogenic nuclide inventory of Oued Awlitis 001 records ejection from the Moon 0.3 Ma ago from a depth of at least 4 m and little mass loss due to ablation during its passage through Earth's atmosphere. The terrestrial residence time must have been very short, probably less than a few hundred years; its exact determination was precluded by a high concentration of solar cosmic ray‐produced ¹⁴C. If the impact that excavated Oued Awlitis 001 also launched it, this event likely produced an impact crater >10 km in diameter. Using petrologic constraints and Lunar Reconnaissance Orbiter Camera and Diviner data, we test Giordano Bruno and Pierazzo as possible launch craters for Oued Awlitis 001.  相似文献   

Physical parameters identification for full-scale ten-story reinforced concrete building with degrading tri-linear model by modal iterative error correction method     

Takuya Uesaka  Kunihiko Nabeshima  Naohiro Nakamura  Takuya Suzuki 《地震工程与结构动力学》2022,51(1):153-168

To assess the post-earthquake seismic safety of buildings, it is crucial to predict seismic response, and it is necessary to set the appropriate physical parameters of the response analysis model. Numerous methods have been proposed to identify physical parameters. However, most of them are limited to linear systems, and previous researches on nonlinear systems have difficulties in practical applications. In this paper, a nonlinear response analysis model is identified for a full-scale ten-story reinforced concrete building with the degrading tri-linear stiffness model by the modal iterative error correction (MIEC) method, and the accuracy of this technique is discussed by comparing with the shaking table test.  相似文献   

Two extraterrestrial dust horizons found in the Dome Fuji ice core,East Antarctica     

Keiji Misawa  Mika Kohno  Takayuki Tomiyama  Takaaki Noguchi  Tomoki Nakamura  Keisuke Nagao  Takashi Mikouchi  Kunihiko Nishiizumi 《Earth and Planetary Science Letters》2010,289(1-2):287-297

Two silicate-rich dust layers were found in the Dome Fuji ice core in East Antarctica, at Marine Isotope Stages 12 and 13. Morphologies, textures, and chemical compositions of constituent particles reveal that they are high-temperature melting products and are of extraterrestrial origin. Because similar layers were found ～ 2000 km east of Dome Fuji, at EPICA (European Project for Ice Coring in Antarctica)-Dome C, particles must have rained down over a wide area 434 and 481 ka. The strewn fields occurred over an area of at least 3 × 10⁶ km². Chemical compositions of constituent phases and oxygen isotopic composition of olivines suggest that the upper dust layer was produced by a high-temperature interaction between silicate-rich melt and water vapor due to an impact explosion or an aerial burst of a chondritic meteoroid on the inland East Antarctic ice sheet. An estimated total mass of the impactor, on the basis of particle flux and distribution area, is at least 3 × 10⁹ kg. A possible parent material of the lower dust layer is a fragment of friable primitive asteroid or comet. A hypervelocity impact of asteroidal/cometary material on the upper atmosphere and an explosion might have produced aggregates of sub-μm to μm-sized spherules. Total mass of the parent material of the lower layer must exceed 1 × 10⁹ kg. The two extraterrestrial horizons, each a few millimeters in thickness, represent regional or global meteoritic events not identified previously in the Southern Hemisphere.  相似文献   

Fault trace complexity, cumulative slip, and the shape of the magnitude-frequency distribution for strike-slip faults: a global survey   总被引：4，自引：0，他引：4  

Mark W. Stirling  Steven G. Wesnousky  Kunihiko Shimazaki 《Geophysical Journal International》1996,124(3):833-868

  相似文献   

近200年来黑河下游天鹅湖湖泊沉积记录的环境变迁   总被引：12，自引：2，他引：12  

马燕  郑祥民  曹希强  远藤邦彦 《湖泊科学》2006,18(3):261-266

根据2002-2004年洞庭湖水质监测数据,参照GB3838-2002中Ⅲ类水质标准,选用内梅罗水污染指数法和黄浦江污染指数对洞庭湖水质现状进行评价,结果表明:(1)洞庭湖水体的主要污染指标是总磷,总氮和粪大肠菌群;(2)黄浦江污染指数平均值为0．27,所以洞庭湖12个断面水质无黑臭现象发生;(3)枯水期西洞庭湖和南洞庭湖水质污染最严重,平水期西洞庭湖水质污染最严重,洞庭湖丰水期的污染程度小于平水期;(4)洞庭湖的大部分水体的水质主要处于轻度污染的状态,局部水体的水质在枯水期达到重污染的状态．  相似文献   

Temporal behavior of the background seismicity rate in central Japan, 1998 to mid-2003   总被引：1，自引：0，他引：1  

Yoshiki Tsukakoshi  Kunihiko Shimazaki 《Tectonophysics》2006,417(1-2):155

We studied the temporal behavior of the background shallow seismicity rate in 700 circular areas across inland Japan. To search for and test the significance of the possible rate changes in background seismicity, we developed an efficient computational method that applies the space–time ETAS model proposed by Ogata in 1998 to the areas. Also, we conducted Monte Carlo tests using a simulated catalog to validate the model we applied. Our first finding was that the activation anomalies were found so frequently that the constant background seismicity hypothesis may not be appropriate and/or the triggered event model with constraints on the parameters may not adequately describe the observed seismicity. However, quiescence occasionally occurs merely by chance. Another outcome of our study was that we could automatically find several anomalous background seismicity rate changes associated with the occurrence of large earthquakes. Very significant seismic activation was found before the M6.1 Mt. Iwate earthquake of 1998. Also, possible seismic quiescence was found in an area 150 km southwest of the focal region of the M7.3 Western Tottori earthquake of 2000. The seismicity rate in the area recovered after the mainshock.  相似文献   

The CM carbonaceous chondrite regolith Diepenveen     

Marco Langbroek  Peter Jenniskens  Leo M. Kriegsman  Henk Nieuwenhuis  Niek De Kort  Jacob Kuiper  Wim Van Westrenen  Michael E. Zolensky  Karen Ziegler  Qing‐Zhu Yin  Matthew E. Sanborn  Josh Wimpenny  Akane Yamakawa  Sebastiaan J. De Vet  Matthias M. M. Meier  Kees C. Welten  Kunihiko Nishiizumi  Marc W. Caffee  Aaron S. Burton  Jason P. Dworkin  Daniel P. Glavin  Qinghao Wu  Richard N. Zare  Alexander Ruf  Mourad Harir  Philippe Schmitt‐Kopplin   《Meteoritics & planetary science》2019,54(7):1431-1461

A carbonaceous chondrite was recovered immediately after the fall near the village of Diepenveen in the Netherlands on October 27, 1873, but came to light only in 2012. Analysis of sodium and poly‐aromatic hydrocarbon content suggests little contamination from handling. Diepenveen is a regolith breccia with an overall petrology consistent with a CM classification. Unlike most other CM chondrites, the bulk oxygen isotopes are extremely ¹⁶O rich, apparently dominated by the signature of anhydrous minerals, distributed on a steep slope pointing to the domain of intrinsic CM water. A small subset plots closer to the normal CM regime, on a parallel line 2 ‰ lower in δ¹⁷O. Different lithologies in Diepenveen experienced varying levels of aqueous alteration processing, being less aqueously altered at places rather than more heated. The presence of an agglutinate grain and the properties of methanol‐soluble organic compounds point to active impact processing of some of the clasts. Diepenveen belongs to a CM clan with ~5 Ma CRE age, longer than most other CM chondrites, and has a relatively young K‐Ar resetting age of ~1.5 Ga. As a CM chondrite, Diepenveen may be representative of samples soon to be returned from the surface of asteroid (162173) Ryugu by the Hayabusa2 spacecraft.  相似文献   

Cosmic‐ray exposure age and preatmospheric size of the Bunburra Rockhole achondrite     

Kees C. WELTEN  Matthias M. M. MEIER  Marc W. CAFFEE  Matthias LAUBENSTEIN  Kunihiko NISHIZUMI  Rainer WIELER  Phil A. BLAND  Martin C. TOWNER  Pavel SPURNÝ 《Meteoritics & planetary science》2012,47(2):186-196

Abstract– Bunburra Rockhole is the first meteorite fall photographed and recovered by the Desert Fireball Network in Australia. It is classified as an ungrouped achondrite similar in mineralogical and chemical composition to eucrites, but it has a distinct oxygen isotope composition. The question is if achondrites like Bunburra Rockhole originate from the same parent body as the howardite‐eucrite‐diogenite (HED) meteorites or from several separate, differentiated parent bodies. To address this question, we measured cosmogenic radionuclides and noble gases in the Bunburra Rockhole achondrite. The short‐lived radionuclides ²²Na and ⁵⁴Mn confirm that Bunburra Rockhole is a recent fall. The concentrations of ¹⁰Be, ²⁶Al and ³⁶Cl as well as the ²²Ne/²¹Ne ratio indicate that Bunburra Rockhole was a relatively small object (R approximately 15 cm) in space, consistent with the photographic fireball observations. The cosmogenic ³⁸Ar concentration yields a cosmic‐ray exposure (CRE) age of 22 ± 3 Myr, whereas ²¹Ne and ³He yield approximately 30% and approximately 60% lower ages, respectively, due to loss of cosmogenic He and Ne, mainly from plagioclase. With a CRE age of 22 Myr, Bunburra Rockhole is the first anomalous eucrite that overlaps with the main CRE peak of the HED meteorites. The radiogenic K‐Ar age of 4.1 Gyr is consistent with the U‐Pb age, while the young U,Th‐He age of approximately 1.4 Gyr indicates that Bunburra Rockhole lost radiogenic ⁴He more recently.  相似文献   

II-1 On the cross flow turbine for wave power plant (1st report, the characteristics of the turbine in steady air flow)     

Masahiko Akabane  Haruyuki Suzuki  Kunihiko Yamauchi 《Ocean Engineering》1985,12(6):562

  相似文献   

东海岛屿风尘地层中火山玻璃的发现及环境意义   总被引：3，自引：0，他引：3  

郑祥民  Kunihiko ENDO  周立旻  赵健 《海洋地质与第四纪地质》2003,23(3):82-82,90

近年来通过对东海诸岛屿第四纪风尘沉积的研究表明 ,东海嵊泗列岛上广泛接受晚更新世以来的风尘堆积[1] 。嵊山岛是浙江沿海舟山群岛最外缘的岛屿之一 ,位于 30°4 5′N、12 2°5 0′E的东海海域 ;岛屿面积约 4 2 5km2 ,该岛屿主要由花岗岩基岩组成 ,岛屿最高点海拔达 10 0多米。岛屿大部分地区基岩直接出露地表 ,厚达数米的风尘黄土直接覆盖在基岩之上。该岛风尘堆积地层较为典型 ,保存较为完好 ,风尘地层记录诸多古气候、古环境变化的信息 ,是研究中国东部第四纪风尘沉积、第四纪环境演变和全球变化区域响应的良好载体。通过对岛屿风尘…  相似文献