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Origin and Evolution of Ultramafic Rocks along the Sagaing Fault, Myanmar

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Journal of Earth Science 2023年第1期34卷 122-132页

作者： Tomoaki Morishita Hnin Min Soe Hla Htay Than Htut Lwin Juan Miguel Guotana akihiro tamura Tomoyuki Mizukami Khin Zaw 无 Faculty of Geosciences and Civil Engineering Kanazawa UniversityKanazawa920-1192Japan Lamont-Doherty Earth Observatory Columbia UniversityPalisadesNY10964USA Volcanoes and Earth’s Interior Research Center Japan Agency for Marine-Earth Science and Technology2-15 NatsushimaKanagawa237-0061Japan Geology Department University of MandalayMandalay05092Myanmar Geology Department Dagon UniversityNorth Dagon11422Myanmar Taunggoke Degree College TaunggokeTaunggoke Township07161Myanmar Graduate School of Natural Science and Technology Kanazawa UniversityKanazawaIshikawa920-1192Japan CODES ARC Centre of Excellence in Ore Deposits University of TasmaniaTasmania7001Australia

The active Sagaing fault in Myanmar defines the boundary between the Indian Plate and the Eurasian Plate and causes seismic damage in the major cities of Myanmar. Small bodies of serpentinite occur along the fault. We for the first time investigated the highly sheared serpentinite bodies in the Sheinmagar area and Yega Inn area along the Sagaing fault. Extensively sheared/brecciated serpentinites and related rocks, such as talc and/or chlorite-bearing rocks contains small rock fragments of serpentinites. Serpentine texture and mineral chemistry indicate that the protolith of these serpentinites were mainly harzburgite with minor amounts of dunite, some of which are cut by gabbroic veins. No shape-preferred orientation of the antigorite is present, indicating that the serpentinization was occurred under relatively static conditions. Protolith and serpentine minerals are similar to those of the jadeitite-bearing serpentinites in the north of the Sagaing fault(the Jade Mine belt). Chemical variations of spinels in the studied area are within the compositional range of forearc peridotites and those in the mantle section of nearby ophiolites. After the formation of antigorite serpentinite under static conditions, these serpentinites were subsequently, but locally deformed, probably due to the activity of the Sagaing fault, resulting in the formation of serpentinite schist/brecciated rock. The presence of the less-deformed antigorite serpentinite in the sheared/brecciated zone indicates the strain localization mainly along the surrounding serpentine-talc(±chlorite) schistose rocks, which is probably formed by the reaction between serpentinite and country rocks. Further studies are needed to better understand whether the distribution of serpentinized peridotites cause variations in the activity of the Sagaing fault.

关键词： Sagaing fault serpentinite deformation ophiolite

Deserpentinization and high-pressure(eclogite-facies) metamorphic features in the Eoarchean ultramafic body from Isua,Greenland

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Geoscience Frontiers 2022年第1期13卷 297-309页

作者： Juan Miguel Guotana Tomoaki Morishita Ikuya Nishio akihiro tamura Tomoyuki Mizukami Kenichiro Tani Yumiko Harigane Kristoffer Szilas D.Graham Pearson Graduate School of Natural Science&Technology Kanazawa UniversityJapan School of Environmental Science and Management University of the Philippines Los BañosLagunaPhilippines Lamont-Doherty Earth Observatory Columbia UniversityPalisadesNY 10964USA Volcanoes and Earth’s Interior Research Center Japan Agency for Marine-Earth Science and Technology2-15 NatsushimaKanagawa 237-0061Japan National Museum of Nature and Science 4-1-1AmakuboTsukuba-shiIbaraki 305-0005Japan Institute of Geology and Geoinformation Geological Survey of Japan/AIST Central 71-1-1 HigashiTsukubaIbaraki 305-8567Japan Department of Geosciences and Natural Resource Management University of CopenhagenØster Voldgade 101350 CopenhagenDenmark Department of Earth&Atmospheric Sciences University of AlbertaEdmontonABCanada

Discontinuous chains of ultramafic rock bodies form part of the 3800–3700 Ma Isua Supracrustal Belt(ISB),hosted in the Itsaq Gneiss Complex of southwestern *** bodies are among the world’s oldest outcrops of ultramafic rocks and hence an invaluable geologic *** rocks from Lens B in the northwestern limb of ISB show characteristics of several stages of serpentinization and deserpentinization forming prograde and retrograde mineral ***-rich humite-group minerals such as titanian chondrodite(Ti-Chn)and titanian clinohumite(Ti-Chu)often occur as accessory phases in the metamorphosed ultramafic *** Ti-rich humite minerals are associated with metamorphic *** host olivine is highly forsteritic(Fo96-98)with variable Mn O and Ni O *** concentrations of the rare-earth elements(REE)and high-field strength elements(HFSE)of the metamorphic olivine are higher than typical mantle *** textural and chemical characteristics of the olivine indicate metamorphic origin as a result of deserpentinization of a serpentinized ultramafic protolith rather than primary assemblage reflecting mantle residues from high-degrees of partial *** close association of olivine,antigorite and intergrown Ti-Chn and Ti-Chu suggests pressure condition between$1.3–2.6 GPa within the antigorite stability field(<700°C).The overall petrological and geochemical features of Lens B ultramafic body within the Eoarchean ISB indicate that these are allochthonous ultramafic rocks that recorded serpentine dehydration at relatively lower temperature and reached eclogite facies condition during their complex metamorphic history similar to exhumed UHP ultramafic rocks in modern subduction zone channels.

关键词： Titanian chondrodite Titanian clinohumite Isua supracrustal belt UHP Deserpentinization

Devonian to Permian evolution of the Paleo-Tethys Ocean:New evidence from U–Pb zircon dating and Sr–Nd–Pb isotopes of the Darrehanjir–Mashhad “ophiolites”,NE Iran

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Devonian to Permian evolution of the Paleo-Tethys Ocean:New ...

Sahara’s surface transformation forced an abrupt hydroclimate decline and Neolithic culture transition in northern China

中国科学院地质与地球物理研究所2015年度（第15届）学术年会

作者： Hadi Shafaii Moghadam Xian-Hua Li Xiao-Xiao Ling Robert J.Stern Mohamed Zaki Khedr Massimo Chiaradia Ghasem Ghorbani Shoji Arai akihiro tamura State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of Sciences School of Earth Sciences Damghan University Geosciences Dept. University of Texas at Dallas Department of Earth Sciences Kanazawa University Department of Geology Faculty of ScienceKafrelsheikh University Département de Minéralogie Université de Genève

Middle to Late Paleozoic ophiolites,which are remnants of the Paleo-Tethys Ocean,are aligned in two main zones in northern Iran:Darrehanjir-Fariman-Mashhad,and Rasht in the north and Jandagh-Anarak ophiolites to the *** new U-Pb zircon dating results show that the-200 km long Darrehanjir-Mashhad mafic-ultramafic body is not a single ophiolite but a composite igneous complex composed of Permian pillow lavas and pelagic sediments in fault contact with a small outcrop of Devonian intrusive and ultramafic *** intrusive rocks have U-Pb zircon ages of 380.6±3.7 Ma and 382.9±3.7 Ma respectively,-100 Ma older than published ages for gabbros and radiolarites intercalated with lavas near Mashhad and *** peridotites from the Devonian complex contain low Cr#spinel,similar to that in MORB-type *** Darrehanjir gabbros and Permian Mashhad sequences both have boninitic and calc-alkaline signatures,***δOvalues from the Devonian ferrodiorite(δO-4.6±0.3‰)are slightly lower than the 5.2 to5.4‰expected for MORB-type zircons whereas Devonian plagiogranitic zircons mostly haveδO103)and lowεNd(<5.4)for both Permian and Devonian *** Darrehanjir-Mashhad rocks are characterized by radiogenicPb/Pb andPb/Pb,indicating the involvement of subducted terrigenous sediments in the *** Mashhad-Darrehanjir mafic-ultramafic complex demonstrates that this part of Paleo-Tethys evolved from oceanic crust formation above a subduction zone in Devonian time to accretionary convergence in Permian *** Paleozoic ophiolites and oceanic igneous complexes along with those of the Caucasus and Turkey in the west and Afghanistan,Turkmenistan

关键词： Paleozoic ophiolites U–Pb zircon dating Zircon εHf(t) Komatiite Supra-subduction zone-type magmatism

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The Innovation 2024年第1期5卷 70-79页

作者： Yandong Hou Hao Long Sumiko Tsukamoto Zhengyao Lu Jie Chen Daniel EIbarra Toru tamura Qiong Zhang Weiyi Sun Jingran Zhang Lei Gao Manfred Frechen Ji Shen State Key Laboratory of Lake Science and Environment Nanjing Institute of Geography and LimnologyChinese Academy of Sciences(NIGLAS)Nanjing 210008China Leibniz Institute for Applied Geophysics(LIAG) Department of Geochronology30655 HannoverGermany Department of Physical Geography and Ecosystem Science Lund University22100 LundSweden Key Laboratory of Western China’s Environmental Systems(Ministry of Education) College of Earth and Environmental SciencesLanzhou UniversityLanzhou 730000China College of Atmospheric Sciences Lanzhou UniversityLanzhou 730000China Institute at Brown for Environment and Society and Department of Earth Environmentaland Planetary SciencesBrown UniversityProvidenceRI 02912USA Geological Survey of Japan National Institute of Advanced Industrial Science and TechnologyTsukubaIbaraki 305-8567Japan Graduate School of Frontier Sciences University of TokyoKashiwaChiba 277-8561Japan Department of Physical Geography and Bolin Centre for Climate Research Stockholm University10691 StockholmSweden School of Geography Nanjing Normal UniversityJiangsu Centre for Collaborative Innovation in Geographical Information Resource Development and ApplicationKey Laboratory of Virtual Geographic EnvironmentMinistry of Education of ChinaNanjing 210023China School of Geography and Ocean Science Nanjing UniversityNanjing 210023China

The remote forcing from land surface changes in the Sahara is hypothesized to play a pivotal role in modulating the intensity of the East Asian summer monsoon(EASM)through ocean-atmospheric *** modulation has far-reaching consequences,particularly in facilitating societal shifts documented in northern ***,we present a well-dated lake-level record from the Daihai Lake Basin in northern China,providing quantitative assessments of Holocene monsoonal precipitation and the consequent migrations of the northern boundary of the *** reconstruction,informed by a water-and-energy balance model,indicates that annual precipitation reached700 mm during 8–5 ka,followed by a rapid decline to tween 5 and 4 *** shift coherently aligns with a signi550 mm be-ficant300 km northwestward movement of the EASM northern boundary during the Middle Holocene(MH),in contrast to its current *** findings underscore that these changes cannot be entirely attributed to orbital forcing,as corroborated by simulation *** model simulations deployed in our study suggest that the presence of the Green Sahara during the MH significantly strengthened the EASM and led to a northward shift of the monsoon rainfall ***,the Sahara’s reversion to a desert landscape in the late Holocene was accompanied by a corresponding southward retraction of monsoon *** dramatic hydroclimate changes during5–4 ka likely triggered or at least contributed to a shift in Neolithic cultures and societal transformation in northern *** decreasing agricultural productivity,communities transitioned from millet farming to a mixed rainfed agriculture and animal husbandry ***,our findings elucidate not only the variability of the EASM but also the profound implications of a remote forcing,such as surface transformations of the Sahara,on climatic changes and cultural evolution in northern China.

关键词： Holocene monsoon abrupt

Increasing spatial coverage in rough terrain and vegetated areas using InSAR optimized pixel selection:application to Tohoku,Japan

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Geo-Spatial Information Science 2022年第2期25卷 295-311页

作者： Tamer ElGharbawi Masayuki tamura Civil and Earth Resources Engineering Department Kyoto UniversityKyotoJapan

One of the major limitations of using Interferometric Synthetic Aperture Radar(InSAR)in time series analysis is the low-phase coherence associated with rough terrain and vegetated areas,which results in limited spatial coverage in such *** scatterers technique was introduced to overcome this limitation using time-series ***,identifying major scatterers within a pixel requires the single-looked pixels oversampling which can be a demanding process especially with large interferometric stacks and vast study ***,using multilooked temporal coherent pixels was proposed to increase processing efficiency and coverage by utilizing distributed targets,but this technique may exclude pixels with reliable phase returns because of their temporal varying neighboring *** this paper,we propose a technique to identify multilooked temporal stable pixels with reliable phase returns independent of their neighboring *** conduct a simulation analysis to relate the spatial coherence of a pixel with its expected temporal correlation in the time series analysis *** found that a liberal temporal correlation threshold of 0.53 in multilooked pixels stack is equivalent to a spatial coherence threshold of 0.2 when using number of looks of 9,which is considered acceptable in temporal coherent pixels,in terms of phase standard *** these findings to study the 2011 Tohoku earthquake in the northeastern part of Japan resulted in increasing the number of usable pixels and spatial coverage index by nearly 50.4%and 36.8%,respectively,compared to the temporal coherent ***,we propose an approach to integrate GPS observations with InSAR time series analysis,which resulted in deformation maps of the megathrust 2011 Tohoku earthquake with mean RMSE of 11.4 mm and a correlation of 98%in comparison to GPS observations.

关键词： 2011 Tohoku earthquake temporal stable pixels coherence phase noise GPS coverage index

Alterations of tumor suppressor and tumor-related genes in the development and progression of gastric cancer

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World Journal of Gastroenterology 2006年第2期12卷 192-198页

作者： Gen tamura Department of Pathology Yamagata University School of MedicineYamagata 990-9585Japan

The development and progression of gastric cancer involves a number of genetic and epigenetic alterations of tumor suppressor and tumor-related genes. The majority of differentiated carcinomas arise from intestinal metaplastic mucosa and exhibit structurally altered tumor suppressor genes, typified by p53, which is inactivated via the classic two-hit mechanism, i.e. loss of heterozygosity （LOH） and mutation of the remaining allele. LOH at certain chromosomal loci accumulates during tumor progression. Approximately 20% of differentiated carcinomas show evidence of mutator pathway tumorigenesis due to hMLH1 inactivation via hypermethylation of promoter CpG islands, and exhibit high-frequency microsatellite instability. In contrast, undifferentiated carcinomas rarely exhibit structurally altered tumor suppressor genes. For instance, while methylation of E-cadherin is often observed in undifferentiated carcinomas, mutation of this gene is generally associated with the progression from differentiated to undifferentiated carcinomas. Hypermethylation of tumor suppressor and tumor-related genes, including APC, CHFR, DAP- kinase, DCC, E-cadherin, GSTP1, hMLH1, p16, PTEN, RASSF1A, RUNX3, and TSLC1, can be detected in both differentiated and undifferentiated carcinomas at varying frequencies. However, the significance of the hypermethylation varies according to the analyzed genomic region, and hypermethylation of these genes can also be present in non-neoplastic gastric epithelia. Promoter demethylation of specific genes, such as MAGE and synudein y, can occur during the progressive stages of both histological types, and is associated with patient prognosis. Thus, while the molecular pathways of gastric carcinogenesis are dependent on histological background, specific genetic alterations can still be used for risk assessment, diagnosis, and prognosis.

关键词： Gastric cancer p53 E-cadherin hMLH1 Methylation

Pediatric kidney transplantation during the COVID-19 pandemic

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World Journal of Clinical Cases 2022年第34期10卷 12494-12499页

作者： Hiroshi tamura Department of Pediatrics Kumamoto UniversityKumamoto 860-8556Japan

A waiting list for non-emergency transplant medical care was recommended in the first half of 2020 due to the coronavirus disease 2019(COVID-19)***,the number of kidney transplants temporarily ***,the waiting list for transplant medical care was lifted in the latter half of 2020 with the establishment of a polymerase chain reaction test system and the spread of infection *** basic stance is to recommend vaccination to posttransplant recipients,recipients,and donors who are scheduled to undergo transplantation,and their families,with the start of vaccine therapy in *** mortality rate of patients undergoing kidney transplants who had COVID-19 is slightly higher than healthy persons,and acute kidney injury was reported to lead to graft ***,pediatric cases of severe disease are rare and without *** transplantation medical care will be continuously provided by implementing infection prevention and treatments based on the latest evidence,promoting donated kidney transplantation,and hoping that pediatric patients with renal failure will grow up healthy,both physically and mentally,and become independent members of society,just like healthy children.

关键词： Kidney transplantation COVID-19 pandemic Children

Response of understory vegetation over 10 years after thinning in an old-growth cedar and cypress plantation overgrazed by sika deer in eastern Japan

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Forest Ecosystems 2017年第2期4卷 93-102页

作者： Atsushi tamura Masanobu Yamane Division of Forest Research and Nature Restoration Planning Kanagawa Prefecture Natural Environment Conservation Center 657 Nanasawa AtsugiKanagawa 243-072 Japan

Background： Forest management strategies such as thinning have long been used to enhance ecosystem functions, especially in *** in plantations with high deer density, however, may not yield a desired increase in understory vegetation because deer graze on germinating plants after ***, we examine the changes in understory vegetation after thinning in plantations that have been overgrazed by sika deer to provide insight into the effects of thinning on ecosystem functions such as soil conservation and biological ***： We conducted our survey in the Tanzawa Mountains of eastern *** surveyed the change in understory vegetation within and outside of three deer exclosures on a single slope with three levels of understory vegetation cover： sparse（1%, exclosure ＂US＂）, moderate（30%, exclosure ＂MM＂）, and dense（80%, exclosure ＂LD＂） over10 years after a 30% thinning of an old-growth cedar and cypress plantation which was overgrazed by sika ***： Understory vegetation cover, biomass and species richness increased within and outside the ＂US＂ and＂MM＂ exclosures after thinning, and biomass was greater within than outside the exclosures at 10 years after *** species dominated both ＂US＂ and ＂MM＂ exclosures before thinning, and trees and shrubs dominated within the exclosures over time after *** contrast, unpalatable, grazing-tolerant, perennial,and annual species increased outside the ＂US＂ and ＂MM＂ *** noticeable changes were observed within and outside the ＂LD＂ exclosure when compared with the ＂US＂ and ＂MM＂ ***： Our results suggest that thinning a stand by 30% based on volume resulted in an increase in understory vegetation cover mainly composed of both unpalatable and grazing-tolerant species in a plantation forest where understory vegetation is sparse or moderate and sika deer density is *** emphasize that establishing deer exclosures or controlling deer is essential to ma

关键词： Biomass Deer exclosure Grazing-tolerant species Understory cover Unpalatable species

Dynamic robust optimal reorder point with uncertain lead time and changeable demand distribution

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2010年第12期11卷 938-945页

作者： Masaki tamura Kazuko MORIZAWA Hiroyuki NAGASAWA Department of Electrical and Information Systems Engineering Graduate School of EngineeringOsaka Prefecture University Osaka Prefectural College of Technology

In fixed order quantity systems,uncertainty in lead time is expressed as a set of scenarios with occurrence probabilities,and the mean and variance in demand distribution are supposed to be changeable according to a known pattern.A new concept of "dynamic robust optimal reorder point" is proposed in this paper and its value is calculated as a "robust optimal reorder point function with respect to reorder time".Two approaches were employed in determining the dynamic optimal reorder *** first is a shortage rate satisfaction approach and the second is a backorder cost minimization *** former aims at finding the minimum value of reorder point at each reorder time which satisfies the condition that the cumulative distribution function (CDF) of shortage rate under a given set of scenarios in lead time is greater than or equal to a basic CDF of shortage rate predetermined by a *** the latter approach,the CDF of closeness of reorder point is defined at each reorder time to express how close to the optimal reorder points under the set of scenarios,and the dynamic optimal reorder point is defined according to stochastic *** numerical examples demonstrate the features of these dynamic robust optimal reorder points.

关键词： Reorder point Lead time Robust optimum Uncertainty Scenario