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Interaction between protokimberlite melts and mantle lithosphere:Evidence from mantle xenoliths from the Dalnyaya kimberlite pipe,Yakutia(Russia)

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Geoscience Frontiers 2017年第4期8卷 693-710页

作者： I.V.Ashchepkov T.Ntaflos Z.V.Spetsius R.F.Salikhov h.downes Institute of Geology and Mineralogy SD RAS Vienna University Alrosa Stock Company Department of Earth and Planetary Sciences Birkbeck University of London

The Dalnyaya kimberlite pipe（Yakutia,Russia） contains mantle peridotite xenoliths（mostly Iherzolites and harzburgites） that show both sheared porphyroclastic（deformed） and coarse granular textures,together with ilmenite and clinopyroxene *** peridotites contain high-temperature Fe-rich clinopyroxenes,sometimes associated with picroilmenites,which are products of interaction of the lithospheric mantle with protokimberlite related *** orthopyroxene-derived geotherm for the lithospheric mantle beneath Dalnyaya is stepped similar to that beneath the Udachnaya *** granular xenoliths fall on a geotherm of 35 mWm-2 whereas deformed varieties yield a 45 mWm-2）geotherm in the 2-7.5 GPa pressure *** chemistry of the constituent minerals including garnet,olivine and clinopyroxene shows trends of increasing Fe~#（=Fe/（Fe＋Mg））with decreasing *** may suggest that the interaction with fractionating protokimberlite melts occurred at different *** major mantle lithologies are distinguished by the trace element patterns of their constituent minerals,determined by ***,some clinopyroxenes and rare garnets are depleted in Ba,Sr,hFSE and MREE and represent relic lithospheric ***-fertilized garnet and clinopyroxene are more *** distribution of trace elements between garnet and clinopyroxene shows that the garnets dissolved primary orthopyroxene and *** high temperature clinopyroxenes related to the protokimberlite melts partially dissolved these *** show decreases in Ni and increases in Al,Ca and Ti from Mg-rich varieties to the more Fe-rich,deformed and refertilized *** showing higher Fe~#（0.11-0.15） are found within intergrowths of low-Cr ilmenite-clinopyroxene-garnet related to the crystallization of protokimberlite melts in feeder *** P-f（O_2） diagrams,garnets and Cr-rich clinopyroxenes indicate reduced conditions at the base of the lithosphere at-5

关键词： Mantle xenoliths Trace element Melt interaction Kimberlite Pyrope Cr-diopside

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Monomineral universal clinopyroxene and garnet barometers for peridotitic,eclogitic and basaltic systems

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Geoscience Frontiers 2017年第4期8卷 775-795页

作者： I.V.Ashchepkov T.Ntaflos A.M.Logvinova Z.V.Spetsius h.downes N.V.Vladykin V.S.Sobolev Institute of Geology and Mineralogy SB RAS Vienna University Alrosa Stock Company Department of Earth and Planetary Sciences Birkbeck University of London Institute of Geochemistry SD RAS

New versions of the universal Jd-Di exchange clinopyroxene barometer for peridotites,pyroxenites and eclogites,and also garnet barometer for eclogites and peridotites were *** were checked using large experimental data sets for eciogitic（~530） and peridotitic systems（〉650）.The precision of the universal Cpx barometer for peridotites based on Jd-Di exchange is close to Cr-Tschermal

关键词： Clinopyroxene Barometer Peridotite Eclogite Kimberlite Garnet

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法国中央地块麻粒岩相包体的铅、氧同位素分类:与地壳作用的内在联系

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地质地球化学 1992年第5期20卷 35-44页

作者： h.downes 李培忠

给出了法国中央地块第三纪碱性火山岩中一麻粒岩相包体序列的Pb、O同位素数据。该序列包括超镁铁质堆积岩、镁铁质堆积岩、变辉长岩(可当作基性流体)、长英质变火成岩(紫苏花岗岩)和变沉积岩。镁铁质包体、长英质变火成岩和变沉积岩的δ... 详细信息

给出了法国中央地块第三纪碱性火山岩中一麻粒岩相包体序列的Pb、O同位素数据。该序列包括超镁铁质堆积岩、镁铁质堆积岩、变辉长岩(可当作基性流体)、长英质变火成岩(紫苏花岗岩)和变沉积岩。镁铁质包体、长英质变火成岩和变沉积岩的δ^(18)O值范围分别为+6.9‰～+9.8‰、+9.3‰～10.2‰和+6.1‰～11.8‰。相比之下,该区地幔橄榄岩的δ^(18)O值为+5.1‰至+6.9‰,而区内海西花岗岩类的δ^(18)O值则为+8.6‰～12.1‰。麻粒岩相包体的^(206)Pb/^(204)Pb比值在17.77和19.19之间,^(207)Pb/^(204)Pb比值为15.51～15.69,^(208)Pb/^(204)Pb比值为38.07～40.07。通常,变沉积的麻粒岩中放射成因Pb的含量较高,而镁铁质变火成岩中放射成因Pb的含量较少。因此,这些同位素的特征可解释为镁铁质岩浆与其侵位的变沉积岩地壳相互作用的结果。热量的释放也引起了下地壳易熔部分的熔融和海西造山运动晚期花岗岩类的形成。但是,在花岗岩类的源区还需要有一个能提供少量放射成因Pb的额外组分;这个组分可能是长英质变火成岩包体或中/上地壳片麻岩。

关键词：麻粒岩矿物包体铅氧同位素

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Comparison of mantle lithosphere beneath early Triassic kimberlite fields in Siberian craton reconstructed from deep-seated xenocrysts

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Geoscience Frontiers 2016年第4期7卷 639-662页

作者： I.V.Ashchepkov S.S.Kuligin N.V.Vladykin h.downes M.A.Vavilov E.N.Nigmatulina S.A.Babushkina N.S.Tychkov O.S.Khmelnikova lnstitute of Geology and Mineralogy SD RAS Koptyug ave 3NovosibirskRussia Institute of Geochemistry SD RAS Favorskky str laIrkutskRussia Department of Earth and Planetary Sciences Birkbeck University of LondonLondonUK Institute of Geology of Diamonds and Noble metals SD RAS Lenina ave 39YakutskRussia

Mantle xenocrysts from early Triassic kimberlite pipes from Kharamai, Ary-Mastakh and Kuranakh fields in the Anabar shield of Siberia revealing similar compositional trends were studied to estimate the superplume influence on the subcratonic lithosphere mantle （SCLM）. Pressure-temperature （PT） reconstructions using monomineral thermobarometry for 5 phases show division of the SCLM beneath the Kharamai field into 6 units： pyroxenitic Fe-rich （1-2 GPa） and Mg-rich （2-3 GPa） layers; middle with two levels of Gar-Sp pyroxenites at - 3 and 4-5 GPa; Gar-dunite-harzburgites - 4.5-6.5 GPa subjected to llm-Px vein metasomatism; and a Mg-rich dunite lower part. In the Anabar shield （Ary-Mastakh, Dyuken and Kuranakh fields） mantle lithosphere is composed of three large units divided into two parts： upper part with amphiboles and phlogopite; two levels of pyroxenites and eclogites at 3 and 4 GPa, and a lower part composed of refertilized dunites. Diagrams showing P-Fe#Gar clusters for garnets and omphacites illustrate the differences between SCLM of these localities. Differences of Triassic SCLM from Devonian SCLM are in simple layering; abundance of Na-Cr-amphiboles and metasomatism in the upper SCLM part, thick pyroxenite-eclogite layer and lower part depletion, heated from SCLM base to 5.0 GPa. Kharamai mantle clinopyroxenes represent three geochemical types：（1） harzburgitic with inclined linear REE, hFSE troughs and elevated Th, U; （2） lherzolitic or pyroxenitic with round TRE patterns and decreasing incompatible elements; （3） eclogitic with Eu troughs, Pb peak and high LILE content. Calculated parental melts for garnets with humped REE patterns suggest dissolution of former Cpx and depression means Cpx and garnets extraction. Clinopyroxenes from Ary-Mastakh fields show less in- dined REE patterns with hMREE troughs and an increase of incompatible elements. Clinopyroxenes from Kuranakh field show flatter spoon-like REE patterns and peaks in Ba, U, Pb and St, similar to th

关键词： Mantle lithosphere Monomineral thermobarometry Mineral geochemistry Triassic kimberlite Layering

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Alakit and Daldyn kimberlite fields,Siberia,Russia:Two types of mantle sub-terranes beneath central Yakutia?

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Geoscience Frontiers 2017年第4期8卷 671-692页

作者： I.V.Ashchepkov A.M.Logvinova T.Ntaflos N.V.Vladykin S.I.Kostrovitsky Z.Spetsius S.I.Mityukhin S.A.Prokopyev N.S.Medvedev h.downes Institute of Geology and Mineralogy SD RAS Institute of Geochemistry SD RAS Dept.of Lithospheric Research University of Vienna Alrosa Stock Company Nikolaev Institute of Inorganic Chemistry 3 Department of Earth and Planetary Sciences Birkbeck University of London

Mineral data from Yakutian kimberlites allow reconstruction of the history of lithospheric *** occur in compositions of mantle pyropes and clinopyroxenes from large kimberlite pipes in the Alakit and Daldyn *** the Alakit ***-diopsides are alkaline,and Stykanskaya and some other pipes contain more sub-calcic pyropes and dunitic-type diamond inclusions,while in the Daldyn field harzburgitic pyropes are *** eclogitic diamond inclusions in the Alakit field are sharply divided in types and conditions,while in the Daldyn field they show varying compositions and often continuous Pressure-Temperature（P-T） ranges with increasing Fe~# with decreasing *** Alakit,Crpargasites to richterites were found in all pipes,while in Daldyn,pargasites are rare Dalnyaya and Zarnitsa ***-diopsides from the Alakit region show higher levels of light Rare Earth Elements（LREE）and stronger REE-slopes,and enrichment in light Rare Earth Elements（LREE）,sometimes Th-U,and small troughs in *** the Daldyn field,the high Field Strength Elements hFSE troughs are more common in clinopyroxenes with low REE abundances,while those from sheared and refertilized peridotites have smooth *** from Alakit show hREE minima,but those from Daldyn often have a trough at Yand high U and ***/O2 diagrams from both regions show similarities,suggesting similar layering and *** degree of metasomatism is often higher for pipes which show dispersion in P-Fe~# trends for *** the mantle beneath Udachnaya and Aykhal,pipes show 6-7 linear arrays of P-Fe~# in the lower part of the mantle section at 7.5-3.0 GPa,probably reflecting primary subduction *** the Sytykanskaya pipe,there are several horizons with opposite inclinations which reflect metasomatic *** high dispersion of the P—Fe~# trend indicating widespread metasomatism is associated with decreased diamond *** explanation of the differences in miner

关键词： Thermobarometry Geochemistry Daldyn Alakit Craton Lithosphere

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上地幔中的剪切带与地幔橄榄岩内的地球化学富集和变形的关系

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地质科学译丛 1991年第1期8卷 18-22页

作者： h.downes 陈欣

幔源尖晶石橄榄岩的结构变化过去常被认为是软流圈地幔底辟存在的证据,并指示大范围(几公里～几十公里)内变形的非均一性.但许多火山口都挟带有变形及未变形的捕虏体,同时橄榄岩体中所呈现的野外关系表明:因为大量的岩石圈剪切带的存在... 详细信息

幔源尖晶石橄榄岩的结构变化过去常被认为是软流圈地幔底辟存在的证据,并指示大范围(几公里～几十公里)内变形的非均一性.但许多火山口都挟带有变形及未变形的捕虏体,同时橄榄岩体中所呈现的野外关系表明:因为大量的岩石圈剪切带的存在,变形与未变形橄榄岩的蚀变规模较小(几厘米～几米).极少数捕虏体既含变形的、又含未变形的橄榄岩.在变形与交代矿物生长之间也存在明显关系,角闪石通常富集在强烈变形带、橄榄岩体和变形捕虏体中,有时也出现于交切状脉及其周围的接触变质带中.人们还可以看到在变形作用和地球化学富集作用标志之间存在一定的关系.许多变形尖晶石橄榄岩中的单斜辉石显示出轻稀土元素富集的特点,而未变形尖晶石橄榄岩中的单斜辉石通常具有洋中脊玄武岩(MORB)型轻稀土元素亏损模型.未变形橄榄岩的Sr和Nd放射性同位素组成通常与MORB的相似.并且有低ε_(Sr)值和高ε_(Nd)值.相反,含或不含角闪石的变形橄榄岩常具高ε_(Sr)电和低ε_(Nd)值.这表明了富大离子亲石元素和富轻稀土元素的流体或熔体的地球化学富集作用,从上所述可推断:在浅部地幔内有岩石圈韧性剪切带存在,角闪石和单斜辉石在这些剪切带的交代流体中发生沉淀.

关键词：上地幔剪切带橄榄岩地球化学

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The Sytykanskaya kimberlite pipe:Evidence from deep-seated xenoliths and xenocrysts for the evolution of the mantle beneath Alakit,Yakutia,Russia

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Geoscience Frontiers 2015年第5期6卷 687-714页

作者： I.V.Ashchepkov A.M.Logvinova L.F.Reimers T.Ntaflos Z.V.Spetsius N.V.Vladykin h.downes D.S.Yudin A.V.Travin L.V.Makovchuk V.S.Palesskiy O.S.Khmel'nikova Institute of Geology and Mineralogy SB RAS Vienna University Alrosa Stock Company Institute of Geochemistry SB RAS Birkbeck College University of LondonUKMalet Street

Mantle xenoliths（>150） and concentrates from late autolithic breccia and porphyritic kimberlite from the Sytykanskaya pipe of the Alakit field（Yakutia） were analyzed by EPMA and LAM ICP *** P-TX-f（O2） diagrams minerals from xenoliths show widest variations,the trends P-Fe#-CaO,f（O2）for minerals from porphyric kimberlites are more stepped than for xenocrysts from *** PTX points mark moving for protokimberlites from the lithosphere base（7.5 GPa） to pyroxenite lens（5-3.5 GPa） accompanied by Cr increase by AFC and creation of two trends P-Fe#OI10-12%and13-15%.The Opx-Gar-based mantle geotherm in Alakit field is close to 35 mW/m2 at 65 GPa and 600 C near Moho was *** oxidation state for the megacrystalline ilmenites is lower for the metasomatic associations due to reduction of protokimberlites on peridotites than for uncontaminated varieties at the lithosphere *** inclined linear REE patterns with deep hFSE troughs for the parental melts of clinopyroxene and garnet xenocrysts from breccia were influenced by differentiated *** for metasomatic xenoliths reveal less inclined slopes without deep troughs in spider *** reveal S-shaped REE *** clinopyroxenes from graphite bearing Cr-websterites show inclined and inflected in Gd spectrums with LREE variations due to AFC *** for garnets display less inclined patterns and Ba-Sr troughs but enrichment in ***40Ar/39Ar ages for micas from the Alakit mantle xenoliths for disseminated phlogopites reveal Proterozoic（1154 Ma） age of metasomatism in early Rodinia *** glimmerites with richterite- like amphiboles mark1015 Ma plume event in Rodinia ***600-550 Ma stage manifests final Rodinia *** last 385 Ma metasomatism is protokimberlite-related.

关键词： Kimberlites Mantle lithosphere Mantle xenoliths Th

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欧洲下地壳的性质——深源包体岩石学和地球化学证据

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地质科学译丛 1994年第4期11卷 68-76页

作者： h.downes 赵志丹 Birkbeck/UCL Research School of Geological and Geophysical Sciences University College Gower St. London WC1E6BT UK

欧洲碱性火山岩中下地壳包体的研究揭示出,下地壳存在多种岩石类型,从榴辉岩、含或不含石榴石的镁铁质麻粒岩、长英质麻粒岩到高级变沉积岩。包体岩套及推测的下地壳的化学成分与矿物学变化非常大。依据一个包体岩套中不同岩石类型的比... 详细信息

欧洲碱性火山岩中下地壳包体的研究揭示出,下地壳存在多种岩石类型,从榴辉岩、含或不含石榴石的镁铁质麻粒岩、长英质麻粒岩到高级变沉积岩。包体岩套及推测的下地壳的化学成分与矿物学变化非常大。依据一个包体岩套中不同岩石类型的比例估计出下地壳的组成可以从基性(SiO_2<50ω_B％)到中性(SiO_2≈55ω_B％)。下地壳的年龄尚未确定,但地壳包体中的锆石却常常比地表出露的最老岩石要年轻。这预示着较多的镁铁质下地壳已通过侵入或垫托作用加积到先存地壳的底部了。这种加积作用可能发生在俯冲、裂陷或造山塌陷的过程中。放射性和稳定同位素证据表明确实存在镁铁质岩浆被先存地壳广泛混染的作用。地震波速度限制显示在,欧洲的某些地区,如德国,镁铁质麻粒岩被限制于地壳底部,但在其它地区(苏格兰西北部,匈牙利)则占据下地壳的大部分。在波罗的地盾(科拉)的北部,厚地壳在30～48km深度上含有变化于退变质和变质之间的榴辉岩。

关键词：地壳深源包体岩石学地球化学

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Free vibration and buckling analysis of polymeric composite beams reinforced by functionally graded bamboo fbers

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Applied Mathematics and Mechanics(English Edition) 2024年第3期45卷 543-562页

作者： h.M.FEIZABAD M.h.YAS Department of Mechanical Engineering Razi UniversityKermanshah ***Iran

Natural fibers have been extensively researched as reinforcement materials in polymers on account of their environmental and economic advantages in comparison with synthetic fibers in the recent *** fibers are renowned for their good mechanical properties,abundance,and short cycle *** beams are one of the fundamental structural components and are susceptible to mechanical loads in engineering applications,this paper performs a study on the free vibration and buckling responses of bamboo fiber reinforced composite(BFRC)beams on the elastic *** different functionally graded(FG)layouts and a uniform one are the considered distributions for unidirectional long bamboo fibers across the *** elastic properties of the composite are determined with the law of *** hamilton’s principle,the governing equations of motion are *** generalized differential quadrature method(GDQM)is then applied to the equations to obtain the *** achieved outcomes exhibit that the natural frequency and buckling load values vary as the fiber volume fractions and distributions,elastic foundation stiffness values,and boundary conditions(BCs)and slenderness ratio of the beam ***,a comparative study is conducted between the derived analysis outcomes for BFRC and homogenous polymer beams to examine the effectiveness of bamboo fibers as reinforcement materials,demonstrating the significant enhancements in both vibration and buckling responses,with the exception of natural frequencies for cantilever beams on the Pasternak foundation with the FG-◇fiber ***,the obtained analysis results of BFRC beams are also compared with those for carbon nanotube reinforced composite(CNTRC)beams found in the literature,indicating that the buckling loads and natural frequencies of BFRC beams are lower than those of CNTRC beams.

关键词： bamboo fiber free vibration buckling analysis functionally graded(FG)beam elastic foundation generalized differential quadrature method(GDQM)

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holographic dark energy in non-conserved gravity theory

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Communications in Theoretical Physics 2024年第4期76卷 126-133页

作者： h R Fazlollahi Institute of Gravitation and Cosmology Peoples Friendship University of Russia(RUDN University)6 Miklukho-Maklaya StMoscow117198Russia

Recently, reconsidering the Rastall idea T_(μ;νν)^(v)=α_(,μ) through relativistic thermodynamics gives a new form for the scalar field α which led us to construct modern modified theory of gravity debugged ‘non-conserved gravity theory’ Fazlollahi 2023 Euro. Phys. J. C 83 923. This theory unlike other modified theories of gravity cannot directly explain the current acceleration expansion in the absence of the cosmological constant and or existence of other forms of dark energy. hence, in this study we have reinvestigated holographic dark energy Ρ_(X)~h^(2) in the non-conserved theory of gravity. In this context, the density and pressure of dark energy depend on the non-conserved term and density of the dust matter field. As shown, due to non-conservation effects on large-scale structures, unlike the original holographic model, our model onsets an acceleration epoch for the current Universe satisfies observations. Moreover, the interaction and viscous scenarios are studied for this model.

关键词： non-conserved gravity covariant form of thermodynamics holographic dark energy

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