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The Imataca Complex, NW Amazonian Craton,Venezuela： Crustal evolution and integration of geochronological and petrological coolinghistories

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Episodes 2004年第1期27卷 3-12页

作者： ColomboC.G.Tassinari JoseM.U.Munha WilsonTeixeira TeresaPalacios allenp.nutman CesarSosaS. AdjairP.Santos BrunoO.Calado CentrodePesquisas Geocronol6gicasInstitutodeGeocienciasUniversidadedeSaeoPauloRuadoLago562CidadeUniversitariaButantaSaoPauloBrasil.CEP05588-900 Centro／Dept.Geologia EdificioC25°pisoFaculdadeCienciasUniversidadedeLisboaCampoGrande1749-016LisboaPortugal. ResearchSchoolofEarthSciences AustralianNationalUniversity. MinisteriodeMinasdeVenezuela CiudadBolivar. Cia.MineraSOPEVEN Venezuela.

SHRIMP U/Pb-zircon data and Nd mean crustal residence ages indicate that the lmataca Complex developed from an Archean (≥3.2Ga) continental protolith which has undergone considerable isotopic disturbance plus and juvenile accretion during late-Archean (-2.8Ga) times. Transamazonian granulites experienced peak metamorphic conditions of 750-800℃, 6-8kbar with associated transpressive thrusting and tectonic imbrication. Geochronology on zircon, pyroxene and garnet constrains the timing of peak metamorphism at 1.98-2.05Ga. Diffusion modeling of Fe-Mg exchange between biotite inclusions and host garnet yields (near metamorphic peak) cooling rates of 50-100℃/Ma, with petrological cooling rates being generally consistent with cooling rates determined from geochronology. Combining the retrograde P-T path with cooling rates suggests that after the metamorphic peak, large portions of the lmataca Complex were exhumed from 30 to 17km at a rate of 7-2km/*** this, exhumation rates progressively decreased as the rocks approached the surface. Rapid overall upliftlerosion had ceased when the rocks passed below 600-550℃ at 2.01-1.96 Ga ago. Observed variations in mineral cooling ages are interpreted as to reflect episodic differential tectonic exhumation within major fault systems. Inferred (maximum) ages of fault re-activation generally coincide with major continental accretion events in the Amazonian Craton and reflect long-term thermal evolution of the lmataca terrane, as conditioned by variable response to continued continental convergence during the Proterozoic.

关键词：亚马逊河钕地质年代学太古代

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Protoliths of enigmatic Archaean gneisses established from zircon inclusion studies:Case study of the Caozhuang quartzite,***,China

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Geoscience Frontiers 2014年第4期5卷 445-455页

作者： Allen P.nutman Ronni Maciejowski Yusheng Wan GeoQuEST Research Centre School of Earth & Environmental SciencesUniversity of Wollongong Beijing SHRIMP Center Institute of GeologyChinese Academy of Geological Sciences

A diverse suite of Archaean gneisses at Huangbaiyu village in the North China Craton, includes rare fuchsite-bearing （Cr-muscovite） siliceous rocks - known as the Caozhuang quartzite. The Caozhuang quartzite is strongly deformed and locally mylonitic, with silica penetration and pegmatite veining common. It contains abundant 3880-3600 Ma and some Palaeoarchaean zircons. Because of its siliceous nature, the presence of fuchsite and its complex zircon age distribution, it has until now been accepted as a （mature） quartzite. However, the Caozhuang quartzite sample studied here is feldspathic. The shape and cathodoluminescence petrography of the Caozhuang quartzite zircons show they resemble those found in immature detrital sedimentary rocks of local provenance or in Eoarchaean polyphase orthog- neisses, and not those in mature quartzites. The Caozhuang quartzite intra-zircon mineral inclusions are dominated by quartz,

关键词： North China CratonCaozhuang quartziteZircon inclusionsEoarchaean rocksArchaean crustal evolution

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Convergent plate boundary environments for formation of≥3800 Ma mafic-ultramafic assemblages(Isua area,Greenland):Implications for early global geodynamics

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Geoscience Frontiers 2024年第3期15卷 119-136页

作者： Allen P.nutman Clark R.L.Friend Vickie C.Bennett School of Earth Atmospheric and Life SciencesUniversity of WollongongWollongongNSW 2522Australia Glendale TiddingtonOxon OX92LQUK Research School of Earth Sciences Australian National UniversityCanberraACT 2601Australia

In the gneiss terrane on the south side of the Eoarchean Isua supracrustal belt,ultramafic rocks with relict abyssal peridotite mineralogy(Bennett et al.,2002;Friend et al.,2002;nutman et al.,2007;Rollinson,2007;van de Löcht et al.,2020),layered gabbros with cumulate ultramafic rocks,basalts and associated siliceous sedimentary rocks were tectonically-imbricated,prior to and during intrusion of ca.3800 Ma *** with3800 Ma basalts in the Outer Arc Group of the nearby Isua supracrustal belt,the composition of all these mafic rocks(e.g.,Th-Hf-Nb systematics,high Th/Yb,Ba/Nb,Ba/Yb ratios and negative Nb and Ti anomalies)shows affinity with modern suprasubduction rocks whose genesis involved fluid fluxing of the upper ***,the majority of these samples have Ba/Nb and Ba/Yb values less than in modern island arc magmas,but similar to many backarc basin magmas(e.g.,Pearce and Stern,2006).It is unknown whether these ca.3800 Ma mafic rocks are,(i)arc rocks where the Ba/Nb and Ba/Yb signatures reflect lower surficial Ba in Eoarchean oceanic settings,or(ii)in direct comparison with Phanerozoic suites,these signatures reflect a back-arc setting with interplay between fluid fluxing and decompressional *** tectonic intercalation of upper mantle with lower and upper crustal rocks,combined with the fluid-fluxing influences seen in chemistry of all the mafic rocks is best accommodated in a compressional Eoarchean convergent plate boundary setting within a mobile-lid *** stagnant lid scenarios of crust formation,if operative,must have co-existed or alternated with mobile-lid regimes by 3800 Ma.

关键词： Eoarchean Fluid-fluxing Plate tectonics Suprasubduction Crustal evolution

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Seeing through the magnetite:Reassessing Eoarchean atmosphere composition from Isua(Greenland) ≥3.7 Ga banded iron formations

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Geoscience Frontiers 2017年第6期8卷 1233-1240页

作者： Allen P.nutman Vickie C.Bennett Clark R.L.Friend GeoQuEST Research Centre School of Earth and Environmental SciencesUniversity of WollongongWollongongNSW 2522Australia Research School of Earth Sciences Australian National UniversityCanberraACT 0200Australia Glendale TiddingtonOxonOX9 2LQUK

Estimates of early atmosphere compositions from metamorphosed banded iron formations(BIFs)including the well-studied ≥3.7 BIFs of the Isua supracrustal belt(Greenland)are dependent on knowledge of primary versus secondary Fe-mineralogical *** new observations from locally well preserved domains,we interpret that a previously assumed primary redox indicator mineral,magnetite,is secondary after sedimentary Fe-clays(probably greenalite)±*** ~3.7 Ga Isua BIF,pre-tectonic nodules of quartz+Fe-rich amphibole±calcite reside in a finegrained(≤100 μm)quartz+magnetite *** interpret the Isua nodule amphibole as the metamorphosed equivalent of primary Fe-rich clays,armoured from diagenetic oxidative reactions by early silica ***,in another low strain lacunae,~3.76 Ga BIF layering is not solid magnetite but instead fine-grained magnetite+quartz *** magnetite+quartz aggregates are interpreted as the metamorphosed equivalent of Fe-clay-rich layers that were oxidised during diagenesis,because they were not armoured by early *** almost all Isua BIF exposures,this evidence has been destroyed by strong ductile *** Fe-clays likely formed by abiotic reactions between aqueous Fe^(2+)and *** clays along with silica±carbonate were deposited below an oceanic Fe-chemocline as the sedimentary precursors of *** of the clays on the sea floor may have been by anaerobic oxidation of Fe^(2+),a mechanism compatible with iron isotopic data previously published on these *** new determinations of the primary redoxsensitive Fe-mineralogy of BIF significantly revise estimates of early Earth atmospheric oxygen and CO_2 content,with formation of protolith Fe-rich clays and carbonates compatible with an anoxic Eoarchean atmosphere with much higher CO_2 levels than previously estimated for Isua and in the present-day atmosphere.

关键词： Banded iron formation Eoarchean Early atmosphere Greenalite Magnetite

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The Mesoproterozoic to early Neoproterozoic passive margin Lajeado Group and Apiaí Gabbro, Southeastern Brazil

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Geoscience Frontiers 2016年第4期7卷 683-694页

作者： G.A.C.Campanha M.S.Basei F.M.Faleiros A.P.nutman Instituto de Geociencias da Universidade de Sao Paulo Brazil School of Earth and Environmental Sciences University of Wollongong Wollongong New South Wales 2500 Australia Beijing SHRIMP Center Chinese Academy of Geological Sciences 26 Baiwzhuang Road Beijing 100037 China

The Lajeado Group in the Ribeira Belt, southeastern Brazil, corresponds to an open-sea carbonate platform, comprised of seven overlapping siliciclastic and carbonatic formations, intruded in its upper portion by the Apiai Gabbro. These rocks have a Neoproterozoic tectonometamorphic overprint related to arc magmatism and the Brasiliano collisional orogeny. Geochronological constraints are given by new U- Pb SHRIMP and LA-ICP-MS data for Lajeado Group detrital zircons and for magmatic zircons from the Apial Gabbro. The youngest detrital zircons in the Lajeado Group are 1400-1200 Ma, and constrain its maximum age of deposition to be 〈1200 Ma, whereas the 877 ~ 8 Ma age for magmatic zircons in the Apiai Gabbro give the minimum age. Detritus source areas are mainly Paleoproterozoic （2200-1800 Ma） with some Archean and Mesoproterozoic contribution （1500-1200 Ma）, with distal or tectonic stable cratonic character. The Lajeado Group should be a Stenian-Tonian carbonate platform passive margin of a continent at this time, namely the Columbia/Nuna or the Rodinia. The Apial Gabbro displays similar age to other intrusive basic rocks in the Lajeado and Itaiacoca groups and represents tholeiitic MORB-like magmatism that we relate to the initial break-up of a Mesoproterozoic continent and the formation of the Brasiliano oceans.

关键词： Mesoproterozoic continent Passive margin Carbonate platform Brasiliano oceans Zircon U-Pb dating

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The Pushtashan juvenile suprasubduction zone assemblage of Kurdistan (northeastern Iraq): A Cretaceous (Cenomanian) Neo-Tethys missing link

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Geoscience Frontiers 2017年第5期8卷 1073-1087页

作者： Sabah A.Ismail Sarmad A.Ali Allen P.nutman Vickie C.Bennett Brain G.Jones Department of Applied Geology College of Sciences Kirkuk University Kirkuk 36001 Iraq GeoQuEST Research Centre School of Earth & Environmental Sciences University of Wollongong Wollongong NSW 2522 Australia Research School of Earth Sciences Australian National University ACT 0200 Australia

The Pushtashan suprasubduction zone assemblage of volcanic rocks, gabbros, norites and peridotites occurs in the Zagros suture zone, Kurdistan region, northeastern Iraq. Volcanic rocks are dominant in the assemblage and consist mainly of basalt and basaltic andesite flows with interlayered red shale and limestone horizons. Earlier lavas tend to be MORB-like, whereas later lavas display island arc tholeiite to boninitic geochemical characteristics. Tholeiitic gabbros intrude the norites and display fractionation trends typical of crystallisation under low-pressure conditions, whereas the norites display calc-alkaline traits, suggesting their source included mantle metasomatised by fluids released from subducted oceanic crust. Enrichment of Rb, Ba, Sr, Th and the presence of negative Nb anomalies indicate generation in a suprasubduction zone setting. Trondhjemite and granodiorite intrusions are present in the volcanic rocks, gabbros and norites. SHRIMP U-Pb dating of magmatic zircons from a granodiorite yields a mean^(206)Pb/^(238)U age of 96.0 ±2.0 Ma(Cenomanian). The initial ε_(Hf) value for the zircons show a narrow range from +12.8 to+15.6, with a weighted mean of + 13.90±0.96. This initial value is within error of model depleted mantle at 96 Ma or slightly below that, in the field of arc rocks with minimal contamination by older continental crust. The compositional bimodality of the Pushtashan suprasubduction sequence suggests seafloor spreading during the initiation of subduction, with a lava stratigraphy from earlyerupted MORB transitioning into calc-alkaline lavas and finally by 96 Ma intrusion of granodioritic and trondhjemitic bodies with juvenile crustal isotopic signatures. The results confirm another Cretaceous arc remnant preserved as an allochthon within the Iraqi segment of the Cenozoic Zagros suture zone. Implications for the closure of Neo-Tethys are discussed.

关键词： Pushtashan suprasubduction assemblage Cretaceous Zircon U-Pb dating Hf isotopes Kurdistan region lraq Neo-Terhys

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淋巴丝虫病和盘尾丝虫病的免疫应答调节

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国外医学（寄生虫病分册） 1992年第2期19卷 72-73页

作者： King CL nutman TB 蒋作君

本文讨论丝虫感染中IL-4,IL-5和IFN-γ诱导速发型变态反应的分子机理与变态反应在对丝虫抗原的免疫及免疫耐受中的作用,并借此解释某些个体对丝虫感染削弱的免疫应答和持续的微丝蚴状态。

关键词：淋巴丝虫病盘尾丝虫病免疫调节

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中国最老岩石和锆石

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岩石学报 2009年第8期25卷 1793-1807页

作者：万渝生刘敦一董春艳 nutman A Wilde SA 王伟颉颃强殷小艳周红英中国地质调查局天津地质矿产研究所澳大利亚科汀大学应用地质系北京离子探针中心中国地质科学院地质研究所

在中国大陆的许多地区都已发现大于3.4Ga的锆石和岩石。鞍山是全球仅有几个存在≥3.8Ga岩石的地区之一。它们以不大的规模存在于白家坟、东山、深沟寺杂岩中,由糜棱岩化奥长花岗岩、奈带状奥长花岗岩和变质石英闪长岩组成。近年来,在鞍... 详细信息

在中国大陆的许多地区都已发现大于3.4Ga的锆石和岩石。鞍山是全球仅有几个存在≥3.8Ga岩石的地区之一。它们以不大的规模存在于白家坟、东山、深沟寺杂岩中,由糜棱岩化奥长花岗岩、奈带状奥长花岗岩和变质石英闪长岩组成。近年来,在鞍山地区还发现了许多3.7～3.6Ga岩石和锆石。锆石Hf同位素组成表明鞍山地区在3.8～3.6Ga期间存在周期性的地幔添加和陆壳形成。除鞍山外,在中国许多地区的不同类型岩石中也获得了≥3.4Ga锆石,虽然它们大多数都是碎屑和残余成因。(1)华北克拉通冀东铬云母石英岩中3.85～3.55Ga碎屑锆石;(2)华北克拉通信阳中生代火山岩长英质麻粒岩中3.66Ga岩浆锆石;(3)华南克拉通宜昌地区杨子地块新元古代砂岩中3.80Ga碎屑锆石(一颗);(4)华南克拉通华夏地块新元古代-古生代变质沉积岩中3.76～3.6Ga碎屑锆石;(5)西北地区塔里木地块阿克塔什塔格地区古元古代片麻状花岗岩中3.6Ga残余锆石;(6)西秦岭奥陶纪变质火山岩中4.08Ga捕掳锆石(一颗);(7)西藏普兰地区奥陶纪石英岩中4.1Ga碎屑锆石(一颗,有3.61Ga增生边)。一些古老锆石有高达4.1～4.0Ga的Hf同位素模式年龄。在中国,>3.4Ga地壳物质的比例以往被低估了,发现冥古宙和始太古代物质的可能性仍然存在,它们将对中国早期陆壳演化提供新的制约。

关键词：最古老岩石最古老锆石中国早期地壳演化锆石定年 Hf同位素

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冀东青龙地区新太古代朱杖子群和单塔子群形成时代:锆石SHRIMP U-Pb定年

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地质论评 2010年第6期56卷 888-898页

作者：孙会一董春艳颉颃强王伟马铭株刘敦一 Allen nutman 万渝生中国地质科学院地质研究所北京离子探针中心北京100037

本文报道了冀东青龙地区新太古代朱杖子群和单塔子群变质岩的锆石SHRIMP U-Pb定年结果。朱杖子群底部张家沟组砾岩中的TTG砾石、花岗岩砾石和基质的岩浆锆石207Pb/206Pb加权平均年龄分别为2515±9Ma(MSWD=1.9)、2510±10Ma(MSWD=1.6)和2... 详细信息

本文报道了冀东青龙地区新太古代朱杖子群和单塔子群变质岩的锆石SHRIMP U-Pb定年结果。朱杖子群底部张家沟组砾岩中的TTG砾石、花岗岩砾石和基质的岩浆锆石207Pb/206Pb加权平均年龄分别为2515±9Ma(MSWD=1.9)、2510±10Ma(MSWD=1.6)和2512±7Ma(MSWD=1.0),朱杖子群底部张家沟组黑云斜长片麻岩碎屑锆石207Pb/206Pb加权平均年龄为2540±6Ma(MSWD=1.6),朱杖子群桲罗台组变质酸性火山岩岩浆锆石207Pb/206Pb加权平均年龄为2516±8Ma(MSWD=1.1),单塔子群鲁杖子组黑云变粒岩碎屑锆石207Pb/206Pb加权平均年龄为2504±7Ma(MSWD=1.8),另有一个数据点的207Pb/206Pb年龄为3.04Ga。根据本文定年结果和前人资料,获得主要结论如下:朱杖子群和单塔子群形成于新太古代晚期,很可能为岛弧环境的产物;朱杖子群与下伏单塔子群之间虽存在角度不整合关系,但时间间断不长,朱杖子群底部张家沟组砾岩不具有底砾岩性质;③绿片岩相—角闪岩相的朱杖子群和单塔子群与角闪岩相—麻粒岩相的遵化深变质绿岩带—三屯营—太平寨—迁安岩浆杂岩区变质程度差异很大,但形成时代相同,是后期构造作用把它们置于同一地壳平面。

关键词：朱杖子群单塔子群冀东新太古代 SHRIMP定年

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西澳大利亚纳里耶片麻岩杂岩的高敏度质谱分辨离子探针U-Pb锆石地质年代学

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国外前寒武纪地质 1992年第1期 23-46页

作者： A.P.nutman P.D.Kinny 孙淑芬

澳大利亚伊尔岗克拉通的纳里耶片麻岩杂岩的高敏度质谱分辨离子探针(SHRIMP)U-Pb锆石地质年代学已经进一步证明。该区的东半部含有丰富的早太古代片麻岩(3300-3730Ma),而且在其西半部发现了只有3000Ma或小3000Ma的片麻岩。在研究程度较... 详细信息

澳大利亚伊尔岗克拉通的纳里耶片麻岩杂岩的高敏度质谱分辨离子探针(SHRIMP)U-Pb锆石地质年代学已经进一步证明。该区的东半部含有丰富的早太古代片麻岩(3300-3730Ma),而且在其西半部发现了只有3000Ma或小3000Ma的片麻岩。在研究程度较高的纳里耶片麻岩杂岩的南部地区,早太古代片麻岩被划分为埃乌拉达(Eurada)片麻岩组合(最老的岩石为3490Ma)和努卡瓦拉片麻岩组合(最老的岩石为3730Ma)。在这两个组合中,只有最老的岩石是英闪质的,而所有较年轻的岩石是花岗闪长质或花岗质的。这两个组合,虽然构造上可能并列在一起,但直到发生3280-3300Ma的花岗岩和伟晶岩侵位为止,却表现为不同的演化历史。人们发现这两个片麻岩组合与纳里耶上壳岩组合呈互层,上壳岩组合含有丰富的富含石英的碎屑沉积岩。该岩石组合的最大露头形成了纳里耶山和杰克山(Jack HilIs),该区沉积物内少部分碎屑锆石年龄>4000Ma。碎屑锆石年龄数目(Populations)在纳里耶上壳岩组合中因样品而异。这些年龄数目的分析表明,除去3800—4280Ma的锆石因物源尚不知道外,其它碎屑锆石均以不同比例来源于努卡瓦拉和埃乌拉达片麻岩组合岩石。早太古代片麻岩组合之间的原始关系,由于几期花岗岩岩席的侵入作用,其与纳里耶上壳岩呈夹层以及2750Ma和2620Ma之间的褶皱,之后又伴随有太古宙末期或元古宙的近垂直剪切带运动,而面目全非。晚太古代事件与整个伊尔岗克拉通的事件完全相似,并且认为可能在几个不同的幕中通过地体组合伴随着克拉通的增长。

关键词：片麻岩杂岩离子探针 U-Pb锆石

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