Eocene and pliocene outliers between Chipstead and Headley,Surrey     

A.W. Groves 《Proceedings of the Geologists' Association. Geologists' Association》1928,39(4):471-485

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LZIFU: an emission-line fitting toolkit for integral field spectroscopy data     

I-Ting Ho  Anne M. Medling  Brent Groves  Jeffrey A. Rich  David S. N. Rupke  Elise Hampton  Lisa J. Kewley  Joss Bland-Hawthorn  Scott M. Croom  Samuel Richards  Adam L. Schaefer  Rob Sharp  Sarah M. Sweet 《Astrophysics and Space Science》2016,361(9):280

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Advances in SHRIMP geochronology and their impact on understanding the tectonic and metallogenic evolution of southern Brazil     

L. A. Hartmann  J. A. D. Leite  L. C. Da Silva  M. V. D. Remus  N. J. McNaughton  D. I. Groves 《Australian Journal of Earth Sciences》2013,60(5):829-844

Significant improvements, both in understanding the evolution of zircons and in understanding the geotectonic and metallogenetic evolution of the complex terrain of southern Brazil, are obtained from a SHRIMP geochronology study and reviewed in this paper. The use of backscattered electron and cathodoluminescence images, prior to SHRIMP isotopic determinations, proved of enormous fundamental value for this technique. Zircon is a domainal open‐system mineral in many geological conditions; very old domains may be preserved, but the same crystal may show ages of younger tectonic events. Zircons may recrystallise inwards from the rims or outwards from the cores, and also along euhedral high‐U or metamict thin zones. Zircons also may be recrystallised during gold‐related hydrothermalism, phyllic alteration of granitic rocks. The precise dating of amphibolite dykes can be achieved by the identification and dating of magmatic zircons. Precambrian orogenies are identified along with the intervening intracratonic tectonic cycles of supercontinents in southern Brazil from 3300 to 470 Ma. Granulite protoliths were formed during the Jequié Orogeny (ca 2600 Ma), but extensive arc accretion occurred in the Palaeoproterozoic (ca 2250 Ma) Encantadas Orogeny. Late in the Transamazonian Cycle, granites were formed by crustal melting at about 2000 Ma in the Camboriú Orogeny. Both accretionary and collisional orogenies are also identified in the Neoproterozoic Brasiliano Cycle. These are the accretionary Passinho Orogeny (ca 900 Ma) and São Gabriel Orogeny (ca 700 Ma), that were succeeded by the collisional Dom Feliciano Orogeny (ca 600 Ma). Base‐metal and gold deposition occurred in juvenile island arcs and in late orogenic porphyry‐copper‐type magmatic‐hydrothermal settings during the Neoproterozoic.  相似文献   

Lead ages,reset rubidium-strontium ages and implications for the Archaean crustal evolution of the Diemals area,Central Yilgarn Block,Western Australia     

M.J Bickle  H.J Chapman  L.F Bettenay  D.I Groves  J.R de Laeter 《Geochimica et cosmochimica acta》1983,47(5):907-914

The Pb-Pb whole-rock geochronology of Archaean granitic and gneissic rocks from the Diemals area in the Central Yilgarn granite-greenstone terrain provides important constraints on crustal evolution. The regionally extensive banded gneisses, previously considered as candidates for basement to the greenstones give a Pb-Pb whole-rock age of 2700 ± 97 Ma (2σ errors). This is within error of previously published Rb-Sr and Sm-Nd gneiss ages and also within error of the Sm-Nd ages on the greenstones in the Eastern Goldfields Province. Two synkinematic plutons give Pb-Pb whole-rock ages (2737 ± 62 Ma and 2700 ± 100 Ma) and Pb isotopic compositions consistent with the hypothesis, based on field and geochemical relations, that these plutons were derived by partial melting of the precursors to the banded gneisses. Assuming this, the combined data date the melting event at 2723 ± 25 Ma with a model source μ value of 8.18 ± 0.02. This source μ value is close to the range postulated for mantle values and restricts the crustal history of the precursors to less than ~200 Ma. A post-kinematic pluton with a whole-rock Pb-Pb age of 2685 ± 26 Ma and μ value of 8.26 ± 0.02 puts a younger limit on this relatively short lived crustal accretion-differentiation event.Comparison of Pb-Pb and Rb-Sr whole-rock dates for the plutons suggests that the latter became closed systems up to 200 Ma after the Pb-Pb ages, and that the plutons gained or lost Rb or Sr at this time.  相似文献   

Single zircon U-Pb dating of the Kongling high-grade metamorphic terrain: Evidence for >3.2 Ga old continental crust in the Yangtze craton   总被引：4，自引：0，他引：4  

Shan Gao  Yumin Qiu  Wenli Ling  McNaughton Neal J.  Groves David I. 《中国科学D辑(英文版)》2001,44(4):326-335

Single zircons from two trondhjemitic gneisses and two clastic metasedimentary rocks without Eu anomaly of the Kongling high-grade metamorphic terrain are dated by thein situSHRIMP U-Pb method. The results show that the trondhjemitic magma emplaced at 2947-2903 Ma. Concordant age of as old as 3.3 Ga is present in the detrital zircons from the clastic metasedimentary rocks. Together with the depleted mantle Nd model age (T_DM =3.2-3.3 Ga) of the clastic metasedimentary rocks, this documents the presence of Paleoarchean continental crust in the Yangtze craton.  相似文献   

澳大利亚纳沃日金矿流体混合与金的成矿作用   总被引：9，自引：0，他引：9  

范宏瑞  D I Groves  E J Mikuckj  N J McNaughton 《矿床地质》2001,20(1):37-43

流体包裹体研究表明，纳沃日金矿成矿脉体中流体包裹体类型有三种，富CH4、CH4－CO2－H2O和富H2O包裹体。初始成矿流体是富CH4热液，在主矿化阶段，另一来源的CO2－H2O流体与CH4流体发生了不均匀混合，并且在石英－磁黄铁矿阶段最为强烈，造成不同矿化部位的xCH4变化极大，早期近于纯CH4流体被充分“稀释”后，石英－黄铁矿阶段的xCH4显著减小，到成矿晚期只剩CO2－H2O流体。正是由于不同性质流体的混合，造成热液的pH及fo2的升高，流体中的金－硫络合物分解，金沉淀成矿。  相似文献   

Abiologial origin of described stromatolites older than 3.2 Ga     

Buick R  Groves DI  Dunlop JS 《Geology》1995,23(2):191

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Architecture and emplacement of the Nebo–Babel gabbronorite-hosted magmatic Ni–Cu–PGE sulphide deposit,West Musgrave,Western Australia     

Zoran Seat  Stephen W. Beresford  Benjamin A. Grguric  Rob S. Waugh  Jon M. A. Hronsky  M. A. Mary Gee  David I. Groves  Charter I. Mathison 《Mineralium Deposita》2007,42(6):551-581

The Nebo–Babel Ni–Cu–platinum-group element (PGE) sulphide deposit in the West Musgrave Block, Western Australia, is the largest nickel sulphide discovery in the last 10 years. The deposit is hosted within a concentrically zoned, olivine-free, tube-like (chonolithic), gabbronorite intrusion associated with the, approximately, 1,078-Ma Giles Complex-layered intrusions in the Warakurna large igneous province. Emplaced into sulphide-free amphibolite facies orthogneiss, the fault-offset Nebo–Babel chonolith extends for 5 km and has a cross-section of 1 × 0.5 km. Igneous mineralogy, fabrics, and textures are well preserved. The lithostratigraphy includes variably textured leucogabbronorites (VLGN) that form an outer shell around mineralised gabbronorite (MGN), with barren gabbronorite (BGN) and oxide–apatite gabbronorite (OAGN) in the middle and lower parts of the chonolith. Mineral and whole-rock geochemistry indicate that the units become progressively evolved in the order: VLGN, MGN, BGN, and OAGN, and that incompatible trace-element concentrations increase downwards within the MGN and BGN. The mineralisation, which is confined to the early, more primitive units (VLGN and MGN), occurs as massive sulphide breccias and stringers and as disseminated gabbronorite-hosted sulphides. The massive sulphides were emplaced late in the intrusive sequence, have different PGE chemistry and Cu tenor to the disseminated sulphides, and have undergone sulphide fractionation. The distribution of disseminated sulphides, which are primary magmatic in origin, is related to chonolith geometry and magma flow regimes, rather than to gravitational settling. Sulfur-bearing country rocks are absent in the Nebo–Babel deposit area, and thus, local crustal S addition was unlikely to have been the major mechanism in achieving sulphide immiscibility. The Nebo–Babel intrusion is part of an originally continuous magma chonolith with multiple and related magma pulses. The parental magma was medium- to low-K tholeiite with 8–9 wt% MgO. The initial magma pulse (VLGN), the most primitive and sulphide saturated, was probably emplaced along a linear weakness in the country rock. After crystallisation of VLGN, marginally more fractionated, sulphide-saturated magma was injected through the thermally insulated core of the conduit, forming the MGN. Successive pulse(s) of more fractionated magma (BGN) were emplaced in the core of the intrusion. After magma flow ceased, closed system crystal fractionation produced consistent mineral and chemical fractionation trends within BGN and OAGN. After crystallisation, the intrusion was overturned and then offset by the Jameson Fault resulting in the apparent ‘reverse’ chemical and mineral trends in Nebo–Babel.  相似文献   

冀东都山花岗岩基及相关花岗斑岩脉SHRIMP锆石U-Pb法定年及其意义   总被引：22，自引：1，他引：22  

罗镇宽  苗来成  关康  裘有守  Y.M.Qiu  N.J.McNaughton  D.I.Groves 《地球化学》2003,32(2):173-180

都山花岗岩体是冀东地区最大的花岗岩基,在其周边产有众多与其有关的“卫星”岩体和岩脉。采用先进的SHRIMP定年方法,测得都山花岗岩基的206Pb/238U年龄为(223±2)Ma,其东侧三家金矿区成矿前花岗斑岩脉的年龄为(222±4)Ma,二者在误差范围内一致,花岗岩基和花岗斑岩脉可视为同一次岩浆活动的产物。这种晚古生代末—早中生代印支期的花岗岩在华北克拉通北缘广泛分布,显示它是一次重要的构造-岩浆事件的产物。根据岩石化学和微量元素特征及有关判别图,都山等印支期花岗岩可能属中朝板块与西伯利亚板块碰撞造山作用的后碰撞花岗岩。花岗斑岩脉中发现有新太古代的继承锆石,表明花岗斑岩的部分源岩为区内新太古代八道河岩群变质岩。都山花岗岩与花岗斑岩脉同时、同源,推测其源岩也有部分为新太古代结晶基底的变质岩。花岗岩与区内金矿化有较大的时差,两者不存在直接的成因联系,仅表明成矿晚于早中生代印支期。  相似文献   

金厂沟梁—二道沟金矿田内花岗岩类侵入体锆石的离子探针U—Pb年代及意义   总被引：13，自引：5，他引：13  

苗来成  范蔚茗  翟明国  Qiu Y M  McNaughton N J  Groves D I 《岩石学报》2003,19(1):71-80

金厂沟梁-二道沟金矿田内花岗岩类侵入体SHRIMP锆石U-Ph定年结果表明,该区中生代以来到少经历了三次中酸性岩浆侵入作用,它们分别以西台子二长花岗岩、娄上含辉石石英闪长岩和西对面沟花岗闪长岩及闪长玢岩脉在218±4Ma(印支期)、161±1Ma(燕山早期)和126±1Ma(燕山晚期)的侵位为标志。花岗岩类的地球化学资料表明,这些花岗岩类侵入体形成与造山作用有关,为造山后或陆内拉张作用的产物。二道沟矿区成矿前或成矿期闪长玢岩脉的年龄126±1Ma限定了该区金矿化的最大年龄;结合前人有关年代学资料,认为本区金矿化应发生在126～118Ma。这说明金厂沟梁-二道沟金矿田的金矿床与我国胶东、小秦岭和辽东等地区的金矿床是同时形成的,再次证明燕山晚期是中国最重要而广泛的金成矿期。此外,在这些主要的金矿区内,金矿化时间上均具有与各自区内最晚一次花岗质岩浆作用同时或稍晚的特征,这可能指示金矿床是造山作用或区域构造-岩浆演化最晚期的产物。  相似文献