scholarly journals Zircon at the Nanoscale Records Metasomatic Processes Leading to Large Magmatic–Hydrothermal Ore Systems

Minerals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 364 ◽  
Author(s):  
Courtney-Davies ◽  
Ciobanu ◽  
Verdugo-Ihl ◽  
Slattery ◽  
Cook ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
South Australia ◽  
Dark Field ◽  
Oscillatory Zoning ◽  
Irradiation Damage ◽  
Magmatic Zircon ◽  
Time Interval ◽  
Nanoscale Structures ◽  
Inductively Coupled ◽  
Scanning Transmission

The petrography and geochemistry of zircon offers an exciting opportunity to better understand the genesis of, as well as identify pathfinders for, large magmatic–hydrothermal ore systems. Electron probe microanalysis, laser ablation inductively coupled plasma mass spectrometry, high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) imaging, and energy-dispersive X-ray spectrometry STEM mapping/spot analysis were combined to characterize Proterozoic granitic zircon in the eastern Gawler Craton, South Australia. Granites from the ~1.85 Ga Donington Suite and ~1.6 Ga Hiltaba Suite were selected from locations that are either mineralized or not, with the same style of iron-oxide copper gold (IOCG) mineralization. Although Donington Suite granites are host to mineralization in several prospects, only Hiltaba Suite granites are considered “fertile” in that their emplacement at ~1.6 Ga is associated with generation of one of the best metal-endowed IOCG provinces on Earth. Crystal oscillatory zoning with respect to non-formula elements, notably Fe and Cl, are textural and chemical features preserved in zircon, with no evidence for U or Pb accumulation relating to amorphization effects. Bands with Fe and Ca show mottling with respect to chloro–hydroxy–zircon nanoprecipitates. Lattice defects occur along fractures crosscutting such nanoprecipitates indicating fluid infiltration post-mottling. Lattice stretching and screw dislocations leading to expansion of the zircon structure are the only nanoscale structures attributable to self-induced irradiation damage. These features increase in abundance in zircons from granites hosting IOCG mineralization, including from the world-class Olympic Dam Cu–U–Au–Ag deposit. The nano- to micron-scale features documented reflect interaction between magmatic zircon and corrosive Fe–Cl-bearing fluids in an initial metasomatic event that follows magmatic crystallization and immediately precedes deposition of IOCG mineralization. Quantification of α-decay damage that could relate zircon alteration to the first percolation point in zircon gives ~100 Ma, a time interval that cannot be reconciled with the 2–4 Ma period between magmatic crystallization and onset of hydrothermal fluid flow. Crystal oscillatory zoning and nanoprecipitate mottling in zircon intensify with proximity to mineralization and represent a potential pathfinder to locate fertile granites associated with Cu–Au mineralization.

Relationship between elemental concentration and age from otoliths of adult snapper (Pagrus auratus, Sparidae): implications for movement and stock structure

2005 ◽  
Vol 56 (5) ◽  
pp. 661 ◽  
Author(s):  
A. J. Fowler ◽  
B. M. Gillanders ◽  
K. C. Hall
Keyword(s):  
Mass Spectrometry ◽  
Inductively Coupled Plasma ◽  
Elemental Concentration ◽  
South Australia ◽  
Stock Structure ◽  
Habitat Types ◽  
Inductively Coupled ◽  
Age Related ◽  
Pagrus Auratus ◽  
Plasma Mass Spectrometry

The present study investigated the stock structure of snapper (Pagrus auratus) in South Australia, and the extent to which this is influenced by adult movement. Fish from the 9+ age class were sampled from six different regions, encompassing >2000 km of coastline and different habitat types. The chemistry of transverse sections of otoliths was sampled using laser ablation inductively coupled plasma-mass spectrometry, providing elemental profiles that were related to age for the first nine years of the fish’s lives. The age-related annual averages for both 88Sr and 138Ba differed significantly between regions. They were, however, similar for the first three years, then diverged considerably between the ages of three to five years, and then remained consistently different through to the age of nine years. This suggests that all fish, regardless of where captured, originated from only one or two nursery areas, but dispersed throughout the different regions between the ages of three to five years, before becoming resident to their new regions of occupancy. Thus, this population of snapper represents a single, large, stock where the individuals have a common origin, but through age-related emigration ultimately disperse and supplement the low abundance populations in regional State waters.

A Palaeoarchean–Mesoarchean micro-continent entrained in the Jiao-Liao-Ji Belt at the southeastern North China Craton: evidence from the zircon record in the Bengbu area

2019 ◽  
Vol 156 (9) ◽  
pp. 1565-1586 ◽  
Author(s):  
Chaohui Liu ◽  
Guochun Zhao ◽  
Fulai Liu ◽  
Jia Cai
Keyword(s):  
Trace Element ◽  
North China Craton ◽  
Inductively Coupled Plasma ◽  
North China ◽  
Detrital Zircons ◽  
Magmatic Zircon ◽  
Inductively Coupled ◽  
Multi Stage ◽  
Plasma Mass Spectrometry ◽  
Trace Element Contents

AbstractThe Bengbu area in the southeastern North China Craton (NCC) consists predominantly of Archean–Palaeoproterozoic (gneissic) granitoids with minor supracrustal rocks (the Fengyang and Wuhe groups). This study presents new zircon laser ablation – inductively coupled plasma – mass spectrometry U–Pb and Lu–Hf isotopic data and trace-element contents for these granitoids, which improve understanding the Archean–Palaeoproterozoic crustal evolution of the NCC. Magmatic zircon U–Pb data reveal that zircons in the (gneissic) granitoids were generated by multi-stage events at 2.93, 2.73, 2.53–2.52 and 2.18–2.13 Ga. Metamorphic zircon U–Pb data obtained from these rocks show two distinct metamorphic ages of 2.49–2.52 and 1.84 Ga, suggesting that the Bengbu area experienced a regional metamorphic event at the end of the Neoarchean Era and encountered reworking by a tectonothermal event associated with the formation of the Palaeoproterozoic Jiao-Liao-Ji Belt. Trace-element compositions of magmatic zircons reveal the highest Ti concentrations (8.08±3.38 ppm) and growth temperatures (718±44 °C) for the zircons aged 2.13–2.17 Ga and an increase in zircon U/Yb ratios from 2.93 Ga (0.34±0.12) through 2.73 Ga (0.96±0.42) to 2.53 Ga (1.05±0.46), but an evident decrease at 2.17–2.13 Ga (0.61±0.40 ppm). Similar Palaeoarchean xenocrystic and detrital zircons with negativeɛHf(t) values, late Mesoarchean magmatic zircons with juvenile Hf isotopic features, early Neoarchean magmatic zircons with model ages of 2.9–3.0 Ga, and two regional metamorphic events at 2.52–2.48 and 1.88–1.80 Ga in the Bengbu and Jiaobei areas indicate a Palaeoarchean–Mesoarchean micro-continent entrained in the Jiao-Liao-Ji Belt at the southeastern NCC.

scholarly journals Silician Magnetite: Si–Fe-Nanoprecipitates and Other Mineral Inclusions in Magnetite from the Olympic Dam Deposit, South Australia

Minerals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 311 ◽  
Author(s):  
Cristiana L. Ciobanu ◽  
Max R. Verdugo-Ihl ◽  
Ashley Slattery ◽  
Nigel J. Cook ◽  
Kathy Ehrig ◽  
...  
Keyword(s):  
South Australia ◽  
Dark Field ◽  
Ore Deposits ◽  
Spinel Type ◽  
Diverse Range ◽  
Scanning Transmission ◽  
Copper Gold ◽  
Annular Dark Field ◽  
Definition Of ◽  
Olympic Dam

A comprehensive nanoscale study on magnetite from samples from the outer, weakly mineralized shell at Olympic Dam, South Australia, has been undertaken using atom-scale resolution High Angle Annular Dark Field Scanning Transmission Electron Microscopy (HAADF STEM) imaging and STEM energy-dispersive X-ray spectrometry mapping and spot analysis, supported by STEM simulations. Silician magnetite within these samples is characterized and the significance of nanoscale inclusions in hydrothermal and magmatic magnetite addressed. Silician magnetite, here containing Si–Fe-nanoprecipitates and a diverse range of nanomineral inclusions [(ferro)actinolite, diopside and epidote but also U-, W-(Mo), Y-As- and As-S-nanoparticles] appears typical for these samples. We observe both silician magnetite nanoprecipitates with spinel-type structures and a γ-Fe1.5SiO4 phase with maghemite structure. These are distinct from one another and occur as bleb-like and nm-wide strips along d111 in magnetite, respectively. Overprinting of silician magnetite during transition from K-feldspar to sericite is also expressed as abundant lattice-scale defects (twinning, faults) associated with the transformation of nanoprecipitates with spinel structure into maghemite via Fe-vacancy ordering. Such mineral associations are characteristic of early, alkali-calcic alteration in the iron-oxide copper gold (IOCG) system at Olympic Dam. Magmatic magnetite from granite hosting the deposit is quite distinct from silician magnetite and features nanomineral associations of hercynite-ulvöspinel-ilmenite. Silician magnetite has petrogenetic value in defining stages of ore deposit evolution at Olympic Dam and for IOCG systems elsewhere. The new data also add new perspectives into the definition of silician magnetite and its occurrence in ore deposits.

Genetic significance of zircon in orthogneisses from Sierra Nevada (Betic Cordillera, Spain)

2017 ◽  
Vol 81 (1) ◽  
pp. 77-101 ◽  
Author(s):  
M. D. Ruiz-Cruz ◽  
C. Sanz de Galdeano
Keyword(s):  
Sierra Nevada ◽  
Inductively Coupled Plasma ◽  
Morphological Changes ◽  
Betic Cordillera ◽  
Geodynamic Setting ◽  
Magmatic Zircon ◽  
Common Source ◽  
Inductively Coupled ◽  
Model Based ◽  
Complete Study

AbstractZircon from two types of orthogneisses (inheritance-rich and inheritance-poor) from Sierra Nevada (Betic Cordillera, Spain) was investigated by integrating U–Pb geochronology, cathodoluminescence and back-scattered SEM imaging, laser-ablation inductively coupled plasma mass spectrometry analyses and Raman spectroscopy to examine the conditions of magmatic zircon growth and the variable extent and mechanisms of the Alpine modifications. Zircon from inheritance-rich gneiss consists of two main domains: inherited (Neoproterozoic-to-Early Paleozoic and Devonian) cores and magmatic overgrowths, which provided 206Pb/238U concordant ages of 286 ± 3 Ma. In inheritance-poor gneiss, zircons consist of magmatic cores and very altered rims defining a discordia with an upper intercept with the Concordia at 287 + 21 –22 Ma and a lower intercept at 20.8 + 48.6 –20.8 Ma. Magmatic domains of zircon from inheritance-rich gneiss have lower rare-earth element (REE) contents than magmatic domains from inheritance-poor gneiss, reflecting the less evolved nature of the melt. Altered domains in zircon from inheritance-poor gneisss how greater U concentrations, lower REE concentrations and lower Th/U ratios relative to the cores, interpreted as representing Pb loss from the U-rich magmatic domains during the Alpine event. Morphological changes within single grains and between populations reflects the evolution during magmatic cooling. We show that, whereas classic methods allow two different interpretations for the geodynamic setting of the two types of gneisses, a complete study of composition, morphology and structure of zircon can help to decide that a model based on a common source for the granitic melt better fits the zircon characteristics than a model based on melts generated in two different geotectonic settings.

scholarly journals Tetrameric Aryl Palladium Bromide Intermediates Leading to Facile Transmetalation in Suzuki–Miyaura Cross-Couplings with Pd@MIL-101-NH2(Cr)

2021 ◽  
Author(s):  
Alejandro Valiente ◽  
Cheuk-Wai Tai ◽  
Mårten Ahlquist ◽  
Belén Martín-Matute
Keyword(s):  
Inductively Coupled Plasma ◽  
Density Functional ◽  
Nuclear Magnetic Reso ◽  
Coupling Reaction ◽  
Optical Emission ◽  
Ionization Mass ◽  
Activation Free Energy ◽  
Inductively Coupled ◽  
Cross Coupling Reaction ◽  
Scanning Transmission

The composition and structure of catalytic intermediates in the context of the Suzuki–Miyaura cross-coupling reaction cata-lyzed by Pd@MIL-101-NH2(Cr) has been investigated. Trimeric and tetrameric palladium species with formula [Br-Pd-Ar]nBr- (n = 3–4) have been identified by electrospray ionization mass spectrometry (ESI-MS) and density-functional theory (DFT) calculations, and their role in the transmetalation step has been studied. The weak nature of the bonds between Pd and the bridging halides in these species enables a very easy transmetalation step, with an estimated activation free energy of only 10 kcal/mol. Further experimental support for Pd speciation was obtained using scanning transmission electron micros-copy (STEM), inductively coupled plasma-optical emission spectroscopy (ICP-OES), and fluorine-19 nuclear magnetic reso-nance spectroscopy (19F NMR).

scholarly journals Formation of nanoscale structures by inductively coupled plasma etching

2013 ◽  
Author(s):  
Colin C. Welch ◽  
Deirdre L. Olynick ◽  
Zuwei Liu ◽  
Anders Holmberg ◽  
Christophe Peroz ◽  
...  
Keyword(s):  
Plasma Etching ◽  
Inductively Coupled Plasma ◽  
Nanoscale Structures ◽  
Inductively Coupled Plasma Etching ◽  
Inductively Coupled

Tectonic significance of the Variscan suture between Brunovistulia and the Bohemian Massif

2020 ◽  
pp. jgs2020-176
Author(s):  
S. Collett ◽  
P. Štípská ◽  
K. Schulmann ◽  
J. Míková ◽  
A. Kröner
Keyword(s):  
Bohemian Massif ◽  
Inductively Coupled Plasma ◽  
Sensu Stricto ◽  
Geochemical Data ◽  
Magmatic Zircon ◽  
Analytical Methodology ◽  
Content Type ◽  
Inductively Coupled ◽  
Single Zircon ◽  
Supplementary Material

The Velké Vrbno Dome crops-out at the boundary between the Brunovistulian Terrane and the internal parts of the Bohemian Massif. Here, eclogite boudins occur within an Ediacaran volcano-sedimentary sequence. Strong Nb depletion (Nb/Nb* = 0.19 – 0.82) combined with moderately positive Nd isotopic compositions (εNd(i) = +3.89 – +5.77) are used to argue for emplacement of the eclogite protoliths in a transitional supra-subduction to continental-rift setting. Conversely, heterogeneously enriched large ion lithophile elements and highly radiogenic Sr isotopic ratios (87Sr/86Sr = 0.705–0.720) are interpreted to have been modified following fluid infiltration subsequent to eclogite-facies metamorphism.U-Pb laser ablation inductively coupled plasma mass spectrometry dating of magmatic zircon from the rift-type eclogite indicates Early Cambrian emplacement (c.535 Ma) following episodic Ediacaran volcanic arc activity. Moreover, a continental setting is emphasised by zircon dating of a mylonitic orthogneiss, revealing a fragment of Palaeoproterozoic (c.2000 Ma) basement, the first such finding within the Brunovistulian Terrane sensu stricto.The new data from eclogite confirm that rifting in this segment of Gondwana pre-dated the Ordovician opening of the Rheic Ocean and therefore that the suture between Brunovistulia and the rest of the Bohemian Massif likely represents the vestige of an older hyperextended basin or oceanic tract.Supplementary material: Previously unpublished single zircon evaporation ages from Ediacaran orthogneiss from the Velké Vrbno Dome (supplement A); detailed analytical methodology (supplement B); whole rock geochemical data (supplement C); and U-Pb LA-ICP-MS zircon data (supplement d). https://doi.org/10.6084/m9.figshare.c.5233079

scholarly journals Crystals from the Powellite-Scheelite Series at the Nanoscale: A Case Study from the Zhibula Cu Skarn, Gangdese Belt, Tibet

Minerals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 340 ◽  
Author(s):  
Jing Xu ◽  
Cristiana L. Ciobanu ◽  
Nigel J. Cook ◽  
Ashley Slattery
Keyword(s):  
Solid Solution ◽  
Rare Earth ◽  
Inductively Coupled Plasma ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Growth Direction ◽  
Dark Field ◽  
Atomic Scale ◽  
Oscillatory Zoning ◽  
Compositional Range

Scheelite (CaWO4) and powellite (CaMoO4) are isostructural minerals considered as a non-ideal solid solution series. Micron- to nanoscale investigation of a specimen of skarnoid from Zhibula, Gangdese Belt, Tibet, China, was carried out to assess the identity of the phases within a broad scheelite-powellite (Sch-Pow) compositional range, and to place additional constraints on redox changes during ore formation. An electron probe microanalysis shows that Mo-rich domains within complex oscillatory-zoned single crystals, and as thin sliver-like domains, have a compositional range from 20 mol.% to 80 mol.% Pow. These occur within a matrix of unzoned, close-to-end-member scheelite aggregates (87 mol.%–95 mol.% Sch). Laser-ablation inductively coupled plasma mass spectrometry spot analysis and element mapping reveal systematic partitioning behaviour of trace elements in skarn minerals (grossular50, diopside80, anorthite, and retrograde clinozoisite) and scheelite-powellite aggregates. The Mo-rich domains feature higher concentrations of As, Nb, and light rare earth elements LREE, whereas W-rich domains are comparatively enriched in Y and Sr. Transmission electron microscopy (TEM) was carried out on focused-ion-beam-prepared foils extracted in situ from domains with oscillatory zoning occurring as slivers of 20 mol.%–40 mol.% Pow and 48 mol.%–80 mol.% Pow composition within an unzoned low-Mo matrix (20 mol.% Pow). Electron diffractions, high-angular annular dark field (HAADF) scanning-TEM (STEM) imaging, and energy-dispersive spectroscopy STEM mapping show chemical oscillatory zoning with interfaces that have continuity in crystal orientation throughout each defined structure, zoned grain or sliver. Non-linear thermodynamics likely govern the patterning and presence of compositionally and texturally distinct domains, in agreement with a non-ideal solid solution. We show that the sharpest compositional contrasts are also recognisable by variation in growth direction. Atomic-scale resolution imaging and STEM simulation confirm the presence of scheelite-powellite within the analysed range (20 mol.%–80 mol.% Pow). Xenotime-(Y) inclusions occur as nm-wide needles with epitaxial orientation to the host scheelite-powellite matrix throughout both types of patterns, but no discrete Mo- or W-bearing inclusions are observed. The observed geochemical and petrographic features can be reconciled with a redox model involving prograde deposition of a scheelite+molybdenite assemblage (reduced), followed by interaction with low-T fluids, leading to molybdenite dissolution and reprecipitation of Mo as powellite-rich domains (retrograde stage, oxidised). The observation of nanoscale inclusions of xenotime-(Y) within scheelite carries implications for the meaningful interpretation of petrogenesis based on rare earth element (REE) concentrations and fractionation patterns. This research demonstrates that HAADF-STEM is a versatile technique to address issues of solid solution and compositional heterogeneity.

Petrogenesis of the southern Qiangtang mafic dykes, Tibet: Link to a late Paleozoic mantle plume on the northern margin of Gondwana?

2019 ◽  
Vol 131 (11-12) ◽  
pp. 1907-1919 ◽  
Author(s):  
Ming Wang ◽  
Cai Li ◽  
Xiao-Wen Zeng ◽  
Hang Li ◽  
Jian-Jun Fan ◽  
...  
Keyword(s):  
Partial Melting ◽  
Mantle Plume ◽  
Inductively Coupled Plasma ◽  
Crustal Contamination ◽  
Late Paleozoic ◽  
Magmatic Zircon ◽  
Early Permian ◽  
Northern Margin ◽  
Inductively Coupled ◽  
Gondwana Margin

AbstractThis study presents 13 new U-Pb zircon ages obtained by laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) together with whole-rock geochemical, Sr-Nd isotopic and zircon Hf isotopic data for a mafic dike swarm in the southern Qiangtang area of Tibet. These data provide the basis for a new model of the late Paleozoic evolution of the Tethys. Combined with the results of previous zircon U-Pb dating, the magmatic zircon grains extracted from mafic dikes yield latest Carboniferous to Early Permian ages (317–279 Ma). The geochemistry of the southern Qiangtang mafic rocks indicates the presence of low-Ti (QLT) and high-Ti (QHT) suites. The magmas that formed the QLT suite underwent higher degrees of partial melting (>5%) and display evidence of crustal contamination, whereas the QHT suite was derived from magmas generated by low-degree (1%–5%) partial melting of a garnet-bearing mantle source, with a greater extent of fractional crystallization than the QLT suite, and no evidence of crustal contamination. We propose that the QHT and QLT suites may have been derived from magmas from different parts of a single mantle plume. The formation of the southern Qiangtang mafic dikes (latest Carboniferous to Early Permian; 317–279 Ma) may have been related to the northward drift of the Cimmerian continent from the northern Gondwana margin, which resulted in the opening of the Meso-Tethys Ocean.

scholarly journals Columbite U-Pb Geochronology of Kalu’an Lithium Pegmatites in Northern Xinjiang, China: Implications for Genesis and Emplacement History of Rare-Element Pegmatites

Minerals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 456 ◽  
Author(s):  
Yonggang Feng ◽  
Ting Liang ◽  
Ze Zhang ◽  
Yiqian Wang ◽  
Yi Zhou ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Rare Metal ◽  
Oscillatory Zoning ◽  
Granitic Magma ◽  
Rare Element ◽  
Inductively Coupled ◽  
Electron Probe Micro Analyzer ◽  
Sector Zoning ◽  
Icp Ms ◽  
History Of

The Kalu’an-Azubai pegmatite field, one of the most important rare-metal metallogenic regions in China, contains a large number of pegmatite dikes belonging to spodumene and lepidolite subtypes. Columbite-group minerals (CGMs) collected from three spodumene subtype pegmatites (No. 802, No. 803, and No. 805 pegmatites) were analyzed for major element contents using EPMA (electron probe micro-analyzer) and dated using LA-ICP-MS (laser ablation-inductively coupled plasma mass spectrometer). The crystallization ages of the CGMs from No. 802, No. 803, and No. 805 pegmatites are 209.5 ± 1.4 Ma (2σ), 198.3 ± 2.0 Ma (2σ), and 224.3 ± 2.9 Ma (2σ), respectively. Oscillatory zoning and/or sector zoning along with the associated mineral assemblages suggest that the dated columbite is of magmatic origin. The crystallization ages of the columbite grains thus represent the emplacement ages of the Li pegmatites. Therefore, our dating results indicate that there were three emplacement events of the Li-rich pegmatite-forming melts in a timeframe of ~30 Ma. In combination with previous studies, we conclude that the Li pegmatites were formed before the Be-Ta-Nb pegmatites (~194–192 Ma), which precludes the genesis of rare-metal pegmatites via fractional crystallization of a granitic magma in the Kalu’an-Azubai region.

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