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Elemental Scientific Lasers’ NWR Systems

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Birth of an ocean in the Red Sea: Oceanic-type basaltic melt intrusions precede continental rupture

ID: 2585
Authors: Ligi, M;Bonatti, E;Bosworth, W;Cai, Y;Cipriani, A;Palmiotto, C;Ronca, S;Seyler, M;
Year Published: 2018
Journal: Gondwana Research
Product: New Wave;New Wave Research;

The role of magmatism in continental rupture at the birth of a new ocean is poorly understood. Continental rupture can take place with voluminous volcanism, as in the southern Red Sea, or in a relatively non-volcanic mode, as in the northern Red Sea. We report geophysical, geochemical and geochronological evidence suggesting that continental rupture in the northern Red Sea is preceded by MORB-type basaltic melt intrusions that cooled at depth forming gabbros at progressively shallower crustal levels as rifting progressed towards continental separation. One of these gabbros yielded an 40Ar/39Ar age of 25 ± 6 Ma, suggesting intrusion during early rifting. A magma chamber we detected 3.5 km below Thetis Deep, an axial segment of initial oceanic crust accretion, represents the final stage in this progression. Oceanic crust accretion in the Red Sea rift starts first at depth before continental rupture and initiation of sea floor spreading.

Pore structure, wettability and tracer migration in four leading shale formations in the Middle Yangtze Platform, China

ID: 3097
Authors: Yang, R;Hu, Q;He, S;Hao, F;Guo, X;Yi, J;He, X;
Year Published: 2018
Journal: Marine and Petroleum Geology
Product: UP213;New Wave;

Deposited in different sedimentary settings, four leading shale formations (Late Ordovician Wufeng, Early Silurian Longmaxi, Late Permian Dalong, and Early Jurassic Dongyuemiao Shales) are currently the most promising zones for shale gas development in the Middle Yangtze Platform of South China. Based on complementary tests [low pressure gas physisorption, mercury injection capillary pressure (MICP), contact angle measurement, fluid imbibition into initially dry shale, and tracer diffusion into initially fluid-saturated shale followed by tracer mapping with laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS)], this work investigates their pore structure (both geometry and connectivity) and wettability characteristics, as well as the coupled effects of these characteristics on fluid flow and tracer migration.

Process optimization for arsenic removal of fine coal in vibrated dense medium fluidized bed

ID: 803
Authors: Zhou, E;Fan, X;Dong, L;Zhao, Y;Yang, X;Duan, C;Liu, Q;
Year Published: 2018
Journal: Fuel
Product: NWR213;

The dry separation of fine coal provides a feasible, low-cost and pollution-free method for the pre-arsenic removal from coal prior to combustion. In this study, the arsenic (As) occurrence of the coal from Wangjiazhai coal mine in China and the corresponding migration law in the dissociation process were investigated. Accordingly, it was proposed for the vibrated dense medium fluidized bed (VDMFB) to be utilized, where it was suitable to separate the fine coal for As removal. The fluidization characteristics and the improvement of fluidization quality under the collaborative effect of vibration amplitude (A), vibration frequency (f) and air velocity (Ua) were also explored. It was discovered that the fluidized bed density was uniform and beneficial to separate coal through settling velocity when the fluidization number, Nv, was 1.0-1.83 with A of 0.5-3 mm and f of 5-30 Hz. Moreover, the bed density was driven to periodically fluctuate in a low range, based on the periodic vibration energy input in the bed. Furthermore, thirteen separation experiments for fine coal with various parameter combinations were executed through the Box-Behnken RSM method. The results demonstrated that the three operation parameters importance on the segregation degree of As content (SAs) was as follows: vibration amplitude > air velocity > vibration frequency. Compared to raw coal, the As content of the clean coal was reduced by 81.06%, whereas a 90.29% of As was concentrated into the tailing, indicating that the VDMFB can achieve a satisfactory performance for the dry arsenic removal in coal.

Redox state of the Archean mantle: Evidence from V partitioning in 3.5-2.4 Ga komatiites

ID: 325
Authors: Nicklas, RW;Puchtel, IS;Ash, RD;
Year Published: 2018
Journal: Geochimica et Cosmochimica Acta
Product: UP213;New Wave;

Oxygen fugacity of the mantle is a crucial thermodynamic parameter that controls such fundamental processes as planetary differentiation, mantle melting, and possible core-mantle exchange. Constraining the evolution of the redox state of the mantle is of paramount importance for understanding the chemical evolution of major terrestrial reservoirs, including the core, mantle, and atmosphere. In order to evaluate the secular evolution of the redox state of the mantle, oxygen fugacities of six komatiite systems, ranging in age from 3.48 to 2.41 Ga, were determined using high-precision partitioning data of the redox-sensitive element vanadium between liquidus olivine, chromite and komatiitic melt. The calculated oxygen fugacities range from -0.11 ± 0.30 ΔFMQ log units in the 3.48 Ga Komati system to +0.43 ± 0.26 ΔFMQ log units in the 2.41 Ga Vetreny system. Although there is a slight hint in the data for an increase in the oxygen fugacity of the mantle between 3.48 and 2.41 Ga, these values generally overlap within their respective uncertainties; they are also largely within the range of oxygen fugacity estimates for modern MORB lavas of +0.60 ± 0.30 ΔFMQ log units that we obtained using the same technique. Our results are consistent with the previous findings that argued for little change in the mantle oxygen fugacity since the early Archean and indicate that the mantle had reached its nearly-present day redox state by at least 3.48 Ga.

Permian arc evolution associated with Panthalassa subduction along the eastern margin of the South China block, based on sandstone provenance and U-Pb detrital zircon ages of the Kurosegawa belt, Southwest Japan

ID: 4436
Authors: Hara, H;Hirano, M;Kurihara, T;Takahashi, T;Ueda, H;
Year Published: 2018
Journal: Journal of Asian Earth Sciences
Product: UP213;New Wave;

We have studied the petrography, geochemistry, and detrital zircon U-Pb ages of sandstones from shallow-marine forearc sediments, accretionary complexes (ACs), and metamorphosed accretionary complexes (Meta-ACs) within the Kurosegawa belt of Southwest Japan. Those rocks formed in a forearc region of a Permian island arc associated with subduction of the Panthalassa oceanic crust along the eastern margin of the South China block (Yangtze block). The provenance of the shallow-marine sediments was dominated by basaltic to andesitic volcanic rocks and minor granitic rocks during the late Middle to Late Permian. The ACs were derived from felsic to andesitic volcanic rocks during the Late Permian. The provenance of Meta-ACs was dominated by andesitic volcanic rocks in the Middle Permian. The provenance, source rock compositions, and zircon age distribution for the forearc sediments, ACs and Meta-ACs have allowed us to reconstruct the geological history of the Permian arc system of the Kurosegawa belt. During the Middle Permian, the ACs were accreted along the eastern margin of the South China block. The Middle Permian arc was an immature oceanic island arc consisting of andesitic volcanic rocks. During the Late Permian, the ACs formed in a mature arc, producing voluminous felsic to andesitic volcanic rocks. A forearc basin developed during the late Middle to Late Permian. Subsequently, the Middle Permian ACs and part of the Late Permian AC underwent low-grade metamorphism in the Late to Early Jurassic, presenting the Meta-ACs.

Origin and implications of troilite-orthopyroxene intergrowths in the brecciated diogenite Northwest Africa 7183

ID: 2905
Authors: Zhang, A;Bu, Y;Pang, R;Sakamoto, N;Yurimoto, H;Chen, L;Gao, J;Du, D;Wang, X;Wang, RC;
Year Published: 2018
Journal: Geochimica et Cosmochimica Acta
Product: NWR213;NewWave;

Troilite-orthopyroxene intergrowths are present as a common material in the brecciated diogenite Northwest Africa (NWA) 7183. In this study, we report on the petrographic, mineralogical, and rare earth element abundances of the troilite-orthopyroxene intergrowths to constrain their origin and assess their implications for the diverse petrogenesis of diogenites. Two groups of troilite-orthopyroxene intergrowths with various grain sizes and mineral chemistry have been observed in NWA 7183.

Early Carboniferous adakite-like and I-type granites in central Qiangtang, northern Tibet: Implications for intra-oceanic subduction and back-arc basin formation within the Paleo-Tethys Ocean

ID: 606
Authors: Liu, J;Xie, C;Li, C;Wang, M;Wu, H;Li, X;Liu, Y;Zhang, T;
Year Published: 2018
Journal: Lithos
Product: UP213;New Wave;

Recent studies have proposed that the Late Devonian ophiolites in the central Qiangtang region of northern Tibet were formed in an oceanic back-arc basin setting, which has led to controversy over the subduction setting of the Longmucuo-Shuanghu-Lancangjiang Suture Zone (LSLSZ) during the Late Devonian to Early Carboniferous. In this paper we present new data about a suite of granite plutons that intrude into ophiolite in central Qiangtang. Our aim was to identify the type of subduction and to clarify the existence of an intra-oceanic back-arc basin in the LSLSZ during the Late Devonian to Early Carboniferous. The suite of granites consists of monzogranites, syenogranites, and granodiorites. Our laser ablation-inductively coupled plasma-mass spectrometry zircon U-Pb data yielded Early Carboniferous crystallization ages of 357.2 Ma, 357.4 Ma and 351.1 Ma. We subsequently investigated the petrogenesis and tectonic setting of these granites based on their geochemical and Hf isotopic characteristics. First, we divided the granites into high Sr/Y (HSG) and low Sr/Y granites (LSG). The HSG group contains monzogranites and granodiorites that have similar geochemical characteristics to adakites (i.e., high Sr/Y and La/Yb ratios, low MgO, Y, and Yb contents, and no pronounced negative Eu anomaly), although they have slightly lower Sr and Al2O3 contents, caused by crystal fractionation during late magmatic evolution. Therefore, we define the HSG group as adakite-like granites. The study of the HSG shows that they are adakite-like granites formed by partial melting of oceanic crust and experience fractional crystallization process during late evolution. However, some differences between the monzogranites and granodiorites indicate that there are varying degree contributions of subducted sediments during diagenesis. The LSG group contains syenogranites that have distinct negative correlations between their P2O5 and SiO2 contents, and Y and Th contents have significant positive correlations with Rb. The above characteristics indicate that the syenogranites are typical I-type granites. The results of this study also show that the LSG were produced by magma mixing between the mantle and juvenile oceanic crust. The field study found that the Early Carboniferous suite of granites intruded into contemporaneous ophiolites that formed in an intra-oceanic back-arc basin, and were associated with coeval A-type granites in this region. Based on the geochemical and isotopic data presented in this paper and regional geological data, we consider that the HSG were formed during intra-oceanic subduction of the Paleo-Tethys Ocean in the Early Carboniferous. The LSG and A-type granites were formed in an intra-oceanic back-arc basin setting caused by roll-back of the Paleo-Tethys Ocean slab. This confirms that the subduction of the Paleo-Tethys Ocean in the Early Carboniferous was intra-oceanic subduction, and provides important evidence for the existence of an intra-oceanic back-arc basin during the Late Devonian to Early Carboniferous.

Geochronology and geochemistry of the granitoids and ore - forming age in the Xiaoyao tungsten polymetallic skarn deposit in the Jiangnan Massif tungsten belt, China: Implications for their petrogenesis, geodynamic setting, and mineralization

ID: 641
Authors: Su, Q;Mao, J;Wu, S;Zhang, Z;Xu, S;
Year Published: 2018
Journal: Lithos
Product: NewWave;

The Xiaoyao tungsten polymetallic skarn deposit in the eastern Jiangnan Massif of Yangtze Block is located at the contact between a granodiorite pluton and Sinian-Cambrian limestone. The intrusions in the tungsten-rich district comprise the Xiaoyao and other granodiorite plutons and granite porphyry dikes. The age determinations by LA-ICP-MS U-Pb dating of zircons indicate that the granodiorite formed at 149.4 ± 1.1 Ma, whereas the granite porphyry was emplaced at 133.2 ± 0.7 Ma. Re-Os dating of molybdenite from the skarn orebodies yielded a weighted average age of 148.7 ± 2.3 Ma (n = 5). These ages indicate that the tungsten mineralization is temporally related to the granodiorite. The granodiorites are metaluminous (A/CNK = 0.86-0.98) and in the high-K calc-alkaline series. They contain hornblende and have a negative correlation between P2O5 and SiO2, indicating that they are typical I-type intrusions. The granite porphyries exhibit high alkali contents (Na2O + K2O = 7.97-9.53%), elevated FeOT/(FeOT + MgO) ratios (0.83-0.94), high concentrations of Zr, Nb, Ce, and Y, and high Zr saturation temperatures (average of 812 °C); thus, they are geochemically similar to A-type intrusions. The initial 87Sr/86Sr and εNd(t) values range respectively from 0.7074 to 0.7083 and from - 7.9 to - 1.3 for the granodiorite, and from 0.7008 to 0.7083 and from - 6.3 to - 4.7 for the granite porphyry. In addition, two-stage Nd model ages (T2DM) of 1.0-1.6 Ga for the granodiorite and 1.3-1.4 Ga for the granite porphyry indicate that the Proterozoic crustal rocks of the Shangxi Group could have contributed to the Xiaoyao magmas. The rhenium contents of the molybdenite grains vary from 32 to 136 ppm, suggesting that the molybdenum was derived mainly from a mixture of mantle and crustal sources. Based on the new geochemical data and regional geological investigations, we propose that the Late Jurassic mineralization-related I-type granodiorite was derived from the Neoproterozoic Shangxi metamorphic rocks with some additional input of mantle material. The magmatism was triggered by asthenospheric upwelling induced by slab tearing during oblique subduction of the paleo-Pacific plate beneath the South China Block.

Identifying New World majolica from 16th-18th Century sites on Peru's north coast

ID: 2200
Authors: Kelloway, SJ;VanValkenburgh, P;Iñañez, JG;Dussubieux, L;Quilter, J;Glascock, MD;
Year Published: 2018
Journal: Journal of Archaeological Science: Reports
Product: UP213;New Wave;

This study presents the results of instrumental neutron activation analysis (INAA), laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) and thin-section analysis of 74 majolica sherds from 16th-18th Century sites in the Zaña Valley and Magdalena de Cao Viejo, Peru, and Panama Viejo, Panama. The majority of majolica samples from Peru are chemically associated with Panamanian reference groups, indicating their production in Panama; however, the remainder appears to be Andean-made, based on their distinct chemical signatures. These latter vessels seem to have been produced in Peru and build upon our understanding of colonial majolica manufacture in South America. Furthermore, the presence of blue-series decoration makes important contributions to our understanding of the Andean sphere of loza production.

A stand-alone Co mineral deposit in northeastern Hunan Province, South China: Its timing, origin of ore fluids and metal Co, and geodynamic setting

ID: 3740
Authors: Zou, S;Zou, F;Ning, J;Deng, T;Yu, D;Ye, T;Xu, D;Wang, Z;
Year Published: 2018
Journal: Ore Geology Reviews
Product: NWR193;

The Hengdong cobalt (Co) deposit, located in northeastern Hunan Province of South China, is hosted by the low-grade metamorphic volcaniclastic sedimentary rocks of the early Neoproterozoic Lengjiaxi Group. The Co orebodies strictly controlled by the NE- to ENE-trending Changsha-Pingjiang deep fault zone (CPDFZ) and its secondary structures. Occurring in altered breccias and cataclasites with similar mineral assemblages, Co mineralization is characterized by zoned alteration with predominant silicification and chloritization proximal to the orebodies, and sericitization and carbonatization distal from the mineralization. The integrated field and microscope observations reveal three hydrothermal stages marked by quartz + pyrite + muscovite ± chalcopyrite of the early-stage mineralization (E-stage), quartz + polymetallic sulfides + chlorite of the middle-stage mineralization (M-stage), and quartz + chlorite + carbonate of the late-stage mineralization (L-stage). Muscovite from both the E-stage Co-bearing altered breccia and the CPDFZ mylonite yield 40Ar-39Ar plateau ages of 124.7 ± 0.6 Ma (1σ) and 130.3 ± 1.4 Ma (1σ), respectively, indicating an early Cretaceous mineralization likely associated with the last movement of CPDFZ strike-slip shearing. The δ34S values of pyrite and chalcopyrite ranging from -1.5 to -15.9% with a majority between -7.5 and -15.9%, and the lead isotope compositions of the pyrite (206Pb/204Pb = 18.156-18.761, 207Pb/204Pb = 15.645-15.662 and 208Pb/204Pb = 38.469-39.172) overlapping with those of upper crust, indicate a main crust-derived source. The chemical compositions of pyrite further indicate the ore fluids and metal Co of the Hengdong deposit are most likely linked to the meta-mafic and volcanic rocks of the Neoarchean to Paleoproterozoic Lianyunshan Group, but with a contamination by the wall rocks of Lengjiaxi Group and Lianyunshan granitoids. Fluid inclusion investigations from Hengdong deposit reveal the decreasing homogenization temperatures from 250 to 320 °C (peak of 280-300 °C) at the E stage, through ~220-320 °C (peak of 270-300 °C) at the M stage, and to ~150-230 °C at the L stage without obviously salinity (7.0-15 wt% NaCl equiv.) changed. In the M-stage, the presence of coexisting LV inclusions and V-rich inclusions with the similar homogenization temperature, consistent with the chlorite geothermometry data, is interpreted to be the result of fluid immiscibility, which was caused by cyclic pressure release during fault-zone movement. Combined with the Late Mesozoic tectonism of South China, the present data support the Hengdong deposit formed under an extension-associated tectonic regime most likely induced by slab roll-back of the subducted Paleo-Pacific Plate during the early Cretaceous. This extensional event not only caused the reactivation of the pre-existing structures as manifested by the CPDFZ characteristic of stress transformation from compression to extension but also likely resulted in the release of large amounts of Co-bearing ore fluids from the Proterozoic or older volcanogenic rocks. When the ore fluids migrated along the CPDFZ and its secondary faults, the decompression (adiabatic cooling) of the hydrothermal fluids shifted the ore fluid to the immiscibility field, significantly reduced the degree of cobalt undersaturation, and caused cobalt to precipitate, which finally formed the Hengdong Co mineral deposit.

An approach for quantification of platinum distribution in tissues by LA-ICP-MS imaging using isotope dilution analysis

ID: 683
Authors: Moraleja, I;Mena, ML;Lázaro, A;Neumann, B;Tejedor, A;Jakubowski, N;GÓmez-GÓmez, MM;Esteban-Fernández, D;
Year Published: 2018
Journal: Talanta
Product: NWR213;

Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has been revealed as a convenient technique for trace elemental imaging in tissue sections, providing elemental 2D distribution at a quantitative level. For quantification purposes, in the last years several approaches have been proposed in the literature such as the use of CRMs or matrix matched standards. The use of Isotope Dilution (ID) for quantification by LA-ICP-MS has been also described, being mainly useful for bulk analysis but not feasible for spatial measurements so far. In this work, a quantification method based on ID analysis was developed by printing isotope-enriched inks onto kidney slices from rats treated with antitumoral Pt-based drugs using a commercial ink-jet device, in order to perform an elemental quantification in different areas from bio-images. For the ID experiments 194Pt enriched platinum was used. The methodology was validated by deposition of natural Pt standard droplets with a known amount of Pt onto the surface of a control tissue, where could be quantified even 50pg of Pt, with recoveries higher than 90%. The amount of Pt present in the whole kidney slices was quantified for cisplatin, carboplatin and oxaliplatin-treated rats. The results obtained were in accordance with those previously reported. The amount of Pt distributed between the medullar and cortical areas was also quantified, observing different behavior for the three drugs.

Quantitative mapping of elements in basil leaves (Ocimum basilicum) based on cesium concentration and growth period using laser ablation ICP-MS

ID: 684
Authors: Ko, JA;Furuta, N;Lim, HB;
Year Published: 2018
Journal: Chemosphere
Product: New Wave;

Quantitative elemental mapping of metallic pollutants in sweet basil was studied by laser ablation (LA)-ICP-MS. For this, the sweet basil was cultivated in Hoagland nutrient solution spiked with 100 and 1000 ng mL-1 of Cs for 10-60 days. Then, the Cs distribution in collected leaves was determined by LA-ICP-MS using lab-synthesized standard pellets based on NIST 1573a tomato leaves. For comparison, S, Ca, and K were also simultaneously determined in this measurement with a13C+ signal from the leaves as an internal standard. The obtained calibration curves showed linear coefficient of determination (R2) of 0.991 for K and 0.999 for Cs. The concentration of Cs measured in the basil leaves increased with growth period and pollutant concentration, and accumulation followed the order of leaf margin, petiole, midrib, and veins. Although no visible symptom was detected, significant suppression of the growth rate was observed due to the presence of high-concentration Cs. The experimental model demonstrated herein showed potential for studying the influence of radioactive pollutants on plants and other organisms in the food chain.

Direct synthesis of 3D hierarchically porous carbon/Sn composites via in situ generated NaCl crystals as templates for potassium-ion batteries anode

ID: 3757
Authors: Huang, K;Xing, Z;Wang, L;Wua, X;Zhao, W;Qi, X;Wang, H;Ju, Z;
Year Published: 2018
Journal: Journal of Materials Chemistry A
Product: NWR213;

It has been approved that embedding potassium ions into graphitic carbon interlayer is possible. The intercalation of potassium ions into graphite has been demonstrated feasible while the electrochemical performance of potassium ion battery (PIB) is still unsatisfying. Herein, an in situ formed NaCl serving as hierarchical templates and supporting the formation of 3D polymer-Sn complex is reported. The polymer-Sn complex is heat-treated to obtain a 3D Carbon/Sn network constructed by porous films. In particular, the large specific surface area of the composite and the Sn nanoparticles homogeneously embedded in 3D hierarchically porous carbon shells result in an excellent potassiation/depotassiation performance. Under the optimal conditions (650 °C), the 3D hierarchically porous carbon/Sn composite (3D-HPCS) as an anode material of PIBs demonstrates a high reversible capacity of 276.4 mA h g-1 at 50 mA g-1 (100 cycles) with coulombic efficiency of over 96%. This interesting method can provide new avenues to other high-capacity anode material systems that are subject to significant volume expansion.

Source-to-sink dynamics in the Kyrgyz Tien Shan from the Jurassic to the Paleogene: Insights from sedimentological and detrital zircon U-Pb analyses

ID: 3767
Authors: De Pelsmaeker, E;Jolivet, M;Laborde, A;Poujol, M;Robin, C;Zhimulev, FI;Nachtergaele, S;Glorie, S;De Clercq, S;Batalev, VY;De Grave, J;
Year Published: 2018
Journal: Gondwana Research
Product: NWR193UC;UP213;New Wave;

New insights in the Mesozoic geodynamic evolution and related basin-range interactions in the Kyrgyz Tien Shan were obtained based on new sedimentological and detrital zircon U-Pb (LA-ICP-MS) results from Jurassic to Paleogene sedimentary sequences. Studied sedimentary sections are located in the Fergana and Yarkand-Fergana basins to the west of the Talas-Fergana Fault (TFF) and in the Issyk-Kul and Ming-Kush-Kökömeren basins to the east. The ages of the Phanerozoic zircon grains found in 18 Jurassic to Paleogene sandstones can be divided into four groups: Caledonian (470-390 Ma), Hercynian (315-260 Ma), Triassic (250-210 Ma) and Jurassic (190-160 Ma) ages. The differences in sedimentation pattern and zircon U-Pb results suggest that the TFF played an important role in the distribution of the sedimentary deposits in the Mesozoic. During the Early - Middle Jurassic, the TFF was active and the strongest subsidence occurred in the Yarkand-Fergana Basin. The provenance of its sediments can be explained both by local sources close to the TFF and by more distal sources to the (south)west, probably stretching into the present-day Pamir. During the Late Jurassic - Early Cretaceous, renewed compression led to the inversion of the Yarkand-Fergana Basin. Around the Jurassic - Cretaceous transition, large alluvial fans developing in a semi-arid to arid climate traceable around the whole Tien Shan were also deposited in the Fergana Basin. A mafic sill intruded within these alluvial fans provides an emplacement age of 144 ± 8 Ma (apatite U-Pb) indicating (sub)volcanic activity during the Early Cretaceous. During the Late Cretaceous to early Paleogene, the area to the west of the TFF experienced marine incursions related to the proto-Paratethys Sea. The dominance of Caledonian ages in the Upper Cretaceous - lower Paleogene detrital samples indicates a change in provenance whereby the drainage areas became larger towards low-relief land area east of the TFF.

Detection of Selenoproteins by Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP MS) in Immobilized pH Gradient (IPG) Strips

ID: 1468
Authors: Sonet, J;Mounicou, S;Chavatte, L;
Year Published: 2018
Journal: Methods Mol. Biol.
Product: NewWave;

In contrast to other trace elements that are cofactors of enzymes and removed from proteins under denaturing conditions, Se is covalently bound to proteins when incorporated into selenoproteins, since it is a component of selenocysteine aminoacid. It implies that selenoproteins can undergo several biochemical separation methods in stringent and chaotropic conditions and still maintain the presence of selenium in the primary sequence. This feature has been used to develop a method for the detection of trace levels of human selenoproteins in cell extracts without the use of radioactive isotopes. The selenoproteins are separated as a function of their isoelectric point (pI) using iso-electrofocusing (IEF) electrophoretic strips and detected by laser ablation-inductively coupled plasma mass spectrometry (LA-ICP MS). This method, therefore referred to as IEF-LA-ICP MS, allowed the detection of several selenoproteins in human cell lines, including Gpx1, Gpx4, TXNRD1, TXNRD2, and SELENOF.

Comparative investigation of toxicity and bioaccumulation of Cd-based quantum dots and Cd salt in freshwater plant Lemna minor L.

ID: 3519
Authors: Pavlína, Modlitbová; Karel, Novotný; Pavel, Poří Jakub, Klus; Přemysl, Lubal; Helena, Zlámalová-Gargošová; Jozef, Kaisera;
Year Published: 2018
Journal: Ecotoxicology and Environmental Safety
Product: New Wave;

The purpose of this study was to determine the toxicity of two different sources of cadmium, i.e. CdCl2 and Cd-based Quantum Dots (QDs), for freshwater model plant Lemna minor L. Cadmium telluride QDs were capped with two coating ligands: glutathione (GSH) or 3-mercaptopropionic acid (MPA). Growth rate inhibition and final biomass inhibition of L. minor after 168-h exposure were monitored as toxicity endpoints. Dose-response curves for Cd toxicity and EC50168h values were statistically evaluated for all sources of Cd to uncover possible differences among the toxicities of tested compounds. Total Cd content and its bioaccumulation factors (BAFs) in L. minor after the exposure period were also determined to distinguish Cd bioaccumulation patterns with respect to different test compounds. Laser-Induced Breakdown Spectroscopy (LIBS) with lateral resolution of 200 µm was employed in order to obtain two-dimensional maps of Cd spatial distribution in L. minor fronds. Our results show that GSH- and MPA-capped Cd-based QDs have similar toxicity for L. minor, but are significantly less toxic than CdCl2. However, both sources of Cd lead to similar patterns of Cd bioaccumulation and distribution in L. minor fronds. Our results are in line with previous reports that the main mediators of Cd toxicity and bioaccumulation in aquatic plants are Cd2+ ions dissolved from Cd-based QDs.

Microstructural characterization and in-situ sulfur isotopic analysis of silver-bearing sphalerite from the Edmond hydrothermal field, Central Indian Ridge

ID: 4036
Authors: Wu, Z;Sun, X;Xu, H;Konishi, H;Wanga, Y;Lu, Y;Cao, K;Wang, C;Zhou, H;
Year Published: 2018
Journal: Ore Geology Reviews
Product: NWR193;New Wave;

A close Zn-Ag association has been noted recently in several polymetallic sulfide ore deposits from the Indian Ocean. However, the role of nanotextural controls on invisible" silver distribution within sphalerite (a significant Ag-carrier) is still not well understood. In this study, typical Zn-sulfide samples from the Edmond vent field (Central Indian Ridge) can be roughly classified into three different groups based on their chemical compositions and mineral textures. Among them, sulfosalt-bearing, Fe-poor zinc sulfides in sulfate-dominant outer chimney walls usually contain higher contents of Ag, Cu and Pb (up to wt% levels) than Fe-rich, massive to disseminated sphalerite in Zn-(Fe)-rich chimney fragments coated by silicified crusts. Such sphalerite is represented by colloform/botryoidal aggregates of optically anisotropic ZnS with a strongly disordered structure or hexagonal habit, which are actually formed by coalescence and agglomeration of colloidal nanocrystalline particles. Using high-resolution transmission electron microscopy (HRTEM) and in-situ micro-XRD techniques, we have investigated the ultrastructure and crystal-chemistry of the {1 1 1} twin boundaries and wurtzite-type stacking faults that occur in Ag-rich, colloform or porous dendritic sphalerite. Submicroscopic electrum and Ag nanoparticles appear to nucleate on the micro-/nano-pore walls as cavity-fillings, or occur along grain boundaries between chalcopyrite-tennantite inclusions and the host sphalerite. Interestingly, the inhomogeneous distribution of precious metals and other chalcophile elements is generally concordant with the extent of recrystallization, intragranular porosity as well as various degrees of structural disordering/imperfectness (i.e., bulk defect density) in ZnS domains. Lattice defects and interfaces may play a limited role in promoting the simultaneous introduction of exotic impurities into colloform sphalerite during rapid growth. Even though certain morphological traits and aggregation state at the nanoscale seem to support a biogenic origin of these ZnS particles characterized by admixed polytypic intergrowth structures, the mineralogical and geochemical features of highly-defective sphalerite crystals in addition to their microscale S-isotope signatures.

Mixed-origins of channel catfish in a large-river tributary

ID: 1236
Authors: Spurgeon, JJ;Pegg, MA;Halden, NM;
Year Published: 2018
Journal: Fisheries Research
Product: New Wave;

An understanding of factors responsible for population structure including the origins of individuals from among habitats is fundamental to conservation and management of large-river fishes. The prevalence of population mixing of channel catfish Ictalurus punctatus was evaluated within a large-river tributary environment using information from recent environmental history and natal origin derived from otolith microchemistry. Trace elements in water and otoliths were assessed using univariate and multivariate statistical approaches. Water and otolith trace elements differed among river segments facilitating classification of channel catfish to the river segment of capture. Accuracy of the classification tree model for juvenile channel catfish ranged from 44% to 88%. Recent environmental and natal origin microchemistry signatures suggested the channel catfish population within a large-river tributary comprises individuals from multiple locations. Population demographics of channel catfish is likely influenced by mixing of individuals from across the riverine-network. Consideration of the importance of connectivity between main-stem and tributary systems may, therefore, benefit conservation and management of channel catfish and other large-river fishes displaying similar life-history strategies.

Identifying stock structuring in the sandeel, Ammodytes marinus, from otolith microchemistry

ID: 1238
Authors: Wright, PJ;Régnier, T;Gibb, FM;Augley, J;Devalla, S;
Year Published: 2018
Journal: Fisheries Research
Product: NWR213;NewWave;

Identifying the scale of population processes is important for sustainable fisheries management. In the North Sea, the lesser sandeel, Ammodytes marinus, is now managed as seven stocks delineated on the basis of biophysical model predictions of the limited scale of larval mixing. This study used otolith chemistry to evaluate whether the stock units defined from these predictions actually reflect the degree of isolation of early life stages. Elemental composition near the core, settlement check and summer opaque zone were examined using laser ablation-inductively coupled plasma mass spectrometry in young of the year, sampled across 8 grounds within three of the main fished stocks in 2011. There were significant spatial differences in otolith chemistry enabling post-settled juveniles to be discriminated among stock areas and even between some grounds. Clustering of near core chemistry pointed to four natal sources, with dominant clusters in each of the three stocks studied and one unique to the Central Western North Sea (sandeel assessment area 4). Moreover, near core chemistry was similar to that of post-settled juveniles at the stock area level. Consistency in the scaling of early life mixing predicted by biophysical models and otolith chemistry supports the present stock units used in assessments.

Characterization of diversified Sb (V)-reducing bacterial communities by various organic or inorganic electron donors

ID: 245
Authors: Nguyen, VK;Choi, W;Park, Y;Yu, J;Lee, T;
Year Published: 2018
Journal: Bioresource technology
Product:

This study aims to enrich Sb(V)-reducing bacterial communities from Sb-contaminated soils using various electron donors for bioremediation of Sb-contaminated sites and recovery of Sb from wastewater. When the organic electron donors were used, Sb(V) reduction rates were 2-24 times faster but electron recoveries were 24-59% lower compared to the culture using inorganic electron donor. The morphological crystallizations of the antimony-reduced precipitates were completely different depending on the electron donor. Different microbial populations were enriched with various electron donors but most commonly, only Proteobacteria and Firmicutes phyla were enriched from a diversified soil microbial community. Geobacter sp. seemed to be an important bacterium in organic electron donors-fed cultures whereas an unclassified Rhodocyclaceae was dominant in inorganic electron donor-fed cultures. The results indicated that organic electron donors especially sugar groups were preferable options to obtain rapid Sb(V)-reduction whereas inorganic electron donor like H2 was better option to achieve high electron recovery.

(LA-ICP-MS Zircon U-Pb Ages and Geochemical Characteristics of the Shadi Granitic Pluton in Southern Jiangxi and Their Tectonic Significance) 赣南沙地花岗岩体LA-ICP-MS锆石U-Pb年龄、 地球化学特征及构造意义

ID: 3584
Authors: (Luo, C;Liu, G;) 罗春林,刘高峰
Year Published: 2017
Journal: (Advances in Geosciences) 地球科学前沿
Product: UP213;New Wave;

(This study conducted analysis on the Shadi granitic pluton in the Shadi area, southern Jiangxi Province using LA-ICP-MS zircon U-Pb dating, petrological and geochemical methods. The results show that the zircon U-Pb ages of the positive long granite in the studied areas are 428.3 ± 5.9 Ma, indicating the Shadi granitic pluton formed in Early Silurian. Geochemical result shows that the Shadi granitic pluton has ACNK of 1.07 - 1.19 and K2O/Na2O of 1.07 - 1.73, suggesting that they belong to peraluminous rock. The pluton has a total REE content of (169 - 244) × 10-6, and is enriched in LREE, with distinct right oblique REE patterns, Eu values of 0.10 to 0.40 and obvious negative Eu anomaly. The REE analysis shows the pluton is enriched in Rb, Th, U, La, Ce, Nd, Zr, Hf and Sm, and depleted in Ba, Sr and Ti, with Rb/Sr ratio of 2.90 - 7.28 (averaging 5.12) obviously higher than the average values of continental crust and the upper crust, suggesting that the pluton is of the characteristics of crust derived granite. The Shadi granite pluton might result from the Caledonian movement of late Early Paleozoic, and broke up after collision matching between Cathaysian land mass and Yangtze land mass. S-type granitic magmas, formed by partial melting of the upper crust in the period of Ordovician to Silurian, ascended to the upper crust and yielded the Shadi granite pluton in the period of collision to post-collision.) 摘 要 本文对赣南沙地地区沙地花岗岩体中的正长花岗岩进行了LA-ICP-MS锆石U-Pb定年、岩石学和地球化学 研究。结果表明:正长花岗岩锆石U-Pb年龄为428.3 ± 5.9Ma,表明沙地花岗岩体形成于早志留世;地 球化学特征显示:沙地花岗岩体的铝饱和指数为1.07~1.19, K2O/Na2O为1.07~1.73,属过铝质岩石;稀 土元素总量为(169~244) × 10−6,轻稀土元素富集,稀土配分模式呈明显的右倾型;δEu为0.10~0.40, Eu亏损中等偏高;岩体中Rb、Th、U、La、Ce、Nd、Zr、Hf及Sm相对富集,Ba、Sr及Ti相对亏损;岩 体Rb/Sr为2.90~7.28,平均值为5.12,明显高于大陆地壳平均值和上地壳平均值,具壳源花岗岩特征。 沙地花岗岩体形成于早古生代晚期的加里东构造运动,是华夏地块与扬子地块在新元古代碰撞拼贴之后 发生裂解,在奥陶纪至志留纪上地壳部分熔融形成的S型花岗质岩浆,在碰撞到后碰撞过渡期上升至上地 壳形成的花岗岩体。

Evidence for early life in Earth's oldest hydrothermal vent precipitates

ID: 1
Authors: Dodd, MS;Papineau, D;Grenne, T;Slack, JF;Rittner, M;Pirajno, F;O'Neil, J;Little, CT;
Year Published: 2017
Journal: Nature
Product: NWR193;

Although it is not known when or where life on Earth began, some of the earliest habitable environments may have been submarine-hydrothermal vents. Here we describe putative fossilized microorganisms that are at least 3,770 million and possibly 4,280 million years old in ferruginous sedimentary rocks, interpreted as seafloor-hydrothermal vent-related precipitates, from the Nuvvuagittuq belt in Quebec, Canada. These structures occur as micrometre-scale haematite tubes and filaments with morphologies and mineral assemblages similar to those of filamentous microorganisms from modern hydrothermal vent precipitates and analogous microfossils in younger rocks. The Nuvvuagittuq rocks contain isotopically light carbon in carbonate and carbonaceous material, which occurs as graphitic inclusions in diagenetic carbonate rosettes, apatite blades intergrown among carbonate rosettes and magnetite-haematite granules, and is associated with carbonate in direct contact with the putative microfossils. Collectively, these observations are consistent with an oxidized biomass and provide evidence for biological activity in submarine-hydrothermal environments more than 3,770 million years ago.

Subduction between the Jiamusi and Songliao blocks: Geological, geochronological and geochemical constraints from the Heilongjiang Complex

ID: 513
Authors: Zhu, CY;Zhao, G;Ji, J;MinSun, ;Han, Y;QianLiu, ;PaulREizenhöfer, ;Zhang, X;WenzhuHou, ;
Year Published: 2017
Journal: Lithos
Product: UP213;NewWave;

In Northeast China, oceanic subduction between the Jiamusi and Songliao blocks remains topic of hot debate. The Heilongjiang Complex has been regarded as an accretionary belt resulting from the subduction of an intervening ocean between the two blocks. In this study, we carry out extensive geological, geochemical and geochronological investigations on the sedimentary rocks, amphibolites and blueschists from the Heilongjiang Complex. The detrital zircons from meta-sedimentary rocks yield U-Pb age spams ranging from 268 to 780 Ma. Whereas the interlayered amphibolites show negative Nb-Ta-Ti and positive Pb anomalies and have a protolithic age of 188.2 ± 1.0 Ma, suggesting a subduction zone or magmatic arc origin in the Jurassic. The elevated initial Sr isotopic ratios (0.708-0.711) and negative εNd(t) values (- 4.3 to - 1.3) provide further evidence of the modification by upper continental crust during the magma ascending. LREE/HREE and MREE/HREE ratios suggest that the magma was likely derived from the mixing of lithospheric and asthenospheric melts. The presence of low Th/Ce (0.04-0.12) and Hf/Sm (0.35-0.55), but high Zr/Hf (35.4-43.4) and Pb/Ce (0.25-0.49) ratios strongly implies a contribution from subducted sediments. The identification of active continental margin type magmas of Early Jurassic age suggests that the subduction of the oceanic plate between the Jiamusi and Songliao blocks may have started around Early Jurassic time. In addition, the blueschists have a protolithic age of 186 ± 1.1 Ma and display geochemical affinities of oceanic island basalts, suggesting that the ocean between the Jiamusi and Songliao blocks closed sometime after 186 Ma. Mineral 40Ar/39Ar dating results from the Heilongjiang Complex further indicate that blueschist- to greenschist-facies metamorphism occurred in the Middle to Late Jurassic (158-175 Ma), marking the onset of termination of the oceanic subduction.

Ore genesis and geodynamic setting of the Lianhuashan porphyry tungsten deposit, eastern Guangdong Province, SE China: constraints from muscovite 40Ar-39Ar and zircon U-Pb dating and Hf isotopes

ID: 1025
Authors: Liu, P;Mao, J;Pirajno, F;Jia, L;Zhang, F;Li, Y;
Year Published: 2017
Journal: Mineralium Deposita
Product: UP213;NewWave;

The Lianhuashan deposit has long been regarded as a typical tungsten porphyry deposit, located in the eastern Guangdong Province, in the Southeastern Coastal Metallogenic Belt (SCMB). LA-MC-ICP-MS zircon U-Pb dating of the quartz porphyry yielded a weighted mean 206Pb/238U age of 137.3 ± 2.0 Ma, which is interpreted as the emplacement age of the quartz porphyry. Hydrothermal muscovite yielded a plateau 40Ar/39Ar age of 133.2 ± 0.9 Ma, which is consistent with the zircon U-Pb age, suggesting that the tungsten mineralization is genetically related to the quartz porphyry. Combined with previous studies, we suggest that there is a 145-135 Ma episode linking the granitic magmas with W-Sn ore systems in the SCMB. Zircon εHf (t) values of the quartz porphyry are in range of - 3.8 to 0.9, and the two-stage Hf model ages (TDM2) are 1.1-1.4 Ga, which is younger than the basement rocks in the Cathaysia Block (1.8-2.2 Ga), signifying that the quartz porphyry was predominantly derived from melting of Mesoproterozoic crust containing variable amounts of mantle components. In combination with the newly recognized coeval alkaline/bimodal magmatism and A-type granites in eastern Guangdong, we suggest that the 145-135 Ma W-Sn metallogenic event of the SCMB is related to a geodynamic setting of large-scale lithospheric extension and thinning, which can be ascribed to melting of the crust caused by mantle upwelling, triggered by the oblique subduction of the Izanagi plate.

Geochronological and geochemical constraints on the origin of Yaguila Cretaceous and Palaeogene ore-bearing quartz porphyries, Central Lhasa Terrane, Tibet

ID: 1281
Authors: Gao, YM;Lan, ZW;Chen, YC;Tang, JX;
Year Published: 2017
Journal: Geological Journal
Product: UP213;New Wave;

The quartz porphyries at Yaguila, Tibet, host important polymetallic ore deposits, but their age, source and evolution have received insufficient attention. In this study, LA-ICP-MS U-Pb zircon ages revealed that these quartz porphyries were formed in two stages, i.e. pre-collisional Early Cretaceous period (ca. 128 Ma) and late subduction to initial collision Palaeogene period (ca. 65 Ma). Geochemical evidence including whole-rock major element, trace element and rare earth element, zircon Hf isotopes together with sulphide Pb isotopes suggests the Early Cretaceous quartz porphyries could have formed by means of partial melting of crustal materials from Lhasa Terrane basement in a thickened crustal tectonic setting, whereas the Palaeogene quartz porphyries by enhanced input of mantle components probably were associated with slab rollback and breakoff at that time. Granitoid magmas produced in this way ascended to upper crustal level and interacted with marbles and breccias to form Pb-Zn-Ag ore bodies and Mo ore bodies, respectively. Age and geochemical constraints on the Early Cretaceous and Palaeogene polymetallic ore bodies not only have favoured a skarn and hydrothermal vein origin over a submarine exhalative sedimentary origin but also have consummated ore deposits metallogenic series and built up a reconnaissance model along the Lhasa Terrane. Copyright © 2015 John Wiley & Sons, Ltd.

Economic significance of platinum group elements and water in asteroids: Insights from chondritic meteorites

ID: 2817
Authors: Gilmour, C;
Year Published: 2017
Journal: Thesis
Product: UP213;New Wave;

Asteroids are considered to be rich sources of precious metals, water, and essential volatiles for life. Such a consideration has been derived from the study of meteorites and asteroid reflectance spectra which have both been vital to our understanding of asteroid compositions. The vast amount of valuable resources in asteroids that are in close proximity to Earth (Near-Earth Asteroids; NEAs) has designated such asteroids as prime targets for extra-terrestrial mining. Of the resources that can be extracted from asteroids, the platinum group elements (PGEs) and water are two of the most sought-after materials. The PGEs are highly valuable given their rarity on Earth, while having an available water source in space can help facilitate future space exploration (i.e., rocket fuel, radiation shielding, drinking water, etc.). Before mining of these resources can commence, asteroid miners must develop a detailed understanding of how the different compositions of asteroids can affect the distribution of such resources. Since it is an expensive endeavor to visit asteroids for such an assessment, meteorite studies take precedence in obtaining the necessary information for selecting an asteroid target to mine. The premise of this master's thesis is to provide insight into the PGE and water resources that can be mined from asteroids through the study of chondritic meteorites. In the first study of this thesis, PGE concentrations have been determined in situ in ordinary chondrite metal via laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). This is the first study to provide a detailed account of in situ PGE concentrations in the metal phases among a suite of ordinary chondrites. In situ results reveal that PGE concentrations in ordinary chondrite metal are similar among the different ordinary chondrite groups (H, L, and LL). This discovery is a significant contribution to the asteroid mining industry regarding which ordinary chondrite parent body is most ideal to mine considering that previous studies have claimed that PGE concentrations vary among the three ordinary chondrite groups. The findings from this PGE study are also pertinent to understanding the formation of metal in ordinary chondrites; the minimal variability of PGEs suggest that metal was formed as nebular condensates. The second part of this thesis addresses the effects aqueous alteration has on the abundance of water in carbonaceous material. For this investigation, the unique Tagish Lake carbonaceous chondrite was selected for analysis given that variable aqueous alteration degrees have been reported for three pristine specimens (TL5b < TL11h < and TL11i; Herd et al., 2011; Blinova et al., 2014). Thermogravimetric analysis (TGA), infrared transmission spectroscopy, and X-ray diffraction (XRD) were used to quantify the extent of aqueous alteration in the Tagish Lake specimens based on how much water they contained and their phyllosilicate/olivine ratio. The findings from this study are congruent with the previously reported alteration sequence (Herd et al., 2011; Blinova et al., 2014), allowing for the addition of two new Tagish Lake specimens (TL4 and TL10a) to be incorporated into the sequence. Reflectance spectra of Tagish Lake were also acquired to re-visit the Tagish Lake parent body connection. This Tagish Lake investigation is relevant to the material processing of asteroid mining given that the TGA method records the temperatures at which minerals break down and release water. Furthermore, investigating the meteorite-parent body connection is pertinent for selecting suitable asteroid targets. The findings of this thesis provide valuable insight into the type of asteroids that are suitable for mining PGEs and water. On this basis, I propose that H chondrite parent bodies are ideal for the extraction of PGEs, while CI and CM carbonaceous chondrite parent bodies are best for water resources.

Bridging the gap between the foreland and hinterland II: Geochronology and tectonic setting of Ordovician magmatism and basin formation on the Laurentian margin of New England and Newfoundland

ID: 4353
Authors: Macdonald, FA;Karabinos, PM;Crowley, JL;Hodgin, EB;Crockford, PW;Delano, JW;
Year Published: 2017
Journal: American Journal of Science
Product: UP213;New Wave;

Ordovician strata of the Mohawk Valley and Taconic allochthon of New York and the Humber margin of Newfoundland record multiple magmatic and basin-forming episodes associated with the Taconic orogeny. Here we present new U-Pb zircon geochronology and whole rock geochemistry and neodymium isotopes from Early Paleozoic volcanic ashes and siliciclastic units on the northern Appalachian margin of Laurentia. Volcanic ashes in the Table Point Formation of Newfoundland and the Indian River Formation of the Taconic allochthon in New York yield dates between 466.16 ± 0.12 and 464.20 ± 0.13 Ma. Red, bioturbated slate of the Indian River Formation record a shift to more juvenile neodymium isotope values suggesting sedimentary contributions from the Taconic arc-system by 466 Ma. Eight ashes within the Trenton Group in the Mohawk Valley were dated between 452.63 ± 0.06 and 450.68 ± 0.12 Ma. These ashes contain zircon with Late Ordovician magmatic rims and 1.4 to 1.0 Ga xenocrystic cores that were inherited from Grenville basement, suggesting that the parent magmas erupted through the Laurentian margin. The new geochronological and geochemical data are integrated with a subsidence model and data from the hinterland to refine the tectonic model of the Taconic orogeny. Closure of the Iapetus Ocean by 475 Ma via collision of the peri-Gondwanan Moretown terrane with hyperextended distal fragments of the Laurentian margin is not clearly manifested on the autochthon or the Taconic allochthon other than an increase in sediment accumulation. Pro-foreland basins formed during the Middle Ordovician when these terranes were obducted onto the Laurentian margin. 466 to 464 Ma ashes on the Laurentian margin coincide with a late pulse of magmatism in both the Notre Dame arc in Newfoundland and the Shelburne Falls arc of New England that is potentially related to break-off of an east-dipping slab. Following slab reversal, by 455 Ma, the Bronson Hill arc was established on the new composite Laurentian margin. Thus, we conclude that Late Ordovician strata in the Mohawk Valley and Taconic allochthon of New York and on the Humber margin of Newfoundland were deposited in retro-foreland basins.

The origin of the Zhubu mafic-ultramafic intrusion of the Emeishan large igneous province, SW China: Insights from volatile compositions and C-Hf-Sr-Nd isotopes

ID: 770
Authors: Tang, Q;Zhang, M;Wang, Y;Yao, Y;b, LD;Chen, L;Li, Z;
Year Published: 2017
Journal: Chemical Geology
Product: New Wave;

The Zhubu mafic-ultramafic intrusion of the Permian Emeishan large igneous province (LIP), SW China hosts a magmatic Ni, Cu and platinum-group element (PGE) deposit. It consists of a layered sequence with sub-horizontal modal layering wrapped by a sub-vertical marginal zone. Our new zircon U-Pb isotopic dating gives a mean age of 263.2 ± 5.6 Ma for the layered sequence. The volatiles extracted from the mineral separates of the Zhubu intrusion are composed of predominant H2O (11,769.84 mm3 STP/g, STP-standard temperature and pressure) and minor H2 and CO2. The layered sequence has lower H2O but higher H2, CO2, H2S and SO2 contents than the marginal zone. The CO2 and CH4 extracted at 400-900 °C and 900-1200 °C have light δ13CCO2 varying from - 17.45‰ to - 7.10‰ and δ13CCH4 varying from - 41.35‰ to - 22.88‰. The pyroxene separates have significantly lower (87Sr/86Sr)i values (0.705882 to 0.708912) and slightly higher εNd (t = 263 Ma) values (- 2.8 to 0.7) than the whole rocks. The εHf (t = 263 Ma) values of zircon crystals vary from - 3.05 to + 1.90. The chemical compositions of volatiles from the Zhubu intrusion indicate a slightly reduced condition and a H2O-rich parental magma. The C-Hf-Sr-Nd isotopes for the Zhubu intrusion are consistent with ~ 15 wt% assimilation of the upper crust by a mantle-derived magma. The carbon isotopes indicate that a thermogenic component from sedimentary organic materials was present in the contaminated magma. A weak positive correlation between volatile and PGE contents, together with the C-Hf-Sr-Nd isotopes, indicates that sulfide saturation in the Zhubu magma was triggered by crustal contamination including the addition of volatiles.

Geochemical, zircon U-Pb-Hf, and whole-rock Sr-Nd isotopic study of Late Jurassic Sanming A-type granite in the Wuyi area, Fujian province, Southeast China

ID: 1282
Authors: Zhao, X;Jiang, Y;Yu, S;Xing, G;Yu, M;
Year Published: 2017
Journal: Geological Journal
Product: UP213;NewWave;

The Sanming pluton is the only Late Jurassic A-type granitic intrusion in the Wuyi area, west Fujian Province, Southeast China, and its formation has important implications for our understanding of the tectonic evolution of the region. The U-Pb ages of 157 ± 1 Ma and 159 ± 1.1 Ma were obtained for the pluton by zircon LA-ICP-MS analysis, which is interpreted to be the crystallization age of the Sanming pluton (i.e., Late Jurassic). The pluton has the geochemical characteristics of A-type granite, such as high K2O+Na2O contents (average 7.703 wt%), FeOT/(FeOT + MgO) ratios (average 0.85), and high 10,000 Ga/Al values and Zr + Nb + Ce + Y (380-446.1 ppm, average 419.2 ppm) contents, but relatively low CaO, Sr, and Eu contents. Zircon saturation temperatures range from 875 °C to 890 °C, also similar to other A-type granites. The (87Sr/86Sr)i ratios (0.707368-0.71102) and εNd(t) and εHf(t) values (-5.54 to -6.09, and -6.93 to -1.07, respectively), the 2-stage Nd model ages of 1.50-1.55 Ga, and 2-stage Hf model ages of 1.25-1.62 Ga, suggest the pluton was derived by extensive fractionation of melts containing both mantle materials and Mesoproterozoic crustal components. The Sanming A-type granitic pluton is younger than adakitic rocks in the region (162 Ma), suggesting a localized transition from compressional to intraplate extensional tectonics at 162-159 Ma, with mantle-derived material playing a crucial role in the formation of A-type granites in the Wuyi Mountain area. This tectonic transition is explained by localized rollback of the subducting Pacific plate.

Discriminating between pyroxenite and peridotite sources for continental flood basalts (CFB) in southern Africa using olivine chemistry

ID: 259
Authors: Howarth, GH;Harris, C;
Year Published: 2017
Journal: Earth and Planetary Science Letters
Product: UP213;New Wave;

Continental Flood Basalts (CFB) result from voluminous outpourings of magma that often precede continental break-up. Notwithstanding the petrogenetic importance of CFBs, the nature of the mantle source for such magmas is contentious, particularly with regard to picrites with Ni-rich olivine phenocrysts. Previous studies have suggested that Ni-rich olivines associated with plume volcanism in regions of thickened (>90 km) lithosphere are related to either source mineralogy differences (peridotite versus pyroxenite) or change in olivine-melt partitioning due to pressure increase. In order to evaluate these two hypotheses, we present trace element data for olivines from the Karoo CFB Tuli and Mwenezi picrites and the Etendeka CFB Horingbaai/LTZ-L type picrites, all of which erupted in regions of thickened (>90 km) lithosphere in southern Africa. Karoo picrite olivines are Ni-rich, Ca- and Mn-poor, and have low (1.4) 100*Mn/Fe, which is more consistent with high temperature melting of a dominantly peridotitic source. We also show that the Karoo and Etendeka olivines are characterized by distinct Mn/Zn ratios of 15, respectively. In addition, bulk rock geochemical data compilations and previously reported olivine δ18O for Karoo and Etendeka CFBs are discussed in order to further constrain source components based on previously described pyroxenite melt geochemical indices such as MgO-CaO systematics, FeO/MnO, Zn/Fe, and FC3MS (FeO/CaO-3*MgO/SiO2). These geochemical indices suggest a pyroxenite-dominated source for Karoo CFBs as well as for Etendeka ferropicrites whereas a peridotite-dominated source is indicated for Etendeka Horingbaai/LTZ-L type picrites analyzed in this study. Based on our data, Ni-enrichment of olivine in plume-related magmas in regions of thickened lithosphere in southern Africa is not ubiquitous. We therefore suggest that mineralogical variation of the source is a more likely major control of olivine chemistry and parent melt variations for Karoo and Etendeka CFBs. We also show that olivine Mn-Zn correlations are a useful discriminator for source variation and recommend the use of olivine Mn/Zn15 for a peridotite-dominated source.


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