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Unveiling the nanotoxicological aspects of Se nanomaterials differing in size and morphology

ID: 6456
Year: 2023
Products: UP213;New Wave;New Wave Research;
Authors: Stepankova, H;Michalkova, H;Splichal, Z;Richtera, L;Svec, P;Vaculovic, T;Pribyl, J;Kormunda, M;Rex, S;Adam, V;Heger, Z;
Journal: Bioactive Materials

Although the general concept of nanotechnology relies on exploitation of size-dependent properties of nanoscaled materials, the relation between the size/morphology of nanoparticles with their biological activity remains not well understood. Therefore, we aimed at investigating the biological activity of Se nanoparticles, one of the most promising candidates of nanomaterials for biomedicine, possessing the same crystal structure, but differing in morphology (nanorods vs. spherical particles) and aspect ratios (AR, 11.5 vs. 22.3 vs. 1.0) in human cells and BALB/c mice. Herein, we report that in case of nanorod-shaped Se nanomaterials, AR is a critical factor describing their cytotoxicity and biocompatibility. However, spherical nanoparticles (AR 1.0) do not fit this statement and exhibit markedly higher cytotoxicity than lower-AR Se nanorods. Beside of cytotoxicity, we also show that morphology and size substantially affect the uptake and intracellular fate of Se nanomaterials. In line with in vitro data, in vivo i.v. administration of Se nanomaterials revealed the highest toxicity for higher-AR nanorods followed by spherical nanoparticles and lower-AR nanorods. Moreover, we revealed that Se nanomaterials are able to alter intracellular redox homeostasis, and affect the acidic intracellular vesicles and cytoskeletal architecture in a size- and morphology-dependent manner. Although the tested nanoparticles were produced from the similar sources, their behavior differs markedly, since each type is promising for several various application scenarios, and the presented testing protocol could serve as a concept standardizing the biological relevance of the size and morphology of the various types of nanomaterials and nanoparticles.

A 187Re-187Os, 87Rb-86Sr, highly siderophile and incompatible trace element study of some carbonaceous, ordinary and enstatite chondrite meteorites

ID: 6144
Year: 2022
Products: UP213;New Wave;
Authors: Phelan, N;Day, J;Dhaliwal, J;Liu, Y;Corder, C;Strom, C;Pringle, E;Assayag, N;Cartigny, P;Marti, K;Moynier, F;
Journal: Geochimica et Cosmochimica Acta

New 187Re-187Os, 87Rb-87Sr, triple O-isotope isotope, bulk rock highly siderophile- (HSE: Os, Ir, Ru, Pt, Pd, Re), major- and trace-element abundance data are reported for a variety of carbonaceous, ordinary and enstatite chondrite meteorites. In addition, new mineral chemical data are reported for the Chelyabinsk LL5 ordinary chondrite fall for comparison with existing chondrite data and to investigate element sequestration into metal and mineral phases within some chondrites. The focus of the study is to link the variations observed in the HSE abundances and Re-Os isotopes with other isotopic and elemental data to explore the relative roles of sample sizes, terrestrial alteration and parent body processes more fully on chondrite meteorite compositions. Trace element variations in Chelyabinsk silicate, oxide and metal grains highlight the importance of geochemical heterogeneity imparted by mineralogical variations and mode effects, as well as sample size. Using a range of sample powder aliquot sizes, it is possible to show that this becomes significant for the HSE at

Nd-Hf isotopic composition of the Paleoproterozoic Matupá and Teles Pires intrusive suites: Implications for crustal evolution of the southern Amazonian Craton (Brazil)

ID: 6400
Year: 2022
Products: UP213;New Wave;
Authors: Tarelow Neto, J;Moura, M;
Journal: Journal of South American Earth Sciences

This paper presents Nd-Hf isotopic data for granitic rocks of both the Matupá (∼1859-1881 Ma) and Teles Pires (∼1790-1793 Ma) intrusive suites located in the south-central region of the Amazonian Craton, central Brazil. The Matupá Intrusive Suite consists of two facies of I-type granites with calc-alkaline affinity emplaced in volcanic arc settings. Facies 1 is composed of syenogranite and monzogranite, and facies 2 is composed of granodiorite. The Teles Pires Intrusive Suite varies from syenogranite to monzogranite with calc-alkaline signature that is consistent with mature magmatic arc settings. The Matupá Intrusive Suite derives from a source with Hf model ages ranging between 2.4-1.91 Ga and εHf (t) between +5.71 and −5.50. Zircon grains in the Matupá Intrusive Suite that are correlatable with the Creporizão Intrusive Suite show Hf model ages of between 2.0 to 2.4, and εHf (t) of −3.76 to + 4.10, while the zircon grains correlatable with the Tropas Intrusive Suite show Hf model ages of 2.1 to 2.4 Ga and εHf(t) of −3.93 to + 2.50. Both facies of the Matupá Intrusive Suite provide εNd (t) values varying from −0.61 to −1.66. The wide range of εHf (t) values (from −5.50 to +5.71) in contrast to the uniformly negative εNd (t) values (from −1.66 to −0.61) of the Matupá Intrusive Suite suggest that Nd-Hf decoupling took place in the magma source during to magma mixing processes. Nd-Hf isotope analyses of the Teles Pires Intrusive Suite reveal a source with Hf model age of between 2.3 and 1.9 Ga. This is indicative of mantle contribution and crustal reworking with values of εHf (t) ranging from +7.17 to −3.3, while other values suggest a more crustal contribution with εNd (t) from −0.07 to −0.71. Crustal contribution in the genesis and magmatic evolution of the Teles Pires Intrusive Suite is also evidenced due to the presence zircon grains inherited from Matupá Intrusive Suite. Zircon inheritance record a distant parental source coeval with the Matupá Intrusive Suite. This paper proposes that the origin and evolution of the Matupá Intrusive Suite is linked to the Cuiú-Cuiú Magmatic Arc while the origin and evolution of the Teles Pires Intrusive Suite is linked to the Juruena Magmatic Arc. Another hypothesis is that both suites were generated and evolved from a single magmatic arc. The Juruena Magmatic Arc is divided into two geographic segments. An eastern segment with a magmatic evolution marked by the interaction of crustal components during the orogenic phase of the Cuiú-Cuiú Magmatic Arc (Tapajós Domain of the Tapajós-Parimá Tectonic Province), and a western segment whose magmatic evolution is marked by rebound of the Juruena Magmatic Arc.

Evolution of the sources of TTG and associated rocks during the Archean from in-situ 87Sr/86Sr isotope analysis of apatite by LA-MC-ICPMS

ID: 6656
Year: 2022
Products: NWR193UC;ESI;
Authors: Caton, S;Smit, M;Emo, R;Musiyachenko, K;Kielman-Schmitt, M;Kooijman, E;Scherstén, A;Halla, J;Bleeker, W;Hoffmann, J;Pandey, O;Ravindran, A;Maltese, A;Mezger, K;
Journal: Lithos

Radiogenic isotopes provide an important means towards elucidating Archean crustal evolution. The global Hf and Nd isotope record of Archean crustal fragments has been instrumental to unveiling the history of ancient crustal growth and differentiation. The Rb-Sr system could provide valuable complementary constraints in this regard, as this system is particularly sensitive to magmatic fractionation processes, and the chemical and isotopic evolution of magma sources. Application of this system has so far been complicated, however, by its susceptibility to isotope re-equilibration or alteration of the Rb/Sr parent-daughter ratio. In-situ Sr isotope analysis of primary igneous minerals with very low Rb/Sr, such as apatite, provides a new means to determine the initial 87Sr/86Sr (87Sr/86Sri) values for igneous rocks directly. In this study, we apply in-situ Sr isotope analysis of apatite by LA-MC-ICPMS to tonalite-trondhjemite-granodiorite (TTG) rocks and end-member sanukitoids from Archean cratons worldwide. The 87Sr/86Sri values of sanukitoids are relatively radiogenic, supporting the model in which such rocks are formed by flux melting of a mantle strongly enriched by metasomatism, possibly by slab-derived fluids. The 87Sr/86Sri values for TTGs formed between 3.72 and 3.45 Ga are generally radiogenic, indicating aged amphibolite sources. The 87Sr/86Sri values of younger TTGs are systematically lower and were derived from mafic sources that had an average age of ≤0.2 Gyr. This evolution matches with observations from Hf isotopes for TTGs of similar age and indicates a systematic change in the nature or efficiency of TTG crust formation during the Paleoarchean. In-situ Sr isotope analysis of apatite provides a useful method to uncover the Sr record of the early continental crust, and enables constraints on local source evolution and the general two-step evolutionary process of Archean crust formation.

The solubility of platinum in magmatic brines: Insights into the mobility of PGE in ore-forming environments

ID: 6145
Year: 2022
Products: NWR193;
Authors: Sullivan, N;Zajacz, Z;Brenan, J;Tsay, A;
Journal: Geochimica et Cosmochimica Acta

Several field-based studies have proposed that late-stage magmatic aqueous brines may be responsible for the transportation and redistribution of platinum-group elements (PGE) in mafic-ultramafic igneous systems. We experimentally studied the solubility of Pt in high-temperature aqueous brines as a function of oxygen fugacity (ƒO2), temperature (T), pH and total chloride concentration (Cltotal) in a S-free system. Experiments were conducted at 800-1000 °C and 200 MPa in an externally-heated rapid-quench Molybdenum-Hafnium Carbide (MHC) pressure vessel assembly. We employed the synthetic fluid inclusion (SFI) technique to trap and sample pre-equilibrated, high-salinity brines in quartz cylinders subjected to in situ fracturing during experimental run conditions. Platinum solubility was observed to have a positive correlation with ƒO2, temperature, fluid acidity and Cltotal (salinity). A log Pt versus log ƒO2 diagram derives a weighted-error linear regression slope (m) = 0.48 ± 0.04 which demonstrates that Pt is present in the 2+ oxidation state over the studied ƒO2 range. At relatively oxidizing conditions, 1.44 log units above the Ni-NiO oxygen buffer (NNO+1.44), aqueous brines (containing 63 NaCl eq. wt.%) with a mildly acidic fluid composition (pH = 6.03) can dissolve up to ∼100 µg/g Pt at 900 °C and 200 MPa. Aqueous brines with identical fluid compositions yield a solubility of 4-13 µg/g Pt under more reducing conditions (NNO-0.41 to NNO-1.42). Thermodynamic model calculations suggest that both PtCl2 and PtCl3− are the dominant Pt(II)-chloride complexes which facilitate the transport of Pt in high-temperature aqueous vapors and brines. In fluid compositions with Cltotal >32 m (mol/kg H2O), PtCl3− complex is expected to be the dominant Pt species. In natural mafic-ultramafic systems, high-salinity, orthomagmatic aqueous brines may be important transporting agents if such magmatic fluids can participate in the dissolution of Pt-enriched base-metal sulfides or react with discrete insoluble Pt phases imposing a relatively high activity of Pt (i.e., Pt3Fe). Furthermore, precipitation of Pt from aqueous brines is promoted by a decrease in ƒO2, temperature, acidity and Cltotal.

Cr-pyrope xenocrysts with oxide mineral inclusions from the Chompolo lamprophyres (Aldan shield): Insights into mantle processes beneath the southeastern Siberian craton

ID: 6401
Year: 2022
Products: NWR213;ESI;
Authors: Rezvukhin, D;Nikolenko, E;Sharygin, I;Rezvukhina, O;Chervyakovskaya, M;Korsakov, A;
Journal: Mineralogical Magazine

Pyrope xenocrysts (N = 52) with associated inclusions of Ti- and/or Cr-rich oxide minerals from the Aldanskaya dyke and Ogonek diatreme (Chompolo field, southeastern Siberian craton) have been investigated. The majority of xenocrysts are of lherzolitic paragenesis and have concave-upwards (normal) rare earth element (REEN) patterns that increase in concentration from light REE to medium-heavy REE (Group 1). Four Ca-rich (5.7-7.4 wt.% CaO) pyropes are extremely low in Ti, Na and Y and have sinusoidal REEN spectra, thus exhibiting distinct geochemical signatures (Group 2). A peculiar xenocryst, s165, is the only sample to show harzburgitic derivation, whilst demonstrating a normal-to-weakly sinusoidal REEN pattern and the highest Zr (93 ppm) and Sc (471 ppm). Chromite-magnesiochromite, rutile, Mg-ilmenite and crichtonite-group minerals comprise a suite of oxide mineral inclusions in the pyrope xenocrysts. These minerals are characteristically enriched in Cr with 0.6-7.2 wt.% Cr2O3 in rutile, 0.7-3.6 wt.% in Mg-ilmenite and 7.1-18.0 wt.% in the crichtonite-group minerals. Complex titanates of the crichtonite group enriched in large ion lithophile elements (LILE) are high in Al2O3 (0.9-2.2 wt.%), ZrO2 (1.5-5.4 wt.%) and display a trend of compositions from the Ca-Sr-specific varieties to the Ba-dominant species (e.g. lindsleyite). In the pyrope xenocrysts the oxides coexist with silicates (clino- and orthopyroxene and olivine), hydrous silicates (talc, phlogopite and amphibole), carbonate (magnesite), sulfides (pentlandite, chalcopyrite, breakdown products of monosulfide and bornite solid solutions), apatite and graphite. P-T estimates imply the inclusion-bearing pyrope xenocrysts have been derived from low-temperature peridotite assemblages that resided at temperatures of ~600-800°C and a pressure range of ~25-35 kbar in the graphite stability field. Pyrope genesis is linked to the metasomatic enrichment of peridotite protoliths by Ca-Zr-LILE-bearing percolating fluid-melt phases containing significant volatile components. These metasomatic agents are probably volatile-rich melts or supercritical C-O-H-S fluids that were released from a Palaeo-subduction slab.

The Kalba batholith dyke swarms (Eastern Kazakhstan): Mafic magmas effect on granite formation

ID: 6657
Year: 2022
Products: UP213;New Wave;New Wave Research;
Authors: Khromykh, S;Vishnevskiy, A;Kotler, P;Antsiferova, T;Semenova, D;Kulikova, A;
Journal: Lithos

The Kalba granitoid batholith formed in Early Permian is one of the largest in the western part of the Central Asian Orogenic Belt. Batholith granites are intruded by mafic and intemediate dykes forming several swarms. Previously it was believed that the dykes were Mesozoic and had no relationship with the formation of the batholith. Our geochronological studies allow to determine the age of the dykes at 279 Ma (also Early Permian). Dyke rocks are represented by dolerites, variolites, monzodiorites, and plagioclase porphyrites. The petrographic study of plagioclase porphyrites allow to find the sign of magma mixing. The another indicator of magma mixing are the contacts between mafic and felsic rocks in largest dykes of complex structure. A model for the interaction of mafic magmas with crustal substrates is proposed. Mafic magmas intruded from sublithospheric mantle, provoked a partial melting and then interacted with granitic melts at the basement level of granite batholith. Dyke swarms were formed after the cooling and consolidation of main volume of Kalba batholith by inrtusion of mafic and hybride magmas from the basement level of granite batholith. Chemical diversity of the mafic dykes was caused mainly by the differentiation of parental mafic magmas and also a lesser extent by their interaction with the granitoid magmas. Comparison with data on coeval magmatism in neighboring regions suggests that the Kalba batholith may be included in areal of Early Permian Tarim Large Igneous Province.

Magmatic-hydrothermal tin deposits form in response to efficient tin extraction upon magma degassing

ID: 6146
Year: 2022
Products: NWR193;
Authors: Zhao, P;Zajacz, Z;Tsay, A;Yuan, S;
Journal: Geochimica et Cosmochimica Acta

Most of the global Sn resources are from granite-related ore deposits, which form in response to cassiterite precipitation from hydrothermal fluids. However, the physical and chemical controls on the efficiency of Sn extraction from upper crustal plutons by exsolving magmatic fluids are still unclear. In this study, we determine the partition coefficient of Sn between aqueous fluids and granitic melts () at 800 °C, 150 MPa and the fO2 of the Ni-NiO buffer. To obtain equilibrium partition coefficients, a new experimental method has been used relying on local equilibrium between silicate melt and microscopic-sized fluid bubbles. The latter formed synthetic fluid inclusions in the quenched glasses, which in turn were analyzed by laser ablation inductively coupled plasma mass spectrometry along with the enclosing glass. The results show that at constant aluminum saturation index (ASI = 1.05-1.08) of the silicate melt, increases from 1.9 to 35.0 as the total Cl concentration () in fluid increases from 1.0 to 16.6 mol/kg H2O. At a fixed = 2 mol/kg H2O, increases from 4.3 to 10.6 as the HCl concentration in the solution increases from 0.15 to 0.79 mol/kg H2O, which in turn is a function of the ASI of the melt (ASI = 1.06-1.29). Numerical modeling suggests that Sn is extracted by magmatic fluids from upper crustal plutons most efficiently at the late stage of crystallization and degassing. At a similar degree of crystallization, granitic magma with lower initial water concentration and higher ASI will separate a fluid phase with higher Sn concentration and thus has higher Sn mineralization potential. Due to the relatively high value, fluids exsolved from highly evolved magmas can sequester enough Sn to form Sn deposits and the sub-solidus remobilization of Sn from granite bodies is not a pre-requisite for ore genesis.

What is the relationship between hypoxia, water chemistry, and otolith manganese content?

ID: 6402
Year: 2022
Products: NWR213;ESI;
Authors: Jiang, S;Hong, P;Katayama, S;
Journal: Journal of fish biology

Previous studies have shown an increase in otolith Mn caused by exposure to hypoxic water masses. The mechanism leading to the increases in otolith Mn is still unclear, but might possibly be due to the larger amount of available Mn left in the water column under hypoxia. Thus, this study aimed to examine the relationship between hypoxia, water Mn, and otolith Mn through marbled flounder (Pseudopleuronectes yokohamae, Günther) captured from Tokyo Bay and reared under different water Mn at laboratory. Otoliths from the Bay showed a higher [Mn/Ca]otolith than outside, together with a seasonal trend of high [Mn/Ca]otolith at the start of translucent zones (which form in the summer), supporting the occurrence of summer hypoxia in Tokyo Bay. However, juveniles reared under Control (Mn 0.50 μmol/L), Middle (Mn 6.94 μmol/L) and High (Mn 10.4 μmol/L) treatments of water Mn concentrations showed a disproportional smaller increase in [Mn/Ca]otolith . Comparing the laboratory experiment with the field data, [Mn/Ca]water under hypoxia in Tokyo Bay could reach a low level similar to Control treatment, yet [Mn/Ca]otolith of the Bay showed a higher value than the High treatment. These results revealed an elevated [Mn/Ca]otolith toward hypoxia, but also suggested that changes in water Mn might not be directly recorded by otolith Mn. This article is protected by

The petrogenesis of chemically zoned, phonolitic, Plinian and sub-Plinian eruptions of Somma-Vesuvius, Italy: Role of accessory phase removal, independently filled magma reservoirs with time, and transition from slightly to highly silica undersaturated magmatic series in an ultrapotassic stratovolcano

ID: 6658
Year: 2022
Products: UP213;New Wave;New Wave Research;
Authors: Melluso, L;Scarpati, C;Zanetti, A;Sparice, D;de' Gennaro, R;
Journal: Lithos

A mineralogical, major, LA-ICP-MS trace element mineral chemistry and bulk-rock geochemical study of juvenile samples of the Mercato, Avellino, Pompeii and Pollena eruptions, collected in stratigraphically and volcanologically well-characterized sections of the Somma-Vesuvius stratovolcano (Roman Magmatic Province), along with reference data on the 1944 CE and the Pomici di Base eruptions, highlights the compositional variability of bulk-rock and glass from leucite phonotephrite to garnet-bearing phonolite. The latter products have extreme fractionation of trace elements (e.g., La/Ybn = 126, Zr/Y = 89, Zr/Hf =78, Nb/Ta = 40; Th/U = 2.3), very low Sc, V, Y, HREE and very high As, Tl, Cs, Pb, Th and U. The Pomici di Base products, older than the eruptions described above, range from leucite-bearing shoshonites to trachytes, are devoid of garnet and belong to an independent liquid-line-of-descent, having also different fractionation between trace elements (e.g., La/Ybn = 15; Zr/Y = 12.4, Zr/Hf = 50, Nb/Ta = 15.6; Th/U = 3 in the Pomici di Base trachytes). A marked chemical variability of the observed phases is found. The geochemistry of garnet, amphibole, clinopyroxene and other phases shows wide variations of concentrations and elemental ratios (e.g., La/Ybn up to 520 in the _sadanagaite_ coexisting with garnet). The magmatic evolution is dominated by low-pressure, oxidized, nearly closed-system fractional crystallization of clinopyroxene, plagioclase, leucite, ±magnetite, ±biotite, ±olivine and apatite in the transition tephrite-phonotephrite, and of potassic sanidine (±hyalophane), Fe-clinopyroxene, _melanite_ garnet±Fe-amphibole in the transition tephriphonolite-phonolite. Mineralogic and geochemical evidence and modelling points out the existence of independent, zoned magma batches throughout the activity of the stratovolcano, which possibly started to crystallize at similar depths. The Somma-Vesuvius magmas thus evolved in shallow independent reservoirs with respect to those of the neighbouring volcanic complexes (Campi Flegrei, Ischia) as shown, for instance, by the contrasting compositional trends of clinopyroxene and amphibole, and have very limited evidence of crustal contamination (and/or carbonate assimilation).

The solubility of gold and palladium in magmatic brines: Implications for PGE enrichment in mafic-ultramafic and porphyry environments

ID: 6147
Year: 2022
Products: NWR193;
Authors: Sullivan, N;Zajacz, Z;Brenan, J;Hinde, J;Tsay, A;Yin, Y;
Journal: Geochimica et Cosmochimica Acta

We performed experiments to determine the solubility of Au and Pd in magmatic aqueous fluids as a function of oxygen fugacity (ƒO2), temperature (T), pH and total chloride concentration (Cltotal). Experiments were conducted at 800-1000 °C and 200 MPa in an externally-heated rapid-quench Molybdenum-Hafnium Carbide (MHC) cold-seal pressure vessel assembly. We employed a synthetic fluid inclusion (SFI) technique to entrap equilibrated, hydrothermal fluids in response to in situ fracturing of quartz cylinders at experimental run conditions. The solubility of Au and Pd both have positive relationships with ƒO2, temperature, acidity and chlorinity. Concentrated aqueous brines containing 63 wt.% NaCl can dissolve wt.% levels of Au (∼1.2 wt.%) and Pd (∼1.7 wt.%) at metal saturation in relatively oxidized conditions, 1.44 log units above the Ni-NiO oxygen buffer (NNO+1.44), and mildly acidic pH at 900 °C and 200 MPa. Thermodynamic modeling of experimental results suggests that Au is mainly transported as AuCl(aq) at high pH and low Cltotal conditions, whereas HAuCl2(aq) and potentially AuCl2(aq)− predominates at low pH and high Cltotal conditions. Results from thermodynamic modeling also suggest Pd is mobilized in significant contributions by both PdCl2(aq) and PdCl3(aq)− with the latter gaining predominance in response to increasing Cltotal. Calculated fluid/melt partition coefficients for Au and Pd in low-density, magmatic vapors at 1000 °C and 200 MPa suggest that Pd may experience fractionation from Au in porphyry Au-Cu (±Pd, Pt) systems due to the restricted compatibility of Pd in the fluid phase (requiring strongly acidic and substantially high ƒO2 conditions). Moreover, high-density, concentrated aqueous brines facilitate the compatibility of Pd in the fluid phase which may be important with respect to the formation of platinum-group element (PGE)-enriched horizons in layered mafic intrusions (e.g., J-M Reef, Stillwater Complex, U.S.A.). The potential for magmatic, near-neutral pH, high-salinity brines to dissolve significant amounts of Pd as Pd(II)-chloride complexes (∼400 to ∼900 µg/g) well below the NNO buffer suggests that such fluids may be responsible for late-stage hydrothermal remobilization of Pd within mafic-ultramafic igneous environments (e.g., Cu-Ni-PGE footwall deposits and low-sulfide PGE deposits in the Sudbury Igneous Complex, Canada).

Strontium isotope analysis reveals prehistoric mobility patterns in the southeastern Baltic area

ID: 6403
Year: 2022
Products: NWR193;Electro Scientific Industries;
Authors: Piličiauskas, G;Simčenka, E;Lidén, K;Kozakaitė, J;Miliauskienė, Ž;Piličiauskienė, G;Kooijman, E;Šinkūnas, P;Robson, H;
Journal: Archaeological and Anthropological Sciences

We measured 87Sr/86Sr for all available human remains (_n_ = 40) dating from the Mesolithic to the Bronze Age (ca. 6400-800 cal BC) in Lithuania. In addition, local baselines of archaeological fauna from the same area were constructed. We identified significant and systematic offsets between 87Sr/86Sr values of modern soils and animals and archaeological animals due to currently unknown reasons. By comparing 87Sr/86Sr human intra-tooth variation with the local baselines, we identified 13 non-local individuals, accounting for 25-50% of the analysed population. We found no differences in the frequency of local vs. nonlocals between male and female hunter-gatherers. Six Mesolithic-Subneolithic individuals with 87Sr/86Sr values > 0.7200 may have come from southern Finland and/or Karelia. Two Mesolithic-Subneolithic individuals from the Donkalnis cemetery with 87Sr/86Sr values 

Detrital zircon ages from upper Paleozoic-Triassic clastic strata on St. Lawrence Island, Alaska: An enigmatic component of the Arctic Alaska-Chukotka microplate

ID: 6659
Year: 2022
Products: N/A
Authors: Amato, J;Dumoulin, J;Gottlieb, E;Moore, T;
Journal: Geosphere

New lithologic and detrital zircon (DZ) U-Pb data from Devonian-Triassic strata on St. Lawrence Island in the Bering Sea and from the western Brooks Range of Alaska suggest affinities between these two areas. The Brooks Range constitutes part of the Arctic Alaska-Chukotka microplate, but the tectonic and paleogeographic affinities of St. Lawrence Island are unknown or at best speculative. Strata on St. Lawrence Island form a Devonian-Triassic carbonate succession and a Mississippian(?)-Triassic clastic succession that are subdivided according to three distinctive DZ age distributions. The Devonian-Triassic carbonate succession has Mississippian-age quartz arenite beds with Silurian, Cambrian, Neoproterozoic, and Mesoproterozoic DZ age modes, and it exhibits similar age distributions and lithologic and biostratigraphic characteristics as Mississippian-age Utukok Formation strata in the Kelly River allochthon of the western Brooks Range. Consistent late Neoproterozoic, Cambrian, and Silurian ages in each of the Mississippian-age units suggest efficient mixing of the DZ prior to deposition, and derivation from strata exposed by the pre-Mississippian unconformity and/or Endicott Group strata that postdate the unconformity. The Mississippian(?)-Triassic clastic succession is subdivided into feldspathic and graywacke subunits. The feldspathic subunit has a unimodal DZ age mode at 2.06 Ga, identical to Nuka Formation strata in the Nuka Ridge allochthon of the western Brooks Range, and it records a distinctive depositional episode related to late Paleozoic juxtaposition of a Paleoproterozoic terrane along the most distal parts of the Arctic Alaska-Chukotka microplate. The graywacke subunit has Triassic maximum depositional ages and abundant late Paleozoic grains, likely sourced from fringing arcs and/or continent-scale paleorivers draining Eurasia, and it has similar age distributions to Triassic strata from the Lisburne Peninsula (northwestern Alaska), Chukotka and Wrangel Island (eastern Russia), and the northern Sverdrup Basin (Canadian Arctic), but, unlike the Devonian-Triassic carbonate succession and feldspathic subunit of the Mississippian(?)-Triassic clastic succession, it has no obvious analogue in the western Brooks Range allochthon stack. These correlations establish St. Lawrence Island as conclusively belonging to the Arctic Alaska-Chukotka microplate, thus enhancing our understanding of the circum-Arctic region in late Paleozoic-Triassic time.

A window into an older orogenic cycle: P-T conditions and timing of the pre‐Alpine history of the Dora‐Maira Massif (Western Alps)

ID: 6148
Year: 2022
Products: NWR193UC;ESI;
Authors: Nosenzo, F;Manzotti, P;Poujol, M;Ballèvre, M;Langlade, J;
Journal: Journal of Metamorphic Geology

Compositional profile of pre-Alpine garnet from garnet-staurolite micaschist (GM1) for major (a) and trace elements (b-d). (b) Compositional profile of Y and sum of HREE and MREE. (c) Compositional profile of Zr and Hf. (d) Compositional profile of P. (e) Chondrite-normalized REE pattern (McDonough & Sun, 1995) for pre-Alpine garnet in sample GM1. (f) Compositional profile of polycyclic garnet from garnet micaschist (GM13) (colour coding as in (a)). Vertical orange lines mark the boundaries between the first and second garnet generations. The position of the profiles (a) and (f) is indicated in Figure 6d and Figure 8e, respectively (lines A-B) [Color figure can be viewed at wileyonlinelibrary.com [http://wileyonlinelibrary.com]] A _HP_ mineral assemblage consisting of high-Si muscovite, paragonite, chloritoid, glaucophane (never preserved but pseudomorphed), and rutile developed during the Alpine cycle (Alpine stage 1, Figure 5b). High-Si muscovite (Si = 3.37-3.50 a.p.f.u., XNa = 0.01-0.07) overgrows concentrically pre-Alpine muscovite (Figure S2) or forms new crystals. The latter display numerous tiny rutile crystals and may be derived from pre-Alpine biotite. Paragonite (XNa = 0.92) and chloritoid (~300 μm in size) are postkinematic with respect to the pre-Alpine foliation. Sample GM1 does not display a second generation of garnet. By contrast, tiny (50 to 100 μm in size) idioblastic garnet crystals have been observed in sample GM2 collected in the same area. Chloritoid shows chemical zoning, with increasing Fe content from the core (XFe = 0.70-0.71) to rim (XFe = 0.73-0.79). Fine-grained elongated or lozenge-shaped aggregates of chlorite are interpreted as pseudomorphs after sodic amphiboles, as reported in other Alpine units with similar metamorphic evolution (Compagnoni, 1977; Manzotti et al., 2021). Rutile occurs in the matrix as tiny needles and as large crystals (maximum 100 μm in length). During a second Alpine stage (Alpine stage 2; Figure 5b) chlorite statically grows in the matrix and replaces garnet whereas ilmenite forms coronas around rutile. Paragonite, rare albite, and epidote also grow during this stage.

Rutile to titanite transformation in eclogites and its geochemical consequences: An example from the Sumdo eclogite, Tibet

ID: 6404
Year: 2022
Products: ~
Authors: ZHAO, L;ZENG, L;GAO, L;HU, M;SUN, D;ZHANG, L;
Journal: Acta Geologica Sinica - English Edition

Titanite corona formed after rutile is common in retrograde high- to ultrahigh-pressure meta-mafic rocks, which provides a good opportunity to address the geochemical behavior of HFSE in crustal environments. In the Sumdo eclogite, titanite occurs either as corona around rutile grains or as semi-continuous veins crosscutting the major foliation, whereas rutile grains occur either as inclusions in garnet or omphacite or as relict core surrounded by titanite. Texture relationships and the trace elements characteristics of rutile and titanite with different occurrence indicated that both minerals preferred incorporate Nb and Hf over Ta and Zr in the aqueous fluid. Moreover, the breakdown of omphacite and epidote could release substantial amounts of aqueous fluids enriched in Ca, Si, Fe and REE, which reacts with rutile to form titanite corona and vein. During this process, water-insoluble elements, like HFSE and HREE, behave like mobile elements, but they do not migrate substantially out of the system, instead, they tend to react in situ. This might imply that the aqueous fluids released during the retrograde metamorphic reactions in mafic rocks could not substantially transfer fluid-immobile elements into the overlying mantle wedge in subduction environments.

Origin of the Woxi Orogenic Au-Sb-W Deposit in the West Jiangnan Orogen of South China: Constraints from Apatite and Wolframite U-Pb Dating and Pyrite in-situ S-Pb Isotopic Signatures

ID: 6660
Year: 2022
Products: NWR193;
Authors: Dai, J;Xu, D;Chi, G;Li, Z;Deng, T;Zhang, J;Li, B;
Journal: Ore Geology Reviews

The majority of gold mineralization in the Jiangnan Orogenic Belt (JOB) of South China share similarities with the orogenic type, but the nature of mineralization remains controversial, especially in terms of intracrustal versus subcrustal origin of ore fluids and metals and their relationships with the subduction of the Paleo-Pacific plate. This paper reports results of in situ analyses of minerals closely related to gold mineralization, including U-Pb ages of apatite and wolframite, and S-Pb isotopes of pyrite, from the Woxi Au-Sb-W deposit in the western Jiangnan orogen, and use them to address the above problems. The Woxi deposit, which consists of several auriferous quartz lodes hosted by ductile-brittle shear zones in the Neoproterozoic slate. The hydrothermal mineralization and alteration processes are divided into four stages. Early-ore stage (S1) is characterized by disseminated, euhedral, porous, coarse auriferous pyrite (Py1) with minor amounts of arsenopyrite, siderite, and rutile in the bleached slate. Main-ore stage (S2) is characterized by subhedral to euhedral, auriferous pyrite (Py2) with compositional zoning, with small amounts of wolframite and apatite in quartz veinlets. Late-ore stage (S3) is represented by scheelite and stibnite with minor amounts of native gold and anhedral, dendritic auriferous pyrite (Py3) in quartz veinlets. Post-ore stage (S4) features a quartz-calcite-barite-chlorite mineral assemblage that occurs as veinlets or in pressure shadows of Py1. Apatite and wolframite associated with Py2 yield a consistent U-Pb age of ca. 141 Ma, which is corresponded to a time when the Paleo-Pacific plate started to roll back, and a Basin-and-Range style tectonic regime began to developing in South China. The different stages of pyrite have variable S isotopes, with the δ34SCDT values (mainly between -6‰ and +1‰) largely overlapping with those of the metasomatized mantle (-5‰ ∼ + 5‰), and Pb isotope ratios between crustal and mantle values. Taking these results together, we proposed that the Woxi deposit and many other gold deposits in the JOB formed from subcrustal processes involving the metasomatized upper mantle above the subduction zone. Given the extended distance from JOB to the Paleo-Pacific plate boundary, the metasomatized mantle underneath the JOB is likely initially formed during the plate subduction leading to the formation of the JOB during the Neoproterozoic, which is further fertilized by upwelling asthenosphere due to rollback of the Paleo-Pacific plate in the Mesozoic.

Geochronology and Geochemistry of the Granite Xenolith within the Lamprophyre at the Zhenyuan Gold Deposit (Yunnan Province, SW China)

ID: 6405
Year: 2022
Products: NWR213;
Authors: ZHANG, H;ZHANG, H;HOU, Z;CHAI, P;ZHOU, K;
Journal: Acta Geologica Sinica - English Edition

The xenoliths in host rocks of hydrothermal gold deposits can generally provide much geochemical information of the deep rocks, which may have an implication for the sources of ore-forming materials. Geochronology and geochemical characteristics are reported for a granite xenolith, which is enclosed by the lamprophyre in the Zhenyuan gold deposit (Yunnan Province, SW China). This granite xenolith mainly consists of K-feldspar, quartz, and plagioclase with trace amounts of magnetite, titanite, apatite, zircon, and sulfides. Zircons from the granite xenolith yield a weighted average U-Pb age of 281.1 ± 1.3 Ma (MSWD = 2.1), which could represent the crystallization age of this granite xenolith. The Ti-in-zircon geothermometer and the Mn concentration in apatite calculate that this granite xenolith formed at 685 ± 43°C with the lgfO2 values ranging from NNO + 3.7 to NNO + 6.4. The zircons in the granite xenolith have a restricted range of positive εHf(t) values ranging from +9.4 to +10.8, and the corresponding Hf TDM2 model ages range from 588 to 678 Ma. The zircon U-Pb age and the Hf isotopic compositions indicate this granite xenolith within the Lamprophyre is mainly derived from partial melting of juvenile crustal rocks before the completed closure of the Ailaoshan Ocean. The pyrites in the granite xenolith have higher Bi concentrations, and lower As, Sb, and Tl concentrations than the gold-bearing pyrites of the ores in the Zhenyuan gold deposit. The low Au concentrations of the pyrites together with the ore-forming age of the Zhenyuan gold deposit (Oligocene) indicate the granite xenolith may have limited contribution to the gold mineralization of the Zhenyuan gold deposit.

Geochronology and geochemistry of gneiss and migmatite from the Korla Complex in the Quruqtagh block, NW China: Implications for Proterozoic crustal evolution of the northeastern Tarim Craton

ID: 6661
Year: 2022
Products: UP213;NewWave;
Authors: Sun, X;Li, X;Lei, R;Yang, X;Chen, J;Wu, C;
Journal: Ore Geology Reviews

The Korla Complex in the Quruqtagh block of the northeastern Tarim Craton records Proterozoic tectono-thermal events and provides a window to understand the role of Tarim during the Columbia-Rodinia supercontinent cycle. Here we present zircon U-Pb ages, Lu-Hf isotopic compositions and bulk-rock geochemical data of gneisses and leucosomes of migmatites from the Korla Complex. Zircon grains from the orthogneiss exhibit core-rim structure, nevertheless the core and rim domains have indistinguishable ages, and jointly defined the Paleoproterozoic metamorphism of 1842 ± 35 Ma, which was ascribed to assembly of the Tarim Craton to the Columbia supercontinent along interior accretionary orogen. The leucosomes of migmatites were formed at 814 ± 3 Ma, and the consistent Hf isotope characteristics of newly grown anatectic zircon and inherited zircon of their protolith, indicates that the migmatite was formed by in-situ crustal anatexis associated with subduction-accretion process. Therefore, it is inferred that the assembly of the Tarim Craton to the Rodinia supercontinent lasted at least until ca. 0.81 Ga. Since this accretionary orogenic event (ca. 0.81 Ga) occurred during the initial breakup stage of the Rodinia supercontinent (0.83 Ga), it indicates that the Tarim Craton was probably located at peripheral position in the Rodinia reconstruction with long-lasting peripheral subduction and accretion. Collectively, it is suggested that the Tarim Craton was involved in global scale tectonic evolution during the Columbia-Rodinia supercontinent cycle. In combination with previous studies, it is proposed that the Tarim-North China connection within the Paleoproterozoic Columbia supercontinent must have broken-up before the Tarim-South China affinity within the Neoproterozoic Rodinia supercontinent, ascribed to the breakup of Columbia supercontinent.

Quantitative imaging of trace elements in brain sections of Alzheimer’s disease mice with laser ablation inductively coupled plasma-mass spectrometry

ID: 6150
Year: 2022
Products: NWRimage;
Authors: Liu, J;Zheng, L;Wei, X;Wang, B;Chen, H;Chen, M;Wang, M;Feng, W;Wang, J;
Journal: Microchemical Journal

Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has become a powerful technique for imaging of trace elements in biological samples. However, accurately quantitative imaging is still a complicated task due to lack of matrix-matched standard materials. On the other hand, traditional LA-ICP-MS analysis usually suffers from slow analytical speed and low imaging resolution mainly due to a long washout time of an ablation cell and a low repetition rate of a laser. In this work, a series of homemade matrix-matched standards were produced by homogeneous spiking of gelatin with a known amount of trace elements (Fe, Cu, and Zn). Using these standards, quantitative imaging of Fe, Cu, and Zn in the brains of Alzheimer's disease (AD) and control mice were achieved using a laser ablation system with a low-dispersion cell and a high repetition rate laser coupled to a triple quadrupole ICP-MS. The limits of detection of Fe, Cu, and Zn are 5.4 μg g−1, 0.081 μg g−1, and 0.54 μg g−1, respectively. The concentrations of Fe, Cu, and Zn in mouse brains are 10 ∼ 70 μg g−1, 5 ∼ 30 μg g−1, and 25 ∼ 150 μg g−1, respectively. The quantitative imaging shows different distribution and contents of these metals between AD and control mouse brains. The developed LA-ICP-MS approach is expected to provide a new insight into biological effects of metals and aetiology of metal-related diseases.

Initiation and Development of the Late Cenozoic Uplift of Daluo Mts, Northeastern Margin of the Tibetan Plateau

ID: 6406
Year: 2022
Products: UP213;
Authors: KOU, L;DONG, X;LI, Z;CUI, J;MA, Z;Li, H;
Journal: Acta Geologica Sinica - English Edition

Daluo Mts lies at the leading edge of the arcuate tectonic belt at the northeastern margin of the Tibetan Plateau, and is the landform boundary zone between the active Tibetan Plateau and the stable North China Craton. Understanding the late Cenozoic uplift of Daluo Mts is important for discussing the expansion of the arcuate tectonic belt of the northeastern margin of the Tibetan Plateau and its influence on the western North China Craton. In this study, the late Cenozoic uplift of Daluo Mts is reconstructed from the development of the late Cenozoic alluvial fan around Daluo Mts. The entire sedimentary sequence and framework of the fan was reconstructed on the basis of the newly obtained drilling data. The initial timing of the late Cenozoic uplift of Daluo Mts and the key stages of uplift during the Pleistocene were reconstructed using cosmogenic nuclide, optically stimulated luminescence, and detrital zircon U-Pb dating analyses. The late Cenozoic alluvial fan at the front of Daluo Mts overlies a set of fluvial-facies strata; therefore, the commencement of alluvial-fan development marks the start of the late Cenozoic uplift of Daluo Mts. The timing of this event can be constrained to ∼4.64 Ma. Two extensive gravel layers (dated to ∼0.76-0.6 Ma and ∼0.05 Ma) developed during the Pleistocene, indicating two episodes of considerable uplift. This study provides a new time scale for the uplift and expansion of the arcuate tectonic belt at the northeastern margin of the Tibetan Plateau.

Genesis of the Bayan qagan dongshan Sn-Pb-Zn-Ag deposit, NE China, based on sphalerite chemistry and sulfur isotope

ID: 6662
Year: 2022
Products: UP213;New Wave;
Authors: Zhang, P;Peng, B;Zhao, J;Guo, G;Zuo, Y;Xing, Y;
Journal: Ore Geology Reviews

The Bayan qagan dongshan Sn-Pb-Zn-Ag deposit (223,383 t Sn @ 0.755 %; 9,446 t Ag @ 187.46 g/t; 752,944 t Zn @ 1.60 %; 150,828 t Pb @ 0.521 %) is mainly hosted by the contact zones between early Cretaceous granite porphyry and Permian epimetamorphic rock in the southern part of the Great Khingan Range of northeastern China. Nevertheless, the migration and precipitation form of silver in the deposit is undefined. In this study, seven subtypes of sphalerite (SpⅠ, SpⅡ-1, SpⅡ-2a, SpⅡ-2b, SpⅡ-2c, SpⅡ-3a and SpⅡ-3b) were identified according to mineral assemblages in the quartz-tourmaline-sericite-sphalerite stage (Ⅰ) and cassiterite-sulfide stage (Ⅱ) of the deposit. SpⅠ is distributed in the granite porphyry as disseminated ores, accompanied by tourmalinization and fluoritization. SpⅡ-1 is predominantly associated with cassiterite, whereas SpⅡ-2 (including SpⅡ-2a, SpⅡ-2b and SpⅡ-2c) mainly coexisted with stannite, in which chalcopyrite exsolution is found. SpⅡ-3 (including SpⅡ-3a and SpⅡ-3b) is mainly characterized by its irregular shape, and intimately associated with galena and Sb-bearing mineral. Representative time-resolved depth profile and inter-element correlation analyses based on the LA-ICP-MS method illustrated that: 1) Fe, Cd, Mn, Co, Cu, In, Ag and Sb are present in solid solutions formed through direct cation substitution as Zn2+ ↔ (Fe2+, Cd2+, Mn2+, Co2+) and coupled substitution as Zn2+ ↔ Cu+ + In3+ and Zn2+ ↔ Ag+ + Sb3+; 2) Pb, Bi, Sn and Te may be intimately associated with galena and Sn-bearing telluride inclusions hosted by sphalerite. The characteristics of trace and minor elements, along with the results of sulfur isotope studies, suggest that: 1) the ore forming temperature of Bayan qagan dongshan deposit gradually decreases and the silver mineralization mainly occurred in the late stage; 2) the changes of physicochemical conditions (e.g., temperature and pressure) are likely to be an important depositional mechanism for Ag in the Bayan qagan dongshan deposit; 3) the Bayan qagan dongshan deposit may belong to magmatic-hydrothermal origin.

Timing constraints on alkaline magmatic activity and implications for lithospheric thinning beneath the North China Craton: evidence from zircon geochronology of syenite from the Huyanshan complex in the Lyuliangshan uplift belt, Shanxi Province

ID: 6407
Year: 2022
Products: NWR193;ESI;
Authors: Liu, Y;Zou, G;Zhou, R;Liu, D;
Journal: Arabian Journal of Geosciences

The Huyanshan alkaline complex is distributed in the Huyanshan area of Jiaocheng County, Shanxi province, China. The syenite, representing the last stage of episodic magmatism in the central North China Craton (NCC), can be used to refine the age of this alkaline complex. LA-ICP-MS zircon U-Pb dating was conducted on the syenite and three populations of zircons with three different ages were obtained: ~ 127 Ma, ~ 1.8 Ga, and ~ 1.92 Ga. The last intrusive syenite yields a weighted mean 206Pb/238U age of 127.5 ± 3.4 Ma (_n_ = 3, MSWD = 0.44), implying an Early Cretaceous age, which corresponds to the peak time of magmatic activity and lithospheric thinning in the NCC. The syenite formed in an intraplate extensional setting probably associated with the retreat of the subducting Paleo-Pacific plate. The zircons with an age of ~ 1.92 Ga are the products of important tectono-magmatic and thermal events in the Precambrian, corresponding to the collision between the Yinshan and Ordos Blocks to form the Western Block of the NCC. The age of ~ 1.8 Ga records continental rift-related magmatic events under an extensional regime after the suture of the Western Block and the Eastern Block to form the coherent basement of the NCC.

Age and evolution of the Nanyangshan rare-metal mineralized pegmatite revealed by cassiterite U-Pb geochronology and tourmaline chemistry

ID: 6663
Year: 2022
Products: NWR213;ESI;
Authors: Han, J;Chen, H;Zhang, J;Zhang, Y;Zhang, R;
Journal: Ore Geology Reviews

Determing the age and precise bulk composition of pegmatites is challenging due to 1) the metamictization of zircon grains and 2) their coarse grain size and heterogeneity. Cassiterite and tourmaline are common in pegmatites and in the case of the former can be used to date pegmatites and while the latter can be used to monitor petrogenesis. This study presents in situ cassiterite U-Pb dating and tourmaline geochemical and B isotopic data from the Nanyangshan Li-Be-Nb-Ta-Rb-Cs-Sn mineralized pegmatite in the North Qinling terrane of China to investigate their age and petrogenesis. The Nanyangshan pegmatite host abundant spodumene, lepidotite, beryl, cassiterite, columbite and tourmaline and can be roughly divided into black tourmaline (Tur B)-cassiterite and pink tourmaline (Tur P)-spodumene bearing phases. Most of the cassiterite are homogenous in appearance although some (

Anatexis of metadiorite from the Yaoundé area, Central African Orogenic Belt in Cameroon: implications on the genesis of in-source granodiorite leucosomes

ID: 6408
Year: 2022
Products: NWR193;ESI;
Authors: Metang, V;Nomo Negue, E;Ganno, S;Takodjou Wambo, J;Teme, M;Teda Soh, A;Fossi, D;Mbakam Nkamga, M;Tchameni, R;Nkoumbou, C;Nzenti, J;
Journal: Arabian Journal of Geosciences

This paper presents integrated whole-rock geochemistry, LA-ICP-MS zircon U-Pb geochronology, and zircon and monazite thermometry of the Yaounde in-source granodiorite leucosomes in order to better constrain the crustal growth of the Yaoundé segment of the Central African Orogenic Belt (CAOB). The Yaoundé area is dominantly made up of extensively melted metadiorites hosting partially digested enclaves of metasediments and in-source granodiorite leucosomes. Field investigations have revealed that the regional structure is dominated by the shallow-dipping to occasionally subvertical _S__n_ foliation characterized by variable trending resulting to the transposition of the locally E-W trending _S__n_-1 foliation in metadiorite. New LA-ICP-MS zircon U-Pb geochronology indicates partial melting age crystallization at 595 ± 4 Ma for the in-source granodiorite leucosomes. This in the Yaoundé area is coeval with and emplacement of some syntectonic granitoids of the CAOB. Metadiorites are high-K calc-alkaline while granodiorite leucosomes are medium-K calc-alkaline and both rocks are magnesian, display LREE enrichment, and LILE depletion as well as strong depletion in Nb-Ta, Sr, P, and Ti. The protholith of the Yaoundé metadiorites derived from partial melting of mixed source involving a metasomatized mantle with the contribution of crustal materials. In-source granodiorite leucosomes derived from the partial melting of metadiorites during a period of intense migmatization in the Yaoundé group. The average _T__Zr__ T__Ti-in-zr_ and _T_REE (ca. 794 °C, 767 °C, 821 °C, respectively) estimates of the melts are similar to estimated temperatures (ca. 750-800 °C) for the host metadiorites, suggesting that the melting took place in the deep crustal level as inferred by estimated pressure of 9-13 kbar.

Hydrothermal rutile U-Pb dating of gold mineralization in the Jiangnan Orogen: A case study of the Hengjiangchong gold deposit in northeastern Hunan

ID: 6664
Year: 2022
Products: NWR193;
Authors: Zhan, Y;Shao, Y;Liu, Q;Zhang, X;Chen, M;Lu, Y;Zhang, Y;Tan, H;
Journal: Ore Geology Reviews

The Jiangnan Orogen is a well-known gold belt in China with a large number of gold deposits. The Jiangnan Orogen has complex geological history, and most gold deposits have not been well dated. Consequently, the regional timing of gold mineralization is still controversial. The Hengjiangchong is a representative gold deposit in the orogen. In this study, syn-ore hydrothermal rutile in quartz-polymetallic sulfides-gold-calcite veins was dated by LA-ICP-MS, yielding a Tera-Wasserburg lower intercept U-Pb date of 416.1 ± 7.3 Ma (2σ, n = 26, MSWD = 2.4). This date represents the age of gold mineralization at Hengjiangchong, and falls within the generally accepted timing of gold mineralization in the Jiangnan Orogen (ca. 425-400 Ma). Combined with the regional kinematics, gold mineralization likely occurred during the extension associated with the Yangtze-Cathaysia post-collisional deformation in the Siluro-Devonian intracontinental orogen. This also indicates that the late Silurian was a major gold mineralization epoch in the Jiangnan Orogen, challenging to some previous claims that late Silurian hydrothermal veins are largely ore barren.

Geochemistry and U-Pb zircon age of the Paleoproterozoic metasedimentary rocks from the Bidou I, Nyong Series, Cameroon: Implications for provenance and tectonic setting

ID: 6409
Year: 2022
Products: NWR193;ESI;
Authors: Woguia, B;Nono, G;Tsoungui, P;Njiosseu, E;Kenne, P;Nzenti, J;
Journal: Arabian Journal of Geosciences

The Bidou I polymetallic prospect, located in the Nyong series, belongs to the northwestern edge of the Congo craton and consists of metasedimentary rocks. Combination of geochemistry with U-Pb zircon dating of these metamorphic formations was used to constrain the source and the tectonic setting of their protolith. Samples are highly enriched in SiO2 (54.4-88.06%) and Al2O3 (5.81-19.66%), depleted in CaO with a very high K2O/Na2O ratio > 1, which are characteristics of metasedimentary rocks. The studied samples are garnet gneisses and garnet micaschists having arkoses and greywackes as inferred protoliths, respectively. The felsic/intermediate nature of those protoliths is related to intracrustal differentiation of sedimentary recycling, marked by the accumulation of zircon. The metasediments undergone weak chemical alteration, range from immature to slightly mature and were derived from a moderately altered sedimentary source in an active tectonic setting. The protoliths of the Bidou I metasedimentary rocks are from the upper continental crust and were deposited in an active or passive continental margin. The duality of the tectonic setting highlights the progressive change in the geometry of the basin and the development of a continental island arc. U-Pb zircon dating yields ages of 2065 ± 25 Ma for garnet gneisses and 2405 ± 24 Ma for garnet micaschists. These new ages are consistent with the data presented by previous works at the NW border of the Congo craton in Cameroon.

Contrasting geochemical signatures between fertile and barren granites and multi-isotope (Sr-Nd-Pb-S-He) study in the Lamasu-Saibo deposit, NW China: Implications for petrogenesis and ore genesis

ID: 6665
Year: 2022
Products: NewWave;
Authors: Liu, J;Mao, J;Lai, C;Wang, X;He, J;Xie, H;
Journal: Ore Geology Reviews

There are abundant porphyry/skarn Cu deposits in the Chinese Western Tianshan (NW China). However, the differences between the fertile and barren granitoids, and the metal enrichment mechanism remain controversial. The Lamasu-Saibo deposit (0.6 Mt Cu @ 0.3-6.3 %) is the first large-scale Cu discovery in the Chinese Western Tianshan. The Cu orebodies are mainly hosted in the exoskarn of the Proterozoic Kusongmuqieke Group. Here, we present a geochemical comparison study of the fertile and barren granitoids in the Lamasu-Saibo deposit. The fertile granodiorite porphyry and barren granite porphyry have zircon U-Pb (LA-ICPMS) ages of 381 ± 2 Ma and 379 ± 2 Ma, respectively. Chalcopyrite from skarn ore yielded a Re-Os age of 379 ± 14 Ma. Hence, the Lamasu-Saibo deposit is suggested to be the oldest Cu mineralization in the Chinese Western Tianshan. The granodiorite porphyry and granite porphyry have similar LREE enriched and HREE depleted patterns, typical of average continental crust. The ISr values are calculated to range from 0.707852 to 0.708105 for granite porphyry, 0.708841 to 0.710817 for granodiorite porphyry, respectively. The εNd(t) values of granite porphyry and granodiorite porphyry range from -4.71 to -4.22 and -4.55 to -3.87, respectively. The granite porphyry has 206Pb/204Pb = 18.522 to 18.798, 207Pb/204Pb = 15.552 to 15.569, and 208Pb/204Pb = 38.472 to 38.639; whilst the granodiorite porphyry has 206Pb/204Pb = 18.598 to 18.960, 207Pb/204Pb = 15.544 to 15.566, and 208Pb/204Pb = 38.130 to 38.306. Whole-rock geochemistry and Sr-Nd-Pb isotopes suggest that these granitoids were derived from partial melting of Proterozoic lower crust, and that the parental magma could be metasomatized by subduction-related sediments. The fertile granodiorite porphyry has relatively higher zircon CeN/CeN* ratio (34 - 202, avg. 111), Ce4+/Ce3+ ratio (88-374, avg. 221), Ce/Nd ratio (7 - 23, avg. 15), log ƒO2 (-16.8 to -13.7, avg. -15.6) and ΔFMQ values (-1.0 to + 1.5, avg. 0.3) than those of the barren granite porphyry (zircon CeN/CeN* ratio: 5 - 54 (avg. 34); Ce4+/Ce3+ ratio: 14-123 (avg. 73); Ce/Nd ratio: 2 - 10 (avg. 6); logƒO2 value: -17.4 to -14.5 (avg. -16.3); ΔFMQ value: -3.2 to + 0.5 (avg. -1.0). The fertile granodiorite porphyry has higher apatite Cl content (0.25 to 0.62 wt%, avg. 0.38 wt%) and lower F/Cl ratio (2.8 to 9.9, avg. 6.7) than those of the barren granite porphyry (apatite Cl content: 0.08 to 0.24 wt%, avg. 0.15 wt%; F/Cl ratio: 9.3 to 29.4, avg. 16.4). This suggests that the fertile granodioritic magma was “wetter” and higher oxidized. Sulfide S-Pb isotope compositions indicate that the ore-forming materials were derived from the granitoids, whilst He isotopes indicate that the ore fluids were dominantly crustal-derived.

Neoarchean arc magmatism and Paleoproterozoic high-pressure granulite-facies metamorphism in the southern Motloutse Complex, eastern Botswana: Implications for the western extension of the Limpopo Complex

ID: 6154
Year: 2022
Products: NWR213;ESI;
Authors: Basupi, T;Tsunogae, T;Takahashi, K;Tsutsumi, Y;
Journal: Precambrian Research

We provide the first record of the occurrence of high-pressure garnet-bearing amphibolite and mafic granulite hosted by amphibolites from the Maope area of the southern Motloutse Complex in eastern Botswana. The mineral assemblages of the rocks are garnet + edenite + plagioclase + ilmenite + rutile + quartz (garnet-bearing amphibolite), magnesio-hornblende + orthopyroxene + clinopyroxene + plagioclase + quartz (mafic granulite), and magnesio-hornblende + plagioclase + quartz + ilmenite + epidote + titanite (host amphibolite). The poikiloblastic garnet in the garnet-bearing amphibolite contains inclusions of edenite, ilmenite, quartz, and plagioclase as prograde minerals, while it is mantled by ferro-edenite + plagioclase coronae formed during retrograde metamorphism. The geochemical signatures of the mafic granulite and amphibolite, combined with the enrichment of large-ion lithophile elements and depletion of high-field strength elements (Nb and Ta), indicate subduction-related volcanic arc affinity, whereas the garnet-bearing amphibolite indicates subduction-related volcanic arc or within-plate basalt affinity. The peak metamorphic condition of the garnet-bearing amphibolite was constrained as 850-910 °C and 10.0-10.5 kbar based on phase equilibrium modeling in the Na2O-CaO-FeO-MgO-Al2O3-SiO2-H2O-TiO2-Fe2O3 (NCFMASHTO) system and geothermobarometry. Slightly lower conditions were obtained from the mafic granulite (745-825 °C) and amphibolite (610-750 °C). Zircon grains from the garnet-bearing amphibolite with lower Th/U ratios of 0.02-0.23 yielded a weighted-mean 207Pb/206Pb age of 2020.2 ± 4.9 Ma as the timing of high-grade metamorphism. In contrast, oscillatory-zoned zircons from the mafic granulite with higher Th/U ratios of 0.44-0.86 recorded a magmatic age of 2648.8 ± 9.8 Ma. As the age is consistent with previously reported age of a tonalite gneiss (2645 Ma) from the same region, we infer bimodal arc magmatism during Neoarchean. The results of this study indicate that the southern Motloutse Complex underwent high-pressure granulite-facies metamorphism with post-peak decompression along a single clockwise P-T evolution during Paleoproterozoic Era (∼2.02 Ga). Our integrated petrological and geochronological studies suggest that the southern Motloutse Complex is nearly equivalent to the Beit Bridge Complex as a possible western extension of a collisional suture (the Central Zone of the Limpopo Complex) between the Archean Kaapvaal and Zimbabwe Cratons. The occurrence of ca. 2.0 Ga high-pressure granulite-facies rocks from the southern Motloutse Complex might suggest multiple collisions of discrete crustal units during Neoarchean to Paleoproterozoic.

Zircon U-Pb dating and geological significance of the Dzhalinda intrusion in the Kirovskoe gold deposit, Russia

ID: 6410
Year: 2022
Products: NewWave;
Authors: Li, B;Yang, Y;Wang, J;
Journal: Arabian Journal of Geosciences

The Dzhalinda intrusion is closely related to the mineralization of the Kirov gold deposit in the Far East of Russia. Based on the characterization of the petrology, geochemistry, and zircon U-Pb chronology of the Dzhalinda intrusion, this paper investigates the age, geochemical characteristics, and tectonic setting of the intrusion. The main rock is granodiorite. Petrological and geochemical analysis results show that the rocks have quartz (20%), potash feldspar (15%), plagioclase (60%), and biotite (3%), and belong to the calc-alkaline series. Trace element and rare earth element (REE) abundances suggest that the magma may primarily have originated from above the oceanic crust subduction of oceanic lithosphere mantle partial melting, wedge, and contamination by crustal material. Zircon U-Pb dating indicates that the Dzhalinda intrusion was formed in the Early Cretaceous, 125.44 ± 0.69 Ma. Combined with regional data, the Dzhalinda intrusion is considered to be formed by the subduction of the ancient Pacific plate with the Eurasische plate. Mineralization of the Kirovskoe gold deposit was the filling of the hydrothermal fluid along the NNE- and NW-trending faults following the magmatic period of the Dzhalinda intrusion.

Episodic Au-Mo mineralization events in the Xiaoqinling district, southern margin of the North China Craton

ID: 6666
Year: 2022
Products: NWR193;
Authors: Liu, J;Wang, Y;Mao, J;Jian, W;Hu, Q;Wei, R;Zhang, X;Hao, J;Wang, J;
Journal: Ore Geology Reviews

The Xiaoqinling district, located in the southern margin of the North China Craton, is one of China’s most significant gold districts (resources of > 630 t Au). A complex series of overprinting Mesozoic tectonic and related hydrothermal events associated with the metallogenic evolution in this region has led to controversial interpretations and models. Here we present new geological, mineralogical, ore texture, geochronological, and in-situ S isotope data from the Dahu Au-Mo, Qinnan Au-Mo, and Tonggou Au deposits from this region which indicate that the Mo and Au were introduced in two discrete mineralization events. The Mo-bearing mineral assemblage mainly comprises quartz, anhydrite, pyrite, molybdenite, and rutile that yielded an age of 216.1 ± 9.7 Ma at Dahu. In-situ LA-ICP-MS δ34S values for the molybdenite and related pyrite cluster tightly at -10 to -9‰. On the other hand, the Au-bearing mineral assemblage mainly comprises quartz, pyrite, galena, sphalerite, chalcopyrite, native gold, and Te (±Bi) minerals. Hydrothermal rutile and monazite associated with auriferous pyrite yielded ages of 124.7 ± 3.9 Ma (Dahu), 121.5 ± 1.3 Ma (Qinnan), and 122.1 ± 2.0 Ma (Tonggou). The in-situ δ34S values of gold-related sulfides fall within a range of -4 to + 3 ‰. Although Mo and Au ores are both present in the same ore veins, their mineral assemblage, mineralization age, fluid properties and sources are different. Textural relationship shows that the earlier Mo-bearing quartz-anhydrite veins were overprinted by later auriferous fluids. Several lines of evidence support a multiphase mineralization process of Mo and Au, which are genetically linked to the post-collisional extension of the Qinling orogen and the Paleo-Pacific post-subduction tectonics, respectively. The episodic hydrothermal mineralization in Xiaoqinling represents a protracted and complex lode system.

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