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The transmission electron microscopy (TEM) specimen with thickness in nanometer scale is susceptible to hydrocarbon contamination and oxidation, and the specimen holder is also susceptible to contaminants, which would deteriorate the quality of TEM imaging and degrade the efficiency of TEM experiments. Conventional pretreatment devices often have limited functions and low practicability, which may cause problems for TEM specimens and holders. In this work, a multifunctional apparatus for plasma cleaning and storage of TEM specimens and specimen holders is developed based on the specific design of the vacuum joints. The apparatus includes a plasma cleaning system, holder storage station, and specimen storage station, which share the same vacuum system. The cleaning of hydrocarbon contaminants on the specimen and storage of the specimens and holders can be achieved simultaneously in this apparatus. TEM imaging and energy‐dispersive X‐ray spectroscopy (EDS) analyses of two treated specimens using the apparatus demonstrated that it could effectively remove hydrocarbon contaminants on the specimen. The holder storage station, used to preserve TEM holders in vacuum conditions, can also be modified as a specimen storage station by an appropriate design of the specimen storage platform, in which specimens are protected from water and contaminations. The designed apparatus not only robustly avoids damage to the ultrathin specimen and holders but also improves the working efficiency and reduces costs. These advantages could make our apparatus more appealing for the complement to the present commercial plasma cleaning and storage devices. Highlights: An apparatus for the pretreatment of transmission electron microscopy (TEM) specimens and specimen holders with three functions—plasma cleaning, holder storage, and specimen storage—was designed and fabricated. Using this single apparatus, the cleaning of hydrocarbon contaminants on the specimen and storage of the specimens and holders can be achieved simultaneously. The designed apparatus can not only robustly avoid damage to the ultrathin specimen and holders but also improve the working efficiency and reduce costs by adopting a single vacuum system. These advantages could make our apparatus more appealing for the complement to the present commercial plasma cleaning and storage devices. [ABSTRACT FROM AUTHOR]

Quartz veins in high-pressure (HP) to ultrahigh-pressure (UHP) rocks are the products of fluid-rock interaction, and thus provide insight into fluid processes in subduction zones. In this paper, we report an integrated study of mineral inclusion, trace-element, U-Pb age, and Lu-Hf isotope compositions of hydrothermal zircon grains from a quartz vein within an UHP eclogite outcrop from the Hong'an area, western Dabie Mountains. These data are used to decipher the age, conditions of formation, and source of fluid for zircon formation during the exhumation of UHP rocks. Zircon grains from the vein have perfect euhedral shape, and show sector zoning or weak zoning, indicating that they precipitated from the aqueous fluid responsible for the vein formation. Raman spectroscopy analysis reveals that the zircon grains contain inclusions of garnet, omphacite, rutile, quartz, and [H.sub.2]O, implying that they crystallized from aqueous fluid under HP eclogite-facies conditions. The zircon grains show low Th/U and Lu/Hf ratios, nearly flat HREE patterns, absent Eu anomalies and low LREE contents. These characteristics are consistent with their precipitation in the presence of garnet and epidote, and absence of feldspar, and thus suggest that trace-element concentrations in hydrothermal zircon are controlled by co-precipitation of mineral assemblages. Crystallization temperatures of 670 to 712[degrees]C, which were calculated using the Ti content of zircon, are consistent with their formation under eclogite-facies conditions and may correspond to the temperature of the infiltrating fluid. The weighted mean [sup.206]Pb/[sup.238]U age of 224.7 [+ or -] 1.3 Ma is taken as the best estimate for the age of quartz-vein formation and records aqueous fluid flow during the early exhumation stage of UHP rocks. The zircon grains in the quartz-vein have Hf compositions similar to those in the host eclogite, which demonstrates isotopic equilibrium between fluid and rocks and that the fluid-rock ratio was likely low. Keywords: Hydrothermal zircon, trace element, Lu-Hf isotope, U-Pb age, HP-UHP metamorphism, quartz vein, western Dabie Mountains

Potassium (K)-rich mafic rocks are viewed as being derived from partial melting of an enriched mantle source, but it is controversial about which processes cause the mantle enrichment. The Fushui intrusive complex is the largest early Paleozoic K-rich intrusive complex in the eastern Qinling orogen. Therefore, detailed studies on the Fushui complex can contribute not only to understanding of the petrogenesis of K-rich mafic rocks, but also to unraveling the Paleozoic evolution of the Qinling orogen. In this study, we provide an integrated investigation of in situ zircon U-Pb dating and Hf-O isotopes, in combination with whole-rock major and trace elements, as well as Sr-Nd-Hf isotopes, for the Fushui intrusive complex. In situ zircon secondary ion mass spectrometry (SIMS)/laser ablation induction coupled plasma mass spectrometry (LA-ICPMS) U-Pb dating reveals that different rock types of the Fushui complex have identical formation ages of 488-484 Ma. The Fushui complex belongs to the shoshonitic series, and is characterized by extreme large ion lithophile element (LILE, e.g., Ba, U, Th and Sr) and Pb enrichment and depletion of high field-strength elements (HFSEs, e.g. Nb, Ta, Zr, Hf, P and Ti). It shows high initial Sr isotopic ratios (0.7100-0.7151), negative whole-rock [ζ.sub.Nd](0 (-3.97 to -5.68) and negative to slight positive whole-rock (-2.24 to 2.38) and zircon (-2.85 to 0.34) [ζ.sub.Hf](t) values, as well as high zircon δ[sup.18]O values (6.86 ± 0.13 ‰). The Hf-Nd isotopic systems are decoupled with positive Δ[ζ.sub.Hf] values (3.85-5.37). These geochemical features indicate that the mantle source has incorporated subducted zircon-barren oceanic sediments. A simple two-endmembers mixing model constrains the amount of subducted sediments in the Fushui mantle source to 5-8 %. The Fushui complex originated from 1 to 6 % equilibrium melting of a phlogopite-bearing garnet lherzolite by non-modal melting. As shoshonitic magmas have been discovered in modern nascent arcs, we suggest that the generation of the Fushui complex was induced by the subduction of the Paleotethyan Ocean, when it jumped from the northern to the southern boundary of the North Qinling microcontinent. Keywords Zircon Hf-O isotope * Geochemistry * K-rich mafic rock * Qinling orogen * Subducted sediment, Introduction Potassium (K)-rich mafic rocks are common, albeit minor, in both orogenic belts and cratons (Foley and Peccerillo 1992; Nowell et al. 2004; Prelevic et al. 2010), and are viewed [...]

Abstract: Mantle xenoliths provide direct information about lithospheric evolution and asthenosphere–lithosphere interaction, and therefore precise dating of the host basalts which carried the xenoliths is important. Here we report 40Ar/39Ar geochronology of phlogopite separates from five spinel lherzolite xenoliths collected from the North China Craton (Hannuoba of Hebei Province, Sanyitang of Inner Mongolia Autonomous Region and Hebi of Henan Province), as well as the groundmass of the host basalts. Argon extraction was performed by conventional step heating technique and ultra-violet laser ablation microprobe (UVLAMP) technique. 40Ar/39Ar incremental heating results on groundmass yielded geologically meaningless ages. However, conventional step heating on phlogopites produced Miocene cooling ages, identical to the eruption ages obtained from the K–Ar dating methods of the Hannuoba and Sanyitang basalts. Adopting procedures to exclude potential influence of excess radiogenic Ar from a deep fluid source on a phlogopite separate from lherzolite yielded results with a good agreement of ages suggesting that the argon isotopes are distributed homogenously in this mineral, with no influence of excess argon. Phlogopites from Hebi yield ages between 6.43 and 6.44Ma which are slightly older than those obtained from K–Ar method on whole-rocks. The discrepancy in the K–Ar ages obtained from the altered whole-rock samples suggests partial loss of 40Ar. As a consequence, phlogopite Ar–Ar ages are considered more accurate than that of the whole-rocks. These results suggest that 40Ar/39Ar chronology of phlogopite provides reliable and precise 40Ar/39Ar ages of host basalts. [Copyright &y& Elsevier]