Novel U-Pb isotopic zircon data on the rhyolite of the Saf’yanovskoe Cu-Zn deposit (Middle Urals)

Research subject. Zircons from the Saf’yanovskoe Cu-Zn deposit rhyolite (Middle Urals). For the first time, zircon U-Pb dating for the rhyolite of the ore-bearing volcanic-sedimentary rocks of the Saf’yanovskoe deposit was performed. The volcanites are characterized by an andesite-rhyodacite composition and are localized at the southern edge of the Rezhevskaya structural-formation zone (SFZ) of the Eastern Ural megazone. A number of publications assign these rocks either to the basalt-rhyolite formation of the Middle Devonian, or to the basalt-andesite-dacite-rhyolite formation of the Lower-Middle Devonian.Aim. To estimate the age of the ore-bearing volcanic rocks under study using the U-Pb SHRIMP-II isotop ic system of zircon from the rhyolite of the eastern side of the Saf’yanovskoe deposit. By its chemical composition, the rhyolite belongs to the silicic varieties of subvolcanic rocks. Methods and results. The U-Pb isotopic system of zircon was studied by 5-collector mass-spectrometer of high precision and emission of the secondary ions SHRIMP-II (ASI, Australia) in the VSЕGEI Institute. U-Pb relations were investigated by a procedure developed by I.S. Williams. The U-Pb data obtained based on 13 zircon grains showed the age of 422.8 ± 3.7 Ma. Conclusions. The U-Pb dating of zircon obtained previously from the lens-shaped andesite bodies of the western side of the Safyanovskoe deposit gave the age of 422.8 Ma, which corresponds to the Przydoli series epoch of the Upper Silurian. We established that, among the volcanic rocks of the Saf’yanovskoe deposit, the effusive formations of the Upper Silurian are present.

In situ observations of ions and magnetic field around Phobos: the mass spectrum analyzer (MSA) for the Martian Moons eXploration (MMX) mission

The mass spectrum analyzer (MSA) will perform in situ observations of ions and magnetic fields around Phobos as part of the Martian Moons eXploration (MMX) mission to investigate the origin of the Martian moons and physical processes in the Martian environment. MSA consists of an ion energy mass spectrometer and two magnetometers which will measure velocity distribution functions and mass/charge distributions of low-energy ions and magnetic field vectors, respectively. For the MMX scientific objectives, MSA will observe solar wind ions, those scattered at the Phobos surface, water-related ions generated in the predicted Martian gas torus, secondary ions sputtered from Phobos, and escaping ions from the Martian atmosphere, while monitoring the surrounding magnetic field. MSA will be developed from previous instruments for space plasma missions such as Kaguya, Arase, and BepiColombo/Mio to contribute to the MMX scientific objectives.

Characteristics of Particulate Matter at Different Pollution Levels in Chengdu, Southwest of China

Air pollution is becoming increasingly serious along with social and economic development in the southwest of China. The distribution characteristics of particle matter (PM) were studied in Chengdu from 2016 to 2017, and the changes of PM bearing water-soluble ions and heavy metals and the distribution of secondary ions were analyzed during the haze episode. The results showed that at different pollution levels, heavy metals were more likely to be enriched in fine particles and may be used as a tracer of primary pollution sources. The water-soluble ions in PM2.5 were mainly Sulfate-Nitrate-Ammonium (SNA) accounting for 43.02%, 24.23%, 23.50%, respectively. SO42−, NO3−, NH4+ in PM10 accounted for 34.56%, 27.43%, 19.18%, respectively. It was mainly SO42− in PM at Clean levels (PM2.5 = 0~75 μg/m3, PM10 = 0~150 μg/m3), and mainly NH4+ and NO3− at Light-Medium levels (PM2.5 = 75~150 μg/m3, PM10 = 150~350 μg/m3). At Heavy levels (PM2.5 = 150~250 μg/m3, PM10 = 350~420 μg/m3), it is mainly SO42− in PM2.5, and mainly NH4+ and NO3− in PM10. The contribution of mobile sources to the formation of haze in the study area was significant. SNA had significant contributions to the PM during the haze episode, and more attention should be paid to them in order to improve air quality.

Dynamic modeling of ion sputter yields in agreement with recent experimental data

<p>Atmosphere-free celestial bodies are constantly irradiated by solar wind or magnetospheric ions. In the case of Mercury, the intrinsic magnetic field, although weak, leads to localized plasma precipitation around the magnetospheric cusps and nightside precipitation below the magnetotail [1, 2, 3]. The material ejected by the impacting ions (sputtering) thereby contributes to the exosphere and magnetosphere surrounding Mercury [4, 5, 6]. Magnetospheric ions originate from ionization of exospheric atoms or ions directly sputtered from the surface. Those can become part of the magnetospheric plasma, and have trajectories that lead them back to Mercury’s surface [7, 8].</p> <p> </p> <p>We explored different scenarios of the sputtering of Mercury’s surface with a strong focus on dynamic surface alteration and sputtering. This includes time varying inputs from varying solar wind conditions as well as contributions of secondary ions originating from Mercury’s exosphere and magnetosphere. We rely on the dynamic sputter model SDTrimSP [9] and compare the simulation results with more simplistic TRIM [10] simulations as well as recent laboratory results of solar wind ion sputtering on Mercury analogues [11, 12, 13].</p> <p> </p> <p> </p> <p>[1] Winslow, R.M., et al. (2017). <em>J. Geophys.Res.-Space</em>, <em>122</em>(5), 4960–4975. </p> <p>[2] Winslow, R.M., et al.  (2014). <em>Geophys. Res. Lett.</em>, <em>41</em>(13), 4463–4470.</p> <p>[3] Schmidt, C.A. (2013). <em>J. Geophys.Res.-Space</em>, <em>118</em>(7), 4564–4571. </p> <p>[4] Killen, R.M., & Ip, W. H. (1999). <em>Rev. Geophys.</em>, 37(3), 361–406.</p> <p>[5] Raines, J.M., et al. (2016). <em>Plasma Sources of Solar System Magnetospheres</em> (pp. 91–144). Springer.</p> <p>[6] Wurz, P., et al., (2019). J. <em>Geophys. Res.,</em> 124, 2603–2612.</p> <p>[7] Yagi, M., et al. (2017). <em>J. Geophys.Res.-Space</em>, <em>122</em>(11), 10,990-11,002. </p> <p>[8] Delcourt, D.C., et al. (2003). <em>Ann. Geophys.</em>, <em>21</em>(8), 1723–1736.</p> <p>[9] Mutzke, A., et al. (2019). <em>SDTrimSP Version 6.00</em>. Max-Planck-Institut für Plasmaphysik.</p> <p>[10] Ziegler, J.F., et al. (2010). <em>Nucl. Instrum. Methods Phys. Res. B,</em> 268, 1818–1823. </p> <p>[11] Jäggi, N., et al. (2021). <em>Icarus,</em> 365, 114492. </p> <p>[12] Biber H., et al. (2020). <em>Nucl. Instrum. Methods Phys. Res. B,</em> 480, 10. </p> <p>[13] Szabo, P.S., et al. (2018)<em>.</em> <em>Icarus,</em> 314, 98–105.</p>

Energetic ion irradiation of N2O ices relevant for Solar system surfaces

ABSTRACT Ices are the dominant surface material of many Solar system objects, such as comets and trans-Neptunian objects. They are continuously exposed to ion bombardment by solar wind ions and cosmic rays, which trigger secondary ion emission, contributing to the exosphere formation. Laboratory studies demonstrated the effects of energetic processing of ices at low temperature, showing the production of molecules and free radicals of astrophysical interest. Nitrous oxide (N2O) is one of the molecular species observed in star-forming sites, reason why it may be present in the ices covering some minor bodies in the outer Solar system. In the current work, N2O ice at 10 K was irradiated by energetic (MeV/u) multicharged heavy ions (e.g. 105Rh and 140Ba); the sputtered species were detected and analysed by the TOF-PDMS technique (time-of-flight plasma desorption mass spectrometry). Small positive and negative secondary ions were identified: N+, N2+, NO+, O+, and O−. The bombardment also induces production of ion cluster series: (N2)nR$_{m}^+$, (NO)nR$_{m}^+$, (N2O)nR$_{m}^+$, where R = N+, N2+, NO+, N2O+, Om+ (n up to ∼ 10, m = 1−3). Their yield distributions follow the sum of two decreasing exponentials, one fast -F and another slow -S, suggesting a two-regime formation. Most of the yield distributions have the same pair of exponential decay constants, around kF ∼ 1.4 and kS ∼ 0.15 u−1. Based on this behavior, an emission description for aggregates is proposed, useful to understand the processes by which neutral and ionized molecular species are delivery to the gas phase in space.

Outstanding Radiation Tolerance of Supported Graphene: Towards 2D Sensors for the Space Millimeter Radioastronomy

We experimentally and theoretically investigated the effects of ionizing radiation on a stack of graphene sheets separated by polymethyl methacrylate (PMMA) slabs. The exceptional absorption ability of such a heterostructure in the THz range makes it promising for use in a graphene-based THz bolometer to be deployed in space. A hydrogen/carbon ion beam was used to simulate the action of protons and secondary ions on the device. We showed that the graphene sheets remain intact after irradiation with an intense 290 keV ion beam at the density of 1.5×1012 cm−2. However, the THz absorption ability of the graphene/PMMA multilayer can be substantially suppressed due to heating damage of the topmost PMMA slabs produced by carbon ions. By contrast, protons do not have this negative effect due to their much longer mean free pass in PMMA. Since the particles’ flux at the geostationary orbit is significantly lower than that used in our experiments, we conclude that it cannot cause tangible damage of the graphene/PMMA based THz absorber. Our numerical simulations reveal that, at the geostationary orbit, the damaging of the graphene/PMMA multilayer due to the ions bombardment is sufficiently lower to affect the performance of the graphene/PMMA multilayer, the main working element of the THz bolometer, which remains unchanged for more than ten years.

In Situ Observations of Ions and Magnetic Field Around Phobos: The Mass Spectrum Analyzer (MSA) for the Martian Moons eXploration (MMX) Mission

The Mass Spectrum Analyzer (MSA) will perform in-situ observations of ions and magnetic fields around Phobos as part of the Martian Moons eXploration (MMX) mission to investigate the origin of the Martian moons and physical processes in the Martian environment. MSA consists of an ion energy mass spectrometer and two magnetometers which will measure velocity distribution functions and mass/charge distributions of low-energy ions and magnetic field vectors, respectively. For the MMX scientific objectives, MSA will observe solar wind ions, those scattered at the Phobos surface, water-related ions generated in the predicted Martian gas torus, secondary ions sputtered from Phobos, and escaping ions from the Martian atmosphere, while monitoring the surrounding magnetic field. MSA will be developed from previous instruments for space plasma missions such as Kaguya, Arase, and BepiColombo/Mio to contribute to the MMX scientific objectives.