Tag: virtual-ta

20-EPN2-057: A Zircon Provenance Study of the Kanye Basin (Botswana) to Constrain Terrestrial Geodynamics Across the Archaean-Proterozoic Transition.

Virtual visit by Denice Borsten and Jochem Sikkes (Vrije Universiteit Amsterdam, Netherlands) to TA2 Facility 26 – KBSI Sensitive High Resolution Ion MicroProbe / SHRIMP-IIe/MC (South Korea).
Dates of visit: 23 September 2021 -17 February 2022

Report Summary: This study investigates the Neoarchaean to Paleoproterozoic Transvaal Supergroup sedimentary sequence in Botswana that formed in the centre of the Kaapvaal Craton during the early oxygenation of the atmosphere. We used U-Pb dating on magmatic and sedimentary zircons from throughout the sedimentary sequence to determine the tectono-magmatic evolution of the hinterland basement. This approach constrains regional crustal growth, uplift and erosion events and establishes if additional cratons were in the hinterland, e.g. Pilbara. Knowledge of zircon provenance will allow critical comparison to known tectonic scenarios, e.g. Alpine style molasse basin and any potential change in Neoarchaean tectonics by considering erosion and crustal growth-reworking. The geochronology results help evaluate spatial and temporal variations in depositional environments associated with oxygenation of the atmosphere. Results indicate that the age of the basement, Gaborone Granite and the Kanye volcanic are indistinguishable (2768.9 ± 6.0 Ma). Sediments deposited from 2.642 Ga to 2.550 Ga are also dominated (> 90%) by zircons of ~2.77 Ga. This implies that there was a major crustal growth event in the Kanye region at 2.77 Ga that included minimal crustal reworking. Erosion products to the Kanye Basin are derived from this juvenile crust throughout the Archaean and Proterozoic until > 2.0 Ga.  Only then are older and younger basement rocks recorded in the sedimentary sequence. This region of the planet yields no evidence of a major tectono-magmatic event associated with the oxygenation of the atmosphere. 

20-EPN-049: The Irradiation of Oxygen-Bearing Ices on Top of Pure Elemental Sulphur Layers (former title: Millimetre-Wave Polarimetry of Space Relevant Ices Exposed to Energetic Ions)

Virtual visit by Olivier Auriacombe, Chalmers University of Technology (Sweden), to TA2.11 Atomki Ice Chamber for Astrophysics / Astrochemistry (ICA) (Hungary).
Dates of visit: 20 June – 4 September 2022

Report Summary: The chemistry of sulphur in icy extra-terrestrial settings such as the dense interstellar medium and the outer Solar System remains poorly constrained. In particular, the chemical routes towards the formation of SO₂ ice (and other volatile sulphur-bearing species) is not completely understood, despite the detection of this species in interstellar icy grain mantles, on the surface of Europa, and on comets. We have therefore explored the possibility of forming SO₂ ice as a result of the irradiation of oxygen-bearing ices (including O₂, CO, CO₂, H₂O, and CH₃OH) deposited on top of pure elemental sulphur layers, both of which are known to exist in the dense interstellar medium and the outer Solar System where radiation chemistry may be engendered by galactic cosmic rays or the solar wind. 

Our results demonstrate that SO₂ may indeed be produced after the 1 MeV He⁺ ion irradiation of O₂ and CO₂ ices deposited on top of elemental sulphur, but not as a result of similar irradiations conducted using CO, H₂O, or CH₃OH ices. Other volatile radiation product species incorporating sulphur, such as CS₂, OCS, and H₂SO₄, were also detected in different experiments. Our work should therefore contribute to a better understanding of solid-phase sulphur astrochemistry and the role of elemental sulphur in the formation of volatile sulphur-bearing species in icy extra-terrestrial settings.

20-EPN2-045: Irradiation Effects of Energetic H⁺ and S⁺ Ion Implantation in Salts and Minerals Relevant to the Surface of Europa

Virtual visit by Duncan Mifsud, University of Kent (UK) to TA2.11 Atomki Ice Chamber for Astrophysics / Astrochemistry (ICA) (Hungary).
Dates of visit: 21-29 November 2022 and 18-20 January 2023

Report Summary: The surface of Europa is host to a rich radiation environment, in which ions from the giant Jovian magnetosphere drive physico-chemical transformations of surface ices and minerals. Although a number of previous studies have looked into the irradiation of surface ice analogues in order to better constrain the chemistry occurring on Europa, considerably fewer studies have investigated the radiation chemistry of plausible mineral analogues.

Therefore, in this study, we have irradiated four mineral species (halite, fayalite, epsomite, and berthierine) using 1 MeV H⁺ and 1 MeV S⁺ ions to better understand the dissociation pathways of these minerals and the associated radiolysis products. Our preliminary results have shown that irradiation brings about significant changes in the appearances of the minerals that signify alterations in the structures and chemical compositions. Further infrared, visible, and ultraviolet spectroscopic analyses of retained mineral samples (both irradiated and pristine) are planned for the near future.

20-EPN-025: Radioresistance of aromatic complex organic molecules (nucleobases)

Virtual visit by Alicja Domaracka and Anna Bychkova, CIMAP-CNRS (France) to TA2.11 Atomki Ice Chamber for Astrophysics / Astrochemistry (ICA) (Hungary).
Dates of visit: 17-28 January 2022

Report Summary: Over the last decades it became clear that we live in a “molecular universe”. Carbon forms the basis of the majority of the molecular species that so far have been identified in space. Although small carbon-based molecules, like CO and CO₂, are some of the most abundant molecules in space, only a small fraction of the carbon is expected to be locked up in such species. It was proposed that a large portion of the interstellar carbon, up to 20%, is built in polycyclic aromatic hydrocarbons (PAHs) and fullerenes. Several laboratory studies were carried out to investigate the effects of vacuum ultraviolet photolysis on PAH:H₂O ices. However, data about interaction energetic ions with PAH ices are very scare.

We therefore studied the radiolysis of the pure pyrene ice and mixed pyrene- water ices at different concentrations at 20 K with 200 keV and 2 MeV H⁺ and 2 MeV C²⁺ beams at Atomki. The preliminary analysis of water-pyrene ices irradiated 200 keV H⁺ (with pyrene concentration from about 5 to 100% of pyrene) indicates that pyrene is more radio-resistant at high concentrations. The results are preliminary and analysis is ongoing.

20-EPN2-081: Vis-NIR reflection spectroscopy of ammonium salts relevant for icy planetary surface characterisation

Virtual visit by Maximiliano Fastelli, University of Perugia (Italy), to TA2.8 CSS (Cold Surfaces Spectroscopy) at IPAG (France).
Dates of visit: 13 October – 5 November 2021

Report Summary: During this TA visit under Europlanet 2024 RI 2nd call, reflectance VIS-NIR spectra of several ammonium salts were collected at the CSS facility (IPAG laboratory) in Grenoble, France. Different temperature steps were chosen to collect cryogenic data down to 90 K. Samples were characterised by low temperature crystalline phase transitions, and for these reasons, the measurement steps have been increased in the proximity of the expected temperature of mineral transformation. Cooling and heating experiments, using the same cooling/heating rate, were performed to bracket the phase transition T and verify its reversibility. All the spectra were collected with three different grain size (150/125 – 125/80 – 80/32 μm) in the spectral range from 1 to 4.6 μm at low T. Typical absorption features due to overtones and combinations of NH₄⁺ groups were identified in the spectral range investigated. Phase transitions, when detected, show an interesting behaviour with change in shape and position of some (sensitive) absorption bands which could be useful for the identification of these phases at non-ambient T. Moreover, the effect of low T and different granulometry were observed.

It has been proposed that ammonium minerals are present in varying percentages in icy planetary bodies. The availability of these compounds is linked to the upwelling of ammonium salts (NH₄⁺) with ice from the subsurface of possible oceans resulting from cryovolcanism phenomena. The identification of these minerals on the surface can give information about internal composition/dynamics and potential habitability of icy bodies.

20-EPN-029: VIS-NIR reflectance analysis of analogue mixture representative of young Haulani crater on Ceres to assess the mineralogical composition of bright areas.

Virtual visit by Fabrizio Dirri, IAPS-INAF (Italy), to TA2.8 CSS (Cold Surfaces Spectroscopy) at IPAG (France).
Dates of visit: 15-26 March 2021

Report Summary: In this project different bright areas of Haulani crater (e.g. Southern floor, i.e. ROI3 and North-east crater wall, i.e. ROI4) on Ceres have been studied by arranging different analogue mixtures and comparing them with Dawn VIR data. The end-members have been identified based on previous studies (Tosi et al. 2018, 2019) and the analogue mixtures have been produced with grain size 50-100µm for two bright crater regions. The two initial mixtures have been acquired in the VIS-NIR spectral range (0.35-4.5µm) at low temperature, i.e. from 200K to 300K similar to Haulani by using Cold Spectroscopy Facility (CSS) (IPAG, France). 

By comparing the spectral parameters (Band Center, Band Depth and FWHM of absorption bands at 2.7, 3.1, 3.4µm, spectral slope in the 1.2-1.9µm range and reflectance level at 2.1µm) with the obtained spectra of mixtures and VIR data, the best candidate to reproduce Haulani’ bright areas is the mixture A3-8. That mixture exhibits values for the 2.7BD (Antigorite, Illite), 3.1BD (NH4-Montmorillonite), 3.4 BD (NaCO₃) and the 3.1 µm FWHM very close to Haulani ROI3 and ROI4. In order to better reproduce Haulani areas some improvements may be performed in the next future, e.g., by changing the dark component with a mixture of graphite plus magnetite to better reproduce the spectral slope of Haulani or by adding hydrous natrite in low percentage to the mixture, e.g. 2-8% to assess the role of this component found in Haulani bright areas and how is the contribution to 2.7 µm spectral band.

Read full report (published with kind permission of Dr Dirri).

20-EPN-042: Reflectance spectroscopy of ammonium-bearing minerals – A tool to improve the knowledge of the surface of icy planetary bodies.

Virtual visit by Maximiliano Fastelli, University of Perugia (Italy), to TA2.8 CSS (Cold Surfaces Spectroscopy) at IPAG (France).
Dates of visit: 09-27 November 2020

Report Summary: In the frame of the Europlanet 2024 1st TA call, reflectance VIS-NIR spectra were collected. Ten different temperature steps were chosen to collect cryogenic data: 270-245-220-180-160-140-120-100-90-270 up K.

For the samples characterized by a low temperature phase transitions (mascagnite (NH₄)2SO₄, sal-ammoniac NH₄Cl, ammonium phosphate (NH₄)H₂PO₄, tschermigite (NH₄)Al(SO₄)₂·12(H₂O) and ammonium nitrate NH₄NO₃), the measurement steps have been increased in the proximity of the expected temperature of mineral transformation. Cooling and heating experiments, using the same cooling/heating rate, were performed to break the phase transition T. In particular, mascagnite, sal-amoniac and ammonium phosphate monobasic samples showed clear and very interesting spectral bands variations during cooling, indicating that a phase transition occurred. Spectra were collected with three different grain size (150/125 – 125/80 – 80/32 μm) in the spectral range from 1 to 4.8 μm. 

The collected data will help on the interpretation of VIR remote spectra from Europa, Pluto’s moons, Enceladus and other icy celestial bodies surface where NH4 minerals have been supposed to occur. Moreover, the study of ammonium bearing minerals and their behavior at very low temperature might give information on how the phase transition affects the bands position and shapes inside the reflectance spectra. Overtones and combinations of NH₄ bands are in the 1-3 μm range, whereas fundamental vibrational modes (ν₁ and ν₃) are present in the ~3 μm area.

20-EPN2-088: High spectral resolution / low-temperature IR study of carbonates.

Virtual visit by Simone De Angelis and Cristian Carli, IAPS-INAF(Italy), to TA2.8 CSS (Cold Surfaces Spectroscopy) at IPAG (France).
Dates of visit: 11 May – 04 June 2021

Report Summary: We planned to acquire reflectance spectra of anhydrous carbonates in the infrared range (3.2-4.6 μm), at high spectral sampling/resolution and at different cryogenic temperatures in the range 60-270K. 

The analysed materials were calcite, dolomite, siderite, natrite, malachite and magnesite; all the minerals were prepared and measured at fine powders, d<50 μm.  These measurements provide new spectral data in the IR that will be useful in the interpretation  of remote-sensing spectroscopic observations of Solar System rocky bodies such as Mars, Jovian satellites and minor bodies by current and future missions (Mars 2020, ExoMars-2022, JUICE, Europa Clipper, OSIRIS-REx).