Acquisition of terrestrial neon during accretion – A mixture of solar wind and planetary components

Mars' atmospheric neon suggests volatile-rich primitive mantle

“…A combination of the solar-wind implantation and erosion of the outer layers of the grains, where 20 Ne enriches, results in the 20 Ne/ 22 Ne ratio slightly lower than the solar value (12.52-12.75, Figure 4). The solar-wind-implanted dust has been proposed to the origin of Earth's mantle Ne alternative to the nebula gas (Trieloff et al, 2000;Moreira and Charnoz, 2016;Jaupart et al, 2017;Péron et al, 2017;Vogt et al, 2019). We note that both solar-wind-implanted dust and IDPs are the same materials, but the former and latter denote those in the planet formation stage and in the current Solar System, respectively, in our definition following the terminology in the literature.…”

Noble gases in Dome C micrometeorites - An attempt to disentangle asteroidal and cometary sources

“…One concerns the origin and evolution of the atmospheres of Earth and other inner solar system rocky planets, which is one of the outstanding questions in planetology. A variety of processes contributing the volatiles H, C, N and noble gases have been considered (e.g., Maurette et al, 2000;Trieloff et al, 2000;Pepin and Porcelli, 2002;Marty, 2012;Alexander et al, 2012;Albarède et al, 2013;Vogt et al, 2019;and references therein), including the possibility of accretion of volatile-rich materials by the forming planets. This infalling material may have been in form of planetesimals and/or interplanetary dust grains, from the outer asteroid belt, as well as cometary material from the outer solar system (Pepin, 2006;Marty, 2012;Bradley et al, 2014).…”

“…Based on an early set of data, Maurette et al (2000) evaluated the possible contribution of micrometeorites to neon, organics, carbon dioxide, nitrogen and water on Earth and they concluded that early accretion of primitive micrometeorites may have played a major role in the formation of the terrestrial atmosphere and oceans. In a more recent evaluation, Vogt et al (2019) conclude that interplanetary particles (IDPs) and micrometeorites (MMs) may very well be an important source of Earth's neon (both interior and atmospheric). However, a crucial ingredient in these estimates is the pre-Archean micrometeorite flux that has to be extrapolated from the present-day flux with an uncertainty that is still a matter of debate.…”

Methane formation driven by light and heat prior to the origin of life and beyond

“…All needed components: (i) methylated S-and N-compounds, (ii) Fe 2+ and (iii) ROS are found under early-earth conditions. (i) In a prebiotic world, methylated S-compounds like methanethiol, dimethyl sulfide (DMS) or dimethyl sulfoxide (DMSO) were formed abiotically under the reducing conditions of hydrothermal vents [17][18][19] or transported to Earth by carbonaceous meteorites during early Earth meteorite bombardment 20,21 . Upon the emergence of life, more methylated S-/N-compounds were produced by cells and organisms, i.e.…”