Thermal History of Asteroid Parent Bodies Is Reflected in Their Metalorganic Chemistry

Abstract

Organo-magnesium compounds were shown to contribute significantly to the soluble carbon molecular complexity and diversity of meteorites, and their analysis increases our knowledge on carbon stabilization/sequestration processes in the asteroidal parent body. Here we present a new group of sulfur-magnesium-carboxylates detected using ultra–high-resolution mass spectrometry in a variety of meteorites. These novel compounds show increased abundance correlated with the thermal history of the asteroid parent bodies. By comparing the soluble organic extracts of 44 meteorites having experienced variable post-accretion history, we describe distinct organic compound patterns of sulfur-magnesium-carboxylates in relation to their long- and short-duration thermal history. It is shown that the exceptional stability of these molecules enables survival of carbon under harsh thermal extraterrestrial conditions, even in the vitrified fusion crust formed during entry into the Earth's atmosphere. Sulfur-magnesium-carboxylates augment our understanding of parent body proceedings with regard to carbon sequestration and speciation in space.

Heterogeneous nature of the carbonaceous chondrite breccia Aguas Zarcas – Cosmochemical characterization and origin of new carbonaceous chondrite lithologies

“…Organomagnesium compounds (CHOMg) have been shown to be markers of shock/heating history in the parent body (Ruf etal., 2017, Bischoff et al, 2019b (Fig. S6); Kerraouch et al, 2019, Matzka et al, 2021. High pressure and temperature events generally lead to a higher number of CHOMg and CHOSMg compounds together with a loss in chemical diversity, especially of nitrogen and sulfur compounds (Langbroek et al, 2019).…”

Complex carbonaceous matter in Tissint martian meteorites give insights into the diversity of organic geochemistry on Mars

“…In addition, the abundance and structural diversity of high-pressure chemical markers dihydroxymagnesium carboxylates [RCO 2 Mg(OH) 2 ] (CHOMg) progressively increased with shock metamorphism ( 31 ). Similarly, sulfur-bearing organomagnesium compounds [RCO 2 Mg(OH) 2 SO 2 ] (CHOSMg) were described as thermal-stress chemical witnesses in meteorites, enabling tracking of peak temperatures or long-duration thermal effects ( 34 ). The close relationships between respective CHO and CHO(S)Mg chemical spaces are thus dependent on pressure and temperature conditions and indicative of a coevolution of organic molecules and colocalized minerals in Mars rocks as well.…”

Chirality in Organic and Mineral Systems: A Review of Reactivity and Alteration Processes Relevant to Prebiotic Chemistry and Life Detection Missions

“…Recently, there have been several reports of metal-organic compounds in meteoritic organic matter that have implications for understanding parent-body interactions with origins of life implications [141][142][143]. A study by Ruf and colleagues surveyed 61 meteorites over a wide range of petrologic types.…”

“…Another study looked at the soluble organic fraction of 44 meteorites and found a novel homologous series of sulfur magnesium carboxylates. They appear to be thermally stable and their abundance was correlated with increasing thermal maturity [143]. Smith and colleagues looked at the origin of cyanide in the CM2 Murchison meteorite and found that it was primarily bound (and subsequently released) as iron cyanocarbonyl ([Fe II (CN) 5 (CO)] 3− and [Fe II (CN) 4 (CO) 2 ] 2− ) organometallic complexes.…”

“…Secondary minerals include phyllosilicates, Fe oxides, carbonates, and sulfates. Common ices of volatile phases are driven by the "frost line" of that volatile phase during the early Solar System, or the distance at which that phase can condense into liquid form and resist further migration outward by the solar wind [143,144]. The abundance of water, ammonia, and methane ices are relatively low and dependent on regional conditions in the inner Solar System and more common from the Main Asteroid Belt outwards (Table 2).…”