A team of personnel from Saint Petersburg University, in partnership with international colleagues, identified the initial ammonium mineral in extraterrestrial material within the Orgueil meteorite. This information was shared in an article published in the journal American Mineralogist. The specimen belongs to a rare type of CI carbonaceous chondrites; the meteorite descended near the French village of Orgueil in 1864.
Carbonaceous chondrites exhibit elevated levels of carbon and volatile compounds and are considered analogs to the matter of the Ryugu and Bennu asteroids. The examined fragments of Orgueil are held at the V. I. Vernadsky Institute of Geochemistry and Analytical Chemistry of the Russian Academy of Sciences.
Ammonium is a crucial carrier of biogenic nitrogen in space, an elemental form involved in processes linked to the origin of life. Scientists anticipate that discovering an ammonium mineral in a meteorite will aid in refining potential pathways for life-essential compounds entering early Earth.
In this meteorite, the ammonium carrier was nickel-bearing boussingaultite $(\text{NH}_4)_2(\text{Mg},\text{Ni})(\text{SO}_4)_2\cdot 6\text{H}_2\text{O}$, which belongs to the Epsomite family of salts. The presence of ammonium was verified using equipment from the resource centers “X-ray Diffraction Research Methods” and “Geomodel” at SPbU Science Park.
The paper’s authors suggest that finding boussingaultite in the meteorite will foster a better comprehension of the formation and alteration conditions of minor Solar System bodies. The mineral might serve as an indicator of bound ammonia in comets and asteroids. It is likely associated with peculiarities in the infrared spectra around 3.2 microns observed for Comet Churyumov–Gerasimenko and Ceres.
Ammonium minerals are difficult to detect because they are water-soluble and possess a low decomposition temperature. Previously, their existence was mainly inferred from indirect spectral data. Now, a tangible sample is available for in-depth examination.
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