¹N. Randazzo,¹R. W. Hilts,¹M. C. Holt,¹C. D. K. Herd,²B. Reiz,²R. M. Whittal
Meteoritics & Planetary Science (in Press) Open Access Link to Article [https://doi.org/10.1111/maps.14189]
¹Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta, Canada
²Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
Published by arrangement with John Wiley & Sons

We analyzed the methanol extracts of six pristine specimens of the Tagish Lake meteorite (TL1, TL4, TL5A, TL6, TL7, and TL10a) and heated and unheated samples of Allende using high-performance liquid chromatography coupled with high-resolution, accurate mass–mass spectrometry (HPLC-HRAM-MS). All samples contained ppm levels of sulfate and methyl sulfate. The most abundant organosulfur compound in the methanol extracts of the Tagish Lake and Allende samples was methyl sulfate, which was likely formed primarily via an esterification reaction between intrinsic sources of methanol and sulfate. A homologous series of polythionic acids was also observed in the extracts of the Tagish Lake specimens and Allende. The polythionic acids were the most abundant soluble inorganic sulfur species found in the meteorites. Our results were confirmed using retention time, accurate mass, isotope matching, and tandem mass spectrometry (MS/MS). Hydroxymethanesulfonic acid, previously reported in Tagish Lake, was found only in an unheated Allende sample and in low abundance. Here, we propose possible sulfate formation pathways that begin with interstellar dimethyl sulfide, dimethyl disulfide, methyl sulfide, or methanethiol via cold, nebular processes within the interstellar medium and continue via MSA as an intermediary compound ending within planetary bodies with sulfate and methyl sulfate as the final products.

^1,2,3,4Maria Gritsevich et al.(>10)
Meteoritics & Planetary Science (in Press) Open Access Link to Article [https://doi.org/10.1111/maps.14173]
¹Faculty of Science, University of Helsinki, Helsinki, Finland
²Swedish Institute of Space Physics (IRF), Kiruna, Sweden
³Finnish Fireball Network, Ursa Astronomical Association, Helsinki, Finland
⁴Institute of Physics and Technology, Ural Federal University, Ekaterinburg, Russia
Published by arrangement with John Wiley & Sons

The discovery of the Ischgl meteorite unfolded in a captivating manner. In June 1976, a pristine meteorite stone weighing approximately 1 kg, fully covered with a fresh black fusion crust, was collected on a mountain road in the high-altitude Alpine environment. The recovery took place while clearing the remnants of a snow avalanche, 2 km northwest of the town of Ischgl in Austria. Subsequent to its retrieval, the specimen remained tucked away in the finder’s private residence without undergoing any scientific examination or identification until 2008, when it was brought to the University of Innsbruck. Upon evaluation, the sample was classified as a well-preserved LL6 chondrite, with a W0 weathering grade, implying a relatively short time between the meteorite fall and its retrieval. To investigate the potential connection between the Ischgl meteorite and a recorded fireball event, we have reviewed all documented fireballs ever photographed by German fireball camera stations. This examination led us to identify the fireball EN241170 observed in Germany by 10 different European Network stations on the night of November 23/24, 1970, as the most likely candidate. We employed state-of-the-art techniques to reconstruct the fireball’s trajectory and to reproduce both its luminous and dark flight phases in detail. We find that the determined strewn field and the generated heat map closely align with the recovery location of the Ischgl meteorite. Furthermore, the measured radionuclide data reported here indicate that the pre-atmospheric size of the Ischgl meteoroid is consistent with the mass estimate inferred from our deceleration analysis along the trajectory. Our findings strongly support the conclusion that the Ischgl meteorite originated from the EN241170 fireball, effectively establishing it as a confirmed meteorite fall. This discovery enables to determine, along with the physical properties, also the heliocentric orbit and cosmic history of the Ischgl meteorite.