Meteorites & Asteroids

The Massalia Asteroid Family As The Origin Of Ordinary L Chondrites

By Keith Cowing
Status Report
March 20, 2024
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The Massalia Asteroid Family As The Origin Of Ordinary L Chondrites
Measured mineralogy (in terms of olivine-to-pyroxene ratio; ol/(ol+opx)) of 15 asteroids from the Massalia family (retrieved from a total of 21 individual spectra), compared to the mineralogy of ordinary chondrites (H, L, LL types) from RELAB. Average values are indicated at the top for each S-type family (families marked with an asterisk had their largest member removed before computing the average). Measurements of (20) Massalia are indicated in the plot (X). While this body lays between the peaks of the H-chondrite and L-chondrite distributions, other family members are clearly compatible with L chondrites. — astro-ph.EP

Studies of micrometeorites in mid-Ordovician limestones and Earth’s impact craters indicate that our planet witnessed a massive infall of ordinary L chondrite material 466 million years (My) ago (Heck et al. 2017, Schmieder & Kring 2020, Kenkmann 2021) that may have been at the origin of the first major mass extinction event (Schmitz et al. 2019).

The breakup of a large asteroid in the main belt is the likely cause of this massive infall. In modern times, material originating from this breakup still dominates meteorite falls (>20% of all falls) (Swindle et al. 2014).

Here, we provide spectroscopic observations and dynamical evidence that the Massalia collisional family is the only plausible source of this catastrophic event and of the most abundant class of meteorites falling on Earth today. It is suitably located in the inner belt, at low-inclination orbits, which corresponds to the observed distribution of L-chondrite-like near-Earth objects (NEOs) and of interplanetary dust concentrated at 1.4 degrees (Sykes 1990, Reach et al. 1997).

Michaël Marsset, Pierre Vernazza, Miroslav Brož, Cristina A. Thomas, Francesca E. DeMeo, Brian Burt, Richard P. Binzel, Vishnu Reddy, Allison McGraw, Chrysa Avdellidou, Benoit Carry, Stephen M. Slivan, David Polishook

Comments: 35 pages, 11 pages, under revision
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2403.08548 [astro-ph.EP] (or arXiv:2403.08548v1 [astro-ph.EP] for this version)
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Submission history
From: Michaël Marsset
[v1] Wed, 13 Mar 2024 14:00:10 UTC (5,459 KB)

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻