Exploring exogenic sources for the olivine on Asteroid (4) Vesta

The Saric ßic ßek howardite meteorite shower consisting of 343 documented stones occurred on September 2, 2015 in Turkey and is the first documented howardite fall. Cosmogenic isotopes show that Saric ßic ßek experienced a complex cosmic-ray exposure history, exposed during~12-14 Ma in a regolith near the surface of a parent asteroid, and that añ 1 m sized meteoroid was launched by an impact 22 AE 2 Ma ago to Earth (as did one-third of all HED meteorites). SIMS dating of zircon and baddeleyite yielded 4550.4 AE 2.5 Ma and 4553 AE 8.8 Ma crystallization ages for the basaltic magma clasts. The apatite U-Pb age of 4525 AE 17 Ma, K-Ar age of~3.9 Ga, and the U,Th-He ages of 1.8 AE 0.7 and 2.6 AE 0.3 Ga are interpreted to represent thermal metamorphic and impact-related resetting ages, respectively. Petrographic; geochemical; and O-, Cr-, and Ti-isotopic studies confirm that Saric ßic ßek belongs to the normal clan of HED meteorites. Petrographic observations and analysis of organic material indicate a small portion of carbonaceous chondrite material in the Saric ßic ßek regolith and organic contamination of the meteorite after a few days on soil. Video observations of the fall show an atmospheric entry at 17.3 AE 0.8 km s À1 from NW; fragmentations at 37, 33, 31, and 27 km altitude; and provide a pre-atmospheric orbit that is the first dynamical link between the normal HED meteorite clan and the inner Main Belt. Spectral data indicate the similarity of Saric ßic ßek with the Vesta asteroid family (V-class) spectra, a group of asteroids stretching to delivery resonances, which includes (4) Vesta. Dynamical modeling of meteoroid delivery to Earth shows that the complete disruption of ã 1 km sized Vesta family asteroid or a~10 km sized impact crater on Vesta is required to provide sufficient meteoroids ≤4 m in size to account for the influx of meteorites from this HED clan. The 16.7 km diameter Antionia impact crater on Vesta was formed on terrain of the same age as given by the 4 He retention age of Saric ßic ßek. Lunar scaling for crater production to crater counts of its ejecta blanket show it was formed~22 Ma ago.A field expedition to the area was conducted by the

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“…The reddish material has been interpreted as Rheasilvia impact melt or HED material rich in exogenic (non‐HED) material (Le Corre et al. , ).…”

Section: Discussionmentioning

confidence: 99%

The Sariçiçek howardite fall in Turkey: Source crater of HED meteorites on Vesta and impact risk of Vestoids

Ünsalan

Jenniskens

Yin

et al. 2019

Meteorit & Planetary Scien

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“…A final possibility that has been recently proposed is that most if not all of the olivine identified to now on the vestan surface could be the result of exogenous delivery by olivine-rich impactors instead of mantle excavation (Turrini et al, 2014;Le Corre et al, 2015;Turrini et al, in preparation). The limited number of olivine enrichments on Vesta and their association to post-Rheasilvia craters not capable to excavate the crust are actually consistent with this possibility, as impacts of A-type asteroids from Rheasilvia's formation to now are in principle capable to supply enough events to explain the two most olivine-rich sites Arruntia and Bellicia, all the additional less olivine-rich sites identified here and/or in Ruesch et al (2014), and the possible presence of 1-3 of them inside Rheasilvia (Turrini et al, 2014;Turrini et al, in preparation).…”

Section: Olivine As a Tracer Of Vesta's Internal Structurementioning

confidence: 99%

Detection of new olivine-rich locations on Vesta

Palomba

Longobardo

Sanctis

et al. 2015

Icarus

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“…; Le Corre et al. ; Palomba et al. ) may represent either endogenous material originating from the Vestan mantle (Lunning et al.…”

Section: Discussionmentioning

confidence: 99%

“…Olivine with a similar composition has also recently been identified in association with Mg-rich pyroxene (En >85 ) in what have been described as harzburgitic clasts in howardite Dominion Range (DOM) 10105 (Hahn et al 2015). It has been suggested that such Mg-rich olivine in howardites and observations of olivine of the Vestan surface (Ammannito et al 2013;Le Corre et al 2015;Palomba et al 2015) may represent either endogenous material originating from the Vestan mantle (Lunning et al 2014), or exogenous material from surviving silicate fragments of asteroid collisions with the Vestan surface (e.g., Turrini et al 2014;Le Corre et al 2015).…”

Section: Magnesian (Fo >86 ) Olivine Fragmentsmentioning

confidence: 99%

Geochemistry and petrology of howardite Miller Range 11100: A lithologically diverse piece of the Vestan regolith

Gregory

Joy

Strekopytov

et al. 2016

Meteorit & Planetary Scien

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General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Full terms of use are available: http://www.bristol.ac.uk/pure/about/ebr-terms it is akin to the fragmental howardite meteorites. The strong lithological heterogeneity across this 29 sample suggests that at least some parts of the Vestan regolith show heterogeneity on the mm-scale. 30We combine the outcomes of this study with data from NASA's Dawn mission and hypothesize on 31 possible source regions for this meteorite on the surface of Vesta. 32 33

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Exploring exogenic sources for the olivine on Asteroid (4) Vesta

Cited by 37 publications

References 101 publications

The Sariçiçek howardite fall in Turkey: Source crater of HED meteorites on Vesta and impact risk of Vestoids

The Sariçiçek howardite fall in Turkey: Source crater of HED meteorites on Vesta and impact risk of Vestoids

Detection of new olivine-rich locations on Vesta

Geochemistry and petrology of howardite Miller Range 11100: A lithologically diverse piece of the Vestan regolith

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