User:MJCato/Jbilet Winselwan meteorite
Jbilet Winselwan meteorite[edit]
| Jbilet Winselwan | |
|---|---|
 | |
| Type | Chondrite |
| Class | Carbonaceous chondrite |
| Group | CM2 |
| Shock stage | S1 |
| Weathering grade | W1 |
| Country | Western Sahara |
| Region | Northwest Africa |
| Coordinates | 20°40′3″N 11°40′38″W / 20.66750°N 11.67722°W |
| Observed fall | No |
| Found date | 24 May 2013 |
| TKW | 6 kg |
| Strewn field | Yes |
 | |
The Jbilet Wiselwan meteorite is a CM-type carbonaceous chondrite found in Western Sahara in 2013[1]. It is notable for having a low shock stage and weathering grade with a large total known weight. Thus, it provides a large amount of relatively pristine material without the cost premium associated with meteorite falls.
Jbilet Winselwan has been identified as a good analog for C-type asteroid sample return missions, such as Hayabusa2[2]. Further study has also indicated that it represents a unique view of C-type asteroid regolith based on micro-scale dehydration textures found throughout the meteorite[3][4].
History[edit]
The meteorite was reported in early June 2013 by a meteorite hunter from Smara, Western Sahara. The accessibility of the strewn field, being only 7 miles south of Smara, lead to a large number of meteorite hunters visiting the area from the summer of 2013 onward. The majority of specimens range from 3 to 200 grams with a few larger samples occurring, the largest being ~900g. Samples reached the market quickly and the official classification was approved by The Meteoritical Society on the 12th of August, 2013.[1]
Classification and Composition[edit]
Jbilet Winselwan was classified as CM-type carbonaceous chondrite at The National Museum of Natural History, France, and The University of Hassan II Casablanca based on its oxygen-isotopic composition, petrography, and mineral compositions. The meteorite contains CAIs and both type I and type II condrules ranging up to 1.2mm with the majority around 200 μm. X-ray diffraction used in classification showed strong peaks for serpentines, broad but weaker peaks for smectites, and a weak broad peak for tochilinite. Major silicate compositions are: Olivine; Fa0.98±0.44 and Fa25-40, and Pyroxene; Fs2.6±1.5 and Fs40-61. Rare kamacite with 5.8 wt% Ni was identified. The oxygen isotopic compositions were measured for two fragments for identification, at δ18O 3.811±0.09 and 5.851±0.016, δ17O -2.446±0.040 and -0.601±0.026, respectively. The isotope values plot well inside the CM chondrite region.[1][5]
Further Study[edit]
As a result of its pristinity and relative ease to obtain, Jbilet Winselwan has been extensively studied for a northwest Africa find. The earliest studies identified its extreme degree of brecciation[1][3][5], showing that it likely represents the the uppermost portion of its parent asteroid; the regolith. This regolith context has been of particular interest, as two missions are currently underway to collect asteroid regolith, Hayabuusa2 and OSIRIS-REx. Jbilet Winselwan has specifically been identified as an analog for Hayabusa2, as the mission is targeting a C-type asteroid, the same class as its likely parent body[2]. In this context, the meteorite was further characterized in its major and minor elements[2], alteration textures[2], hydrocarbons[6], and thermal metamorphism[6].
The extremely brecciated characteristics of Jbilet Winselwan have also lead people to use it as an indicator of the thermal and hydration history of its parent body. A single thin section will contain multiple lithologies ranging from typically-hydrated CM chondrite material with tightly-packed chondrules to significantly more dehydrated material with few, poorly preserved chondrules. It has been suggested that some Jbilet Winselwan lithologies represent prime examples of post-shock aqueous alteration[3], including some regions which have formed as a result of cyclical events[4].
References[edit]
- ^ a b c d "Meteoritical Bulletin Database: Jbilet Winselwan".
{{cite web}}: CS1 maint: url-status (link) - ^ a b c d King, A. J.; Russell, S. S.; Schofield, P. F.; Humphreys‐Williams, E. R.; Strekopytov, S.; Abernethy, F. A. J.; Verchovsky, A. B.; Grady, M. M. (2018-12-13). "The alteration history of the Jbilet Winselwan CM carbonaceous chondrite: An analog for C‐type asteroid sample return". Meteoritics & Planetary Science. doi:10.1111/maps.13224. ISSN 1086-9379.
- ^ a b c Zolensky, Michael; et al. (2016). "Unique View of C Asteriod Regolith from the Jbilet Winselwan CM Chondrite". LPSC XLVII.
{{cite journal}}: Explicit use of et al. in:|last2=(help) - ^ a b Cato, Michael J.; Fagan, Amy L. (2017). "An overview of type II chondrules in the CM chondrite Jbilet Winselwan LPSC" (PDF). LPSC XLVIII.
- ^ a b Friend, Pia; Hezel, Dominik C.; Barrat, Jean-Alix; Zipfel, Jutta; Palme, Herbert; Metzler, Knut (2018-06-25). "Composition, petrology, and chondrule-matrix complementarity of the recently discovered Jbilet Winselwan CM2 chondrite". Meteoritics & Planetary Science. 53 (12): 2470–2491. doi:10.1111/maps.13139. ISSN 1086-9379.
- ^ a b Kato, Hiroki; Yabuta, Hikaru (2019). "Polycyclic aromatic hydrocarbons and aliphatic hydrocarbons in Jbilet Winselwan carbonaceous chondrite : Attempt to evaluate the thermal metamorphism degree on the parent body". Japan Geoscience Union Meeting.