NWA 869 represents an L chondritic regolith breccia containing
preirradiated components. The meteoroid had an initial radius of about
2 m with a mass of about 110 metric tons. The transit time to Earth was
about 4-5 Ma. Large variations of shielding depths between samples
indicate that break-up of the meteoroid must have occured high in
atmosphere. This would also explain the large inferred ablation loss,
which is typical for large chondrite showers.
Ref:
"The L3-6 Regolith Breccia Northwest Africa 869: Petrology, Noble
Gases, and Cosmogenic Radionuclides"
Metzler, K.; Ott, U.; Welten, K. C.; Caffee, M. W.; Franke, L.
39th Lunar and Planetary Science Conference, (Lunar and Planetary
Science XXXIX), held March 10-14, 2008 in League City, Texas.
LPI Contribution No. 1391., p.1120
Publication Date: 03/2008
http://www.lpi.usra.edu/meetings/lpsc2008/pdf/1120.pdf
-----Original Message-----
From: Melanie Matthews <[email protected]>
To: MeteoriteList <[email protected]>
Sent: Fri, Nov 4, 2011 2:10 am
Subject: [meteorite-list] Question about NWA 869
Hi list,
Are there any estimates in how long ago this wonderful meteorite fell
to Earth,
and how large it might have been before it entered the atmosphere? It
must have
been a massive meteoroid, much larger than the one that produced the
Buzzard
Coulees.
-----------
-Melanie "MetMel" - avid meteorite collector/enthusiast from Canada!
IMCA#: 2975
eBay: metmel2775
I eat, sleep and breath meteorites 24/7.
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