Pinpointing the source of a lunar meteorite: implications for the evolution of the Moon.
The lunar meteorite Sayh al Uhaymir 169 consists of an impact melt breccia extremely enriched with potassium, rare earth elements, and phosphorus [thorium, 32.7 parts per million (ppm); uranium, 8.6 ppm; potassium oxide, 0.54 weight percent], and adherent regolith. The isotope systematics of the meteorite record four lunar impact events at 3909 +/- 13 million years ago (Ma), approximately 2800 Ma, approximately 200 Ma, and <0.34 Ma, and collision with Earth sometime after 9.7 +/- 1.3 thousand years ago. With these data, we can link the impact-melt breccia to Imbrium and pinpoint the source region of the meteorite to the Lalande impact crater.
Institut für Geologie, Universität Bern, Baltzerstrasse 1, CH-3012 Bern, Switzerland. gnos@geo.unibe.ch
Edwin
E
Gnos
Beda A
BA
Hofmann
Ali
A
Al-Kathiri
Silvio
S
Lorenzetti
Otto
O
Eugster
Martin J
MJ
Whitehouse
Igor M
IM
Villa
A J Timothy
AJ
Jull
Jost
J
Eikenberg
Bernhard
B
Spettel
Urs
U
Krähenbühl
Ian A
IA
Franchi
Richard C
RC
Greenwood
D003460:Crystallization; D004602:Elements; D019419:Evolution, Planetary; D007554:Isotopes; D007854:Lead; D008674:Metals, Rare Earth / Q000032:analysis; D019110:Meteoroids; D016081:Moon; D010758:Phosphorus / Q000032:analysis; D011188:Potassium / Q000032:analysis; D013910:Thorium / Q000032:analysis; D014501:Uranium / Q000032:analysis
D004602:Elements; D007554:Isotopes; D008674:Metals, Rare Earth; D010758:Phosphorus; D007854:Lead; D014501:Uranium; D013910:Thorium; D011188:Potassium