Editing Martian meteorite (section)

===Age estimates based on cosmic ray exposure===
[[File:Martian meteorite crafted into a small pendant.jpg|thumb|right|A Martian meteorite crafted into a small pendant and suspended from a gold necklace.]]
The amount of time spent in transit from Mars to Earth can be estimated by measurements of the effect of cosmic radiation on the meteorites, particularly on isotope ratios of [[noble gas]]es. The meteorites cluster in families that seem to correspond to distinct impact events on Mars. It is thought that the meteorites all originate in relatively few impacts every few million years on  Mars. The impactors would be kilometers in diameter and the craters they form on Mars tens of kilometers in diameter. Models of impacts on Mars are consistent with these findings.<ref name="Eugster">O. Eugster, G. F. Herzog, K. Marti, M. W. Caffee [http://www.lpi.usra.edu/books/MESSII/9004.pdf Irradiation Records, Cosmic-Ray Exposure Ages, and Transfer Times of Meteorites, see section 4.5 Martian Meteorites] LPI, 2006</ref>

Ages since impact determined so far include<ref>L.E. NYQUIST, D.D. BOGARD1, C.-Y. SHIH, A. GRESHAKE, D. STÖFFLER [http://seismo.berkeley.edu/~manga/nyquist.pdf AGES AND GEOLOGIC HISTORIES OF MARTIAN METEORITES] 2001</ref><ref>Tony Irving [http://www.imca.cc/mars/martian-meteorites.htm Martian Meteorites – has graphs of ejection ages] – site maintained by Tony Irving for up to date information on Martian meteorites</ref>
{| class="wikitable"
|-
! Type !! Age ([[Year#mya|mya]])
|-
| Dhofar 019, olivine-phyric shergottite|| 19.8 ± 2.3<ref name=Eugster/>
|-
|  ALH 84001, orthopyroxenite||15.0 ± 0.8<ref name=Eugster/>
|-
| Dunite (Chassigny) || 11.1 ± 1.6<ref name=Eugster/>
|-
| Six nakhlites || 10.8 ± 0.8<ref name=":0" /><ref name=Eugster/>
|-
| Lherzolites  || 3.8–4.7<ref name=Eugster/>
|-
| Six basaltic shergottites || 2.4–3.0<ref name=Eugster/>
|-
| Five olivine-phyric shergottites || 1.2 ± 0.1<ref name=Eugster/>
|- 
| EET 79001 || 0.73 ± 0.15<ref name=Eugster/>
|}