NORTHWEST AFRICA 2797


L3.8
northwest africa 2797 photo
Purchased 2005
no coordinates recorded

A single unequilibrated chondrite weighing 1,211 g was found in the Sahara Desert and sold to G. Hupé in Erfoud, Morocco. This chondrite was analyzed and classified at Northern Arizona University (J. Wittke and T. Bunch) and was assigned to subtype L3.8, with a shock stage of S2 and a weathering grade of W2.

In their modeling of the accretion and impact history of ordinary chondrites, Blackburn et al. (2017) calculated the timing of the catastrophic disruption of the H- and L-chondrite parent bodies to be ~60 m.y. after CAIs. This timing is consistent with two competing dating techniques—Pb–Pb (and Hf–W) chronometry and metallographic cooling rates (Ni diffusion profiles in Fe-metal)—which record cooling associated with both an onion shell structure prior to disruption and a rubble pile after disruption, respectively. The specimen of NWA 2797 pictured above is a 3.2 g partial slice.