NWA 16071 is a newly discovered ureilite, primarily composed of olivine and pigeonite, with small a
mounts of carbonaceous materials, metals, and sulfides filling between mineral particles. This meteorite exhibits
two structural areas. One is granular texture area, consisting mainly of coarse-grained olivine and pigeonite. The
other one is poikilitic texture area, where it is common to find pigeonite host crystals enclosing spherical olivine
and metallic spheres. Olivines in the sample widely displays reduction rims with a thickness of 20 to 50 μm,
where the rims are richer in Mg than in cores. Pyroxene is predominantly pigeonite(En
83. 7
Fs
8. 9
Wo
7. 4
), with small
amounts of enstatite(En
96. 5
Fs
2. 6
Wo
0. 9
) appearing at the olivine rims. Diamonds are irregularly granular and dis
tributed within graphite, while a large amount of cristobalite is found in limonite veins. Petrological and mineral
chemistry characteristics indicate that NWA 16071 is an olivine-pigeonite ureilite with poikilitic texture, and its
chemical composition falls within the range of low FeO/ MgO(high-Fo) Ⅲ-type. Raman spectra studies reveal that
graphite has a low degree of crystallization, and diamond is of shock origin. Silicate minerals ubiquitously exhibit
shock fractures,the planar deformation of olivine and the presence of diamonds suggest that the shock level of the
sample is above S5. Poikilitic texture, exsolution of daubreelite, and presence of cristobalite indicate that the
temperature after the shock is between 1 500 and 1 700 °C, with high temperatures and annealing processes elimi
nating some shock metamorphic features.