Meteorite NWA 15200 – Algeria, Northwest Africa

The Martian meteorite NWA 15200 belongs to the group of achondrites, more specifically to the group of nakhlites. It was discovered in Algeria in 2022 and the total mass found is only 196 grams, making it a very rare and highly prized specimen among collectors. Nakhlites come from Mars and are named after the village of El-Nakhla in Egypt, where the first meteorite of this type was found in 1911. Nakhlites are composed primarily of pyroxene and olivine, and their structure suggests that they were formed in the presence of water, which is key to understanding conditions on Mars. Scientific analysis of these meteorites can provide evidence for the presence of water and possible past life on Mars.

Composition

Meteorite NWA 15200 is a cumulate rock rich in the mineral augite along with other components such as ferrohypersthene, fayalitic olivine, andesine plagioclase, and mesostasis rich in aluminium and potassium. It also contains titanochrome magnetite, ilmenite and troilite.

• Augite grains: These grains may be larger than a millimetre in size and show weak zonation, meaning that they have layers with slightly different chemical compositions.
• Ferrohypersthene: This mineral occurs as a distinct phase but may also form coatings on some augite grains, indicating chemical interactions between the two minerals.
• Olivine: It has a relatively uniform composition with no evidence of igneous zonation, meaning that its chemical composition is the same throughout the grain.
• Plagioclase and mesostasis: These minerals fill the gaps between the larger grains of pyroxene and olivine, indicating that they formed later during the crystallization process.
• Absence of maskelynite: This phase, which is formed by shock during impact, is not present in this meteorite.