Ευθυγραμμισμένος αχονίτης - regmaglypts, γραμμές ροής και χείλος ανατροπής - κλάσμα αστεροειδούς 4 - 53 g

Αυτό είναι ένα εκθαμβωτικό προσανατολισμένο δείγμα από τη Βορειοδυτική Αφρική 16179, ένα επίσημα ταξινομημένο HED αχονίτης.

Ένα ιδιαίτερα ελκυστικό δείγμα with well-preserved atmospheric flight features. The exterior retains a fresh fusion crust, with clearly developed flow lines, regmaglypts and roll-over lip. Together, these features provide an excellent record of the specimen's passage through Earth's atmosphere and its orientation during atmospheric ablation. The roll-over lips and flow lines are special characteristics meteorite orientation. As the leading face of the stone experienced intense heating and ablation during atmospheric entry, molten material was displaced towards the trailing edges, producing the raised lip visible around the specimen. The associated flow lines preserve the direction in which this material was swept across the surface.

NWA 16179 is an officially classified HED achondrite, eucrite, and is interpreted as material from the differentiated asteroid 4 Vesta, the parent body of the HED meteorites. The Meteoritical Bulletin describes NWA 16179 as an equilibrated basaltic eucrite breccia. Its interior is dominated by exsolved pyroxene and plagioclase fragments, with an average plagioclase grain size of approximately 66 μm. Minor phases include silica, apatite, Cr-bearing ilmenite, chromite and troilite. The pyroxene and plagioclase compositions are consistent with a basaltic eucrite of the HED group.

The meteorite experienced moderate shock (M-S2) and has a low degree of terrestrial weathering, helping to preserve its original mineralogical characteristics.

Eucrites represent basaltic material produced by extensive igneous differentiation on their parent body. In the case of the HED suite, that body is widely identified with 4 Vesta, one of the largest differentiated asteroids in the Solar System.

This specimen therefore records two very different stages of its history: an ancient history of igneous activity and impact brecciation on its parent asteroid, followed billions of years later by the intense physical processes of atmospheric entry on Earth.

I am a member of the Meteoritical Society (#7743) and the Global Meteorite Association (#G0129) and have been collecting meteorites for over 16 years.