Collection
Classification: LL4-6 (Low iron low metal)
Observed fall: No
Year found: 2018
City, Country: Northwest Africa
Mass: 1239 g
In collection
Weight #1 : 1,8 g
Certificate of authenticity: Yes (1)
NWA 13509 is an LL4–6 ordinary chondrite, meaning it is a low-iron, low-metal meteorite that spans multiple metamorphic grades. This classification indicates that, within a single specimen, regions have experienced varying degrees of thermal metamorphism—ranging from type 4 (where chondrules are still visible, albeit partially recrystallized) to type 6 (where chondrules are largely obliterated and the rock appears more uniformly granular). Consequently, NWA 13509 preserves a spectrum of chondritic textures and mineral equilibrations, providing important clues about the heterogeneous heating processes that occurred on its parent asteroid.
When examining a thin section of NWA 13509 – an LL4–6 chondrite under a light microscope, you can observe regions reflecting different degrees of thermal metamorphism. In areas corresponding to the lower grade (type 4), chondrules are still partially discernible, their boundaries faint but present. As you move to higher-grade zones (type 5–6), the chondrules become increasingly blurred or almost entirely subsumed into a granular, recrystallized matrix. Throughout the sample, metallic iron-nickel and sulfide grains are relatively sparse—consistent with the “low iron, low metal” classification—and appear as small, opaque spots under reflected light. This spectrum of textures, from partially preserved chondrules to nearly complete recrystallization, illustrates the diverse thermal history captured in a single meteorite.
