* Astronomy

Thermal and shock metamorphic episodes of the Duwun L6 chondrite: Petrological evidence

The Duwun meteorite fell on 23 November 1943 in Duwun-Myeon, Gohung-Gun, Jeonlanam-Do, Korea. Duwun is classified as ordinary chondrite of L group and type 6. Duwun consists of olivine, pyroxene, plagioclase, Fe-Ni metals, troilite,chromite and apatite. Relic chondrules with barred olivine, porphyritic olivine, radial pyroxene and cryptocrysalline textures are found. Thermometries using on compositions of pyroxene suggest the recrystallisation temperature of 840 oC. Various shock features recognised in Duwun include planar fractures and wavy extinction in olivine, occurrence of maskelynite, silicate darkening and polycrystalline texture of kamacite. These observations suggest that the Duwun meteorite experienced shock stresses at S3 or S4 stages (20 GPa).
Read more