Khatyrka, a new CV3 find from the Koryak Mountains, Eastern Russia

Abstract

Abstract-A new meteorite find, named Khatyrka, was recovered from eastern Siberia as a result of a search for naturally occurring quasicrystals. The meteorite occurs as clastic grains within postglacial clay-rich layers along the banks of a small stream in the Koryak Mountains, Chukotka Autonomous Okrug of far eastern Russia. Some of the grains are clearly chondritic and contain Type IA porphyritic olivine chondrules enclosed in matrices that have the characteristic platy olivine texture, matrix olivine composition, and mineralogy (olivine, pentlandite, nickel-rich iron-nickel metal, nepheline, and calcic pyroxene [diopsidehedenbergite solid solution]) of oxidized-subgroup CV3 chondrites. A few grains are finegrained spinel-rich calcium-aluminum-rich inclusions with mineral oxygen isotopic compositions again typical of such objects in CV3 chondrites. The chondritic and CAI grains contain small fragments of metallic copper-aluminum-iron alloys that include the quasicrystalline phase icosahedrite. One grain is an achondritic intergrowth of Cu-Al metal alloys and forsteritic olivine AE diopsidic pyroxene, both of which have meteoritic (CV3-like) oxygen isotopic compositions. Finally, some grains consist almost entirely of metallic alloys of aluminum + copper AE iron. The Cu-Al-Fe metal alloys and the alloy-bearing achondrite clast are interpreted to be an accretionary component of what otherwise is a fairly normal CV3 (oxidized) chondrite. This association of CV3 chondritic grains with metallic copperaluminum alloys makes Khatyrka a unique meteorite, perhaps best described as a complex CV3 (ox) breccia.

Impact-induced shock and the formation of natural quasicrystals in the early solar system

“…The correlation is based on O-isotope measurements of an olivine grain ( Fig. 1), and the presence of the same types of minerals and rare Cu-Al phases found in the other Khatyrka samples [5][6][7] . Also, the shocked portion of no.…”

“…125 is part of the same CV3 CC as nos: 5 and 121 (ref. 7). The correlation is based on O-isotope measurements of an olivine grain ( Fig.…”

“…121 (ref. 7). Because all of the grains in this meteorite are so small, we only have polished grain mounts and not thin sections.…”

“…125 of the Khatyrka meteorite, a sample that provides clear evidence that the meteorite was subjected to a high-pressure impact shock, supplemented by studies of individual phases found in sample nos: 5, 121 and 126 (ref. 7). On the basis of the new data, our hypothesis is that the shock produced a heterogeneous distribution of high pressure and temperature, with localized melting of Al-Cu-bearing minerals followed by rapid cooling.…”

“…It was discovered in the Khatyrka meteorite [5][6][7] , an oxidized subgroup (Allende-like) CV3 carbonaceous chondrite (CV3 CC) that formed at least 4.5 billion years ago. The preservation of a quasicrystal in a meteorite that formed at the early stages of the solar system indicates that it can be stable over cosmic time scales, giving new insights on the existence and stability of these materials in nature 5,6 .…”