The Yamato 691 (abbreviated Y-691) is a 4.5 billion year old chondrite meteorite discovered by members of the Japanese Antarctic Research Expedition[3] on the blue ice field of the Queen Fabiola Mountains (Yamato Mountains) in Antarctica, on December 21, 1969.[2]
| Yamato 691 | |
|---|---|
| Type | Chondrite |
| Class | Enstatite chondrite |
| Composition | Pl (An32-75), En-99.2, Wo-0.3, tro., nini., oldh., perr., schr., metal (2.2–2.5% Ni, 0.16–0.22% CO)[1] |
| Country | Antarctica |
| Region | Queen Fabiola Mountains (Yamato Mountains) |
| Coordinates | 71°50′S 36°15′E / 71.833°S 36.250°E / -71.833; 36.250[2] |
| Observed fall | No |
| Fall date | 4.5 billion years ago |
| Found date | December 21, 1969 |
| TKW | 715 grams (1.576 lb) |
Yamato 691 was one among 9 meteorite specimens identified by the Japanese Expedition Team in 1969. It was later studied at the Max Planck Institute for Chemistry, Mainz, Germany.[4]
In April 2011, NASA and co-researchers from the United States, South Korea and Japan have found a new mineral named "Wassonite" in Yamato 691.[5]
This meteorite is a stony enstatite chondrite. Minerals reported from the meteorite include:[6]