Boon and Albritton (1937)とDaly (1947)によって、衝突構造だとされた。シャッターコーン、コーサイト (Martin 1978)、スティショバイト (Martin 1978) などの物証が発見され、衝突起源であることが実証された。
Ar‐Ar年代測定によると、形成年代は20億2700万年前である(Spray et al., 1995)。現在の大きさは124~140 kmだが、形成当時には300 km近くあった(Therriault et al., 1997)。
図 地質図 (Therriault et al., 1997, Meteorites & Planetary Science, 32,71–77, Fig. 1より)。
文献
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