HENBURY CRATERS

group of 13 meteorite craters in a desert area 8 mi (13 km) west-southwest of Henbury, Northern Territory, central Australia, within the Henbury Meteorite Conservation Park. The craters, recognized in 1931, lie in an area of 0.5 sq mi (1.25 sq km) and are distributed in a scattering ellipse typical of a cluster fall of meteorites. The largest crater (thought to be a coalescence of two smaller craters) is 733 ft (217 m) long, 366 ft wide, and 50 ft deep. The others range from 30 to 266 ft in diameter. The larger craters contain rock flour and fused silica glass. Meteoritic fragments found in the area show evidence of having been heated to about 1,562 F (850 C), indicating the occurrence of an explosion; it is thought that the three largest craters were formed by explosions while the rest are impact craters. The fragments are composed of nickel-iron; the extensive decay of some indicates great age.