Henbury
A dozen craters from one shattered iron, remembered in local tradition.
Key facts
- When
- about 4,200 years ago
- Where
- Near Alice Springs, Northern Territory, Australia
- What hit
- an iron meteoroid of several tonnes or more, which broke up in the air
- Era
- In the age of humans
- Location
- 24.57° S, 133.15° E
The largest crater probably took an energy of roughly ten kilotons of TNT; the smaller ones far less.
Perhaps somewhat less than the Hiroshima bomb for the biggest crater.
What happened
In the red country of central Australia lies a group of about a dozen craters, the largest about 180 m across and the smallest a few metres. They were made when an iron meteoroid broke apart in the atmosphere and its pieces struck the ground together.
Thousands of pieces of Henbury iron, a medium octahedrite, have been collected around them, from fragments of a few grams to masses of more than a hundred kilograms. When scientists studied the craters in the 1930s, they were among the first in the world shown to have been made by meteorites.
The Arrernte name for the place is Tatyeye Kepmwere. Aboriginal accounts recorded in the early 20th century speak of a fire-devil that came from the sun, and of people who would not drink water that collected in the craters.
Effects
The craters were blasted out within seconds of one another. Because the site is young, it still shows ejecta rays and meteorite fragments mixed with ejected rock.
The evidence
Iron meteorites, melted droplets of iron and impact glass around the craters, and the craters' layout along the direction of travel.
Did you know?
Henbury is protected as a conservation reserve: collecting meteorites there is illegal.
The Henbury meteorites are medium octahedrites of iron group IIIAB.
Related pages
How is impact energy measured? See energy explained, or try the impact calculator.