Recent history
This crater is believed to have been discovered in 1920 by an aboriginal stockman, Billy Seward, when he almost rode into it at a full gallop during a muster on the station it was named after. He showed his find to the station manager Gerard Wellard.
Wellard realised this was a significant scientific discovery and gathered up enough fragments of the meteorite to fill an old gallon tin (about 4.5lts) and sent them to the WA Museum for analysis.
Wellard visited the museum a year later to find the whereabouts of his samples was unknown, probably due to a move of the Mines Department from the Museum Building, and they had simply been forgotten.
In 1938 one of the rock samples was found and a report analysing the piece was prepared and released so authentication of the crater was established. Unfortunately misspelling of Wellards name had the report state the crater was first reported by Mr Willard. This caused a problem in years to come which was only resolved by an extraordinary coincidence.
After the publication of a scientific paper in 1960, interest in Dalgaranga was once again revived. In 1961 Professor Pearl from the US flew to WA to examine the crater and understandably wanted to talk to Mr Wellard. But because of the misspelling of his name he left without finding him.
Professor Pearl headed back home on a cruise ship and three days out of Perth his wife was talking to another lady aboard and the subject of meteorites came up. Incredibly the other woman turned out to be George Wellards wife on a world cruise. Excitedly the women told their husbands and the two men were soon together discussing the crater.
Australia has no less than 18 impact craters, including the more well known Wolfe Creek, Henbury and Gooses Bluff
Some other Australia craters in order from largest to smallest are:-
- Acraman in South Australia being 160km across.
- Tookoonooka in Queensland being 55km across.
- Teague in Western Australia being 30km across.
- Strangways in the Northern Territory being 25km across.
- Gooses Bluff in the Northern Territory being 22km across.
- Lawn Hill in Queensland being 18km across.
- Spider in Western Australia being 13km across.
- Kelly West in the Northern Territory being 10km across.
- Connolly Basin in Western Australia being 9km across.
- Picaninny in Western Australia being 7km across.
- Goat Paddock in Western Australia being 5.1km across.
- Goyder in the northern territory being 3km across.
- Liverpool in the Northern Territory being 1.6km across.
- Wolfe Creek in Western Australia being 875mts across.
- Boxhole in the Northern Territory being 170mts across.
- Henbury in the Northern Territory being 157mts across and consisting of 12 craters.
- Veevers in Western Australia being 80mts across.
- And this one Dalgeranga being a approximately 21mts across and 3mts to 5mts deep.
The Geology
Impact craters are geologic structures formed when a large meteoroid, asteroid or comet smashes into a planet or a satellite. All the inner bodies in our solar system have been heavily bombarded by meteoroids throughout their history. The surfaces of the Moon, Mars and Mercury, where other geologic processes stopped millions of years ago, record this bombardment clearly.
A not widely known fact is that the earth has been even more heavily impacted than the Moon, however, craters are continually erased by erosion as well as by volcanic resurfacing and tectonic activity. Thus only about 160 terrestrial impact craters have been recognized, the majority in the geologically stable regions of North America, Europe and Australia where most exploration has taken place. Spacecraft Orbital Imagery has helped to identify sites in more remote locations for further investigation.
Dalgeranga crater may be small but it is special as it is the smallest authenticated crater in Australia and also one of the youngest in the earth’s surface. Because of its young age the impact crater is well preserved for its small size, and the meteorite fragments have not weathered away.
The discovery of fragments of mesosiderite (stony-iron meteorite) around the crater confirms an impact Origin.
The bedrock exposed in this area is weathered Archaean granite.
The oldest rock formations exposed on the surface of the Earth are Archaean or slightly older,
(2.5 billion years.)
Logging Requirements
From the information provided and your powers of observation at GZ simply email us the answers to following questions:
1. . List three things that make this crater stand out from its peers.
2. From where you are standing use the information on the board and your deduction skills and describe what angle you think the meteor struck the ground.
3. To prove you visit what is the non natural item in the centre of the crater.
Referanced:
On site info.
We hope you enjoy your visit and learned something about our fascinating planet.