* Astronomy

We present results of field analysis, microscopy, and remote sensing mapping of two circular structures in Australia of which the meteorite impact origin is not yet confirmed.
Piccaninny, Western Australia (17°25' 30" S, 128°26' 10" E, 7.5 km diameter): The circular structure (Beere 1983; Shoemaker and Shoemaker, 1985) forms a plateau in the Purnululu National Park that is built up by Devonian conglomerates and sandstones. It is framed by beehive-like domes and the Piccaninny Gorge, both make the access to the elevated plain difficult. The structure is defined by a centerward dipping circular monocline (5-15° dip), a very gentle ring syncline, and a weak central rise with a stratigraphic uplift of 40-50 m.
The distinct regional cleavage pattern outside the plateau displays a systematic deflection towards the center of the structure. On the plateau the vertical cleavage planes are reactivated as faults. These fault zones typically contain comminuted decimeter-wide gouge zones and meter-wide process zones in which anastomozing subsidiary fault networks occur. Some of the interconnected shear zones resemble breccia dikes. Strata are offset by faults. Minor strata tilting and the apparent lack of shock features suggest a considerable amount of erosion (>2 km) of the possible impact crater

Read more  (PDF)



Expand ( 800 x 600)
Age: < 360 million years
It belongs to Purnululu National Park, UNESCO world heritage site since 2003

Piccaninny "crater" refers to an impact structure (or astrobleme), the eroded remnant of a former impact crater, situated in northern Western Australia. It was named after Piccaninny Creek and lies within the Purnululu (Bungle Bungle) National Park.
The site is marked by a circular topographic feature on top of the flat-topped sandstone and conglomerate Bungle Bungle Range, clearly visible on remotely sensed images

Read more