Possible impact origin for the Middle Miocene (Serravallian) Puffin Structure, Ashmore Platform, northwest Australia

Abstract

The Puffin Structure is interpreted from high-quality 3D seismic data as a small multiringed impact structure formed by collision of a meteorite or small asteroid with unconsolidated, water-saturated shallow-marine shelf carbonates during the Middle Miocene (mid to late Serravallian). The impact created a dish-shaped structure about 2.5 km in diameter with annular rings and no central uplift.

Fossil leaves of Banksia, Banksieae and pretenders: resolving the fossil genus Banksieaephyllum

“…Conversely, marls of this age are preserved in distal areas of the North West Shelf (Quilty 1977, Apthorpe 1988 where rising sea levels allowed carbonate accumulation to recommence during the Late Oligocene. Gorter and Bayford (2000) have proposed that a small multi-ringed structure (Puffin Structure) on the Ashmore Platform, North West Shelf was formed by the impact of a meteorite or small asteroid into unconsolidated shallow marine carbonates sometime during the Middle Miocene. By this time, the northern margin was at about palaeolatitude 20 0 S and, during the mid-Miocene, began to collide with South-East Asia.…”