Areas W07-8, W07-9, W07-10 and W07-11
Yampi-Leveque Shelf, Browse Basin
Release Area Geology
The Yampi and Leveque shelves mark the southeastern edge of the Browse Basin, and are characterised by shallow, gently basinward-dipping to relatively flat-lying basement (Struckmeyer et al, 1998). Basement comprises Proterozoic metasediments and rhyolitic–dacitic volcanics (Kimberley Basin), and is typically highly eroded with a rugose palaeo-topographic relief (Gracia-Garay, 2006). This basement is onlapped by Permian to Mesozoic and Cainozoic sediments that progressively thin across the terrace and shelf from about 5 km to less than 500 m thick.
The Leveque Shelf forms the offshore continuation of the King Leopold Mobile
Zone, and the northern margin of the mobile zone marks the boundary between
the Yampi and Leveque shelves. The edges of these shelves are characterised
by faulting in places that are of varying ages and not necessarily linked.
The basinward boundary of the shelves is the ‘hingepoint’ from
more or less flat lying basement to gently basinward-dipping basement, beyond
which is the Prudhoe Terrace, a fault bounded terrace at intermediate depth
between the shelves and the central depocentre of this basin (Hocking et
al, 1994).