The crustal thickness of Australia

We investigate the crustal structure of the Australian continent using the temporary broadband stations of the Skippy and Kimba projects and permanent broadband stations. We isolate near-receiver information, in the form of c rustal P-to-S conversions, using the receiver function technique. Stacked r eceiver functions are inverted for S velocity structure using a Genetic Alg orithm approach to Receiver Function Inversion (GARFI). From the resulting velocity models we are able to determine the Moho depth and to classify the width of the crust-mantle transition for 65 broadband stations. Using thes e results and 51 independent estimates of crustal thickness from refraction and reflection profiles, we present a new, improved, map of Moho depth for the Australian continent. The thinnest crust (25 km) occurs in the Archean Yilgarn Craton in Western Australia; the thickest crust (61 km) occurs in Proterozoic central Australia. The average crustal thickness is 38.8 km (st andard deviation 6.2 km). Interpolation error estimates are made using krig ing and fall into the range 2.5-7.0 km. We find generally good agreement be tween the depth to the seismologically defined Moho and xenolith-derived es timates of crustal thickness beneath northeastern Australia. However, benea th the Lachlan Fold Belt the estimates are not in agreement, and it is poss ible that the two techniques are mapping differing parts of a broad Moho tr ansition zone. The Archean cratons of Western Australia appear to have rema ined largely stable since cratonization, reflected in only slight variation of Moho depth. The largely Proterozoic center of Australia shows relativel y thicker crust overall as well as major Moho offsets. We see evidence of t he margin of the contact between the Precambrian craton and the Tasman Orog en, referred to as the Tasman Line.