Passive seismic studies of the Capricorn Orogen, Western Australia

Summary

The study of incoming seismic waves from teleseismic earthquakes can be used to investigate the deep structure of the Earth’s crust and upper mantle. Resolving the deep crustal structure and locating potential mantle-tapping structures is critical for understanding the metallogeny of mineral deposits at the surface. From 2014 to 2018, a network of 83 seismic monitoring stations was moved across the Capricorn Orogen in Western Australia. This survey was intended to complement the previous deep crustal seismic reflection lines, and although the resolution was lower, the survey covered the majority of the orogen in 3D and provided different geophysical information from the reflection surveys.

Results from studies of receiver functions provide the depth to Moho and average composition of the crust for the orogen. The distribution of more felsic crust and a deeper Moho outline the extent of the Archean Glenburgh Terrane in the central part of the orogen. Common conversion point (CCP) studies provide a view of compositional layering in the crust, and have led to a revised interpretation of the 10GA-CP2 seismic reflection line. Intriguing features within the upper mantle obtained by bodywave tomography have yet to be interpreted within the context of the tectonic evolution of the orogen.

• Capricorn Orogen
• receiver function
• ambient noise
• tomography