The wide-angle reflection seismic survey coincident with regional transect through Northern Yilgarn focused on the Leonora-Laverton Tectonic Zone, Western Australia was carried out to supplement deep seismic reflection studies. The major objectives were to collect high-density refraction information for offsets up to 60 km, to carry out a comparative study of near-vertical and wide-angle recordings of vibroseis energy at various offsets within the Leonora-Laverton tectonic zone and to obtain velocity information for upper crust. The survey deployed 120 short period recorders with spacing of 500 m. Acquisition parameters used for wide-angle reflection experiment were selected to fit into conventional reflection survey. The same vibrations were recorded in both surveys simultaneously. The major challenge in processing the Vibroseis data is to manage the huge volume of data. The processing of data includes several steps: sorting into receiver and source gathers, cross-correlation with reference sweeps and summing original seismic traces to form single source point traces, producing seismograms from individual traces and finally creating seismic record section from separate seismograms. The major step in processing and interpretation of data is to analyse recorded wave fields on the basis of seismological criteria prior to seismic velocity modelling. Seismic velocity models developed by using forward and inverse travel modelling software will supplement geological interpretations for this complex region and allow an estimation of its crustal composition.

Product no longer exists, please refer to GeoCat #30413 for the data

Product no longer exists, please refer to GeoCat #30413 for the data

Product no longer exists, please refer to GeoCat #30413 for the data

Product no longer exists, please refer to GeoCat #30413 for the data

A significant proportion of the mineral endowment of eastern Australia is related to Phanerozoic granites and comagmatic volcanic rocks. Accordingly, considerable scientific research and data gathering has been focussed on these magmatic systems within eastern Australia, over the last 15 years. A major outcome has been the recognition that the nature and style of this mineralisation (porphyry Cu-Au, porphyry Cu-Mo, vein-style W, Mo, Sn, Au) clearly varies with both the mineralogy and chemistry of the related magmatism (e.g., Blevin & Chappell, 1992). Further research is increasingly recognising that the development of mineralisation, is controlled by many factors other than just the chemistry and intensive parameters intrinsic to the magmatic systems. Wall rock controls, such as oxidation state, chemical reactivity, competency, porosity and structural preparation, are now considered critical as to whether mineralisation will form. The mineralogical composition of the host rocks also appears important; certainly playing an important role in metal precipitation, e.g., many deposits are hosted by rocks rich in reductants such as magnetite, graphite and/or sulphide. Interestingly, empirical data also indicate that deposit types may be host rock specific, e.g., Haynes (2003) suggests Fe-oxide Cu-Au and porphyry Cu deposits are found in settings where host rocks contain little or no reduced carbon minerals (e.g., graphite); conversely, Wyborn (2003) suggests Au-only deposits occur where host rocks are carbonaceous. The potential for host rocks to play a significant role in the mineralising environment is clear, even more so when it is considered that mineralisation may occur up to 2-3 km from the granite body (ref). Unfortunately, previous studies of magmatism and related metallogenesis in eastern Australia have largely ignored country rocks and their role, beyond simple criteria such as level of emplacement and level of exhumation.

Product no longer exists, please refer to GeoCat #30413 for the data

Product no longer exists, please refer to GeoCat #30413 for the data

Product no longer exists, please refer to GeoCat #30413 for the data

Product no longer exists, please refer to GeoCat #30413 for the data