Structure of the Mt Isa region from seismic ambient noise tomography |
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Authors: | E Saygin H McQUEEN L J Hutton B L N Kennett G Lister |
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Institution: | 1. Research School of Earth Sciences, The Australian National University, Canberra ACT 0200, Australiaerdinc.saygin@anu.edu.au;3. Research School of Earth Sciences, The Australian National University, Canberra ACT 0200, Australia;4. Geological Survey of Queensland, Department of Natural Resources and Mines, Level 10, 119 Charlotte Street, Brisbane, QLD 4002, 4000 Australia |
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Abstract: | We use seismic tomography, exploiting group velocities derived from ambient noise, to delineate the crustal structure beneath Mt Isa and the surrounding blocks and basins. The depth extent of the blocks can be traced into the mid-crust and the spatial extent of the associated velocity anomalies mapped over an area of approximately 500 km by 500 km. The Proterozoic Mt Isa block is imaged as a region of elevated seismic velocities comparable to the Yilgarn craton in Western Australia, while the surrounding basins have relatively low velocities. Seismic velocity anomalies display correlations with the regional Bouguer gravity data and with high crustal temperatures in the region. There are a number of isolated low-velocity anomalies under the Millungera basin that suggest either previously unknown thermal anomalies or zones with high permeability, which can also produce lowered velocities. |
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Keywords: | Mt Isa Australia lithosphere Proterozoic seismology ambient seismic noise tomography |
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