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Crustal structure of the southern McArthur Basin, Northern Australia, from deep seismic sounding

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Created 20/01/2025

Updated 20/01/2025

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Deep seismic refraction and vertical reflection recordings have been made in the southern McArthur Basin, over the Bauhinia Shelf and Batten Trough between Daly Waters and the H .Y.C. mineral deposit, and over the Wearyan Shelf between Borroloola and Westmoreland. In the Batten Trough, McArthur Group rocks have a velocity of 5.81 km/s; no velocity contrast was detected between them and basement. Over the Bauhinia Shelf, 100--200 m of Cainozoic, Mesozoic, and perhaps Cambrian sediments, overlie ?Roper Group sediments (P-wave velocity, V = 4.6 km/s). Below these are probable Tawallah Group rocks (V = 5.8-5.9 km/s). Magnetotelluric measurements define a resistivity contrast, possibly basement, at 6-9 km depth. On the Wearyan Shelf at Borroloola, 370 m of Roper Group (V = 3.58 km/s) overlies 2.9 km of Tawallah Group (V = 5.55 km/s). At Robinson River, 650 m of Cainozoic, thin McArthur Group, and, perhaps, upper units of Tawallah Group (V = 4.81 km/s) were detected. Tawallah Group rocks (V = 5.44 km/s) crop out northwest of Robinson River and are about 2.8 km thick. Basement velocity is 6.04 km/s. Between Robinson River and Westmoreland, basement is 3.5-2.7 km deep. At Westmoreland the McArthur Basin sequence thins against the Murphy Ridge . A layer 260 m thick (V = 3.50 km/s) lies on top of a 2.4 km thick layer (V = 5.44 km/s), and the basement velocity of 5.99 km/s increases to 6.06 km/s towards Robinson River. At mid-crustal depths velocities are 5.9--6.9 km/s , and in the lower crust, to depths of 43 km in the west and 40 km in the east, 6.8-7.5 km/s. Below this, a velocity gradient is interpreted until upper mantle velocities are reached at 43-53 km depth in the west (V = 7.5-8.4 km/s) and 44 km in the east (V = 7.9 km/s). Generally, the crustal structure of the North Australian Craton is characterised by high lower-crustal velocities, broad velocity gradients, and thick crust, which probably evolved from an Archaean continental crust during Proterozoic tectonism.

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Title Crustal structure of the southern McArthur Basin, Northern Australia, from deep seismic sounding
Language eng
Licence notspecified
Landing Page https://devweb.dga.links.com.au/data/dataset/568ed5dd-54c7-4b2d-a486-4ab4f39d2543
Contact Point
Geoscience Australia
clientservices@ga.gov.au
Reference Period 20/04/2018
Geospatial Coverage {"type": "Polygon", "coordinates": [[[135.0, -16.5], [136.5, -16.5], [136.5, -16.0], [135.0, -16.0], [135.0, -16.5]]]}
Data Portal data.gov.au

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This dataset was originally found on data.gov.au "Crustal structure of the southern McArthur Basin, Northern Australia, from deep seismic sounding". Please visit the source to access the original metadata of the dataset:
https://devweb.dga.links.com.au/data/dataset/crustal-structure-of-the-southern-mcarthur-basin-northern-australia-from-deep-seismic-sounding

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