Brief description
In July and August 1957 an experimental seismic survey was done in the Oodnadatta area of the Great Artesian Basin. The purposes of the survey were to find whether reflections could be recorded from beneath duricrust, a siliceous surface deposit, and whether structures mapped by surface geological methods persist with depth. Reflections were recorded from beneath the duricrust using shallow pattern holes and six geophones per trace; the sub-surface structure was mapped with reasonable accuracy. In areas where the duricrust is eroded, reflections of fair quality were obtained using a single shot-hole and six geophones per trace. A seismic reflection traverse across the Oodnadatta anticline indicated that the structure was present in a horizon which corresponds to the top of the artesian aquifer at a depth of about 1000 ft below datum (400 ft above MSL). The seismic results indicated that the anticline was of smaller relief than had been e stimated from surface mapping. There was a change from fair-quality persistent reflections at shallow depths to poor-quality less numerous reflections with sporadic dips at greater depths; this probably represents the base of the Cretaceous. The greatest depth from which Cretaceous sediments were recorded was about 2350 ft below datum. Reflection depths computed by seismic methods correspond closely with lithological boundaries, and in particular the base of the Cretaceous sediments, encountered in the Santos No. 1 bore. The results of a refraction traverse on the crest of the Oudnadatta anticline show the presence of a 'basement' refractor with a velocity of 13,900 ft/sec at a depth of about 1245 ft below datum. There is slight evidence of a refractor with a substantially higher velocity at about twice this depth. The 'basement' velocity of 13,900 ft/sec is consistent with the assumption that there is a pre-Cretaceous layer between the Cretaceous sediments and the Precambrian basement complex.Lineage
Maintenance and Update Frequency: asNeededIssued: 1962
Data time period: 1957-07-09 to 1957-08-31
text: westlimit=135.0; southlimit=-27.5; eastlimit=135.5; northlimit=-27.0
User Contributed Tags
Login to tag this record with meaningful keywords to make it easier to discover
Download the file (misc)
uri :
https://d28rz98at9flks.cloudfront.net/76390/L031_Oodnadatta_1957_GeoCat_76390.zip
- URI : pid.geoscience.gov.au/dataset/ga/76390
- global : de71c515-71f5-04f0-e044-00144fdd4fa6