Yorke Peninsula (Moonta Subdomain) GIS Dataset

Brief description

The Moonta Subdomain forms the southern part of the Olympic Cu-Au province on the eastern margin of the Gawler Craton, and underlies most of the Yorke Peninsula and Spencer Gulf. The domain basement comprises metasediments and metavolcanics of the Palaeoproterozoic Wallaroo Group (~1760-1740 Ma) which were deformed and metamorphosed to upper greenschist-amphibolite facies during the Kimban Orogeny (~1720 Ma). These rocks were further deformed and intruded by granitoids and minor mafic intrusions of the Hiltaba Suite between about 1600 Ma and 1575 Ma. The Moonta Subdomain basement is highly prospective for iron oxide-Cu-Au mineralisation associated with the Hiltaba magmatic event. However outcrop of these basement rocks is limited almost entirely to narrow coastal exposures. The majority of the prospective basement is concealed by up to 100 metres of Neoproterozoic to Quaternary sediments, and geological mapping of the basement is largely limited to interpretation of geophysics (airborne magnetics, gravity, AEM) and drilling.

Lineage

Maintenance and Update Frequency: asNeeded

Statement: The geology dataset was compiled primarily from interpretation of airborne magnetic data and drill hole logging, along with gravity and minor AEM data. The magnetic data used for the interpretation was compiled by GA and PIRSA geophysicists from numerous regional government surveys and more detailed private company surveys. The TEISA magnetic dataset (flown 1999, 400 metre line spacing) comprised the bulk of the data over the land area of Yorke Peninsula. Drill hole data comprised logs from the PIRSA database, as well as logging by the author. The model of depth-to-basement was calculated using the ANUDEM topographic modelling algorithm and was based primarily on drill hole data and the mapped limits of basement outcrop. Depth-to-basement in the area of the Stansbury Basin (SE of the survey area) was based on previous modelling by SRK Consulting (available from PIRSA). No attempt has been made to smooth the depth-to-basement contours which have been computer-generated from the gridded model. The vector data was digitised and compiled using ArcInfo 8.0.2. Depth-to-basement data was gridded and contoured using the Topogrid module of ArcInfo 8.0.2 and the Spatial Analyst extension of Arcview 3.2. Geophysical and depth-to-basement images were exported as BIL files from ER Mapper 5.5. The locations of mines and prospects were derived from various geological published papers and unpublished exploration company reports. The locations and names of lodes and mines in the Moonta and Wallaroo mineral fields are primarily from the reports of Jack (1917) and Dickinson (1953). Prospect outlines primarily delineate the extent of exploration surveys and drilling programs by companies such as WMC, NBH, Amalg, CRAE, BHP, MIM, Uranerz, St Joe, Phelps Dodge and others.