Ballard geological map, digital dataset

Brief description

Mapping of outcrop geology on Ballard 1:100 000 map sheet in the Eastern Goldfields, Western Australia, as part of the National Geoscience Mapping Accord (NGMA). Briefly, mapping consists of geological boundaries/units, faults, fractures, folds, veins, dykes, joints, linears, marker beds, trends, structural measurements, and mineral deposits.

Lineage

Maintenance and Update Frequency: irregular

Statement: Geological themes in the western third of the area were generated from field observations and interpretation using aerial photographs (1:25 000 colour) by M.S.Rattenbury in 1990 and A.J.Stewart in 1996; a 1:24 000-scale geological map of Mount Ida greenstone belt south of Lake Ballard prepared by CRA Exploration Pty Ltd 1967, a 1:10 000-scale geological map of the central part of the Mount Ida greenstone belt between 6773000N and 6754000N prepared by M.Gole et al. (CRA exploration Pty Ltd 1973), and field observations by S.Wyche (GSWA) in 1995. In eastern two-thirds of area, geological themes were generated from field observations and interpretation using aerial photographs (1:50 000 b/w), Menzies 1:250 000 geological map 1st edition (Kriewaldt 1971, GSWA), Menzies 1:250 000 regolith-landforms map (Craig and Churchward 1995, AGSO), and satellite imagery (Landsat TM). Geophysical themes were generated from magnetic data (90-m cell size grids derived from airborne magnetic surveys). Mineral deposit locations and information are largely sourced from GSWA data modified by field and air-photo observations. Topographic themes have been provided by AUSLIG and DOLA. Some amendments to that topographic data have been made by the authors. Lineage of topographic data, before receipt from AUSLIG and DOLA, is uncertain. Maps were compiled from unrectified photo-overlays on to topographic bases supplied by AUSLIG and DOLA (see notes on topographic data above). Drainage and, where necessary, other topographic features (e.g., fence lines) were used for spatial control of the geological data. Compilations were digitally captured by scanning and vectorising procedures. Point data with database origins have been located largely by non-differential GPS. Some detail may have been generalised, repositioned, or omitted from the primary data for cartographic purposes.