MDU GeoServer Web Feature Service

Laterite Western Yilgarn GeoChem (Geochem:LateriteYilgarnGeoChem)

This Record is the final release of a 53-element dataset for approximately 3150 laterite samples (59-element dataset for selected samples) from the western Yilgarn Craton. Samples were taken at a nominal 9-km spacing on an approximately triangular grid, with each sample comprising about 1 kg of ferruginous nodules and pisoliths from lateritic residuum, lag formed from lateritic residuum, or of ferruginous gravel contained in locally derived colluvium. Some authigenic pisoliths and nodules formed in depositional regimes might have been included inadvertently. The laterite geochemical database is designed to provide a regional geochemical framework at a sample spacing suffi ciently close to recognize regional geochemical trends and major lithological differences. The wide-spaced sampling may also provide an indication of broad geochemical dispersion patterns from mineralized systems. However, the 9-km spacing was not designed to detect individual geochemical halos, for which 1-km or 500-m spacing is more appropriate. The sample spacing is wide enough to cover a substantial part of the Yilgarn Craton and still provide useful data for exploration and environmental purposes.There are several signifi cant results of the sampling completed in the southwest and northwest quadrants of the Yilgarn Craton. These include: a) increased Au abundances in the northeast part of the sampling area that cluster around known gold deposits; their extent might mean more widespread mineralization in these areas; b) the chalcophile element index (CHI6*) illustrates potential for Au and base metal mineralization in the westernmost part of the Yilgarn Craton; the pegmatophile PEG4* index shows a regional northwest trend north of the Saddleback greenstone belt; c) chromium abundances in nominally granitic terrain might indicate mafi c–ultramafi c remnants outside the known greenstone belts; d) a regional Hg anomaly (as yet unexplained) trends northwest over more than 500 km.This fi nal report, together with the release of the digital analytical data as a database, provides information about the sampling strategy, preparation methods, analysis, and some new element-distribution patterns with significance to exploration.

Yilgarn Observations (gml:TimeInstant)

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HighP Site Feature Type (highp:HighPSiteFeatureType)

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