The inexpensive geochemical exploration technique based on broad-spaced deflation lag sampling played a key role in the discovery of the Babel and Nebo ortho-magmatic Ni–Cu–platinum group elements (PGE) deposits. An area of 1100 km2 in the western Musgrave Block in central Australia was explored using deflation lag samples collected on a 1 km × 0.5 km grid. A total of 35 elements were determined using either inductively coupled plasma mass spectrometry (ICP-MS) or inductively coupled plasma optical emission spectrometry on a sample aliquot digested with mixed acid. The precious elements including Au, Pt and Pd were determined using a lead collection fire assay method with an ICP-MS determination. The multi-element analysis revealed two samples indicative of weathered Ni–Cu sulphides from among many stronger Ni or Cu and Pt anomalies. The most anomalous sample of the two contained concentrations of 566 ppm Ni, 950 ppm Cu and 27 ppb Pt.
The Babel deposit is a large low-grade disseminated deposit that reaches through thin sand cover to sub-crop locally. The Nebo deposit lies 2 km to the NE under a few metres of aeolian dune sand and is smaller, but contains a number of high grade massive sulphide pods. The discovery intersection for the Babel deposit was 148.9 m at 0.3% Ni, 0.42% Cu and 0.29 ppm Pt, Pd+Au and for the Nebo deposit 26.55 m at 2.45% Ni, 1.78% Cu, 0.09 % Co and 0.74 ppm Pt, Pd+Au.
- © 2005 AAG/The Geological Society of London