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SPE 096

Sphalerite and kimberlite indicator minerals in till from the Zama Lake region, northwest Alberta (NTS 84L and 84M)

Canadian Shield rocks, Paleozoic carbonates and quartzite from the Athabasca Basin and the Cordillera. Kimberlite indicator minerals (KIMs) including Cr-pyrope, Cr-diopside and chromite are present in trace amounts (1 to 2 grains in nine ... Show Abstract

Plouffe, A.  Paulen, R.C.  Smith, R.  Kjarsgaard, I.M.  2008-01-08

SPE 087

Chemistry of Kimberlite Indicator Minerals and Sphalerite Derived from Glacial Sediments of Northwest Alberta

Abstract: Previous AGS and GSC work have reported the presence of kimberlite indicator minerals (KIMs), sphalerite and galena in glacial sediments from northwest Alberta. Most of the KIMs, originally identified from optical properties alone, are confirmed following more detailed electron microprobe analyses with the exception of 1) 15 grains, originally classified as low Cr-diopside, are re-interpreted as KIMs because of their Cr2O3 content that exceeds 0.5 wt. % and 2) one grain originally identified as chromite is re-evaluated as crustal ilmenite. These new results confirm the presence of anomalous concentrations of KIMs in 3 glacial sediment (till) samples (6, 7 and 9 KIMs) and suggest an unknown kimberlitic source is reflected in the glacial sediments of northwest Alberta. Electron microprobe analyses (N=180) were completed on 15 sphalerite grains recovered from the region of the sphalerite anomaly (Plouffe et al., 2006a). Sphalerite has an average composition of 33.4 wt % S, 65.4 wt % Zn, 0.7 wt % Fe, 0.43 wt % Cd and traces amount (0.3 to 0.1 wt %) of Cu, Ag, Se and In. A negative correlation exists between Fe and Zn in sphalerite, suggesting the substitution of Fe for Zn in the sphalerite lattice. Place Keywords 84l 84m alberta bistcho lake cameron hills canada hay river rainbow lake zama city Theme Keywords geology glacial sediment heavy minerals kimberlite indicator minerals sphalerite till

Plouffe, A.  Paulen, R.C.  Smith, I.R.  Kjarsgaard, I.M.  2007-04-01