Characterization of Weathering Effects in Holocene Loess and Paleosol, Kluane Lake, Yukon, Canada.

Abstract: When measuring weathering intensity of paleosols there arevarious methods and ratios that can be used. This studyexamines several weathering indicators too see which are bestapplied and most effective on loess and paleosols from Yukon,Canada. This region today is considered sub-arctic, but duringpast time this area and its soils has been characterized byglaciations and interglaciations. These changes are the origin ofthe unweathered Kluane loess and the weathered Slims Soilthat are analyzed in the study. Methods used to determine themost sensitive weathering indicator was; CIA (the ChemicalIndex of Alteration), CPA (the Chemical Proxy of Alteration),oxide ratios ((CaO + Na2O + MgO)/TiO2 and (CaO + Na2O +K2O)/TiO2), and elemental ratios (Rb/Sr, Ba/Sr, Ti/Sr). Theresults from the CIA and oxide ratios show that calcium is thevarying factor, and thereby a good weathering indicator forthese samples. The elemental ratios showed a great variationbetween weathered and unweathered samples, and a cleardecrease strontium is apparent. These ratios would also beuseful indicators, but since Sr is associated with Ca, it isprobably calcium that is the main feature. The methods withoutcalcium as a factor did not give any clear separation betweenKluane loess and Slims Soil. Thereby it is concluded that proxyscontaining Ca are the most useful indicators of weathering inthis area.