ABSTRACT

Diagenetic alterations of drift have received scant attention in the drift geochemical literature, except for discussions of the mineralogical and chemical alterations that take place in the true solum. This chapter aims to document sub-solum diagenetic alteration of a thick till sheet, which contains abundant concentrations of labile minerals, some of which have economic significance. It describes mineralogical and chemical partitioning among various grain sizes in till. The chapter compares carbonate contents of the various grain sizes using three different laboratory procedures—the Chittick method, Leco Carbon Analyzer, and total dissolution. Heavy minerals were separated from a known weight of fine sand using methylene iodide and a separatory funnel, and their weight percent of the fine sand fraction calculated. The comparative study of carbonate analyses shows total dissolution data to be unreliable, particularly when the sub-silt fraction is included in the fraction analyzed.