Stratigraphic investigations

Bezys, R.K. 2000. Stratigraphic investigations and corehole drilling program, 2000. In Report of Activities 2000, Manitoba Industry, Trade and Mines, Manitoba Geological Survey, 196-201. 

In prospecting for raw materials for the manufacture of cement only secondary importance attaches to stratigraphic investigations, because the suitability of the raw materials depends mainly on chemical features and is not confined to any particular geological age. 

Accordingly, stratigraphic investigations are usually limited to macroscopic classification of the drilled cores and to assigning characteristic datum horizons for correlating the individual core borings. 

Again, a stratigraphic estimate of the age of the sediment is used to give t in both equations. The ratio of age-corrected excess °Th to Pa, denoted ( Paxs/ °Thxs)° is that most widely used to investigate the past environment. 

Both CCA and WA require a calibration data set, as already described. For best results, these data sets should be developed carefully and with considerable forethought. The lakes chosen should include the range of limnological conditions that investigators anticipate inferring from the stratigraphic data from cored lakes. Several chemical and other environmental characteristics likely to influence the distribution of taxa should also be measured accurately on as many samples as possible to characterize temporal variability. Insufficient or inadequate chemistry data is an important source of error associated with inferred values. 

Amino acid racemization dating of mollusc shell has not been investigated as extensively as that of fossil bone. Recently several studies have used d/l enantiomeric ratios to resolve stratigraphic relationships (24) and to date geological deposits by the calibration procedure (19,20). Racemization dating has also been applied to midden shell from archaeological sites with limited success (20). 

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