Aminostratigraphy of Quaternary marine and glaciomarine sediments, Qivitu Peninsula, Baffin Island

Abstract

A complex sequence of cyclical marine and glaciomarine lithofacies exposed along the coastal lowlands of the Qivitu Peninsula was deposited during the marine transgressions and regressions that affected this area during repeated glaciation of the region. Multivariate analysis of amino acid ratios measured on shell fragments of the pelecypods Hiatella arctica and Myatruncata in the lithostratigraphic units provides a basis for their chronocorrelation through the use of informal regional aminostratigraphic units termed aminozones. All but the oldest aminozones correspond with particular lithostratigraphic units deposited during transgressive–regressive periods when relative sea level was higher than present sea level. Discriminant analysis shows total amino acid fraction allo/iso ratios from either species are the best overall criteria for assigning a shell sample to a particular aminozone, but free fraction allo/iso ratios are more useful in the younger zones. The distribution of ratios in lithostratigraphic units indicates a large proportion of shell fragments is reworked.Interpretation of all 14C, uranium-series, paleomagnetic, and amino acid data from eastern Baffin Island suggests aminozone 1 is [Formula: see text] years BP, aminozone 2 is [Formula: see text] years BP, aminozone 3 is [Formula: see text] years BP, and aminozone 4 is [Formula: see text] years BP. The extent of isoleucine epimerization in shell samples indicates some aminozones may be of early or pre-Quaternary age.