Constraining clastic input controls on magnetic susceptibility and trace element anomalies during the Late Devonian punctata Event in the Western Canada Sedimentary Basin

Abstract

Terra Nova, 24, 301–309, 2012AbstractFactor analyses were applied to trace element and magnetic susceptibility (MS) records of the Late Devonian palaeoceanographic ‘punctata Event’ perturbation in the Western Canada Sedimentary Basin to constrain the extent to which geochemical anomalies were driven by 1) changes in clastic input (Factor 1; 55.1% of total variance) vs. 2) anoxia in the depositional environment (Factor 2; 35.2% of total variance). MS associates only with Factor 1 (r = 0.971) and is significantly correlated (99.9% level) with acid‐insoluble limestone residues and clastic proxies (Al, Si, K, Ti, Zr; r = 0.542–0.639). Based on XRD analyses of a small subset of these residues (N = 7), a multivariate linear regression model accounts for 97.7% of total MS variance as a function of variable admixing of illite, pyrite, quartz and feldspar, in turn variably diluted by stratigraphic changes in the total carbonate content.