Electronic Thesis and Dissertation Repository

Degree

Master of Science

Program

Geology

Supervisor

Dr. Brian Branfireun

Abstract

Peat from the Hudson Bay Lowlands (HBL) in Northern Ontario, Canada was used to reconstruct historical accumulation of mercury (Hg) over more than 7000 years before present. Nine cores, many with previously published paleoclimate studies, were analyzed for Hg and accumulation rates were calculated. Anthropogenic Hg enrichment factors were calculated based on accumulation rates. A more exclusive calculation of the anthropogenic enrichment factor corroborates modelling efforts that have suggested re-cycling legacy Hg is a much greater contributor to present day deposition than previously thought, but not prior to ~500 cal yrs BP. An older pre-industrial record provides a better background accumulation rate than short cores.

Enrichment factors were then compared across a latitudinal gradient. Enrichment factors decreased with latitude as well as distance from the James Bay. These spatial trends are attributed to differing halogen chemistry above the bay as well as distance from point sources of Hg.


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