Document Type

Thesis

Abstract

Beryllium-7, a short-lived cosmogenic radionuclide (t1/2 = 53.3 d) has been used extensively in recent years to try to understand rates of sedimentation and dynamics of particle transport in marine environments (Canuel et al., 1990; Dibb and Rice, 1988; Dibb, 1989, Olsen et al., 1986; Todd et al., 1989). It is produced in the atmosphere where it associates with aerosols and is therefore able to be harvested by rain to be deposited on the earth’s surface. Such harvesting is most effective at delivering 7Be to the surface during the spring and summer, when atmospheric conditions allow for mixing of the stratosphere where 7Be is produced, and the troposphere where rain is able to remove the isotope (Canuel et al., 1989; Olsen et al., 1986). Once introduced into an estuary, 7Be will readily associate with suspended inorganic particulate matter because of relatively shallow depths and high amounts of suspended particles. These conditions result in an abundance of 7Be found in the particulate phase versus the dissolved phase (Dibb and Rice, 1988). Olsen et al. (1986) determined that there was no correlation between 7Be sorption and particle composition, but did not suggest particle size as a controlling factor. Another study lumped silt and clay size particles together when determining 7Be activity (Dibb and Rice, 1988). Given the popularity and usefulness of 7Be as a tracer of sediment activity in marine environments, this investigation sought to 1) identify if variations in fractional grain size is a controlling factor on the sorption of 7Be, 2) identify the extent to which silt to clay ratios control such sorption, and 3) to determine if silt and clay can be treated as a single entity during further investigations, or if such an assumption is inaccurate.

Date Awarded

2003

Department

Geology

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