Distribution of metals in a modern marine environment

Abstract

Some conclusions can be drawn from this empirical study, but many questions remain unanswered and new questions raised. [The site for this project was Mud Bay, 15 mi. S. of Vancouver, British Columbia, Canada.] The distribution pattern of Fe is explained readily by deposition of detrital magnetite through normal processes of sedimentation. In contrast, the pattern of S is so different to that of Fe that it seems unlikely that one sedimentary process could account for such accumulations of both elements, or that they co-exist as iron sulfide. The S pattern is so similar to the grain-size pattern as to suggest strongly that S accumulates preferentially in fine-grained (and presumably more richly organic) sediments. Both Cu and Zn accumulate in patterns zonally related to shoreline. Cu is concentrated somewhat closer to shore than Zn, and both metals decrease in brackish river outlets. All samples of Mud Bay sediment have unusually high Cu:Zn ratio. The average Cu:Zn ratio is 0.43. This is distinctly anomalous compared to ratio less than 0.10, which are characteristic of numerous unmineralized regions of British Columbia. The main conclusions derived from this project are 1) that both Cu and Zn are trapped and concentrated in tidal sediment of marine shore, and 2) that concentration of Cu is relatively much greater than Zn.