Floating sand in Blueskin Bay estuary

Dewdney, Rob (Robert C.)

Comparisons are made between analyses of the 3.5 phi fraction of floating and shore sand samples from an estuarine tidal channel in Blueskin Bay. A suite of minerals, common to both floating and shore sand, with a density greater than quartz and feldspar (density > 2. 769) is identified Relative. ·concentrations of the mineral suite are found to vary between all samples, and, an anomalous zone of ~0. 7ha with a relatively high concentration of the mineral suite is identified on the channel margin. The flotation process is found to preferentially select for the minerals with a density greater than quartz and foldspar. The relationship between grain angularity, surface wetability and ease of flotation is assessed. Grain angularity is indicated as an important parameter in the preferential flotation of the mineral suite. Transport of sand by flotation appears to be a one-way process and may be contributing to the relatively high concentrations of the mineral suite in the anomalous zone. The relationship between channel morphology, sea breeze/tidal dependence and floating sand deposition is discussed. It is estimated that 14 tonnes of sand per year are transported by flotation towards the head ofthe estuary.

vii, 50 p. : ill. (some col.), maps ; 30 cm.

2001Dewdney