A SURVEY OF SUSPENDED SEDIMENT SETTLING VELOCITY FROM THE GLACIER-FED LAKES OF BRITISH COLUMBIA AND ALBERTA.
Glacier-fed lakes of British Columbia and Alberta contain varved sediment from which interpretations of hydrologic and climatic forcings have been derived on annual to inter-decadal timescales. Creation of these paleoenvironmental records in situ depends upon the settling velocity of suspended sediment ('rate'), as well as the sediment-delivery process. The objective of this study was to survey 18 glacier-fed lakes to (a) provide a reference ‘rate’ database of settling velocity among multiple lakes, (b) assess the influence of ion concentration on rate and, ultimately, (c) shed light on the contribution of cohesive sediments to the character of clastic lacustrine proxies. The vast majority of measured settling velocities correspond with equivalent-density values only marginally greater than water (~1.15 g/cm3), confirming the presence, and prevalence, of composite particles throughout these lakes. These measurements reveal that (a) it is surprising that particles reach the lake floor at all given settling-velocities ≤ 1 m/day (b) there is no representative settling velocity for any particle diameter or lake and (c) clastic proxies are accumulating at a rate three orders of magnitude below that assumed elsewhere.
Hodder, K. R., University of Regina, Canada, email@example.com
Barrett, D. C., University of Regina, Canada
Time: 16:00 - 18:00
Location: Poster/Exhibit Hall
Presentation is given by student: No