Evolution of an anthropic source-to-sink system: Wabush Lake Dominique Turmel a, ⁎, Gary Parker b,c , Jacques Locat a a Département de Géologie et de Génie Géologique, Université Laval, Québec, Québec, Canada b Department of Civil and Environmental Engineering, University of Illinois at Urbana–Champaign, Champaign, IL, USA c Department of Geology, University of Illinois at Urbana–Champaign, Champaign, IL, USA abstract article info Article history: Received 28 September 2014 Received in revised form 29 September 2015 Accepted 20 October 2015 Available online 23 October 2015 Keywords: Delta Hyperpycnal flow Submarine channels Tailings Minibasin Wabush Lake is one of the few very well-constrained source-to-sink sedimentary systems in the world that exhibits near-continuous turbidity currents. In this system, approximately 20 million tons of mine tailings are delivered each year to a 40 km 2 lake. Multibeam bathymetric surveys of this lake were carried out between 1999 and 2011. In addition, a program of extensive sampling and seismic surveys, an airborne LiDAR survey and a photogrammetric survey were carried out during this period. The objective of this study was to determine the evolution through time of this anthropic source-to-sink system, from the point where sediments exit the slurry pipelines at the head of the system to the distal end and bottom of the Lake. The total volume of the Lake is around 1 × 10 9 m 3 . Analysis of subaerial and subaqueous datasets allows the evaluation of disposal strategies on the delta topset and on tailings accumulation. Disposal strategies influence the dynamics of the channels on the topset, thus in turn affecting the accumulation of tailings throughout the lake, as well as the shoreline advancement rate. Subaqueous erosional channels present on the bed of the Lake influence the depositional pattern of tailings as well as their granulometric distribution. These erosional channels are created by the shoreward migration of knickpoints. In some places, this migration can be documented over multiple surveys. Finally, sequential analysis of the 1999, 2004, 2006, 2008 and 2011 surveys has allowed detailed documentation of the infilling of the Lake, including the migration of sediment depocenters, the mechanism of emplacement and the progressive infilling of a series of minibasins. © 2015 Elsevier B.V. All rights reserved. 1. Introduction Sedimentary source-to-sink systems often extend thousands of square kilometers, from high-elevation mountains to abyssal plains. It is usually difficult to obtain a comprehensive overview of all the processes occurring in these systems. Furthermore, the time scale over which the relevant processes take place often means that any direct observations of processes are often little more than snapshots. A better understanding of source-to-sink dispersal systems is important in order to better monitor and model the fate of sediment and pollutants in such systems. This may also help to interpret stratigraphic records, and also to interpret otherwise similar systems that are not evolving as fast as the Wabush Lake system. Iron Ore Company of Canada (IOC) has been discharging iron tailings into Wabush Lake since 1964. In order to reduce environmental impacts on the lake, many studies have been carried out in order to understand the various physical processes occurring in Wabush Lake. As part of their monitoring efforts, IOC tracks sediment discharge. This helps optimize their operations as well as reduce their environmental impact. The case of Wabush Lake provides a rare opportunity to evaluate a near- complete source-to-sink sedimentary system, for which the governing parameters are well-constrained and the basin is closed. The system has its source at several tailings slurry pipeline outfalls, the locations of which are moved from time to time. The rate of sediment output is accurately documented according to the necessities of mine operation. The size distribution of the tailings, which includes sand and silt, is also well-documented. Sediment from the outfalls creates a highly dynamic, actively prograding subaerial fan-delta, where most of the sand-sized particles are emplaced. The flow passing the delta foreset is hyperpycnal in the sense that the sediment-laden water is denser than the water in the lake. Thus, the flow plunges to create near- continuous turbidity currents (Turmel et al., 2015). It has been observed that turbidity currents are volumetrically the dominant sedi- ment transport process on our planet (Talling et al., 2015), thus underlining the relevance of their study. At Wabush Lake, these currents disperse the finer sediment throughout most of the subaqueous part of the system. They also create erosive channels, leveed channels, sedi- ment waves and shoreward-migrating knickpoints, as commonly seen in natural submarine settings. The distal boundary of the Lake Wabush Earth-Science Reviews 151 (2015) 227–243 ⁎ Corresponding author at: 1065 Avenue De la Médecine, Québec, Canada, G1V 0A6. E-mail address: dominique.turmel.1@ulaval.ca (D. Turmel). http://dx.doi.org/10.1016/j.earscirev.2015.10.007 0012-8252/© 2015 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Earth-Science Reviews journal homepage: www.elsevier.com/locate/earscirev