Infering influx rates of sedimentary constituents from varved sediments to improve paleoclimate reconstructions

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This project aims at multiplying, extending and refining climatic and hydrologic reconstructions from sites in the Canadian High Arctic and from the Boreal Forest with annual resolution. Annually laminated (or varved) lake sediment records from a moisture-sensitive site and a temperature-sensitive site will be investigated in the Canadian High Arctic. In the Boreal Forest, this project will develop the first annually resolved paleoclimate sedimentary records from that area. To develop these records, new protocols using a combination of CT-scans, micro-X-Ray fluorescence and image analysis of sediment cores will be used to characterize the absolute density with an annual resolution. This enables to calculate influx rates of sedimentary constituents that can be used to improve statistical inferences models linking sediment properties to climate parameters. Moreover, hydroclimatic deterministic models coupled with a sediment delivery module will be implemented to predict a "varve" and influx rates values are needed to calibrate model discharge and sediment load. This new concept called "forward modeling" or modeling of the climate indicators contained in natural archives, will be tested in the laboratory and in two of our natural sites in the field. Forward modeling will improve predictions of river discharge in a warming climate and extreme events, a topic of interest for the governmental agencies and the hydropower industry. Obtaining density from CT-scans will have direct applications for archaeology (internal structure of metal pieces), metallogeny (alloys 3D structure), geological engineering (geological hazards), construction (concrete strength and alteration). This program will contribute to the training of 4 MSc, 4 PhD and 5 undergraduate students in sedimentology, climate change and instrumentation technology.