Recent sedimentation in a high arctic lake, northern Ellesmere Island, Canada

Abstract

A multiple core study was conducted on laminated minerogenic sediments from Lake C2, northern Ellesmere Island, Canadian High Arctic. Lateral persistence, distal thinning, variation in grain size of these laminations as well as present-day processes of highly seasonal sediment transfer into the lake basin suggest that clastic varves have been formed. Sedimentation rates based on 21~ dating agree well with sedimentation rates based on lamination counts giving further evidence that laminations are annual. Errors in varve counting were reduced from 12% to <2% using the multi-core approach of cross-correlating all records. Varved sediments are occasionally interrupted by thick coarse-grained layers, which are interpreted as deposits of turbidity currents and may be related to extremely high discharge events and slope failures of the delta front. Micro-laminated sediments spanning the last two centuries were studied in detail. Suspension settling is the dominant process of deposition depending upon stream discharge which is controlled by nival melt and summer temperatures. Application of varve chronology thus allows to use lamination thickness measurements as source of high resolution proxy data for palaeoclimatic reconstruction.

Climatic influences on streamflow and sediment flux into Lake C2, northern Ellesmere Island, Canada

“…The varved sediment record from Lake C2 provides annual resolution (Zolitschka, 1996). The thickness of each laminae is therefore a measure of the cumulative sediment transfer that year.…”

“…Lacustrine investigations encompassed the physical and chemical limnology (Ludlam, 1996), diatom ecology , and sediment distribution and deposition patterns (Retelle & Child, 1996). Multiple sediment cores were recovered from the lakes, and used to establish the annual nature of the laminae (Zolitschka, 1996), and to analyze the variability of their thickness through time .…”

The Taconite Inlet Lakes Project: a systems approach to paleoclimatic reconstruction

“…Detailed studies of these cores was carried out to determine if the laminations could be correlated from one location in the lake to another, and if the laminations were indeed annual. The results demonstrated the sediments are indeed varved and that there is strong coherence between the varve thickness from widely separated cores within the lake; details of this work are given in Zolitschka (1996). Sediment flux to the lake, 'predicted' by the temperature record at Alert, closely parallels variations in mean thickness of the varves over the last 40 years enabling a long record of lamination thickness (Lamoureux, 1994) to be interpreted as a record of summer temperature variations.…”

“…Such process-based studies are an essential component of paleoclimatic research, especially in regions where long-term climatic data are sparse or absent. Research focused on: -meteorological controls on snowmelt, discharge and sediment flux (Hardy, 1996) sediment dispersal into lake C-2 (Retelle, 1996) the physical limnology of the lakes and of adjacent Taconite Inlet (Ludlam, 1996a, b) -the near surface sedimentary record (Zolitschka, 1996;Ludlam et al, 1996) the climatic signal in the sediments and…”

Arctic hydroclimate variability during the last 2000 years – current understanding and research challenges

“…These varves are typically composed of a coarse-grained lower lamina that grades into a fine-grained upper lamina (e.g., Lake DV09; Courtney-Mustaphi and Gajewski, 2013; Lake C2; Zolitschka, 1996). Additional coarse grained laminae can be deposited and can be related to multiple pulses of snow melt or 15 rain events (Ringberg and Erlstöm, 1999;Cockburn and Lamoureux, 2008).…”