Research

Paleoenvironmental Reconstruction

Scott Lamoureux, Queens University

Rationale

Taking lake sediment cores at lake #3.
Taking lake sediment cores at lake #3.

Understanding the nature of periodic climate change is important for developing a model of the mechanisms that drive global climate change. The impact of these changes is often significant, and knowledge of the ecological and physical responses to these changes gives important information about the sensitivity of ecosystems to climatic variability. This is especially the case in the Canadian arctic where few detailed, long-term records exist to evaluate the scale of climate change. The Melville Hills, located in Tuktut Nogait National Park, is one of the few areas that may have been unglaciated during the last ice age that occurred 13,000 to 23,000 years ago. Lakes in this area may be good sites for studying past climate conditions.

Objectives

  • To obtain lake sediment records from sites in the Canadian arctic which were possibly unglaciated during the last ice age.
  • To investigate if links exist between global climate change and ocean-atmospheric circulation patterns.
  • To investigate the terrestrial effects of climate patterns detected in marine sediments.

Methods and Information Collected

  • Lake sediment samples were taken in the spring when the ice was still solid enough to travel on and the air temperatures were above freezing.
  • Samples were collected by hammering a sediment corer into the lake bottom. A pulley system extracted the core from the lake bed.
  • Lakes were chosen that had either closed basins or small enough catchments to exclude the possibility of river or creek sedimentation. Excessive sedimentation would overwhelm the paleoclimate signal.
  • Samples will be analysed for organic and inorganic content, grain size, magnetic susceptibility and other bulk physical properties.
  • Macrofossil analysis will be used to examine climatically induced changes in sand and moss particles.
  • Dating the sediment will be done using multiple radiocarbon dates on terrestrial macrofossils found in the samples.

Results

  • The following table contains the location of 4 lakes sampled and information on the sediment cores obtained from each lake.
Lake Number Location (Lat/Long) Water Depth Number of Cores Length of Cores Comments
1
69 16.00/121 21.39
3 m
2
30 cm
ended in heavy clay
2
69 13.68/121 16.36
2.3 m
0
-
bedrock present
3
69 04.86/121 25.75
2.6 m
4
50-100 cm
-
4
69 15.28/121 22.01
2.3 m
1
30 cm
ended in heavy clay

  • Preliminary results have been analysed for Lake 3.
  • The longest core was analysed for organic carbon, inorganic carbon and grain size at 1 cm intervals.
  • Magnetic susceptibility was analysed at 2 mm intervals and sand and moss macrofossils have been counted at 4 cm intervals.
  • Samples for pollen analysis were taken at 4 cm intervals and are currently being prepared for analysis.
  • Samples from 12, 40 and 68 cm depth has been submitted for radio carbon dating.
  • Preliminary assessment of the age of the core suggests that it is 10,000 years old and may extend as far back as 13,000 -15,0000 years.
  • Full results will be available in 2002.
Preliminary results of grain size, sand and moss macrofossil counts and organic and inorganic carbon content from Lake  3.
Preliminary results of grain size, sand and moss macrofossil counts and organic and inorganic carbon content from Lake 3.

 

Contacts

Scott Lamoureux
Assistant Professor
Department of Geography
Queens University
Kingston, ON K7L 3N6
Phone: 613-533-6033
Fax: 613-533-6122
Lab: 613-533-6000 x74639
lamoureux@lake.geog.queensu.ca

Brandon Beierle
Post-Doctoral Fellow
Department of Geography
Queen's University
Kingston, ON K7L 3N6
Phone: (613) 533-6000 x75915
brandon@lake.geog.queensu.ca