Project Title: Landscape evolution, paleoecology and climate change in the Tertiary of the High Arctic
Introduction
The evidence that the Arctic is more susceptible to global climate changes than lower latitudes is mounting.
More precise indications of Arctic paleoclimate change are being compiled from stable isotope climate
proxies preserved in sediment, ice, and carbonate; from past glacier dynamics; and from sedimentary and
ecosystem records of ancient environments. They reveal that rapid or high magnitude climate changes in the
past have had profound effects on fauna, flora, and the Arctic landscape. Moreover, we are becoming more
aware that Arctic processes related to cryosphere, such as sea ice cover, albedo changes, and methane release
during permafrost melt are important drivers of global climate change. In the past 65 million years (i.e.,
Cenozoic Era) the planet has shifted from greenhouse to the icehouse conditions we are currently
experiencing, with many warming and cooling phases occurring along the way 1. The objective of our fiveyear collaborative project is to provide more insights into the forcing mechanisms and impacts of Arctic
climate change by (i) finding, documenting, and dating evidence for the most significant of these changes
throughout the Cenozoic; (ii) testing hypotheses regarding the mechanisms and impacts of Arctic climate
change. An immediate outcome will include more robust paleoecologically-derived paleoclimate data that can
be used to test hindcast predictions of climate models. Furthermore, studies of past ecosystems and
landscapes can help us better understand to what degree modern species and ecosystems may or may not be
resilient to the effects of climate change.
The research program outlined here focuses on terrestrial deposits of the Tertiary Period (65 to 2 million
years ago), and offers an important complement to ongoing marine-based paleoclimate research 2. Compared
to other regions of Canada, the Tertiary terrestrial geological record is well represented in the Arctic and is
characterized by remarkable evidence of past climates in both high degrees of sediment and fossil
preservation (e.g., internationally renowned fossil forests). Our approach is interdisciplinary and addresses the
following goals:
(i) Determine or improve the chronology and paleoenvironmental record of terrestrial, fossil-bearing deposits
in the High Arctic.
(ii) Determine the extent and timing of paleoclimate change through the Cenozoic from species community
composition and stable isotope analyses of organic (fossil bone and teeth as well as wood) and
inorganic (e.g., carbonate rocks) materials.
(iii) Document regional variation within the Arctic for specific time periods (e.g., Eastern vs. Western Arctic)
to test hypotheses which have been proposed to explain landscape or ecosystem changes.
(iv) Identify the role of Arctic climate change in terrestrial community and species evolution.
(v) Reconstruct the history and rates of large-scale landscape uplift and exhumation in the Canadian Arctic in
order to better understand the development of landscape features (e.g., mountain ranges such as the
eastern Arctic Rim, evacuation of the inter-island channels), and the role of local tectonics vs global
climate change in patterning species evolution and regulating regional Arctic climate.
To address these research goals, we propose to conduct our 2009 field work in two main regions: west central
Ellesmere Island and Devon Island.
1) Ellesmere Island
Background and Previous work. Through work that began in the 1960’s, J. Fyles (Geological Survey of
Canada) identified at least 38 sites on west central Ellesmere Island that bore the remains of past
environments and ecosystems, ranging in age from the late Tertiary (Miocene?) to the Holocene. These sites
are characterized by exceptional preservation, such that even the Miocene (?) fossil materials appeared of
Holocene origin 3. Although prior investigations have provided insight into the community composition of
some of the deposits, many aspects of these sites (e.g., including their depositional and temporal context)
remain unresolved3. So far our project has focused on two of these sites: Beaver Pond site and the Ninety
metre section. Best studied is the Beaver Pond site, which was discovered in 1961 by J. Fyles (GSC). This site
was excavated from 1992 to 2002 by C.R. Harington (Canadian Museum of Nature) and crew, and then
revisited in the last three years by teams led by N. Rybczynski. Fossil materials from the site reveal evidence
of a boreal tree-line plant community along with, invertebrates and vertebrates, including numerous mammals
3-7. Temperatures appear to have been 10 to 15 degrees warmer than this region is today 8,9. Fossil samples are
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currently being analyzed to further refine these temperature estimates. We are now using fossil plants to
estimate global carbon dioxide levels for this time period, and sand samples to constrain the burial age of the
deposit and both sites In 2008 we relocated 2 other of Fyle’s sites (Isachsen site, and also Site “C”) but both
appear were significantly colluvium covered and so we have elected not to return to those isolated sites
considering the high risk of low return.
2009 field season objectives. We propose to visit a series of sites located near Eureka Station (near
Romulus Lake and Remus Creek). These are important because compared to the Beaver Pond site these sites
are considered to be younger, and possibly warmer 3. The 2009 sites will provide a better opportunity to
investigate the relationships between climate, ecoystems and carbon dioxide over time. In order to investigate
these relationships we will also study the stratigraphic and geological context these site. Chronology will be
developed mostly using the 26Al/10Be burial dating method. We will collect fossil materials for
paleoenvironmental and paleoecological reconstruction.
2) Devon Island
Background and Previous work. The Haughton Formation, on Devon Island (75°North), formed within
the Haughton impact crater, is the only known deposit which preserves the remains of flora and fauna,
including vertebrates, from the early Miocene Arctic 10,11. First paleontological investigations occurred in the
1980’s. Findings revealed a strange assemblage of vertebrates including a swan and rhinoceros. In summers
2007 and 2008 a research team led by N. Rybczynski discovered fossil fish, rabbits and two new fossil
mammal taxa, including the first early Miocene carnivore from the Arctic (a morphologically primitive –
“missing link” - fossil pinniped)—for which a manuscript has just been submitted to Nature. We identified
first evidence of fossil wood from the shorelines of one of the earliest lakes in the impact crater. We also
collected samples for paleoenvironmental reconstruction (e.g, paleolake salinity, pollen composition).
The lacustrine sediments of the Haughton Formation were originally interpreted as forming immediately
post-impact (~22 Ma ago) based on K-Ar and fission track dating methods 10. However, more recent
mapping and stratigraphic work carried out by G. Osinski12 and a new age for the Haughton impact event of
~39 Ma old (using Ar to date the impact glass)13 suggests that this is not the case. We are currently
attempting a fourth and lower temperature technique—(U-Th)/He on apatites collected in 2008—to verify
the new age and its significance on the paleontological records.
2009 field season objectives. We suspect that most of the fossil bone on the landscape surface has already
been collected during our previous efforts, as significant discoveries have been diminishing. To maximize and
complete our investigation of this critical locality, we propose to use Ground Penetrating Radar to prospect
for buried skeletal remnants in specific areas that has been particularly productive in the past. Detailed
mapping will be carried out in order to delineate the current extent of the Haughton Formation and older
lacustrine and fluvial deposits. Stratigraphic sections will be measured at key outcrops. Indurated horizons
within the Haughton Formation will be sought out and sampled (most of the Haughton Fm. Is
unconsolidated) for carbon and oxygen stable isotope analysis.
To complete the large-scale study of the late Tertiary uplift and evolution of the Eastern Arctic Rim, we
intend to extend our understanding from the Torngat Mountains in Northern Labrador and from north
central Baffin Island to now include Devon Island. Devon Island is situated in an ideal locality to capture any
rift flank uplift associated with the opening of Baffin Bay, in part because of its location, but also because it
does not have the complexities associated with late Tertiary volcanism (on Baffin Island) and the transform
dynamics and recent orogency on Ellesmere Island. Apatite (U-Th)/He low temperature thermochronology
using samples collected along a vertical transect near Cape Sherard will be used to evaluate along-strike
variations in the rifting along Baffin Bay144 and address questions and test hypotheses regarding the processes
responsible for the large-scale landscapes and interisland channels in the eastern archipelago.
The crater provides a suitable setting in which to examine the rates of non-glacial processes that act on
landscapes in the Arctic. Unlike most regions throughout the Arctic, the crater has a reasonable
homogeneous surficial unit (the unconsolidated grey-white impact breccia), a relatively dry climate, and
relatively simple post-glacial evolution. Using a radioactive element (10Be), we can establish the rates of
hillslope and stream erosion processes throughout the crater, in order to measure rates and styles of Arctic
landscape evolution during an interglacial and to test models of evolution that explain the patterns that exist.
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