This morning’s objective was to join the ‘infantry’ on the land/beaches and lend a hand to the folks completing somewhat more terrestrial work. Specifically, Julia Savage is a rising senior at Bates College (under advisor Prof. Mike Retelle) and a Geology/Politics double major. Julia has the ‘unique’ experience of being introduced to Quaternary Geology with me as a high school junior in my environmental science class at Carrabassett Valley Academy and is now working with Mike (my former advisor and good friend). Her senior thesis will be based on this season’s field work and the working title reads “The use of the marine bivalve Arctica Islandica in paleoclimate reconstruction, 3,000 year old marine terrace, Ingoya, Norway.”
Here is a summary of her work so far:
Julia Savage, Bates ’16
Hometown: South Kingstown, R.I.
“The use of the marine bivalve Arctica Islandica in paleoclimate reconstruction, 3,000 year old marine terrace, Ingoya, Norway.”
Climate of the North Atlantic region through post-glacial Holocene
time has been greatly influenced by changes in regional ocean current
systems and associated climate feedback mechanisms. In recent decades,
temperatures at high-latitudes have changed at a faster pace than
those at sub-arctic latitudes, and models predict further amplified
changes in the future. This particular study focuses on climate
reconstruction for the late Holocene, i.e. the last 6,000 years, using
growth increments from the Arctic bivalve Arctica islandica as a proxy
for sea surface temperature (SST) changes.
Our study site, on the Island of Ingoya , northernmost coastal
Norway, is uniquely situated within the influence of three ocean
currents: the Arctic Current, the North Atlantic Current, and the
Norwegian Coastal Current. The northern boundary of the Atlantic
Meridional Overturning Circulation system (AMOC) also occurs in this
region. This boundary is dynamic, meaning that as climate changes, the
AMOC will shift further south or further north. Due to proximity to
these systems, A. islandica samples collected on Ingoya should display
a strong signal of oceanic and atmospheric circulation patterns, such
as the Atlantic Multidecadal Oscillation (AMO) and the North Atlantic
Oscillation (NAO).
The site that I have previously worked on, called the Ingoya Mollo
(Norwegian for “Breakwater”), is a ~3m high terrace that contains
sedimentary layers with abundant bivalves including A. islandica and
other clam species . The majority of samples collected from this
exposure were dated to be ~2,000-3,000 years before present (yr BP),
but outliers fell as far as 5,000yr BP. In this project, I am focusing
on the description and interpretation of the fossiliferous
stratigraphic sequence in the Mollo. This will be done through
sampling and subsequent 14C dating of the shells. From this
information, I hope to then build a reconstruction by crossdating
growth patterns in the shells that will in turn provide a “snapshot”
of marine climate in the period circa 2,000-3,000yr BP. This snapshot
will then be used in hand with snapshots from other climate intervals
to provide context for recent changes in the arctic marine system.
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| Mike, Sam, and Julia calibrating the altimeter to sea level |
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| Measuring the elevation of the marine terraces with the altimeter |
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| Wind excavated shell pavements. The ground is full of bivalves... |
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| Apparently also full of whale bones... |
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| The crew with a raised marine beach terrace (old beach ridge) in the background |
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| Maybe some creative graphics might help visualization...sorry no beach chairs... |
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| Clouds Rolling Over Rolfsoya (Also a Hemingway Novel) |
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| Seagull Eggs in Nest Along Our Hike |
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| Sun dog (real and in atmosphere) and lens flare (has to do with camera aperture shape) leading to hexagonal figures... |
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| The town of Ingoy |
