Department or Program

Geology

Abstract

The Arctic is currently responding to the current warming to a greater degree than any other region on the planet (Serreze and Barry, 2011). For accurate predictions to be made regarding the response of the Arctic to current and future fluctuations in climate, a compilation of high-resolution marine and terrestrial paleoenvironmetal records encompassing the entire region must be compiled. Through a multi-proxy approach, this study aims to reconstruct past environmental conditions of northern Finnmark using combined geochemical, physical and biological analyses. A 65 cm sediment core was scanned for downcore elemental profiles using an ITRAX-XRF core scanner at 500μm resolution, while stable carbon and nitrogen isotopes (δ13C and δ15N), C/N molar ratios, percent carbon (%C) and percent nitrogen (%N), percent loss on ignition (%OM), chlorophyll, magnetic susceptibility and grain size were subsampled for at 1 cm resolution.

An age-depth model spanning 10,500 cal years BP was developed using four AMS radiocarbon dated terrestrial macrofossils. However, based on the well-documented sea level history of the island of Ingøy, and the failure to identify a marine-lacustrine boundary within Core #1 the age-depth model was deemed invalid. The lack of a reliable age-depth model prevented the reconstructed regional paleoclimate and paleoenvironmental conditions of northern Finnmark from being linked to large-scale patterns in climate variability.

Paleoenvironmental conditions within the lake based on the combination of biological and geochemical analyses were characterized by high rates of primary productivity. High percent organic content sourced from C3 terrestrial plant material makes up the majority of the sediment composition. Higher counts of Fe/Mn seen in the bottom half of Core #1 suggests that reducing conditions, resulting in anoxic waters and greater counts of elemental sulfur, dominated the later half of the sediment record. Deposits of eolian transported sand and mica detritus periodically interrupt the gyttja matrix and subsequently dilute the biological and geochemical organic signals.

Level of Access

Open Access

First Advisor

Michael Retelle

Date of Graduation

5-2017

Degree Name

Bachelor of Science

Number of Pages

54

Components of Thesis

1 pdf file

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