Doctor of Philosophy (PhD)


Geology and Geophysics

Document Type



To elucidate how Holocene climatic and environmental conditions have changed in the eastern North Atlantic region, a sedimentological and palynological investigation has been carried out on sediment cores retrieved from Okak Harbor, Labrador, Canada. Okak is located along the Labrador coast, adjacent to the Labrador Sea, and contains both prehistoric and historic human settlement sites. The site is located proximal to the latitudinal tree limit, making the local conifer population vulnerable to even relatively small perturbations in climate. For these reasons, Okak is a desirable site to investigate Holocene paleoenvironmental change in the North Atlantic region. Results from this study illustrate that environmental conditions in the Okak region have undergone several changes in response to climate fluctuations through the late Holocene. Shrub-tundra conditions persisted in the early-mid Holocene, giving way to increasing conifer abundance as the tree limit migrated northward. Concurrent changes in magnetic susceptibility, grain size, and relative vegetation distribution suggest shifting climatic conditions ca.4200 cal BP, which roughly corresponds to the transition from the warm Holocene Thermal Maximum to the cooler Neoglacial conditions previously established for the Labrador area. Comparison of the Okak Harbor data set to GISP2 temperature, accumulation, and ion datasets aids in interpreting local environmental changes in the broader scheme of North Atlantic climate. While correlations can be made between the Okak and GISP2 records through the late Holocene, Okak sediments do not appear to reflect an expression of the 8200 year climatic event, which has been well documented across the North Atlantic region. Though it is difficult to decouple the paleoenvironmental signature of climate change and prehistoric human activities in the sedimentary record, high sedimentation rates and decreasing conifer abundance in the latest Holocene, in addition to ethnographic and archaeological records, suggest the intensive occupation of the Moravian mission site by both European and Labrador Inuit populations may have impacted the local environment.



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Committee Chair

Bentley, Samuel



Available for download on Sunday, September 01, 2030