The Role of Sea-Level Change in Past Human Migration Events

Abstract

Sea-level change has always been and will remain an influential factor impacting human movement. Cycles of sea-level rise and fall across the ice age shaped the landscape that migrants inhabit and traverse. The paleogeography of ancient and historic human migration events is ultimately determined by the subtleties of sea-level physics as expressed at a given time and location. Previous research into the circumstances surrounding migration events, when taking sea-level change into account, have largely relied on a "bathtub" model of sea-level change. This model assumes a uniform lowering or raising of sea-level in line with changes in global ice volume. It is imperative that studies of the drivers of past human migration events utilize more accurate models of sea-level change that incorporate glacial isostatic adjustment to simulate the paleoenvironment. In this thesis, I apply a state-of-the-art sea-level model to several enigmatic migration events of the past. I first detail the mechanics of glacial isostatic adjustment and its impact on archaeological models of human migration. I next consider the impact of regional ice growth and sea-level rise on Norse Viking settlements in Southwestern Greenland contemporaneous with the Little Ice Age. The results suggest that sea level rise, and the associated flooding of low lying landscapes, represented a compounding factor in the abandonment of the Viking's Eastern Settlement. The final part of this thesis presents a simulation of paleo-ocean currents and sea-level change in the Wallacean Archipelago in the construction of a least-cost pathway model of migration from Sunda to Sahul. Application of the model suggests that environmental factors favored an initial migration at 55 ka along a modified Northern Route discussed within the literature. The interdisciplinary work documented here provides a framework for merging geophysical and archaeological research methods to inform longstanding questions of past human migration events.