10.00
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15.30
Bø, 4-311A and Zoom
Alastair Charles Goodship is defending his dissertation for the degree philosophiae doctor (PhD) at the University of South-Eastern Norway. 
The doctoral work has been carried out at the Faculty of Technology, Natural Sciences and Maritime Sciences.
You are invited to follow the trial lecture and the public defence.
Summary
A dramatic release of an ice-dammed lake at the end of the last ice age carved a 10-kilometre-long ravine—Gaccetávži—in Finnmark. This striking feature, clearly visible in modern terrain models, had never been explained before. This PhD study demonstrates for the first time how a sequence of rapidly forming ice-dammed lakes and catastrophic outburst floods during the retreat of the Fennoscandian Ice Sheet produced the ravine and reshaped large parts of the surrounding landscape.
To understand these events and reconstruct how the post-glacial landscape evolved across northeast Finland and northern Norway, the project combined high-resolution LiDAR, drone surveys, remote sensing, and detailed cross-border fieldwork. The study area contains exceptionally well-preserved glacial and post-glacial landforms, allowing a rare opportunity to investigate the final collapse of an ice sheet in detail.
A key challenge in studying such landscapes is determining when sediments were deposited. Luminescence dating provides this information by measuring when sand grains were last exposed to sunlight—but traditional laboratory OSL dating is time-consuming and costly. This thesis tested a newer, portable version of the method (POSL), which allows samples to be analysed rapidly and cheaply in the field. By calibrating 186 POSL measurements with full OSL ages, the study produced a high-resolution chronology of Holocene dune activity that would not have been possible using conventional methods alone.
The results show that aeolian activity began soon after deglaciation (ca. 10.2 ka), increased around 6.5 ka, and rose very sharply during the last 1500 years—likely influenced by climate variability, including the Little Ice Age, and increasing human activity in the region. POSL also proved valuable for identifying changes in sediment composition and depositional environments, demonstrating broader potential for future geological studies.
Overall, this work provides new insights into how rapidly ice sheets can reshape landscapes through both meltwater processes and long-term environmental change. It highlights the value of novel luminescence techniques and modern remote sensing in remote Arctic terrains and benefits from strong Nordic collaboration and fieldwork across the Finnish–Norwegian border. These findings help refine reconstructions of past ice-sheet retreat and contribute data that can support models of future change in Greenland and Antarctica.