High resolution sedimentary records of Maxwell Bay, South Shetland Islands, West Antarctica: A Chronicle of the past 2000 years

• Main Authors: Wittenberg, Nina, Hass, H. C., Kuhn, Gerhard
• Format: Conference Object
• Language: unknown
• Published: 2012
• Subjects: Antarc*; Antarctic; Antarctic Peninsula; Antarctica; Bransfield Strait; Ice Shelves; King George Island; Maxwell Bay; South Shetland Islands; West Antarctica
• Online Access: https://epic.awi.de/id/eprint/31194/; https://hdl.handle.net/10013/epic.40028

Since 50 years the Antarctic Peninsula experiences an average temperature increase stronger than the global warming trend. As a result, the glaciers are retreating and ice shelves shrink. Our study is a subproject within IMCOAST, a large interdisciplinary research project, dealing with the impact of climate induced glacial melting on marine coastal systems in the Western Antarctic Peninsula region. The South Shetland Islands form the northernmost part of Antarctica. They are separated from the Antarctic Peninsula through the Bransfield Strait. King George Island is the largest of the South Shetland Islands. The study area is Maxwell Bay and its tributary fjords located south of King George Island. We measured grain-size distributions of five radiocarbon-dated marine sediment cores that cover approximately the last 2000 years. The cores were recovered from high-accumulation areas along a seismic transect in Maxwell Bay. The results strongly suggest climate-controlled sedimentation in the area. We identified fluctuations in sediment deposition and grain-size distributions related to minor glacial retreats and advances such as the Medieval Warm Period and the Little Ice Age. The cores show two distinct grain-size compositions that are related to different climate phases. The warmer climate phases appear to be characterized by finer sediments that likely have a meltwater origin. Colder climate phases are depleted in finer sediments, which is most likely the result of reduce supply of turbid meltwaters. High-resolution sub-bottom profiles from the area provide information on the deposited facies and allow the interconnection between the different sediment cores. The seismic data further reveal that well-layered sediments only occur below 200 m, while the acoustic penetration is rather low in Potter Cove, a tributary fjord to Maxwell Bay.