Holocene sea-level history and tectonic implications derived from luminescence dating of raised beaches in Terra Nova Ba
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Geosciences Journal
GJ
Holocene sea-level history and tectonic implications derived from luminescence dating of raised beaches in Terra Nova Bay, Antarctica Seongchan Hong1†, Min Kyung Lee2, Yeong Bae Seong1*, Lewis A. Owen3, Hyun Hee Rhee1, Jae Il Lee2, and Kyu-Cheul Yoo2 1
Department of Geography, Korea University, Seoul 02841, Republic of Korea Korea Polar Research Institute, Incheon 21990, Republic of Korea 3 Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University, Raleigh, NC 27695, USA 2
ABSTRACT: Raised beaches are amongst the most important and direct indicators of relative sea-level change and timing of deglaciation in Antarctica. Infrared stimulated luminescence dating of cobble surfaces on two sets of raised beaches in Terra Nova Bay in Victoria Land of Antarctica records relative sea-level change since the Mid-Holocene. This study includes dating on five raised beaches on Inexpressible Island (II-1 to II-5) and five raised beaches at Jang Bogo Station (JS-1 to JS-5). The raised beaches at Jang Bogo Station began to form before 6.0 ± 0.8 ka, emerging at an average rate of 0.9 m/ka. The rate of emergence on Inexpressible Island was 1.6+0.2/–0.1 m/ka from 4.8 ± 0.5 to 1.1 ± 0.1 ka, since when the rate has been 14.9+1.8/–1.0 m/ka. The proximity of the two study sites suggests that glacier melting, and associated glacio-isostatic rebound alone cannot explain the difference between the rates of emergence at the two sets of raised beaches. This spatio-temporal difference in the emergence rates is likely the result of both local tectonics and glacio-isostatic rebound. This view is consistent with recent GPS geodetic analyses, albeit the geologic and geodetic data are on different temporal scales. Moreover, the rapid uplift since 1.1 ka on Inexpressible Island is likely due to vertical movement associated with active faulting. Key words: raised beach, Antarctica, luminescence dating, sea level, differential uplift Manuscript received June 3, 2020; Manuscript accepted August 3, 2020
1. INTRODUCTION Raised or emerged beaches are relict subaerial beaches that initially form on wave-dominant shorelines due to a relative fall in sea level. Raised beaches consist of wave-transported sediment, and they are different from marine terraces that have a broader *Corresponding author: Yeong Bae Seong Department of Geography, Korea University, 145 Anamro, SeongbukGu, Seoul 02841, Republic of Korea Tel: +82-2-3290-2367, E-mail: [email protected] †
Present address: Department of Geography Education, Korea National University of Education, Chungbuk 28173, Korea Electronic supplementary material The online version of this article (https://doi.org/10.1007/s12303-0200031-x) contains supplementary material, which is available to authorized users.
©The Association of Korean Geoscience Societies and Springer 2020
genesis including erosion (e.g., producing wave-cut platforms), deposition (e.g., forming beaches), and biogenic processes (e.g., producing coral reefs). Raised beaches provide direct
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