Holocene sea-level changes in the Spermonde Archipelago, Indonesia: implications for vertical land movements
- 1University Bremen, MARUM – Center for Marine Environmental Sciences, Leobener Straße 8, 28359 Bremen, Germany
- 2ZMT – Leibniz Centre for Tropical Marine Research, Fahrenheitsstraße 6, 28359 Bremen, Germany
- 3NIOZ – Royal Netherlands Institute for Sea Research, 17907 SZ ’t Horntje, Texel, Netherlands
- 4Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Hafenstrasse 43, 25992 List / Sylt, Germany
- 5Helmholtz-Zentrum Potsdam – Deutsches GeoForschungsZentrum (GFZ), Telegrafenberg 14473 Potsdam, Germany
- 6Graduate School, Hasanuddin University, Makassar, 90245, Indonesia
We surveyed the elevation and age (14C) of paleo sea-level indicators in five islands of the Spermonde Archipelago. We describe 24 new sea-level index points from fossil microatolls, and we compare our dataset with both previously published proxies and sea-level predictions from a set of 54 Glacial Isostatic Adjustment (GIA) models, using different assumptions on both ice melting histories and mantle structure and viscosity. We then investigate the implications of our data and models in terms of vertical land movements in the study area, with two main results.
First, data from the heavily populated island of Barrang Lompo are significantly lower (ca. 80 cm) than those at all the other islands. In absence of instrumental data (e.g., GPS or tide gauges) in any of the islands, we advance the hypothesis that this difference may be due to groundwater extraction and loading of buildings on Barrang Lompo, that would cause this island to subside at rates in the order of ~3-11 mm/a.
Second, Common Era data (0-400 a BP) seem to indicate that the islands in the archipelago may be affected by tectonically-driven vertical land motions in the order of -0.88±0.61 mm/a (1-sigma), albeit slight uplift cannot be excluded. Different assumptions on vertical land motions affect, in turn, the assessment of which GIA model shows the best match with Late Holocene (ca. 4-5 ka) sea level data. Tectonic stability or slight uplift would favor iterations of ANICESELEN (De Boer et al., 2014), while subsidence would cause the sea level data to fit better with iterations of ICE-6G (Peltier et al., 2015).
References
De Boer, Bas, Paolo Stocchi, and Roderik Van De Wal. A fully coupled 3-D ice-sheet-sea-level model: algorithm and applications." Geoscientific Model Development 7.5 (2014): 2141-2156.
Peltier, W. R., D. F. Argus, and R. Drummond. Space geodesy constrains ice age terminal deglaciation: The global ICE‐6G_C (VM5a) model. Journal of Geophysical Research: Solid Earth 120.1 (2015): 450-487.
Acknowledgments
This project is funded by SEASCHANGE (RO-5245/1-1) and HAnsea (MA-6967/2-1) from the Deutsche Forschungsgemeinschaft (DFG), part of the Special Priority Program (SPP)-1889 "Regional Sea Level Change and Society". Parts of this study are under review in Climate of the Past (https://www.clim-past-discuss.net/cp-2019-63/)
How to cite: Rovere, A., Bender, M., Mann, T., Stocchi, P., Kneer, D., Schöne, T., Illigner, J., and Jompa, J.: Holocene sea-level changes in the Spermonde Archipelago, Indonesia: implications for vertical land movements, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-13281, https://doi.org/10.5194/egusphere-egu2020-13281, 2020