Holocene sea-level changes in Southeast Asia (SEASchange)

This project aims to investigate Holocene relative sea-level (RSL) changes in South East Asia. We aim to both evaluate former literature data and produce new sea-level index points in order to reconstruct Holocene sea level histories in the region and compare it with predictions of glacial isostatic adjustment (GIA) in order to derive uplift or subsidence patterns in the area.  We focus on an area where relatively little research has been carried out on past sea levels, the Strait of Makassar (see Figure 1 for details). This region includes the Spermonde Archipelago, that is composed by low-lying islands that might prove sensitive to RSL changes.

Fig 1. Map of the Holocene sea-level studies in Southeast Asia, which will be re-analyzed. The square shows the study area of this project.

During this study we will review former datasets and produce new sea level index points following standard procedures (Hijma et al., 2015) that will allow the implementation of datasets from SE Asia into global databases (Khan et al., 2015). Although we will focus mostly on coral microatolls, that are one of the most accurate RSL indicators, we will also adopt other proxies, trying to improve the existing definition of their indicative meaning (e.g. defining where each marker was formed with respect to the paleo sea level).

We will compare existing and newly produced field data with a large set of earth models to represent the GIA effects in the study area, and evaluate processes that might exacerbate current sea level rise problems. Attention will be given to the long-term effect of potential subsidence processes caused by the presence of heavily populated islands of the Spermonde Archipelago.

Fig 2. RSL trend inferred from the fossil microatolls on Pulau Panambungan (Spermonde Archipelago, black rectangles) under the assumption that the tidal range remained stable over the timeframe of analysis, and comparison with De Klerk's (1982) RSL curve (light gray narrow band) and predicted RSL change for the Spermonde Archipelago based on the ice-sheet models ANU-RSES (Lambeck, 1998), ICE-5G (Peltier, 2004) and ANICE-SELEN (De Boer et al., 2014a, 2014b) for a range of plausible mantle viscosity profiles (VKL, VM1 and VM2). Shaded areas of cumulative predicted RSL curves indicate the variability of the GIA signal for each simulation. Solid and dashed horizontal lines indicate msl and the Height of Living Corals, respectively.