Seminar

Relative sea level (RSL), defined as the height of the sea surface relative to the land, is influenced by a combination of factors that act over a variety of spatial and temporal scales. Holocene RSL reconstructions provide context for projections of the magnitude and rate of future sea-level rise. Moreover, they are important for identifying the ice-equivalent meltwater contribution to sea-level change during deglaciation. Spatially, Holocene RSL records differ from global mean sea levels mainly due to glacial isostatic adjustment (GIA), which is the dynamic response of the lithosphere and mantle to ice-water loading and unloading events during a glacial cycle. RSL reconstructions from far-field sites distal from former ice sheets are minimally influenced by isostatic deformation. This research focuses on reconstructing Holocene RSL in Western Australia by investigating the regional variability of sea levels across its coastline.

Holocene RSL evolution in Australia is primarily driven hydro-isostatic processes that result in a mid-Holocene highstand across its coastlines. However, the details of the Holocene RSL record and the nature of the highstand along Australian coastlines are still unclear, in part due to spatial gaps in data, especially in Western Australia. This work focuses on filling these gaps by compiling and standardizing dated coastal archives from the literature and producing new RSL reconstructions. To date, the current compilation of Western Australia sea-level data consists of 402 data points from sedimentary (upper intertidal sediment, estuarine mud, and beach sediment), geomorphic (beach dunes, tidal notches, and coral reefs), and fixed biological indicators (oysters and encrusting bivalves). Moreover, an ICE-6G VM5 GIA model will quantify temporal patterns of change from the highstand to present. Finally, laboratory analyses of microfossils (foraminifera and ostracoda) related to specific depths of zonation will be applied to achieve more precise reconstructions of Holocene sea-level change.

Additional information: Miss. Kayla MURAI, ktmurai@connect.hku.hk