5:15 PM - 6:45 PM
[MIS10-P03] Mid-Holocene rapid retreat and following readvance inferred from GIA modelling around Lützow-Holmbukta, East Antarctica
Keywords:Glacial Isostatic Adjustment, Antarctic Ice Sheet, Mid-Holocene, GNSS, Mantle Viscosity
In this study, we investigate the melting history of the Antarctic ice sheet and the crustal deformation due to Glacial Isostatic Adjustment (GIA), focusing on the viscoelastic response of the Earth's mantle in Antarctica. GIA modelling provides critical insights into relative sea-level changes inferred from geomorphological and geological evidence. In addition, it offers the interpretation of current geodetic observations and quantitative evaluations of the present mass balance of the ice sheet. However, the interaction between the viscoelastic properties of the mantle and the variability of the Antarctic ice sheet with multi-timescales increases the complexity of the Antarctic GIA. Despite these difficulties, geodetic measurements, including Global Navigation Satellite System (GNSS) data, are pivotal in refining the model parameters for the Antarctic GIA.
A recent analysis of glacial geomorphologic records and surface exposure dating in Antarctica has disclosed a detailed history of the ice sheet changes during the mid-Holocene, marked by the rapid height lowering of ice sheet elevation and subsequent expansion, as reported by Johnson et al. (2022). Additionally, Kawamata et al. (2020) indicated a rapid height lowering of approximately 400 m over 3000 years in the mid-Holocene around Lützow-Holmbukta in East Antarctica. This study assesses the GIA signal effects using geodetic data and modelling along the coast of Lützow-Holmbukta. We try to incorporate the rapid height decrease in the ice history model as an input for the GIA model. This is because it addresses the deficiency in conventional deglaciation models, such as ICE-6G_D (Peltier et al., 2018), which do not account for this rapid melting event.
We have conducted a numerical simulation of GIA that incorporates this rapid melting phase and obtained simulation results consistent with the GNSS observations from the study area. These findings support the geodetic validation of the rapid ice sheet melting during the mid-Holocene and show the importance of geodetic observations in determining the melting processes in this region. Additionally, we explore the potential of the readvance followed by rapid retreat and discuss the GIA model parameters that may govern such readvance using precise GIA modelling.
A recent analysis of glacial geomorphologic records and surface exposure dating in Antarctica has disclosed a detailed history of the ice sheet changes during the mid-Holocene, marked by the rapid height lowering of ice sheet elevation and subsequent expansion, as reported by Johnson et al. (2022). Additionally, Kawamata et al. (2020) indicated a rapid height lowering of approximately 400 m over 3000 years in the mid-Holocene around Lützow-Holmbukta in East Antarctica. This study assesses the GIA signal effects using geodetic data and modelling along the coast of Lützow-Holmbukta. We try to incorporate the rapid height decrease in the ice history model as an input for the GIA model. This is because it addresses the deficiency in conventional deglaciation models, such as ICE-6G_D (Peltier et al., 2018), which do not account for this rapid melting event.
We have conducted a numerical simulation of GIA that incorporates this rapid melting phase and obtained simulation results consistent with the GNSS observations from the study area. These findings support the geodetic validation of the rapid ice sheet melting during the mid-Holocene and show the importance of geodetic observations in determining the melting processes in this region. Additionally, we explore the potential of the readvance followed by rapid retreat and discuss the GIA model parameters that may govern such readvance using precise GIA modelling.