Glacio and hydro-isostasy in the Mediterranean Sea: Clarks zones and role of remote ice sheets

• Published in: Annals of Geophysics
• Main Authors: G. Spada, P. Stocchi
• Format: Article in Journal/Newspaper
• Language: English
• Published: Istituto Nazionale di Geofisica e Vulcanologia (INGV) 2007
• Subjects: sea-level variations; glacial isostasy; Mediterranean Sea; Meteorology. Climatology; QC851-999; Geophysics. Cosmic physics; QC801-809; Antarctic; The Antarctic; Antarc*; Antarctica; Ice Sheet
• Online Access: https://doi.org/10.4401/ag-3054; https://doaj.org/article/7e2c451a180c42d68bae843fdd705576

Solving the sea-level equation for a spherically symmetric Earth we study the relative sea-level curves in the Mediterranean Sea in terms of Clarks zones and we explore their sensitivity to the time-history of Late-Pleistocene ice aggregates. Since the Mediterranean is an intermediate field region with respect to the former ice sheets, glacio- and hydro-isostasy both contribute to sea-level variations throughout the Holocene. In the bulk of the basin, subsidence of the sea floor results in a monotonous sea-level rise, whereas along continental margins water loading produces the effect of «continental levering», which locally originates marked highstands followed by a sea-level fall. To describe such peculiar pattern of relative sea-level in this and other mid-latitude closed basins we introduce a new Clarks zone (namely, Clarks zone VII). Using a suite of publicly available ice sheet chronologies, we identify for the first time a distinct sensitivity of predictions to the Antarctic ice sheet. In particular, we show that the history of mid to Late Holocene sea-level variations along the coasts of SE Tunisia may mainly reflect the melting of Antarctica, by a consequence of a mutual cancellation of the effects from the Northern Hemisphere ice-sheets at this specific site. Ice models incorporating a delayed melting of Antarctica may account for the observations across the Mediterranean, but fail to reproduce the SE Tunisia highstand.