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

P. Stocchi, G. Spada


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.


sea-level variations;glacial isostasy;Mediterranean Sea

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Published by INGV, Istituto Nazionale di Geofisica e Vulcanologia - ISSN: 2037-416X