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A. Slootman et al. / Earth and Planetary Science Letters 444 (2016) 192–204  193

Fig. 1. Geography and conceptual cross-section of Favignana Island. (A) The study area (framed) is located offshore western Sicily in the central Mediterranean Basin. Dashed
line indicates the present-day shelf (200 m isobath). The large sea cliff (Fig. 2) is highlighted by the thick line on the NE coast of the island. Rose diagrams each represent
n measurements of the palaeoflow direction of subaqueous dune deposits in two dune cross-bedded clinoform units. Palaeoflow direction suggests that the clinoform
succession of the Favignana carbonate ramp prograded approximately towards SE, away from and sourced by a palaeocarbonate factory between the islands of Favignana
and Levanzo. Encircled numbers show strontium isotope stratigraphy sample locations; see also Table S1 in Supplementary Material. (B) Schematic cross-section displaying
sub-environments on the carbonate ramp and the location of the palaeo-island (projected). (C) Depositional model for dune cross-bedded clinoform units, formed by the
migration of subaqueous dunes during storm-driven, wind-induced currents. (D) Depositional model for backset-bedded clinoform units, deposited by tsunami-induced
sediment gravity flows.

waxing and waning of Early Pleistocene northern hemisphere ice      were proposed to have triggered such flows, including exceptional
sheets (Catalano et al., 1998).                                     storms, strong floods and tsunamis.

    Individual clinoform units, which thus encompass the key ar-        This paper aims to provide a quantitative analysis of the origin
chitectural elements of carbonate ramp clinoform successions, typ-  of (1) backset-bedded deposits and (2) subaqueous dune cross-
ically consist of bioturbated tempestite and/or cross-bedded de-    bedded/tempestite deposits on Mediterranean carbonate ramps, to
posits (e.g. Hansen, 1999; Puga-Bernabéu et al., 2010; Massari      clarify the relationship between the anomalous backset-bedded
and D’Alessandro, 2012), the latter formed by the downramp mi-      units and their background sediments. Using strontium isotope
gration of subaqueous dunes (sensu Ashley, 1990). In addition,      stratigraphy, outcrop-based palaeoflow reconstructions and hy-
several Neogene–Quaternary carbonate ramp successions in the        draulic relations, we estimate the average recurrence periods and
Mediterranean Basin comprise various proportions of clinoform       flow durations of the events linked to both types of deposits in
units of anomalously thick, erosion-based sets displaying a poorly  the ramp succession of Favignana Island. On the basis of original
pronounced, upslope-dipping stratification in concave-up scours      data presented here, deposition of the studied succession is con-
(e.g. Hansen, 1999; Pomar et al., 2002; Andreetta et al., 2008;     strained within several hundred kyr. Furthermore, over an average
Massari and D’Alessandro, 2012). Such sedimentary structures are    period of 14–35 kyr half of the deposits formed during a cumu-
commonly interpreted as backset-beds resulting from hydraulic       lative two years of storm-induced currents, while the remaining
jumps in submerged particulate gravity flows at the transition from  half was deposited in less than six hours by a single, high-energy
erosive, Froude-supercritical flow to depositional, subcritical flow  flow.
(Massari, 1996; Cartigny et al., 2014). A number of extreme events
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