Reconstruction of sediment supply from mass accumulation rates in the Northern Adriatic Basin (Italy) over the past 19,000 years

Abstract

[1] Reconstruction of sediment supply is hampered by the incompleteness of the stratigraphic record. This problem may be partly circumvented by studying mass accumulation rates in closed systems, i.e., basins in which no sediment has bypassed the site of deposition over the time interval of interest. We present time-averaged basin-wide mass accumulation rates and their associated uncertainties from a well-documented closed basin, the Northern Adriatic Basin (Italy), spanning the time interval from 19 ka B.P. to the present. The sediment masses of five basin-wide lithosomes and their associated uncertainties are derived by means of stochastic simulation, using highresolution seismic data, porosity profiles, and radiocarbon datings. This study demonstrates that inferring rates of sediment supply from conformity-bounded stratigraphic units is feasible, as indicated by the excellent agreement of our results of mass accumulation over the past 400 years with two independently derived estimates. Formation of the stratigraphic record is not an instantaneous process. By comparing spatial patterns of mass accumulation rates on three different timescales (decadal, centennial, and millennial) we demonstrate a low preservation potential of sediments presently accumulating near the coast, and a continuous cross-shore and alongshore sediment transport regime. The change from transient to persistent accumulation patterns in the highstand systems tract of the Northern Adriatic Basin occurs at the centennial to millennial timescale. Intrabasinal erosion and recycling of sediments obscure the relation between rates of sediment supply and net basin-wide mass accumulation, which limits the amount of information that can be extracted from the stratigraphic record. Hence, a mismatch between rates of sediment supply and accumulation rates is expected for unconformity-bounded sequence-stratigraphic units. Given the uncertainties associated with our estimates, we are unable to reject the hypothesis that net basin-wide mass accumulation rates have been constant over the time interval of 19,000 years (at a 10% significance level).Citation: Brommer, M. B., G. J. Weltje, and F. Trincardi (2009), Reconstruction of sediment supply from mass accumulation rates in the Northern Adriatic Basin (Italy) over the past 19,000 years,

Sediment-budget modelling of multi-sourced basin fills: application to recent deposits of the western Adriatic mud wedge (Italy)

“…1). Quantitative estimates of bulk sediment accumulation rates on the western Adriatic mud wedge over the past 5500 years based on high‐resolution seismic data (Brommer et al , 2009) are consistent with estimates based on activity‐depth profiles of excess 210 Pb supported by 137 Cs depth distributions (Frignani et al , 2005), estimates based on sediment‐discharge data of modern rivers (Cattaneo et al , 2003), and simulations of sediment supply from the fluvial drainage basins surrounding the northern and western Adriatic (Syvitski & Kettner, 2007). These estimates indicate that the total rate of sediment supply to the mud wedge equals ∼42 Mt yr −1 .…”

“…The western Adriatic has been studied extensively and is fully accessible for sampling (Trincardi et al , 1994; Asioli et al , 2001; Correggiari et al , 2001; Cattaneo et al , 2003; Milligan et al , 2007; Palinkas & Nittrouer, 2007). Sediment‐budget modelling in this basin is comparatively straightforward, since it can be regarded as a closed system on geological time scales (Brommer et al , 2009). In this contribution, we present a procedure for obtaining statistically significant compositional fingerprints of fine‐grained sediments derived from multiple source areas, and show how such fingerprints may be employed to quantify source‐specific sediment budgets in a closed‐basin setting, in order to obtain more insight into the growth pattern of mud wedges on decadal to centennial time scales.…”

Early Anthropogenic Transformation of the Danube-Black Sea System

“…2A; SI). Late Holocene increases in delta plain expansion or sediment storage attributed to changes in land use have been similarly proposed for other European deltas such as the Po181920 and the Rhone21.…”

Mass-Balance Constraints On Stratigraphic Interpretation of Linked Alluvial-Coastal-Shelfal Deposits From Source To Sink: Example From Cretaceous Western Interior Basin, Utah and Colorado, U.S.A

“…We follow a methodology adapted from those of Barnes and Heins (2009), Brommer et al (2009), Carvajal and Steel (2012, and Michael at el. (2013Michael at el.…”