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

Abstract

We analysed modern mass‐accumulation patterns on the western Adriatic mud wedge (Italy), an elongated belt of shelf mud formed by coalesced prodeltas of the Adige, Po, and Apennine rivers, as part of an integrated strategy aimed at producing a quantitative sediment budget model for muddy continental shelves sourced by multiple compositionally distinct fluvial systems. Sediment provenance and source‐specific accumulation rates of surface sediments were quantified by combining results of grain‐size analysis and geochemical analysis of specific size fractions with bulk mass accumulation rates. Statistical classification algorithms adapted to compositional data were used to partition the total (geochemical) variation of sediment properties into size‐related and provenance‐specific factors. We identified geochemically distinct fluvial end‐member sediment types in two different grain‐size fractions, which were grouped into sediments derived from the Apennine rivers, and sediments derived from the Po and Adige rivers. Compositional fingerprints (end‐member compositions) of each source area were estimated by taking into account relative rates of fluvial sediment supply from rivers as predicted by numerical modelling. The end members allow us to explain geochemical compositional variation of mud‐wedge surface sediments in terms of provenance and size‐selective dispersal, and map mass accumulation rates of sediments from individual source areas (grain size<63 μm), as well as bulk sand accumulation rates (grain size>63 μm) across the western Adriatic mud wedge. The source‐specific rates of fine‐grained sediment supply derived from geostatistical estimates of mass‐accumulation rates were used to calibrate the numerical model of sediment supply to present‐day conditions.

Metal deposition in deep sediments from the Central and South Adriatic Sea

“…The distribution of As and Cu could also partially be controlled by redox processes (NAMEROFF et al, 2002), but due to the lack of correlation with Mn and Mo they are Chromium and nickel -Most authors for provenance studies in the Adriatic basin use Cr and Ni to define sources of sediment to the Adriatic along the Western Adriatic Current and its mud belt (AMO ROSI et al, 2002;LUCCHINI et al, 2003;DINELLI et al, 2007;WELTJE & BROMMER, 2011;AMOROSI, 2012;GOUDEAU et al, 2013) influenced by sediment discharge from the Po river and the Apennine rivers. The Ofanto River contributes most to the coastal sediments south of the Gargano promontory along the south eastern coast of Italy (GOUDEAU et al, 2013).…”

“…Studies on the geochemistry of the core samples have been undertaken for the western part of the Adriatic Sea, using the geochemistry as a tracer for both provenance and pollution studies along the WAC (AMOROSI et al, 2002;WELTJE & BROMMER, 2011;GOU DEAU et al, 2013;ROMANO et al, 2013). Only the studies of DOLENEC et al (1998) and DE LAZZARI et al (2004) provided geochemical data for surface sediments along the southern part of the Eastern Adriatic Current (EAC).…”

An examination of geochemical modelling approaches to tracing sediment sources incorporating distribution mixing and elemental correlations

“…One established approach of determining the source of sediment is to trace the elemental geochemistry of sediment back to their lithogenic origins (Olley and Caitcheon, ; Hardy et al , ; Weltje and Brommer, ). This geochemical ‘fingerprinting’ technique is based on the fact that different rock types often produce soils and sediments with unique elemental compositions (Klages and Hsieh, ; Wood, ; Caitcheon et al , ).…”

Sediment fingerprinting in fluvial systems: review of tracers, sediment sources and mixing models

“…Sediment geochemistry has been widely used to identify the spatial sources of sediments delivered to waterways Hardy et al 2010;Weltje et al 2011). Rock types, through soil formation and weathering, have a profound influence on the geochemical properties of their soils and accordingly the geochemical characteristics of their eroded sediments (Klages et al 1975;.…”