HR: 10:20h
AN: OS51D-01    [PDF]
TI: Sediment Accumulation Along the Italian Adriatic Coast
AU: * Palinkas, C M
EM: cpalinkas@ocean.washington.edu
AF: University of Washington, School of Oceanography Box 357940, Seattle, WA 98195 United States
AU: Nittrouer, C A
EM: nittroue@ocean.washington.edu
AF: University of Washington, School of Oceanography Box 357940, Seattle, WA 98195 United States
AU: Wheatcroft, R A
EM: raw@coas.oregonstate.edu
AF: Oregon State University, College of Oceanic and Atmospheric Sciences, Corvallis, OR 97331 United States
AU: Langone, L
EM: leonardo.langone@bo.ismar.cnr.it
AF: ISMAR-CNR, Via P. Gobetti, 101, Bologna, 40129 Italy
AU: Miserocchi, S
EM: stefano.miserocchi@bo.ismar.cnr.it
AF: ISMAR-CNR, Via P. Gobetti, 101, Bologna, 40129 Italy
AU: Ogston, A S
EM: ogston@ocean.washington.edu
AF: University of Washington, School of Oceanography Box 357940, Seattle, WA 98195 United States
AU: Fain, A
EM: afain@ocean.washington.edu
AF: University of Washington, School of Oceanography Box 357940, Seattle, WA 98195 United States
AB: Sediment supply to the Adriatic Sea is dominated by the Po and Apennine Rivers in the northern and southern regions, respectively. Recent investigations have revealed that processes impacting sedimentation in this area are active on a variety of time-scales, ranging from events (e.g., floods) to seasonal and decadal variations. In the northern region, flooding of the Po River is common, and a 100-year flood event occurred in October 2000. Using $^{7}$Be (half-life 53.3 days) as a tracer of flood sediment, the deposit was found to be up to 15-cm thick. However, the depth of $^{234}$Th (half-life 24.1 days) exceeds $^{7}$Be in cores of the flood deposit, indicating that thicknesses derived from $^{7}$Be are minimum estimates and that the first sediment deposited during the flood event likely originated from the river channel. The location of the flood deposit immediately adjacent to the distributary channels at the river mouth can be predicted considering the relatively low-energy physical oceanographic conditions during the time of emplacement. Near the Po River Delta, sediment from flood events contributes significantly to longer-term (100-year) sediment accumulation. The signature of flood layers is observed in radiochemical (low $^{210}$Pb activities; half-life 22.3 years) and textural (fine grain size) profiles, which lead to accumulation rates $>$2 cm/y. Southward, the character of sediment accumulation transitions to steady state, reflecting the decreased impact of event sedimentation, and accumulation rates decrease to levels near and below 1 cm/y in the southern portion of the Po River dispersal system. Sedimentation near the Apennine Rivers is even more strongly impacted by anthropogenic activities (dam construction), which increased after the second World War. These activities have resulted in a reduction of sediment accumulation in the area, evidenced by changes in $^{210}$Pb profiles. Across-shelf accumulation rates reach a maximum on the foreset of a shelf clinoform and are $\sim$~1 cm/y.
DE: 3022 Marine sediments--processes and transport
SC: Ocean Sciences [OS]
MN: 2003 Fall Meeting