Journal of Sedimentary Research, 2011, v. 81, 118–137 Research Article DOI: 10.2110/jsr.2011.11 LINKING ONSHORE–OFFSHORE SEDIMENT DISPERSAL IN THE GOLO SOURCE-TO-SINK SYSTEM (CORSICA, FRANCE) DURING THE LATE QUATERNARY TOR O. SØMME, 1 DAVID J.W. PIPER, 2 MARK E. DEPTUCK, 3 AND WILLIAM HELLAND-HANSEN 1 1 Department of Earth Science, The University of Bergen, Allegaten 41, N-5007 Bergen, Norway e-mail: tor.somme@geo.uib.no , 2 Geological Survey of Canada (Atlantic), Bedford Institute of Oceanography, P.O. Box 1006, Dartmouth, Nova Scotia B2Y 4A2, Canada 3 Canada-Nova Scotia Offshore Petroleum Board, 1791 Barrington Street, Halifax, Nova Scotia B3J 3K9, Canada ABSTRACT: Spatial and temporal relationships between climate, tectonics, and sea level have a primary control on sediment transport, storage, and deposition in onshore and offshore depositional environments. Although many simplistic models have tried to predict onshore system behavior and sediment partitioning between onshore and offshore depositional environments in response to changes in these boundary conditions, the alluvial response to changes in external forcings coupled with autogenic processes can be highly complex and unpredictable. The Golo source-to-sink system, on the eastern margin of the island of Corsica in the Mediterranean Sea, provides an ideal laboratory to study sediment partitioning in both onshore and offshore realms. The terrestrial part of the system consists of the Golo River, which debouches onto a narrow shelf (, 10 km), which in turn passes into a narrow (, 45 km) confined basin known as the Corsica Trough, dominated by submarine fan deposits. Estimates on timing of late Quaternary fluvial aggradation are compared with timing of sediment storage on the shelf and on the basin-floor fan. The results indicate that onshore deposition and storage of sediment in the fluvial system may occur both during sea-level highstand, transgression, and lowstand. Volume calculations from the alluvial record show that onshore storage is relatively low (, 13%) relative to the overall sediment budget. Comparing estimated deposition rates with a sediment prediction model further suggests that deep-sea fan sedimentation rates at times may be up to 50% higher or 25% lower than what is being supplied by the river, indicating temporary storage and release of sediment on the shelf. On average, however, there is good agreement between predicted and calculated sediment volumes in the Golo system. The study demonstrates the value of investigating the entire source-to-sink system in order to obtain a comprehensive understanding of sediment dispersal between onshore and offshore depositional environments over 10 4 year timescales. Observations suggest that alternating periods of aggradation and degradation of the Golo River are controlled by system thresholds controlled from within the catchment. Comparison with climate proxy data and timing of major alluviation events elsewhere in the Mediterranean region supports the notion that each source-to-sink system has a unique threshold that must be exceeded to induce regional aggradation and subsequent terrace formation. The same is also inferred for timing of sediment dispersal to the deep-sea environment. In addition, preservation of onshore sediment is controlled by local factors such as uplift rate and its impact on the aggradational response. It is, therefore, expected that the onshore record may be diachronous on local, regional, and global scales, making detailed correlation difficult except for the most extreme events. Finally, stream incision rates appear to be one to two orders of magnitude higher than regional hinterland denudation rates, indicating that the Golo system is characterized by increasing landscape relief. INTRODUCTION The study of sediment partitioning on 10 3 –10 4 year timescales in source-to-sink systems provides information on the overall system response to external and internal forcing mechanisms. It is over these time-scales that source-to-sink systems record both short-term events like major floods or mass-wasting events, and longer-term, slower-working processes like subsidence and tectonic uplift that ultimately control sediment preservation and evolution of the sedimentary basin. Classic sequence stratigraphic models provided the first framework in which system response could be linked to specific forcing mechanisms, such as sediment supply or base-level change (Posamentier et al. 1988). Such models, however, are probably too simplistic to explain the complex behavior of sediment routing systems when exposed to external forcings at various frequencies and magnitudes (e.g., Blum and To ¨ rnqvist 2000). Some of the complexity can be explained by autogenic behavior (Beerbower 1964) and autostratigraphic models, which allow the system to have internal response without being triggered by external forcing mechanisms (Muto and Steel 2004; Muto et al. 2007). These autogenic concepts resemble older models applied to fluvial systems, where system response is explained by thresholds and complex responses (e.g., Schumm 1977, 1979; Howard 1980; Bull 1991). These older models acknowledge that the system is likely to be influenced by a number of different external and internal controls operating at different spatial and temporal scales. Copyright E 2011, SEPM (Society for Sedimentary Geology) 1527-1404/11/081-118/$03.00