Late-Holocene Channel Meander Migration and Mudflat Accumulation Rates, Lagoon of Venice, Italy

Coring in the Lagoon of Venice mudflats along previously collected high-resolution subbottom seismic-reflection survey profile lines has enabled the collection of interlayered radiocarbon-datable terrestrial plant material. Along present and former meander bends, dipping laminated sandy channel-bank deposits rest in sharp lithostratigraphic and chronologic contrast to the adjacent and overlying mudflat deposits. Horizontal channel migration rates of roughly 10 to 20 meters per century are orders of magnitude faster than the minimum estimates of vertical mudflat silt accumulation, which range from 5 to 25 centimeters per century. Given the nearly 6000-year history since the late-Holocene marine transgression that produced the initial lagoon environments of deposition, it is no surprise that channel meander migration has left a prevalence of channel-bank deposits in the subsurface lithostratigraphy. Furthermore, regional subsidence and rising relative sea level continue to enhance the net accumulat...