These sediments are exported almost entirely to the deep surrounding slopes. They have been deposited in the past 9,000-10,000 years and form periplatform wedges on the middle and upperslopes , which are seen clearly on 3.5 kHz seismic profiles. Radiocarbon ages of the wedge surface sediment range between 230 and 610 YBP and provide clear evidence for the contemporaneous production of sediments on the shallow bank and shelf and their instanteneous export to the upper slopes. Deposition of the metastable bank-derived carbonate sediments occurred as soon as sea level rose to flood the bank and shelf which flank Walton Basin, following the last glacial lowstand. This indicates tectonic activity or failure during sea-level lowstands.
Some individual blocks are hundreds of meters across.
Megabreccia deposits extend up to 18 km out in to the basins and may be up to 200 m in thickness each. Turbidites , debris flows, and hemipelagic sedimentation may be important in areas where there does not appear to be mass-wasting. Calciturbidites in cores recovered from basins on the north and south side of Pedro Bank are clearly bundled and occurred during sea level highstands. Commonly, the first turbidite layer in each highstand bundle occurred during the initial last third of the sea level transgression, corresponding to the initial bank top flooding of Pedro Bank at each glacial to interglacial stage boundary, whereas the last turbidite layer in the highstand bundle appears to be tied to the bank top exposure. It is quite a surprise to observe this prevalent highstand shedding pattern in a tectonically active area such as the northern Nicaragua Rise.