Abstract Sediment deposition along the coasts of French Guiana depends on three different processes: mass deposition when a mudbank reaches the area, seasonal exchange between the mudbank and the shoreline, and the effect of tide cycles. The objectives of this work were to determine whether the three different processes are recorded in the sediments, and if rhythmites are discernible, preserved, and usable for paleoenvironmental studies. The study area was in the Kaw estuary, southeast of Cayenne (French Guiana) at a latitude of about 4°55′N and longitude about 5°10′W. Four stations were selected for the collection of push cores, which were then split and described. Redox and water content were measured; grain-size analyses, radioisotopic measurements (210Pb geochronology), and X-ray image-analyses were carried out. The SCOPIX X-ray image-processing tool was used for establishing gray-scale profiles. After mass deposition, sediment processes are dominated by reworking of the muddy sediment with a predomin...