Recently, Tertiary incised valley fills (IVF's) have become an active area of investigation because of their importance as hydrocarbon reservoirs. Transgression of river valleys cut into continental margins results in rapid sedimentation of both siliciclastics and organic material. The investigation of organic matter constituents, including palynomorphs, in Holocene IVF's provides an analog for interpreting Tertiary systems. The Mobile-Tensaw River delta is the result of IVF sedimentation originating from the fourth largest drainage basin in North America over the last 9,000 years. It is a natural laboratory in which to study the transportation and deposition of palynological debris in a large-scale fluvial system.
Palynological assemblages have been collected at twelve sites throughout the system. These include one site on the Alabama River and one on the Tombigbee River above their confluence. Localities below this confluence include: three sites in the Mobile River; three sites on the Tensaw River; and one site each on the Middle, Raft, Spanish, and Blakely Rivers. These sampling sites cover all fluvial settings beginning in the floodplain and ending in the lower delta plain. Water column and bedload sampling has been done in April, June, October, and December 1997; additional sampling is planned for February and April 1998. Palynological preparations have been made from one grab sample from sediment-water interface and two water column samples at each collection site. Palynological preparations have been evaluated to determine the contribution of pollen (Pinus [Pine], Acer [Maple}, Sabal [Palmetto], and Nyssa [Tupelo]) and spore assemblages to sediment load. In addition, these data have been evaluated to see how well the assemblages correlate with nearby wetland communities.