ABSTRACT

This study was undertaken in order to provide a basis other than standard geomorphology for terrace correlation in Louisiana. It was found that the clay mineralogy and the iron content are useful in differentiating the Pleistocene terrace units. The presence of interlayered chlorite-vermiculite in the terraces is significant as an indicator of the extent of terrace weathering. This clay material was found to be both more abundant and more crystalline with increasing terrace age.

There is a significant concentration of iron material in the B horizon of many of the older terrace units. The zone of iron enrichment is more extensive and seemed to develop earlier in sediments in the fluviatile terraces than in the coastwise terraces. The youngest Louisiana terraces to show the B horizon iron concentration are the Irene in the southeast, the Oberlin in the southwest, and the Montgomery in the northwest fluviatile area. The Montgomery has been described as the time equivalent of the Eunice, not the older Oberlin and Irene terraces (Doering, 1956). Results of this study indicate that the Montgomery is correlative with the Eunice and the Port Hickey Terraces.