USING ARCHAEOLOGICAL DATA TO CONSTRAIN THE NEOTECTONIC AND FLUVIAL HISTORY OF NORTHEASTERN LOUISIANA

Neotectonic uplift and river capture events have affected the river systems of northeastern Louisiana during the middle and late Holocene. The Monroe uplift restricted the flow of the Ouachita River creating a large lake (Paleolake Monroe) that has subsequently drained, and the Ouachita River captured Bayou Bartholomew north of Bonita, LA. Though the breach of the Ouachita uplift has been dated by the sediment fan in the Bayou de Loutre valley at the outlet of Sterlington channel created in this event, the other elements of the fluvial evolution are less amenable to direct dating. Fortunately, several Middle and Late Archaic archaeological sites are known along the edges of the Ouachita River, Bayou Bartholomew, and the abandoned channel segments. By analyzing the paleoenvironmental changes caused by these events and the resulting effects on habitability of these sites for the pre-agrarian Paleo-Indians, we can constrain the timing of these other events. From this, we find that the doming of the Monroe uplift and the formation of Paleolake Monroe began before 7500 BP, and the capture of Bayou Bartholomew occurred about 5000 BP.