GSA Annual Meeting in Denver, Colorado, USA - 2016

Paper No. 341-25
Presentation Time: 9:00 AM-6:30 PM

FACIES AND STRATAL ARCHITECTURES OF THE FALSE RIVER POINT BAR SYSTEM, LOWER MISSISSIPPI RIVER, LOUISIANA


OLSON, Elizabeth D., Geology and Geophysics, Louisiana State University, E235 Howe-Russell-Kniffen Geoscience Complex, Baton Rouge, LA 70803, lizdaltonolson@gmail.com

By focusing on the 80km2 False River Point Bar on the Mississippi River and building off of previous work at three field sites on the point bar, this study hopes to further evaluate the stratigraphic architecture of the point bar and channel tie system surrounding the oxbow lake, add to the understanding of point bar deposits of a continental-scale fluvial system, and use the knowledge gained to better understand point bar deposition in paleoenvironments. Understanding such a large system is especially relevant as previous studies are not able to predict the degree of lateral heterogeneity of larger systems where an understanding on the scale of 1 meter to 100-300 meters is needed due to their focus primarily on small to medium-scale systems. For this reason, we will focus our study on the area noted to have the highest degree of stratal heterogeneity and take sediment cores with close spacing to one another (25 meters) surrounding the sediment core previously taken in this area. Additionally, we will expand the study area to include the channel fill deposits that once connected the present oxbow lake to the Mississippi River. There, we hope that understanding the channel infill will contribute to our knowledge of the facies and stratal architectures of these poorly understood deposits. This study will use a combination of sediment coring and geophysical logging along with a high resolution DEM. We will also gain an optically stimulated luminescence (OSL) date in order to understand the time frame of large-scale point bar formation and compare this information to the point bar’s known abandonment, which is noted in literature.