T125 Eolian Processes, Landforms, and Chronologies (Posters)

Monday, 11 October 2021
2:30 PM - 6:30 PM
Exhibit Hall A

REMNANT RIVERINE DUNES OF THE GEORGIA COASTAL PLAIN: NEW DATA FROM THE VALDOSTA AREA

Paper number: T125-11
Program: Technical Sessions
Time: 2:30 PM – 6:30 PM

Authors

Abstract

Source-parallel linear features on a low relief landscape at the juncture of the Little and Withlacoochee Rivers west of Valdosta, Georgia are here reported as probable remnants of eolian dunes. Similar dunes occur along nearly all of the larger rivers of the Atlantic Coastal Plain in the southeastern United States. The majority are found to the east of the present river courses, oriented transverse to prevailing westerly winds. Age constraints from 14C and luminescence dating suggest a Pleistocene age coinciding with cool, dry climate and reduced vegetation. Previous research on the dunes of the Atlantic Coastal Plain rivers is serving as a template of sorts for the present investigations.

The initial identification of dune features was made during soil mapping and sediment coring of the proposed location for a canoe and kayak "river camp." One low ridge standing approximately three meters above the floodplain to the east of Little River was then examined by coring at the based of two soil pits (TP1 and TP2). Sand size distribution and organic matter content for samples from these cores identify an interval of probable eolian sand deposition above organic matter dated by a single 14C measurement to 230 CE (1720 cal BP). While this date corroborates the field interpretation of an intact deposit of fine-grained, well-sorted sand underlying the organic floodplain soils, additional sampling of this ridge for luminescence dating is currently in progress in order to better constrain the age of deposition. At least fifteen other source-parallel features have been identified in LiDAR topographic data with two foot contours in the area where the Little River joins the Withlacoochee River. It is hoped that this new data can become a basis for a more complete understanding of the changing landscapes of rivers in Georgia such as the Flint, Withlacoochee, Alapaha, and Suwannee whose courses run to the Gulf of Mexico but experienced past climate conditions similar to the Atlantic Coastal Plain Rivers.

Geological Society of America Abstracts with Programs. Vol. 53, No. 6

doi: 10.1130/abs/2021AM-370038

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