Geology Publications:  Maps and Charts

Alluvial Fans are the primary source of recharge to the aquifer underlying the Mississippi-Yazoo Alluvial Plain ("Mississippi Delta"). The fans, which form a discontinuous chain at the foot of a low bluffline, from DeSoto County near Memphis to Wilkinson County near the Louisiana state line, are of great significance in allowing recharge into the Mississippi River Valley alluvial aquifer (MRVA) in Mississippi's "Delta" region. While some fans are fairly recent surficial features, drilling has revealed others have deep roots in the floodplain alluvial sequence and reflect multiple episodes of deposition and burial. While archaeologic data indicates that some have seen virtually no deposition for thousands of years, others have significant deposits which have accumulated since European settlement. There should be awareness of the fans as recharge source areas which may need protection from pollution. The 2 sheets in this report show these fans and also differentiate between the impermeable, hydric clays of the delta and the non-hydric alluvial soils which allow recharge to the MRVA. The Shapefile of the alluvial fans mapped in this report are also available for download.

In color; scale 1:500,000; 35.5 x 46 inches