GSA Today

Figure 4.

(A) Airborne K over the 2019 survey area. Shaded area with green outline delineates urban areas; yellow box shows location of close-up draped over lidar near the Santee River floodplain (C), where highs along tributaries are observed only up to ~15 km from the floodplain (“T”). (B) Mean value of K (%) for the various units. (D) Regional radiometric K over the Lower Coastal Plain of the southeastern U.S. (Duval et al., 2005). White box shows the location of the 2019 survey area. Potassium is elevated for younger sediments. Arrows show the suggested path of heavy minerals along major rivers to offshore areas, transported parallel to the coast, and then redeposited onshore. H—Holocene; SB—Silver Bluff Beds; Wd—Wando; TM—Ten Mile Hill; Ld—Ladson; P—Penholoway; W—Waccamaw; NC—North Carolina; SC—South Carolina; GA—Georgia; FL—Florida.