Age of Soil Landscapes in the Coastal Plain of North Carolina

Abstract

Abstract A stratigraphic and geomorphic study of surficial sediments in the Neuse drainage was completed as part of a general study of the relations between geomorphology and soils in the Coastal Plain of North Carolina. The depositional‐erosional surfaces on the interstream divides have been stable since they were formed, or there have been no recognizable additions or removals on these surfaces except for minor amounts of aerosols. The oldest geomorphic surfaces in the Neuse drainage are in the upper Coastal Plain and are (?) Miocene‐Pliocene, i.e., they may range from >5 to >3.3 million years. The surfaces in the middle Coastal Plain are Pliocene to early Pleistocene, i.e., they range from >5 to 0.5 million years. Surfaces in the lower Coastal Plain are all Pleistocene and are from about 400 to 115, possibly as young as 50 to 35 thousand years. Holocene surfaces, <10 thousand years, are the organic areas of pocosins and most of the valley slopes throughout the Coastal Plain. The Holocene valley slope surfaces are extensive in the middle and upper Coastal Plain, but occupy minor areas of the lower Coastal Plain. The (?) Miocene‐Pliocene‐Pleistocene ages of the Coastal Plain surfaces are estimates of when subaerial weathering of the sediments and soil formation started. These are the time frames against which all changes produced by soil formation must be measured.