| Summary |
Slocum and Hancock creeks are parallel, northward draining tributaries of the Neuse River estuary and are located 20 and 25 (12.4 and 15.5mi) km. respectively, southeast of New Bern, North Carolina. The northern-most portions of both creeks are embayed as a result of rising sea level during the Holocene transgression. Bottom sediments in these embayed tributaries consist primarily of dark brown to black, slightly sandy, strongly odoriferous organic-rich mud. The thickness of the mud increases downstream and away from the shoreline but decreases near the mouths of the creeks, delineating restricted, elongate basins of deposition. Accumulations of mud in excess of 6 m (19.7 ft.) are common in both creeks and maximum accumulations are thought to exceed 7 m (23 ft.). The mud is underlain by a relatively hard sandy substrate. The distribution and thickness of the mud is controlled by the topography of this pre-mud, sandy surface. The sand fraction of the mud consists of moderately to well sorted, fine to very fine sand and averages 5% by weight. Organic matter in the mud averages 167. by weight and increases with depth and with distance upstream. X-ray diffraction analysis of the clay fraction of the mud indicates that kaolinite and dioctohedral vermiculite are the dominant clay minerals in the lower reaches of both creeks, but that their relative abundance decreases rapidly upstream. Smectite and illite are present in minor amounts in the lower reaches and also decrease in abundance upstream, but at slower and more constant rates than kaolinite and dioctohedral vermiculite. Bottom sediments in the adjacent Neuse River estuary constitute the chief source of the mud present in Slocum and Hancock creeks. Shallow bottom sediments in the river are re-suspended by intense wave action and vertical mixing and are carried into the creeks by wind tides that raise the water level in the river. The protected and relatively quiescent waters of Slocum and Hancock creeks allow the trapped suspended load to settle out on the bottom of the creeks. Shoreline erosion in the two creeks is not widespread, and the contribution of eroded bank strata to the bottom sediment is minor. |
