Drilling Quaternary Sediments of the Barrier Island - Estuarine System

in cooperation with Bill Hoffman (bill.hoffman@ncmail.net) of the North Carolina Geological Survey


 

Objectives:

The primary objective of this task is to define the Quaternary geologic framework of the barrier island-estuarine system between Kitty Hawk and Nags Head, and develop a regional sea-level/climate history. The compositional character of part or all of the Holocene record varies dramatically within different portions of the drainage basin. In addition, the spatial and temporal extent, and compositional character of the Holocene record is dependent upon the nature of the drowning basin and the underlying late Pleistocene stratigraphy. The location and elevation of specific portions of the drainage system being flooded determines the timing of flooding and consequently the temporal extent of the resulting Holocene record. The geometry of the specific portions of the basins being intersected by the ocean shoreline determines the types of sediments being deposited and the accommodation space for sediment back-fill. Thus, the character of the coastal system is dependent upon what portion of the drainage basin is being intersected by the flooding sequence.

For example, whether it is a trunk river or a tributary stream, the size and spatial orientation of stream elements is important. In addition, the underlying Pleistocene section contains the climate and sea-level history of numerous glaciation-deglaciation events. The depositional record resulting from the highstands and the erosional episodes during the lowstands built the outer coastal plain of North Carolina; its morphology, drainage systems, groundwater aquifers, etc. Thus, it is imperative that we drill in detail to delineate the Quaternary section. The drill hole data will be used to interpret the high-resolution seismic data from both the shelf and estuarine study areas. Ground-penetrating radar will be used to tie the set of boreholes to each other and provide a better correlation of the borehole stratigraphy to the seismic stratigraphy established on the inner shelf and in the back-barrier estuary.

Related Sites:

NCDOT Outer Banks Task Force

Minerals Management Service - Marine Minerals Program

 




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