Geologic Framework of Sediment Sourcing, Transport, and Deposition in Chesapeake Bay

An understanding of the geologic framework of estuaries and their watersheds is needed to interpret sediment and nutrient cycling, groundwater recharge and discharge zones, and availability of certain resources.

This task documents the geologic framework of the estuary and watershed by:

• Mapping surficial deposits and erosional features in an allostratigraphic framework, and interpreting Holocene history and geology of estuaries in terms of sea level rise, coastal morphology, and antecedant geologic framework.

• Producing geologic maps of tidal tributaries showing deposits and erosional features as a continuum from drowned, sub-bottom deposits to upland deposits and weathered surfaces. This allows spatial analysis of sediment and nutrient cycling, ground-water recharge and discharge zones, and availability of certain resources.

• Determining the contribution of ongoing bluff erosion in selected parts of Chesapeake Bay. This is intended to furnish finite estimates of the volumes of sediment presently held on beaches, carried to the nearshore zone, and carried offshore as suspended sediment. In addition, it seeks to better understand the processes of bluff retreat, landsliding, and slope stabilization in the mid-Chesapeake Bay region.

For more information:

• Geologic history of Popes Creek, Virginia

• Geologic controls on turbidity and iron oxide precipitation, Nassawango Creek, Maryland

• Bluff erosion- Calvert Cliffs, Maryland