The New Jersey Coastal Plain

The New Jersey coastal plain the largest physiographic province in the state of New Jersey, extending from Sandy Hook to Cape May and inland to the Delaware River. Sediment outcrops in irregular bands that trend northeast-southwest with a maximum thickness of 6400 feet. Sediments on the New Jersey coastal plain consist of an eastward thickening wedge of unconsolidated river/deltaic and marine sediments (Owens and Sohl, 1969). These strata lie unconformably on top of Paleozoic crystalline basement rocks. Space for sediments to accumulate is provided primarily by thermoflexural basement subsidence (e.g., Kominz et al., 1998), sea level change (e.g., Miller et al., 2005), and sediment supply variations.  Subsidence of the Atlantic margin began roughly 195 Ma following the rifting of Pangea and the start of oceanic crust production in the north Atlantic.  It was not until the Late Jurassic and Early Cretaceous that the coastal plain was covered by marine sediments (Grow and Sheridan, 1988; Watts and Steckler, 1979). The first significant sedimentation of the mid-Atlantic Coastal Plain began about 120 Ma (Olsson et al., 1988).

The sediments in the NJCP consist of deposits of quartz sand, glauconite sand, silt, and clay. They were deposited in variety of inner, middle, and outer neritic marine, marginal marine, and nonmarine environments. Facies evolved through 8 depositional phases controlled by changes in accommodation, long-term sea-level, and sediment supply: 1) the Barremian-earliest Cenomanian consisted of anastomosing riverine environments associated with warm climates, high sediment supply, and high accommodation; 2) the Cenomanian-early Turonian was dominated by marine sediments with minor deltaic influence associated with long-term (107 yr) sea-level rise; 3) the late Turonian through Coniacian was dominated by alluvial and delta plain systems associated with long-term sea-level fall; 4) the Santonian-Campanian consisted of marine deposition under the influence of a wave-dominated delta associated with a long-term sea-level rise and increased sediment supply; 5) Maastrichtian-Eocene deposition consisted primarily of starved, carbonate ramp shelf environments associated with very high long-term sea level and low sediment supply; 6) the late Eocene-Oligocene was a starved siliciclastic shelf associated with moderately high sea level and low sediment supply; 7) late early-middle Miocene consisted of a prograding shelf under a strong wave-dominated deltaic influence associated with major increase in sediment supply and accommodation due to local sediment loading; and 8) over the past 10 myr, low accommodation and eroded coastal systems were associated with low long-term sea level and low rates of sediment supply due to bypassing.