Abstract

A study of 150 surface sediment samples from a study area 20 miles wide across the New Jersey continental shelf north of Atlantic City has been made to clarify the nature and history of this surface sediment, heretofore known mainly as "relict" sands and gravels. The sediment consists mostly of moderately well-sorted, medium-grained sand with a remarkable absence of particles finer than 125 microns in size. This absence of fine particles is related to the reworking resulting from the Holocene transgression. Mapping of statistical parameters suggests that during the Holocene submergence stillstands occurred at about 40 and 20 fathoms. Empirical criteria for these inferred former stillstands include the characteristics of the present-day shore and Recent nearshore sediments. Morphologic terraces at about 80 and 68 fathoms have been distinguished from a study of echogram charts. The former terrace corresponds to the so-called "Nicholls shoreline." The abundance of hornblende and garnet and the presence of magnetite in the shelf samples contrasts with the absence of these minerals in Cretaceous, Miocene or Quaternary age rocks on the adjacent coastal plain. It is suggested that the continental-shelf sediments may have been derived from an ancestral Hudson River.

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