Seven cores drilled in the eastern fault block of the Newark basin provide continuous lithologic recovery through nearly all of the basin section. The core samples are pristine and show primary sedimentary structures unaltered by weathering. Distinctive bundles of lake cycles from many members of the Passaic Formation can be correlated between overlapping drill cores and also traced with confidence across much of the basin and across fault blocks. Correlation was achieved by matching distinctive patterns of sedimentary cycles coupled with paleomagnetics. The composite stratigraphic column provided by the cores allows precise stratigraphic placement of field sections. For example, the cores show very subtle changes in color and subtle sedimentary structures which indicate very shallow-water lake highstands. The position of these highstand units in the cores provides a template for locating correlative highstands in weathered outcrops.

A fine-scale analysis of the individual lake cycles of several members of the Passaic Formation reveals each highstand has its own unique character, or individual "signature," which reflects not only changes in climate but also its position in the basin. Furthermore, although major changes in sedimentary facies for correlative lake highstands are a function of basin architecture, minor changes are due to irregularities of the basin floor, such as basin highs adjacent to overlapping fault segments, input from relay ramps formed at these fault segments, changing major depocenters within the basin, and proximity to deltas.

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