Seven cores drilled through a major fault block of the Newark basin provide an unparalleled opportunity to study in great detail the sedimentary aspects of paleolake dynamics with regard to depositional environments. Within core overlap sections of the Passaic Formation (the thickest formation in the Newark basin), packages of lacustrine cycles thicken and facies deepen toward the border fault system and/or intrabasinal normal faults as well as toward the longitudinal center of the basin. Most of the observed thickening is accommodated in the mainly red regressive portions of the cycles, resulting from reworking and basinward transport of marginal lake sediments during falling lake level. Precession cycles with well-developed, deeper-water high-stand deposits tend to be thicker than those with shallower-water high-stand deposits, perhaps due to increased accumulation rates during wetter climatic episodes. Precession cycle thickness itself appears to be cyclical with periods of ~2000 kyr.

Typically, highstand deposits in the Passaic Formation consist of black, gray, or purple mudstone. Major sections of the Passaic Formation consist of massive red mudstone with no obvious expression of cyclicity. However, investigation of core overlap sections reveals correlatable lake sequences in the red lithologies. This demonstrates that cyclical variations are properties of the entire Passaic Formation section, not just intervals containing non-red units.
 

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