The Newark basin is a half graben, bounded on its northwestern margin by a system of mostly normal-slip faults, many of which are reactivated Paleozoic thrust faults and were active at least sporadically during the deposition of the entire basin fill. As a result of along-strike variations in displacement on the border-fault system, subsidence increased from the lateral edges toward the center of the basin and from the hinged margin toward the border-fault system. Some intrabasinal faults also formed during the deposition of units currently preserved in their hanging walls. Along-strike variations in the density of intrabasinal faults probably reflect changes in the dip angle of the border-fault system; variations in the amount of extension accommodated on these intrabasinal faults resulted in the formation of a transfer fault. Along-strike variations in fault displacement probably produced the transverse folds in the hanging walls immediately adjacent to border faults and major intrabasinal normal faults; some folds formed syndepositionally. Progressively younger strata onlap "basement" rocks along the hinged margin of the basin, and younger splays of the border-fault system propagated into the footwall; the basin therefore grew deeper, wider, and longer through time.

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