Late Cenozoic fluvial stratigraphy of the New Jersey Piedmont: A record ofglacioeustasy, planation, and incision on a low-relief passive margin

Late Cenozoic fluvial deposits and erosional landforms in the New Jersey Pi edmont record two episodes of valley incision, one in the Late Miocene and one in the Early Pleistocene, separated by periods of planation and fluvial deposition. The upland erosion surface and a fluvial gravel are the remnan ts of a low-relief Late Miocene landscape. Late Miocene incision was follow ed by deposition of a fluvial plain and cutting of straths in the Pliocene. Early Pleistocene incision produced the present valleys, which contain Mid dle to Late Pleistocene fluvial deposits. The two incisions correspond to p ermanent glacioeustatic lowering during expansion of the Antarctic ice shee t in the Middle to Late Miocene and development of Northern Hemisphere ice sheets in the Late Pliocene. Bordering Coastal Plain marine deposits indica te that the upland erosion surface was formed during a rising sea-level tre nd between the Late Oligocene and Middle Miocene. The Pliocene plain and st raths formed during a period of rising sea level in the Early Pliocene. The stratigraphic record indicates that the oldest preserved landforms are no older than Late Miocene, that landscape planation in coastal regions of low -relief passive margins can be achieved in <20 m. yr., and that these surfa ces can be incised and dissected in <5 m. yr.