Merguerian, Charles; and Sanders, J. E., 1995g, Late
syn-intrusive clastic dikes, contact relationships and xenoliths at the base of
the Palisades intrusive sheet, Fort Lee, NJ imply a shallow (~3 to 4 km) depth
of intrusion and NE-directed paleoflow of the Palisades magma (abs.): Geological Society of America Abstracts with
Programs, v. 27, no. 6, p. A-284.
The world-renowned Palisades intrusive sheet is continuously
exposed along the east edge of the Newark Basin from Haverstraw, New York
southwestward to Staten Island, NYC where a possible feeder exists. In Fort Lee, xenoliths, screens, and chaotic
clay-rich- and sandy Lockatong strata have been folded and metamorphosed and
have generated late syn-intrusive "clastic dikes and irregular
apophyses" that crosscut the igneous/sediment interface. Apparently, during- and immediately
following initial cooling of the marginal chilled zone of the Palisades magma,
but before they had been lithified, the Lockatong was heated and mobilized as
cohesionless sediment. In addition to
the clastic dikes, vesicles, pipe amygdales, and brecciated chilled-margin
facies of the Palisades suggest that the mafic magma was intruded at relatively
shallow depths (roughly 3 to 4 km) where the overburden had not yet caused
dewatering and lithification.
The basal contact of the Palisades
sheet cuts across the bedding in a ramp-like fashion toward the northeast. Folded xenoliths and folds of Lockatong
sedimentary strata below the igneous contacts invariably are products of
subhorizontal shear. Their steep-,
overturned-, and recumbent axial surfaces trend E-W and vary from steeply
dipping to subhorizontal. These
marginal relationships suggest that paleoflow of the magma was from SW to NE.
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