The Palisades Sill, New Jersey: A Reinvestigation

The Palisades Sill of New Jersey and New York states was emplaced in the Newark Formation in the Upper Triassic, and is about 1000 feet thick. Its form is typical of a hypabyssal sheet except for some dike-like features, which are mainly in the northern part of the intrusion. The sill is a multiple intrusion in which two magma phases of oversaturated tholeiite have been recognized. Olivine crystallized in appreciable amounts only after the emplacement of the second and larger phase. The accumulation of olivine enveloped in early plagioclase and augite determined the location of the famous hyalosiderite dolerite layer...