37 D17. Igneous Petrology and Volcanology (Posters)

Monday, 21 March 2022
1:30 PM - 5:30 PM
Freedom Hall A

AN UNUSUAL MAFIC DIKE IN EASTON, PENNSYLVANIA

Paper number: 37-2
Program: Technical Sessions
Time: 1:30 PM – 5:30 PM

Authors

Abstract

We present a preliminary report on a newly (re-?)discovered and seemingly unusual mafic dike that cuts Precambrian rocks near Easton, PA (and new data for a previously identified dike/sill located nearby). At its one outcrop, the new dike is about 2m wide, and exhibits sharp contacts with enclosing Mesoproterozoic quartzo-feldspathic gneiss. Based on float located along its apparent strike, the dike also cuts both post-orogenic pegmatite and talc-bearing rocks derived from the Franklin Marble. The dike is porphyritic, and initial petrographic and geochemical analyses suggest that it is likely distinct from the Catoctin-related metadiabase dikes that are relatively common within the Precambrian rocks of the New Jersey Highlands and the Reading Prong. A total alkali vs. silica diagram suggests that the new dike has a basaltic to trachy-basaltic composition.

Geological Society of America Abstracts with Programs. Vol. 54, No. 3

doi: 10.1130/abs/2022NE-375201

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