NEOTECTONICS OF THE NEW YORK RECESS

The present-day (neo-) tectonic framework of the west-central Atlantic continental margin centered on New Jersey is mapped using digital geological and geophysical data for display in Google Earth (GE). Geospatial themes include 1) historical earthquake occurrences, some of which provide focal-mechanism solutions for the current state of crustal stress, 2) current crustal motions including long-term determinations of horizontal drift and vertical ground motion gained from ground-fixed and continuously monitored global-positioning-systems (GPS), and 3) regional geological themes portraying lithic groups and trends of secondary tectonic structures including fold axes and major fracture systems. These themes are used to gain a perspective on the latest brittle structures that may have originated in our current state of crustal stress, that are seen in outcrop or the shallow subsurface using geophysical methods, and that overprint older paleotectonic (ancient) structures. A set of chronostratigraphic groups, separated by major unconformities, are used to summarize, review, and discuss structural features within each domain with respect to their spatial distribution and kinematics. The results point to the need for a reappraisal of some older, classic interpretations of structural and tectonic stages that have impacted our region during the Mesozoic and Cenozoic eras. Although Mesozoic structures and their overprint on earlier Paleozoic and Proterozoic structures aren’t neotectonic in nature, recognition of these older features in the various chronostratigraphic groups is important when identifying the latest brittle structures formed in our current state of crustal stress, including those of favorable orientation for modern reactivation. One main theme arising from this work is the spatial relationship between crustal seismic zones and deep-seated igneous plutons, which suggests that deeply rooted magmatic bodies might locally pin the crust to the mantle and thereby preferentially resist ordinary plate drift.