Lithospheric structure above the Northern Appalachian Anomaly

Kimberly Espinal, Yale University
Maureen Long, Yale University
Vadim Levin, Rutgers University
Paul Karabinos, Williams College
Roberto Masis Arce, Rutgers University

Abstract

The Northern Appalachian Anomaly (NAA) is an estimated 400-km wide and ~200 km deep low-velocity region centered beneath New Hampshire, extending beneath Vermont and Maine. The geophysical anomaly is spatially correlated with accelerated erosion and unusual uplift from the Late Cretaceous. In addition, the upper mantle anomaly is also spatially correlated with Jurassic to Cretaceous magmatism that is often associated with the Great Meteor Hotspot. It remains unclear whether, and to what extent, the anomaly, uplift, and hotspot are linked. Proposed conceptual models for the NAA include a remnant thermal anomaly after the passage of the plume or asthenospheric upwelling associated with edge-driven convection.

The co-location of the geophysical anomaly, Mesozoic intraplate magmatism, and Cretaceous and Miocene rock uplift in the geologic past continues to stir curiosity about whether these crustal and upper mantle processes are related. The deployment of broadband seismometers across Vermont, New Hampshire, and Maine, compromising the northern line of the New England Seismic Transects (NEST) array, allows for detailed imaging of the crust, mantle, lithosphere, and asthenospheric upper mantle to address these questions.

We present results from P-to-S receiver function analysis of NEST data where we can identify discontinuities, such as the Mohorovicic discontinuity and the lithosphere-asthenosphere boundary. This will allow us to characterize the present-day architecture of the crust and lithospheric mantle above the NAA.

Session

Session 6: Advances in Geology, Geochronology, Geophysics