Joint 69th Annual Southeastern / 55th Annual Northeastern Section Meeting - 2020

Paper No. 14-9
Presentation Time: 4:10 PM


KINNEY, Sean T.1, MACLENNAN, Scott A.2, SETERA, Jacob3, SCHOENE, Blair2, VANTONGEREN, Jill3, STRAUSS, Justin V.4, BRADLEY, Dwight4, HART, Austin5, TOWN, Caleb Forrest4 and OLSEN, Paul E.1, (1)Department of Earth and Environmental Sciences, Lamont-Doherty Earth Observatory of Columbia University, 61 Route 9W, Palisades, NY 10964-1000, (2)Department of Geosciences, Princeton University, Guyot Hall, Princeton, NJ 08544, (3)Department of Earth and Planetary Sciences, Rutgers University, 610 Taylor Road, Piscataway, NJ 08854, (4)Department of Earth Science, Dartmouth College, HB 6105 Fairchild Hall, Hanover, NH 03755, (5)US Forest Service, White Mountain National Forest, 33 Kancamagus Hwy, Conway, NH 03818

The Jurassic White Mountain Magma Series (WMMS) and Cretaceous New England Quebec (NEQ) igneous provinces are two episodes of enigmatic post-orogenic magmatism on the Eastern North American Margin (ENAM).

In order to precisely and accurately assess the variety of hypothesized causal mechanisms for both initiating and sustaining magmatism in each province, we conducted CA-ID-TIMS and LA-ICP-MS zircon U-Pb measurements on several units for both the WMMS and NEQ provinces, including: all major igneous centers associated with the WMMS; all igneous centers within the largest composite intrusion of this province, the White Mountain Batholith; and key units within the NEQ province.

Our results constrain the timing of the onset of the WMMS to be no younger than ~199 Ma, though we cannot rule out a potentially older initiation as some samples did not yield zircons. We also demonstrate that the main phase of WMMS magmatism lasted ~20 Myr, significantly shorter duration than published ages suggest.

The spatial and temporal proximity of the WMMS to the CAMP should motivate future examination of the a geodynamic link between the two. However, given the prolonged duration of WMMS magmatism well beyond the punctuated timing of the CAMP, a variety of processes are likely responsible for the generation, transport, and emplacement of these melts.

Our age constraints for the NEQ province demonstrate a relatively brief duration between magmatism in the Monteregian Hills (Québec) and Cretaceous White Mountains (New Hampshire) and provide the first zircon U-Pb chronological test of the Great Meteor Hotspot on land.

Our work provides the necessary boundary conditions for integrating high-precision geochronology, geochemistry, and geophysics to understand the tectono-magmatic history of the ENAM and evaluate to what extent such process had in producing geophysical anomalies (e.g, the Northern Appalachian Anomaly1) observed today.

1Menke et al., GRL. (2016).