MAGMA RESERVOIR DEPTHS AND MAGMA TRANSPORT IN THE CENTRAL ATLANTIC MAGMATIC PROVINCE OF EASTERN NORTH AMERICA, WESTERN NEWARK BASIN, PENNSYLVANIA, USA, ASSOCIATED WITH RIFTING OF PANGAEA
Surprisingly, while P-T results indicate reservoirs throughout the crust, orthopyroxene (OPX) and augite (AUG) core results are significantly different: OPX crystallized from more primitive liquids above 1215°C at 0.9-0.4 GPa, 33-16 km in lower to mid-crust; AUG cores grew in mid- to upper crust at 1208-1156°C, 0.35-0 GPa, 13-0 km from slightly more evolved liquids. Deep reservoirs are consistent with seismic reflections at 24-33 km beneath the rift (Sheridan et al., 1991). Characteristics of crystal histories include growth at different P; partial resorption during ascent; capture by different basaltic magmas; and rapid ascent from middle to upper crust. Crystals in clusters formed at different P-T; textures help distinguish mush from clusters aggregated by transport/emplacement. Possible mush clusters in basalt formed in liquid-rich environments (>85% liquid) at P corresponding to rift basin intrusions. In sum, antecrysts formed at depth with < 10% fractionation before ascent with little evidence for crystal-rich mush at any level of the system at the time of flood basalt eruptions. Results are consistent with low-viscosity, liquid-rich magmas and a reservoir system that facilitated large volume transport and eruption under conditions of accelerated extension (Withjack et al., 2020).