29-26 Geothermobarometric Insights into the 200-million-year-old Magmatic System Beneath the Central Atlantic Magmatic Province.

Session: Undergraduate Research, Part II (Posters)

Presenting Author:

Authors:

Abstract:

The Central Atlantic Magmatic Province (CAMP, ~201 Ma) covered an estimated 10 million km², developing during the breakup of Pangaea. Despite being one of the largest igneous provinces, there are still many outstanding questions as to how it developed. Recent work on the province evaluates the newer models of transcrustal magmatic systems, dominated by interactions of and vertical transfer of magma, crystals and gasses (e.g., Capriolo et al 2020). Analysis of samples from the north of the CAMP Province display evidence for deep sourced melt inclusions and crystallization at mid-crustal levels (Capriolo et al., 2020). This project focuses on the Carolina group dikes to evaluate what the magmatic plumbing system under CAMP may have looked like.

The studied samples range from olivine basalts to olivine gabbros, composed of plagioclase, clinopyroxene, olivine ± Cr-spinel. This study applied various geothermometry and geobarometric methods to determine the pressure-temperature conditions under which the crystals within the dikes formed and equilibrated. Crystallization temperatures range from 1066 to 1340ºC, with equilibration temperatures ranging from 803 to 1239ºC. The depth at which the dikes crystalized was estimated at 8-10 km based on the calculated pressure range of 2.7 to 3.86 kbar. These data, combined with observations that all dike samples show disequilibrium textures as well as at least two populations of crystal sizes, suggests a complex magmatic system. This indicates a mush dominated magmatic system extended throughout the entire crust below the southeastern U.S.A over 200 million years ago.

Reference:

Capriolo, M, Marzoli, A., Aradi, L.E., Callegaro, S., Dal Corso, J., Newton, R.J., Mills, B.J.W., Wignall, P.B., Bartoli, O., Baker, D.R., Youbi, N., Remusat, L., Spiess, R., Szabo, C., 2020, Deep CO2 in the end-Triassic Central Atlantic Magmatic Province: Nature Communications, v.11. 1670, https://doi.org/10.1038/s41467-020-15325-6.

Geological Society of America Abstracts with Programs. Vol. 58, No. 1, 2026

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