THE NATURE AND DISTRIBUTION OF CAMP MAGMATISM ALONG THE SOUTHEASTERN NORTH AMERICAN MARGIN FROM INTEGRATED ANALYSES OF POTENTIAL FIELD DATA

The Central Atlantic Magmatic Province (CAMP) is one of the world’s biggest large igneous provinces, with a preserved extent that spans North America, South America, Africa, and Europe. The nature and the timing of the emplacement of CAMP, much of which is centered in the South Georgia Rift, and its relationship to other regional scale structures has implications for the evolution of the Atlantic rifted margin of the southeastern US, as well as interactions between extension, faulting, and magmatism in rift systems in general. Although the preserved extent of CAMP basalt has been the subject of recent work, the volume and distribution of intrusive CAMP magmatism preserved at upper- to mid-crustal levels, as well as the geometric and temporal relationships between dikes, sills, and conduits remain largely unexplored subjects.

Filtering of densely sampled land and airborne potential field data for the southeastern North American margin and offshore are used to characterize the geophysical expression of CAMP as reflected in the frequency content of CAMP anomalies, as well as the geometry of and depths to sources. The signature of CAMP anomalies is also explored in relation to other prominent anomalies such as the Tifton anomaly, the Higgins and Zietz line, and the Brunswick Magnetic Anomaly, onshore, and the East Coast Magnetic Anomaly, offshore.

In combination with filtering techniques, 2D potential field forward models that integrate seismic and well data and inverse methods such as Euler and Werner deconvolution are used to estimate the volume of CAMP intrusives, as well as define their distribution and relationship to regional scale rift-related and inherited structures. These results are combined with compiled P-T-t geochemical data in order to better resolve the interactions between crustal thinning, faulting, and magmatism.

Results have implications for the geodynamics of continental break up in the southeastern US, and for the suitability of CAMP intrusives as potential reservoirs for CO₂ sequestration and geothermal power generation.