Precambrian blocks and orogen boundaries in the north-central United States determined from gravity and magnetic data


Newly compiled gravity and magnetic data within the north-central United States were used to investigate the crustal structure of the region's Precambrian geology. Gray-scale imaging, gravity stripping, enhanced magnetic gradients, and polynomial trend surfaces were used to delineate the potential field characteristics of each of the Precambrian orogens. This analysis expanded on the previous regional investigations by suggesting that several crustal blocks (or regions of different lithologies/ crust thickness) may exist in each of the known orogens. In addition, the study found that the interpreted location of the orogen boundaries varied depending on the type of potential field analysis used. The Trans-Hudson orogen may extend farther south in Nebraska and the Penokean orogen may extend farther southwest into Nebraska than was previously thought. The reinterpretation of the blocks and orogen boundaries needs additional constraining geological and/or seismic evidence in order for the results of the gravity and magnetic analysis to be completely supported.


Geography, Geology, and Planning

Document Type

Conference Proceeding




Bouguer gravity, Magnetic anomalies, Orogenic belts, Precambrian tectonics

Publication Date


Journal Title

Memoir of the Geological Society of America