Early Proterozoic Central Plains orogen: A major buried structure in the north-central United States

The Midcontinent Strategic and Critical Minerals Project; summary and background information to accompany folio of maps of the northern Midcontinent area, latitude 36-46 degrees N. and longitude 88-100 degrees W.

“…A preliminary examination of the map suggests that many of the major Precambrian structural features, as interpreted by , Sims and Peterman (1986), Anderson and Ludvigson (1986), and others, are reflected in the trends of some of the mapped Phanerozoic structures. Other Phanerozoic structural trends do not appear to relate to any known Precambrian features.…”

“…The orogen separates two major Archean cratons, the Superior on the east and the Wyoming on the west, and represents a major constructional phase in the assembly of Laurentia (Hoffman, 1988), the North American craton. It terminates against the younger Early Proterozoic Central Plains orogen in southern South Dakota (Sims and Peterman, 1986;Bickford and others, 1986).…”

“…The completed map shows basement topography, structure, and principal lithologic terranes comprising more than 50 individual units. The principal geologic contribution resulting from this compilation is the recognition and delineation of a major, buried, northwest-trending Early Proterozoic orogen, named the Central Plains orogen (Sims and Peterman, 1986). It extends from Nebraska through Kansas into Missouri, where it is overlapped by Middle Proterozoic rhyolite-granite terranes, and it sharply truncates Archean rocks and an older Proterozoic erogenic (Penokean) belt in the inner part of the craton.…”

The Midcontinent of the United States: Permissive terrane for an Olympic dam-type deposit?

“…The sequences may also be separated by major unconformities. About 1.63 Ga, there was a major resetting of Rb-Sr ages and minor deformation throughout the southern Lake Superior region (Van Schmus, Thurman, and Peterman, 1975;Sims and Peterman, 1980;Van Schmus and Bickford, 1981;Peterman and others, 1985). At 1.5 Ga, the Wolf River batholith and associated anorthosite were emplaced in central Wisconsin (Van Schmus, Medaris, and Banks, 1975).…”

Southern extension of the Churchill Province (Trans-Hudson orogenic belt) Midcontinent Strategic and Critical Minerals Project, 1985 workshop report

“…3d). This terrane, known as the Central Plains orogenic belt (Sims and Peterman, 1986), is dominated by metavolcanics and associated metavolcanics but produced felsic plutonism and vulcanism in the Trans-Hudson and Penokean belts.…”