Abstract

The northeastern North Carolina Piedmont is made up of a basement sequence of unknown age (possibly a southern extension of the Grenville-age Goochland terrane of eastern Virginia), structurally overlain by a volcanogenic sequence of probable late Precambrian to early Paleozoic age (an eastward continuation of lithologies occurring in the Carolina slate belt). A model is proposed in which the basement and volcanogenic sequences are separated by a pre-Alleghanian [Taconic(?)] décollement. Northwestward and westward vergence of associated folds of the upper plate suggests that the volcanogenic sequence was thrust from the southeast or east over the basement terrane. This deformation occurred during a greenschist-grade (M1) metamorphic event. Alleghanian granites (313 to 285 Ma) intrude both the basement and volcanogenic sequences, clearly cutting the inferred décollement in some areas. This Alleghanian plutonism was accompanied by regional heating to produce the upper greenschist- to amphibolite-grade (M2) assemblages of the Raleigh belt. The Raleigh belt remained hot until late Alleghanian compression produced regional-scale (F3) folds and D3 mylonite zones with the resultant uplift and cooling of this belt by 250–240 Ma.

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