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CAROLINA GEOLOGICAL SOCIETY
Guidebook for 1995 Annual Meeting
Pages 25-32
GEOLOGIC CONTRASTS ACROSS THE CENTRAL PIEDMONT SUTURE IN NORTH – CENTRAL NORTH
CAROLINA
James K. Wilkins, Glenn S. Shell, and James P. Hibbard
Department of Marine, Earth and Atmospheric Sciences
N.C. State University
Raleigh, NC 27695
INTRODUCTION
The central Piedmont suture (CPS) marks the boundary
between two distinct tectonostratigraphic packages in the
southern Appalachians, the Piedmont zone and the Carolina
zone (Figure 1, Hatcher and Zeitz, 1980; for zonation terminology,
see Hibbard and Samson, 1995). This first-order
boundary is recognized along much of its length in Georgia
to South Carolina by the transition from high grade schists
and gneisses with gently dipping foliations in the Piedmont
zone (primarily the Inner Piedmont in this region) into lower
grade, late Precambrian-Cambrian metaigneous and
metasedimentary rocks with steeply dipping foliations in the
Carolina zone (primarily the Carolina slate belt and the
Charlotte belt). Accompanying this transition is a change in
the geophysical signature within each belt (Hatcher and
Zietz, 1980). In particular, magnetic signatures in the Piedmont
zone are characterized by low frequency patterns relative
to higher frequency patterns within the Carolina zone.
Similar contrasts in lithologies, structural style, and geophysical
signature have recently been recognized across a
shear zone separating high grade gneisses from the Carolina
zone of north-central North Carolina. These findings have
led to a proposal that this boundary represents the northern
extension of the CPS (Hibbard, 1993).
In many areas the CPS has been affected by later deformation,
the effects of which vary quite dramatically. For
example, in north-central South Carolina the CPS is
deformed into upright, tight folds (Hatcher and others, 1988;
Dennis, 1991). Elsewhere the CPS has been overprinted by
Alleghanian dextral shear zones (Hooper and Hacher, 1989;
Figure 1. Regional map of the four tectonostratigraphic zones of the southern Appalachians, the black box denotes the study area;
K= Kiokee belt, PMB = Pine Mtn. Elt, SMA = Sauratown Mtns. Anticlinorium’s, U = Uchee belt (after Hibbard and Samson, 1995).
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