Cretaceous-Paleocene Boundary, Lenoir County, North Carolina
Philip M. Brown, James A. Miller, 1986. "Cretaceous-Paleocene Boundary, Lenoir County, North Carolina", Southeastern United States: Third Annual Midyear Meeting, 1986, Raleigh, North Carolina, Daniel A. Textoris
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In eastern Lenoir and western Craven Counties, located in the central part of the North Carolina Coastal Plain, a series of tilted and partially-exposed structural blocks define the limits, at the surface, of a zone of tectonic uplift and subsidence called the Graingers wrench zone (Brown and others, 1977). The segment of the wrench zone exposed at the surface is about 10 miles (16 km) long and 15 miles (24 km) wide. It trends NE-SW, plunges to the NE, is characterized by a sense of left-lateral displacement, and lies athwart the NW-SE trending Neuse River in the vicinity of Graingers, N.C.
The structural blocks characteristic of the wrench zone comprise a mosaic of juxtaposed grabens, half grabens, and horsts. In part, the blocks are composed of Navarroan, Midwayan and Claibornian sediments. The general boundaries of the blocks and their positions relative to each other, are established chiefly from the observed lateral discontinuity and variance in the relative vertical position of essentially flat-lying indurated mudstones (volcaniclastics) of Midway age, and from observed variance in elevation, relative to sea level, of the unconformity between Midwayan and Navarroan sediments.
The purpose of the field trip is to provide the participants with the opportunity to examine and collect from the Cretaceous-Tertiary boundary at five fresh exposures in the wrench zone, to collect from sections where the boundary is exposed, and to observe the manner in which rocks of different ages and and resistance (Midwayan porcelanites and Navarroan clayey sands) have reacted to the same
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Southeastern United States–Guidebook is comprised of twelve field trips that were organized for the Third Annual Midyear Meeting held in Raleigh, North Carolina in 1986. The spectrum of geologic time represented in the Upper Precambrian, Lower Paleozoic, Mesozoic, Cenozoic and the very Recent. The geologic provinces are the Valley and Ridge, Blue Ridge Mountains, Piedmont, and the Coastal Plain. Besides North Carolina, trips include Virginia, South Carolina and West Virginia.