BEDROCK GEOLOGIC MAPS OF THE LITTLETON AND HOLLISTER 7.5-MINUTE QUADRANGLES, NORTH CAROLINA: PROGRESS IN THE NCGS EASTERN PIEDMONT STATEMAP PROGRAM

North Carolina Geological Survey STATEMAP mapping in the eastern Piedmont of North Carolina continues to focus on completion of bedrock geologic maps of 7.5-minute quadrangles. Although for the past decade we have concentrated on new mapping in the Henderson 1:100K sheet, during 2010-2011 we moved into the westernmost Roanoke Rapids sheet. Making use of existing mapping, done in the early 1990’s by Sacks as a postdoc with the USGS and by Boltin in the 1980’s as an M.S. student at NCSU, we completed the mapping of these two important quads.

The Littleton and Hollister quads contain metamorphic rocks of the infrastructural Raleigh terrane in the northwest, in contact to the east, along the Macon fault, with metamorphic rocks of the suprastructural Spring Hope terrane. The Hollister fault separates the Spring Hope terrane from the infrastructural Triplet terrane exposed to the east of the two quads. The eastern half of both quads is dominated by late Paleozoic granitoid rocks that belong to six separate plutons. Some of these granitic rocks are strongly affected by deformation associated with the Macon and Hollister faults; others appear to be post-kinematic. A swarm of 200-Ma rhyolite porphyry dikes transects the older rocks of the quads, as do diabase dikes of similar age.

Over the next several years, we hope to continue mapping in the Henderson sheet and the western Roanoke Rapids sheet, working cooperatively where possible to take advantage of existing mapping.