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CAROLINA GEOLOGICAL SOCIETYGuidebook for 1996 Annual MeetingPages 9 - 18THE COQUINAS OF THE NEUSE FORMATION, NEW HANOVER COUNTY, NORTH CAROLINAJames A. DockalDepartment of Earth SciencesUniversity of North Carolina at WilmingtonWilmington, NC 28403-3297ABSTRACTThe coquinas of the Neuse Formation in southern NewHanover County, North Carolina, represent only a small portionof a depositional suite, which formed in the high-energyenvironment of a Late Pleistocene shoreface at a time correspondingto oxygen isotope stage 3 or 75 to 55 ka BP. Thefauna associated with the coquina indicates climatic conditionsthat are i indistinguishable from the present climate.The coquinas are the product of post-depositional diagenesisof carbonate shell bearing shoreface sands where dissolution,cementation, and calcification of aragonite occurred at ornear the paleo-water table. A later dissolution episode of thecarbonate fraction of the coquina and associated strata byoxygenated meteoric waters resulted in the formation of anunlithified, generally reddish, non-fossiliferous sand whichgenerally blankets the area. IINTRODUCTIONFigure 1. Map of the study area showing the occurrences ofcoquina both on shore and off shore in southern New HanoverCounty, North Carolina. A-A’, B-B’, and C-C’ indicate thelocations of profiles illustrated on Figure 7.The coquina found on the beach in the area of FortFisher in New Hanover County, North Carolina, representsone of the very few naturally occurring rock out croppings inthe Coastal Plain Province of the Carolinas. The coquina isnot laterally extensive nor is it of significant thickness, but itoccurs as sporadic isolated patches in a north to south arcuateband over an area roughly 15 km long by 2 km wide (Figure1}. This paper presents a synopsis of the stratigraphicnomenclature applied to the coquina and then presents adetailed petrologic description and interpretation of the conditionsof deposition and diagenesis of the coquina.The published record of coquinas in southeastern NorthCarolina and especially New Hanover County is sparsealthough the area has been visited frequently by geoscientistsfor over 200 years. The first published record is in Stephenson's(1912} description of the Pamlico Formation under"Detailed Sections" where he notes the presence of coquinarock at "Old Fort Fisher" and at a site “one mile southeast ofCarolina Beach wharf." Stephenson's report, however, onlyprovides a brief list of some of the fauna collected by a Dr.Vaughan and provides a photograph of the outcrop on thebeach at Fort Fisher. U. S. Army engineers, during the courseof a beach erosion study in 1931 made 14 "wash borings" atthe Fort Fisher site (House Document 204, 72 ND Congress,1 st Session). These provide some insight into the lateralvariability of the strata though the records lack detailed lithologicdescriptions. Richards (1936), in describing the faunaof the Pamlico Formation, mentioned the exposures at SnowsCut and Fort Fisher and provided a comprehensive list of thefauna. Wells (1944) provided the first detailed description ofthe Pleistocene strata in the Carolina Beach-Fort Fisher area.He divided the strata into five units: Galveston Sand, PineSand, Castalia Sand, Kure Sand, and Cape Fear Coquina.This is apparently the first in print usage of the term .'CapeFear Coquina." Fallow and Wheeler (1969) in their definitionof the Neuse Formation noted several locations ofcoquina in the Carolina Beach area. They designated thecoquina as representing the .'Coquina facies" of the Neuse9
James A. DockalFormation and they designated the section on the north sideof Snows Cut as a reference section for the proposed NeuseFormation. Fallow (1973) later considered the coquina to bethe "High-energy Facies" of the Neuse Formation. Moorefield(1978 was the first to recognize and describe submergedcoquina outcrops in the area. He noted that thesubmerged outcrops, though identical to those on the landsurface, were encrusted with algae, barnacles, colonies of thebivalve Mytilus, serpulid worms, bryozoans and the coralAstrangia. Moorefield reported that these submerged outcropswere undergoing biological erosion especially by therock- boring bivalve Lithophaga. The U. S. Army Corps ofEngineers (1982), during the course of a design study forbeach stabilization, made a number of split spoon borings atthe Fort Fisher Historic site. Some of these penetrated to theunderlying Castle Hayne Limestone (Eocene). The recordsof these borings in combination with the 1931 records providea good view of the lateral variance in lithology over avery limited geographic area. Prosser (1993) attempted toascertain the age of the coquina by using the Uranium seriesmethod on Mercenaria shells collected at Snows Cut.Dockal (1992, 1995b) applied the radiocarbon method toshells of Donax variabilis, Nassarius obsoleta, and Crassostreavirginica, which were also collected at Snows Cut. Wehmillerand others (1988) and Wehmiller and others (1995)applied the amino acid racemization to specimens of Mercenariafrom the coquina.NOMENCLATURE REVIEWThe fossiliferous sands of Pleistocene age in NewHanover County and adjacent offshore areas are informallyreferred to today as the "Cape Fear Coquina," a term firstused by Wells (1944) for the coquinas between Snows Cutand Fort Fisher. This term can not be used as a formal lithostratigraphicname because the name Cape Fear is already inuse for Cretaceous strata located in the coastal plain of theCarolinas; the Cape Fear Formation.The earliest workers within the southeastern Atlanticseaboard region applied the term Columbia Formation andlater Columbia Group to all the Quaternary strata. Bothterms have not been applied in the region for decades andwere never used in reference to the strata encompassed bythis study outside of Stephenson's (1912) usage of PamlicoFormation which was considered at that time to be a subdivisionof the Columbia Group. Stephenson (1912) and laterRichards (1936) definitely referred to the strata considered inthis report as belonging to the Pamlico Formation; howeverlater workers did not make use of the Pamlico name in alithostratigraphic sense (Figure 2). Du Bar and Solliday(1963) argued not to use the term Pamlico Formation partlybecause the type area was a terrace plane, a geomorphic featureand therefore the unit did not represent a true lithostratigraphicunit. Du Bar and Solliday (1963) proposed theFigure 2. Lithostratigraphic nomenclature that has beenapplied in the literature to the coquina and associated strata insouthern New Hanover County.Fanner Beach Formation to replace the concept of the Pamlicoas a lithostratigraphic unit. The name Fanner Beach hasnever been applied directly to the coquinas of the Cape Fear.Fallaw and Wheeler (1969) objected to usage of the FannerBeach Formation because the name included an assemblageof "distinct lithologic units" or units of terrestrial origin andthose of clearly marine character. Fallaw and Wheeler (1969)proposed the name Neuse Formation which was by definitionto encompass just the "marine fossiliferous Pleistocenedeposits in North Carolina." This they divided into fourfacies: "Fine-grained sand facies", Very fine-grained sand10
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Page 46 and 47: William J. ClearyPHOLOGYFigure 2. A
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Page 50 and 51: William J. ClearyFigure 9. Shorelin
Page 52 and 53: William J. Clearymajor reduction in
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Page 56 and 57: Lynn A. LeonardFigure 2. Stratigrap
Page 58 and 59: Lynn A. LeonardFigure 5. Deposition
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SHORELINE STABILIZATION IN ONSLOW B
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SHORELINE STABILIZATION IN ONSLOW B
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WILLIAM A. DENNISrestored), a museu
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WILLIAM A. DENNISeffective in erosi
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WILLIAM A. DENNISFigure 5. View of
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WILLIAM A. DENNISsurvey, and two po
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WILLIAM J. CLEARY AND ORRIN H. PILK
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CAROLINA GEOLOGICAL SOCIETYGuideboo
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Appendix 2. Post Hurricane Bertha (
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Appendix 4. Post Hurricane Bertha.
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Appendix 6. Post Hurricane Fran (9/
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Appendix 8. Post Hurricane Fran (9/
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