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Cretaceous sediments are disconformably overlain by Pliocene sediments along the banks of Greens Mill Run, Greenville, North Carolina, located in the central coastal plain. The Cretaceous sediments, composed of glauconitic sand and clay, have previously been informally considered part of the Maastrichtian Peedee Formation. The Pliocene sediments are assigned to the Yorktown Formation and consist of shelly, muddy sand overlain with a gradational contact by shell-poor, muddy sand. Foraminifera are abundant in the Cretaceous unit and are dominated by the planktic foraminifera Guembelitria cretacea. Low planktic foraminiferal diversity, the absence of single and double-keeled species, the dominance of planktic over benthic foraminifera, and the occurrence of glauconite and phosphorite grains indicates a middle neritic environment. The age of the Cretaceous unit is late Campanian (Zone CC22c), as indicated by the co-occurrence of the calcareous nannofossils Reinhardtites levis and Reinhardtites anthophorus. For this reason, we assign these deposits to the Donoho Creek Formation of the Black Creek Group rather than to the lithologically similar and younger Peedee Formation. Benthic foraminifera dominate the lower part of the Yorktown Formation, are similar to those from the Rushmere Member of the Yorktown Formation in the southern Salisbury Embayment, and indicate deposition in an inner to middle neritic environment. Phosphorite peloids and intraclasts are likely reworked from underlying strata and suggest wave ravinement and deposition during transgression, which is further supported by a fining upward trend. The upper part of the Yorktown Formation exposure, characterized by abundant molds of small bivalves and barren of foraminifera, represents the Morgarts Beach Member. Sedimentological data are consistent with foraminiferal data as far as expected depositional energy. A restricted inner neritic or estuarine environment is indicated. [ABSTRACT FROM AUTHOR]

Hurricanes with high winds can generate strong ocean circulation, storm surges, and large surface waves that impact coastal regions. In 2018, Hurricane Florence crossed the narrow continental shelf and made landfall in Onslow Bay, North Carolina, USA, a 160 km curved embayment rimmed by a chain of barrier islands with inlets and narrow back-barrier lagoons. This storm had significant impacts to Bear Island, an undeveloped barrier island, including overwash and shoreline recession of the beach/dune system of up to 40 m. The objective of this study is to apply a flexible mesh numerical model to investigate wave generation by wind over the ocean, and the fine-scale response of flow and storm surge in shallow nearshore areas including inlets and back-barrier estuaries. The hydrodynamic conditions surrounding four different barrier island systems that received different hurricane wind and wave forcing relative to the cyclone eye are investigated. The highest total water levels around the barrier islands are driven by the combined tide, storm surge and waves, resulting in complex circulation patterns related to the network of shallow channels in the back-barrier environment. [ABSTRACT FROM AUTHOR]

Barrier islands within sheltered environments are an important natural defense from severe storm impacts for coastal communities worldwide. Despite their importance, these fetch-limited barrier islands remain understudied and their ability to withstand and recover from storms is not well-understood. Here, we present a case study of Sugarloaf Island in North Carolina that demonstrates the operational use of openly accessible LiDAR and aerial imagery data to quantify synoptic habitat, shoreline, and volumetric change between 2014 and 2020, a period that encompasses four hurricanes and a winter storm event. During this time period, our results show: (1) an 11–13% decrease in marsh and shrub habitat, (2) an average landward shoreline migration of 2.9 m yr−1 and up to 5.2 m yr−1 in extreme areas, and (3) a net volume loss of approximately 9800 m3. The results of this study highlight the importance of storms as a driver of morphologic change on Sugarloaf Island and have implications for better understanding the resiliency of fetch-limited barrier islands to storms. This work helps to enhance prerestoration data availability and supports knowledge-based decision-making regarding habitat change, erosional issues, and the efficacy of nature-based solutions to increase the resiliency of a coastal community in North Carolina. [ABSTRACT FROM AUTHOR]

Pamlico Sound, a large back‐barrier estuary in North Carolina, is under threat of climate change due to increased storm activity and sea level rise. The response of this system is investigated by considering what has already happened during changes in sea level over the late Holocene epoch. The hydrodynamic changes that occurred in response to geomorphic evolution are simulated using a 3‐D numerical model for four distinct "time‐slice" scenarios. To accomplish this, the present‐day bathymetry was obtained from a high‐resolution digital elevation model, and paleobathymetric grids were developed from sediment cores and seismic observations. Using the same hydrodynamic forcing for each geomorphic scenario, the models are compared to assess the combined response to: different inlets connecting the back‐barrier estuary to the ocean, changes in basin geomorphology due to sedimentation, and sea level rise. The results indicate that these factors have a considerable effect on hydrodynamics, waves, and salinity in the estuary. The time‐averaged tidal ranges were up to 3 times as high for the past environments in comparison with present‐day water level elevations, and maximum current velocities were over 3 times higher in regions close to paleo‐inlets. The simulations for each time slice suggest that the salinity distribution in Pamlico Sound is strongly influenced by the hydraulic connectivity with other estuaries and the number and size of tidal inlets through the barrier island system. The results indicate that changes to barrier systems induce strong, nonuniform, and complex responses in back‐barrier estuaries with regime shifts in hydrodynamic energy and water mass properties. Key Points: A modeling approach is developed for simulating the response of an estuary to different geomorphological conditions over a long time scaleGeological observations were used to define inlet locations, basin morphology, and sea levels in the hydrodynamic modelThe results indicate controls on the water levels, current velocities, and salinity distributions in paleo‐estuarine environments [ABSTRACT FROM AUTHOR]

Geological investigations of Herndon Bay, a Carolina bay in the Coastal Plain of North Carolina (USA), provide evidence for rapid basin scour and migration during Marine Isotope Stage (MIS) 3 of the late Pleistocene. LiDAR data show a regressive sequence of sand rims that partially backfill the remnant older portions of the bay, with evidence for basin migration more than 600 meters to the northwest. Basin migration was punctuated by periods of stability and construction of a regressive sequence of sand rims with basal muddy sands incorporated into the oldest rims. Single grain OSL ages place the initial formation of each sand rim from oldest to most recent as ca. 36.7 +/- 4.1, 29.6 +/- 3.1, and 27.2 +/- 2.8 ka. These ages indicate that migration and rim construction was coincident with MIS 3 through early MIS 2, a time of rapid oscillations in climate. The fact that Carolina bay basins can migrate, yet maintain their characteristic shape and orientation, demonstrates that Carolina bays are oriented lakes that evolved over time through lacustrine and eolian processes. This research also indicates that Carolina bays can respond rapidly during periods of climatic transition such as Dansgaard-Oeschger or Heinrich events. [ABSTRACT FROM AUTHOR]

Moran, K.L.; Mallinson, D.J.; Culver, S.J.; Leorri, E., and Mulligan, R.P., 2015. Late Holocene evolution of Currituck Sound, North Carolina, USA: Environmental change driven by sea-level rise, storms, and barrier island morphology. The Holocene evolution of Currituck Sound, North Carolina, is investigated using geological data and a hydrodynamic model to understand how this depositional basin changed in response to sea-level rise and regional climate patterns. Five depositional units (one Pleistocene and four Holocene) are defined based on geophysical surveys, lithofacies, biofacies, and geochronological data. The earliest Holocene unit ( ca. 5000 cal YBP) represents a midsalinity (10-25‰) sand shoal above the transgressive ravinement surface. This unit is overlain, successively, by (1) a freshwater swamp forest deposit, (2) a relatively saline (25-35‰) back-barrier estuarine deposit associated with increased inlet activity, and (3) a mid- to low-salinity (<10‰) deposit that is typical of modern (post-1827) Currituck Sound, a back-barrier estuary with no inlets in the barrier island. Geomorphic reconstructions provided the boundary conditions input to hydrodynamically model tide and current patterns and to constrain the probable size and location of inlets. The evolution of this system depends on sea-level rise and barrier morphology, regional hydrological factors, and regional climatic conditions, which modulate storm impacts and inlet activity along the fronting barrier system. The late Holocene stratigraphy reflects climate variability also recorded in the sediments of Chesapeake Bay (to the north) and Pamlico Sound (to the south) and is consistent with an increase in tropical cyclone activity during the Medieval Climate Anomaly and subsequent decrease in tropical storm activity since ca. 500 cal YBP. [ABSTRACT FROM AUTHOR]

Climate change and sea-level rise will have severe impacts on coastal water resources around the world. However, whereas the influence of marine inundation is well documented in the literature, the impact of groundwater inundation on coastal communities is not well known. Here, core analysis, groundwater monitoring, and ground penetrating radar are utilized to assess the groundwater regime of the surficial aquifer on Bogue Banks Barrier Island (USA). Then, geospatial techniques are used to assess the relative roles and extents of groundwater and marine inundation on the dune-dominated barrier island under sea-level rise scenarios of 0.2, 0.5, and 1.0 m above current conditions by 2100. Additionally, the effects of rising water tables on onsite wastewater treatment systems (OWTS) are modelled using the projected sea-level rise scenarios. The results indicate that the surficial aquifer comprising fine to medium sands responds quickly to precipitation. Water-level measurements reveal varying thicknesses of the vadose zone (>3 to 0 m) and several groundwater mounds with radial flow patterns. Results from projected sea-level rise scenarios suggest that owing to aquifer properties and morphology of the island, groundwater inundation may occur at the same rate as marine inundation. Furthermore, the area inundated by groundwater may be as significant as that affected by marine inundation. The results also show that the proportion of land in the study area where OWTS may be perpetually compromised by rising water tables under worst case scenarios may range from ~43 to ~54% over an 86-year-period. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Micropaleontological, geophysical, and chronologic data indicate that normal salinity conditions occurred over currently estuarine back-barrier areas of the Outer Banks of eastern North Carolina during the peak of the Medieval Climate Anomaly. Sedimentary units several meters thick, containing foraminiferal assemblages usually found on the continental shelf of North Carolina, are present in 16 vibracores acquired from the shallow shoals of Pamlico Sound behind Cape Hatteras. Optically stimulated luminescence age estimates from these normal salinity units range from approximately 1360 to 980 calibrated years (cal yr) BP, corresponding with a previously documented collapse of a segment of the southern Outer Banks. It is vital to understand past scenarios of barrier island formation and segmentation to provide insight on how these islands may react to future change in climate and sea level. [ABSTRACT FROM AUTHOR]

Lithofacies analysis is fundamental to unravelling the succession of depositional environments associated with sea-level fluctuations. These successions and their timing are often poorly understood. This report defines lithofacies encountered within the north-eastern North Carolina and south-eastern Virginia Quaternary section, interprets their depositional environments, presents a model for coastal depositional sequence development in a passive margin setting and uses this understanding to develop the stratigraphy and Quaternary evolutionary history of the region. Data were obtained from numerous drill cores and outcrops. Chronology was based on age estimates acquired using optically stimulated luminescence, amino acid racemization, Uranium series and radiocarbon dating techniques. Geomorphic patterns were identified and interpreted using light detection and ranging imagery. Since lithofacies occurrence, distribution and stratigraphic patterns are different on interfluves than in palaeo-valleys, this study focused on interfluves to obtain a record of highstand sea-level cycles with minimal alteration by fluvial processes during subsequent lowstands. Nine primary lithofacies and four diagenetic facies were identified in outcrops and cores. The uppermost depositional sequence on interfluves exhibits an upward succession from shelly marine lithofacies to tidal estuarine lithofacies and is bounded below by a marine ravinement surface and above by the modern land surface. Older depositional sequences in the subsurface are typically bounded above and below by marine ravinement surfaces. Portions of seven depositional sequences were recognized and interpreted to represent deposition from late middle Pleistocene to present. Erosional processes associated with each successive depositional sequence removed portions of older depositional sequences. The stratigraphic record of the most recent sea-level highstands (Marine Isotope Stage 5a and Marine Isotope Stage 3) is best preserved. Glacio-isostatic adjustment has influenced depositional patterns so that deposits associated with late Quaternary sea-level highstands (Marine Isotope Stages 5c, 5a and 3), which did not reach as high as present sea-level according to equatorial eustatic records, are uplifted and emergent within the study area. [ABSTRACT FROM AUTHOR]

Abstract: For the first time, electron spin resonance optical dating (ESROD) has been conducted on littorally transported and aeolian siliciclastic sediments in Florida. ESROD utilizes light-sensitive radiation-sensitive defects at silicon sites that have been replaced by aluminum and titanium atoms to give rise to a time-dependant signal. These defects saturate at higher levels of radiation dose, compared to optically stimulated luminescence, and therefore extend the optical dating range back into the millions of years. Our results show that the Trail Ridge Sequence is a multi-depositional unit that began deposition around 2.2Ma and continued until 6ka. The Osceola Cape, of the Effingham Sequence, was deposited around 1.5Ma, and the Chatham Sequence was a multi-depositional terrace with at least three events preserved. [Copyright &y& Elsevier]

Ground penetrating radar and single-aliquot regenerative-dose optically stimulated luminescence were used to determine the depositional environments and age of unconsolidated siliciclastic sediments near Apalachicola, Florida. Five direct-push cores, five vibracores and 28 optically stimulated luminescence samples were collected, as well as 7 km of ground penetrating radar data. A new model of cosmic dose rate calculation, which removes the effect of a much younger aeolian cap, was utilized to calculate more representative optically stimulated luminescence ages. Five radar facies were identified based on reflector amplitude and orientation. The resulting data indicate that the Tertiary/Quaternary Shelly Sediments were deposited before marine isotope stage 6, the Quaternary Alluvium was deposited during marine isotope stage 6 and the Quaternary Beach Ridge and Dune was deposited during the marine isotope stage 5e sea-level highstand, which peaked at approximately 2·5 m above present sea-level in this area. [ABSTRACT FROM AUTHOR]

Abstract: Foraminiferal analyses of 404 contiguous samples, supported by diatom, lithologic, geochronologic and seismic data, reveal both rapid and gradual Holocene paleoenvironmental changes in an 8.21-m vibracore taken from southern Pamlico Sound, North Carolina. Data record initial flooding of a latest Pleistocene river drainage and the formation of an estuary 9000yr ago. Estuarine conditions were punctuated by two intervals of marine influence from approximately 4100 to 3700 and 1150 to 500calyr BP. Foraminiferal assemblages in the muddy sand facies that accumulated during these intervals contain many well-preserved benthic foraminiferal species, which occur today in open marine settings as deep as the mid shelf, and significant numbers of well-preserved planktonic foraminifera, some typical of Gulf Stream waters. We postulate that these marine-influenced units resulted from temporary destruction of the southern Outer Banks barrier islands by hurricanes. The second increase in marine influence is coeval with increased rate of sea-level rise and a peak in Atlantic tropical cyclone activity during the Medieval Climate Anomaly. This high-resolution analysis demonstrates the range of environmental variability and the rapidity of coastal change that can result from the interplay of changing climate, sea level and geomorphology in an estuarine setting. [Copyright &y& Elsevier]

Abstract: The Outer Banks barrier islands of North Carolina, USA, contain a geologic record of inlet activity that extends from ca. 2200calyr BP to the present, and can be used as a proxy for storm activity. Optically stimulated luminescence (OSL) dating (26 samples) of inlet-fill and flood tide delta deposits, recognized in cores and geophysical data, provides the basis for understanding the chronology of storm impacts and comparison to other paleoclimate proxy data. OSL ages of historical inlet fill compare favorably to historical documentation of inlet activity, providing confidence in the technique. Comparison suggests that the Medieval Warm Period (MWP) and Little Ice Age (LIA) were both characterized by elevated storm conditions as indicated by much greater inlet activity relative to today. Given present understanding of atmospheric circulation patterns and sea-surface temperatures during the MWP and LIA, we suggest that increased inlet activity during the MWP responded to intensified hurricane impacts, while elevated inlet activity during the LIA was in response to increased nor''easter activity. A general decrease in storminess at mid-latitudes in the North Atlantic over the last 300yr has allowed the system to evolve into a more continuous barrier with few inlets. [Copyright &y& Elsevier]

Abstract: A detailed record of late Quaternary sea-level oscillations is preserved within the upper 45 m of deposits along an eight km transect across Croatan Sound, a drowned tributary of the Roanoke/Albemarle drainage system, northeastern North Carolina. Drill-hole and seismic data reveal nine relatively complete sequences filling an antecedent valley comprised of discontinuous middle and early Pleistocene deposits. On interfluves, lithologically similar marine deposits of different sequences occur stacked in vertical succession and separated by ravinement surfaces. Within the paleo-drainage, marine deposits are separated by fluvial and/or estuarine sediments deposited during periods of lowered sea level. Foraminiferal and molluscan fossil assemblages indicate that marine facies were deposited in a shallow-marine embayment with open connection to shelf waters. Each sequence modifies or truncates portions of the preceding sequence or sequences. Sequence boundaries are the product of a combination of fluvial, estuarine, and marine erosional processes. Stratigraphic and age analyses constrain the ages of sequences to late Marine Isotope Stage (MIS) 6 and younger (∼140 ka to present), indicating multiple sea-level oscillations during this interval. Elevations of highstand deposits associated with late MIS 5 and MIS 3 imply that sea level was either similar to present during those times, or that the region may have been influenced by glacio-isostatic uplift and subsidence. [Copyright &y& Elsevier]

Foraminiferal and sedimentary data, supplemented with geochemical dating and ground-penetrating radar transects, show that the barrier island at Pea Island National Wildlife Refuge just north of Rodanthe, North Carolina, has been dominated by a combination of inlet and overwash processes for at least 1000 years. The stratigraphic record of several vibracores does not preserve every, or even many, overwash events but, instead, is characterized by three to four fining-upward sequences. The last three commence with overwash sand or gravel that is overlain by a variety of finer-grained estuarine, inlet, and marsh deposits. The dynamic nature of this segment of the Outer Banks was muted in the late 1930s by construction of artificial barrier dune ridges, extensive planting of grass and shrubs, and construction of Highway 12 in 1953. Subsequently, the road and barrier dune ridge were rebuilt and relocated several times following storm events. [ABSTRACT FROM AUTHOR]

Reports on a study conducted by researchers in the United States, which examines whether the activity of Leishmania donovani secrete acid phosphatase was affected by treatment with various proteases including some similar to those produced within the gut of their sandfly vector host. Influence of bromelain and subtilisin in causing a pronounced reduction in the enzymatic activity of secrete acid phosphatase.

A widespread platinum (Pt) anomaly was recently documented in Greenland ice and 11 North American sedimentary sequences at the onset of the Younger Dryas (YD) event (~12,800 cal yr BP), consistent with the YD Impact Hypothesis. We report high-resolution analyses of a 1-meter section of a lake core from White Pond, South Carolina, USA. After developing a Bayesian age-depth model that brackets the late Pleistocene through early Holocene, we analyzed and quantified the following: (1) Pt and palladium (Pd) abundance, (2) geochemistry of 58 elements, (3) coprophilous spores, (4) sedimentary organic matter (OC and sedaDNA), (5) stable isotopes of C (δ13C) and N (δ15N), (6) soot, (7) aciniform carbon, (8) cryptotephra, (9) mercury (Hg), and (10) magnetic susceptibility. We identified large Pt and Pt/Pd anomalies within a 2-cm section dated to the YD onset (12,785 ± 58 cal yr BP). These anomalies precede a decline in coprophilous spores and correlate with an abrupt peak in soot and C/OC ratios, indicative of large-scale regional biomass burning. We also observed a relatively large excursion in δ15N values, indicating rapid climatic and environmental/hydrological changes at the YD onset. Our results are consistent with the YD Impact Hypothesis and impact-related environmental and ecological changes. [ABSTRACT FROM AUTHOR]