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Book Holocene Evolution of the Ocracoke Inlet Flood tide Delta Region Outer Banks North Carolina

Download or read book Holocene Evolution of the Ocracoke Inlet Flood tide Delta Region Outer Banks North Carolina written by Caroline Faulkner Smith and published by . This book was released on 2016 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: Numerous studies have been conducted along the Outer Banks (OBX) barrier islands of North Carolina to address Holocene climatic change using a combination of lithological, micropaleontological, stratigraphical, and geochronological data to reconstruct Holocene paleoenvironmental reconstructions. These data reveal the importance of inlet formation in the evolution of the modern barrier island chain. However, few studies have been conducted within the Ocracoke Inlet and its associated flood-tide delta (OFTD), which has been proposed to be the most stable inlet along the OBX. Detailed knowledge of the anatomy of the modern, active OFTD is necessary to further elucidate the origin and geologic evolution of Ocracoke Inlet and the OFTD region during the Holocene. Five vibracores, and ca. 100 km of seismic data (boomer and chirp) were collected from the Ocracoke Inlet flood-tide delta (OFTD). Twenty-six age estimates were obtained from the five vibracores (13 AMS radiocarbon age estimates, and 13 Optically Stimulated Luminescence-OSL age estimates). Sediments recovered are all Holocene, except a blue clay interpreted to be Pleistocene that is overlain by a basal peat (core VC1) interpreted to have formed in a freshwater riverine swamp forest (EF VI) environment at ca. 7200 cal yr BP. Sediments are predominantly fine-to-medium grained quartz sand, and contain foraminiferal assemblages composed of 41 taxa dominated by Elphidium excavatum and Ammonia parkinsoniana. Foraminiferal assemblages were used to define four biofacies. The geographical distribution of bio- and lithofacies is related to salinity and to distance from the inlet. Six environmental facies (EFs) were determined by correlating bio-, litho-, and seismic facies. Using the six EFs, three transects and five evolutionary time intervals were produced to reconstruct paleoenvironmental changes recorded in the OFTD region during the Holocene. From ca. 7200-6900 cal yr BP rising sea level caused the initial flooding of the paleo-Pamlico Creek drainage system that was characterized by a freshwater swamp environment (EF VI). Between ca. 6900-6600 cal yr BP EF VI transitioned to a high salinity estuarine environment (EF III). EF IV (undetermined, likely mid-to high salinity) estuarine environments characterized the OFTD region ca. 3400 cal yr BP. Flood-tide delta deposits (core VC3B) occurred in the study area ca. 1100 cal yr BP (during the Medieval Climate Anomaly-MCA) and Royal Shoal began to form ca. 500 cal yr BP (during the Little Ice Age-LIA), when Ocracoke Inlet was first documented in historical maps. EF V represents a sand flat/ shoal environment typical of surficial sediments, specifically near Royal Shoal (core VC2B). OFTD deposits (cores VC3B, VC5A, and VC8A) are characterized by two normal marine salinity FTD depositional environments (EF II-low energy and EF I-high energy). The OFTD region probably existed to the south of the study area when estuarine deposits characterized the study area and migrated northwards as sea-level rose.

Book Holocene Geologic Development of Central Hatteras Flats and Buxton Beach Ridges Outer Banks North Carolina

Download or read book Holocene Geologic Development of Central Hatteras Flats and Buxton Beach Ridges Outer Banks North Carolina written by Katie L. McDowell and published by . This book was released on 2009 with total page 470 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Barrier Dynamics and Response to Changing Climate

Download or read book Barrier Dynamics and Response to Changing Climate written by Laura J. Moore and published by Springer. This book was released on 2018-01-17 with total page 407 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents chapters, written by leading coastal scientists, which collectively depict the current understanding of the processes that shape barrier islands and barrier spits, with an emphasis on the response of these landforms to changing conditions. A majority of the world’s population lives along the coast at the dynamic intersection between terrestrial and marine ecosystems and landscapes. As narrow, low-lying landforms, barriers are especially vulnerable to changes in sea level, storminess, the geographic distribution of grass species, and the rate of sand supply—some barriers will undergo rapid changes in state (e.g., from landward migrating to disintegrating), on human time scales. Attempts by humans to prevent change can hasten the loss of these landforms, threatening their continued existence as well as the recreational, financial and ecosystem service benefits they provide. Understanding the processes and interactions that drive landscape response to climate change and human actions is essential to adaptation. As managers and governments struggle to plan for the future along low-lying coasts worldwide, and scientists conduct research that provides useful guidance, this volume offers a much-needed compilation for these groups, as well as a window into the science of barrier dynamics for anyone who is generally interested in the impacts of a changing world on coastal environments.

Book Holocene Evolution of a Portion of the North Carolina Coast

Download or read book Holocene Evolution of a Portion of the North Carolina Coast written by J. W. Pierce and published by . This book was released on 1971 with total page 2371 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Geology and Origin of Sand Ridges in a Back barrier Estuary Pamlico Sound North Carolina

Download or read book Geology and Origin of Sand Ridges in a Back barrier Estuary Pamlico Sound North Carolina written by Brian K Querry and published by . This book was released on 2018 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Outer Banks of North Carolina have undergone significant geomorphic change, exhibiting varying degrees of barrier island continuity during the late Holocene. These changes affect the environmental conditions (salinity, tidal and wave energy, currents, etc.) in Pamlico Sound, the estuarine system behind the Outer Banks. The modern estuarine system is characterized by minimal tidal energy (tidal range of approximately 10 cm) and limited exchange with the marine environment through three inlets, resulting in the accumulation of organic-rich muds in the Pamlico Sound basin, containing mid- to high- salinity estuarine foraminifera. However, a sand ridge field occurs at approximately 2 to 7 m below sea level in the eastern Pamlico Sound basin, suggesting different hydrodynamic conditions at some time during the Holocene. The sand ridge field extends up to 10 km into the basin, and is oriented perpendicular to the barrier islands. Previous paleoenvironmental work suggests the sand ridges were deposited under high salinity conditions. Defining the mechanism of formation of this sand ridge field will assist in understanding the geological evolution of the region. Six vibracores and 60 km of chirp sub-bottom profiler data have been acquired in order to characterize this system. Two foraminiferal biofacies were identified, High Brackish biofacies A (more diverse) and High Brackish biofacies B (less diverse). To understand the geologic history and origin of this sand ridge field, the cored sediments were analyzed for sedimentology, foraminiferal assemblages, bulk magnetic susceptibility, and geochronology. Chirp seismic data were examined to understand the dimensions and stratigraphy of the sand ridges. Surface samples were collected to understand the modern sedimentology. Vibracores reveal that the sand ridge sediments generally lack mud and have a greater average grain-size farther into Pamlico Sound (i.e., distal to the barrier islands) suggesting that the barrier islands are not the source of the sand. Chirp seismic data delineate a Pleistocene interfluve underlying the sand ridges. Geochronology indicates that sand ridge formation began at approximately 2500 cal yr. BP. There are two intervals at 1000 cal yr. BP and 500 cal yr. BP where an increase in wave and current activity is suggested by seismic horizons. Seismically, the top of the Pleistocene interfluve exhibits two topographic highs that demonstrate the sand ridges are juvenile Class I sand ridges. The sand ridges are interpreted as resulting from the reworking of Pleistocene interfluves during intervals of increased tidal influence and possibly storm activity where winds speeds are 20 mph or greater.

Book The Outer Banks of North Carolina

Download or read book The Outer Banks of North Carolina written by Robert Dolan and published by . This book was released on 1985 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Late Holocene Evolution of a Retrograding Barrier

Download or read book Late Holocene Evolution of a Retrograding Barrier written by Benjamin Adam McGinnis and published by . This book was released on 2004 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Decadal scale Evolution of a Barrier Island

Download or read book Decadal scale Evolution of a Barrier Island written by Ian W. Conery and published by . This book was released on 2014 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt: Eastern North Carolina has over 300 km of barrier islands that comprise the Outer Banks and act as an important buffer from the Atlantic Ocean and boundary to the Albemarle-Pamlico Estuarine System. These islands also draw millions of visitors and dollars to the state every year. With sea-level rise and the persistence of extratropical and tropical storms, it is critical to examine the recent decadal response to storm events and geologic evolution in order to best prepare for future change. In this study, multiple methods were used to evaluate the recent decadal evolution of Ocracoke Island, NC. Shoreline change rates were calculated using a transect-based approach with imagery from 1949, 1974 and 2006. Other aerial imagery time steps were used to look at the spatial impact of historic storms and to select coring and trenching sites based on visible depositional history. The stratigraphic and sedimentological signature of recent and historic storm events was interpreted using seven vibracores and 32 trench excavations. Additionally, LiDAR data was used to assess morphologic change and to test a storm-impact scale based on storm surge, waves and maximum foredune height. The average long-term shoreline change rate for all of Ocracoke Island was determined to be - 0.54 m/yr. The majority of the island has been eroding (over 65% of transects), and the average erosion rate was greatest in the most recent period analyzed (1974-2006). The shoreline change rates highlight the narrowing of the island through time. In some regions island width has decreased by as much as 70% (180 m). Hurricane Isabel (2003) overwashed a total of 9% of the island area with an average thickness of 0.24 m. The storm-impact scale showed a quantitative relationship between overwash and pre-existing dune conditions along the coast. Sedimentation from Isabel represented up to 26% of total backbarrier subaerial volume and was comparable to dune volume loss. Isabel caused up to 40 m of sound-directed migration of the foredune and substantial oceanside erosion, representing more than 20% of long-term net change in some regions of the island. Four other distinct storm deposits were interpreted within the cores based on the sedimentological signatures of moderately to well-sorted fine to medium grained sand, coarse shell hash bases, and heavy mineral laminae. However, few cores had multiple deposits, indicating stacked overwash deposits are spatially and temporally variable. This collection of results shows the complexity of barrier island evolution and the necessity to examine soundward migration in three dimensions.

Book The History of Fort Ocracoke in Pamlico Sound

Download or read book The History of Fort Ocracoke in Pamlico Sound written by Robert Smith and published by History Press Library Editions. This book was released on 2015-03-23 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pamlico Sound is one of the most storied bodies of water among North Carolina's Outer Banks. Early colonists to Roanoke Island used it for protection. Blackbeard the pirate was killed there in 1718, and General Washington relied on it for transportation in the Revolutionary War. It wasn't a surprise, then, that the Confederate bastion of Fort Ocracoke was built in those same waters. Said to be capable of mounting fifty guns, the fort was part of the coastal defense system of the state. After Union victories on nearby Hatteras Island, the fort was destroyed and its whereabouts lost for generations. Author Robert K. Smith led an archaeological mission to find the once lost fort and presents the harrowing story of its past and discovery for the first time.

Book Holocene Evolution of a Nanotidal Brackish Marsh

Download or read book Holocene Evolution of a Nanotidal Brackish Marsh written by Stephen Boyd Benton and published by . This book was released on 1979 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Using Sediment Organic Geochemistry to Interpret Late Holocene Barrier Island and Estuarine Evolution North Carolina USA

Download or read book Using Sediment Organic Geochemistry to Interpret Late Holocene Barrier Island and Estuarine Evolution North Carolina USA written by Jeffrey J. Minnehan and published by . This book was released on 2014 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: Deconvolving the relationship between meteorological and oceanographic phenomena and associated impacts to coastal systems is critical to understanding the future of coastal systems worldwide. North Carolina's barrier islands, commonly known as the Outer Banks, and the associated Albemarle-Pamlico estuarine system is an example of a coastal ecosystem that will be affected in the future by such phenomena. Based on sedimentological and micropaleontological proxies, past research suggests that intense storm activity may have caused extensive segmentation of the Outer Banks during the Holocene. To gain a better understanding of meteorological and oceanographic factors affecting the evolution of North Carolina's coastal system, organic geochemical techniques were applied to sediments from two cores collected within Pamlico Sound. Specifically, down-core trends in total organic carbon (TOC), refractory black carbon (BC), refractory soot carbon, labile organic carbon (OC), total nitrogen (TN), and their stable isotopic signatures ([delta]13C and [delta]15N) were analyzed in order to assess the varying inputs of marine and terrestrial organic matter into Pamlico Sound. In Chapter 1, TOC, BC/TOC, soot/TOC, TOC/TN, and [delta]13C[subscript]TOC were compared to a paleoclimatological proxy of El Niño Southern Oscillation (ENSO) and interpretations of stages of the North Atlantic Oscillation (NAO) throughout the mid-to-late Holocene. These phenomena have been suggested to influence southeast U.S. temperature, precipitation, and Atlantic hurricanes, all of which ultimately affect barrier island and estuarine evolution, as recorded in Pamlico Sound sediments. In general, there has been little consideration of carbon sequestered in coastal systems throughout the Holocene, a period that shows anthropogenic changes in the carbon cycle. This is an important omission, as most of the sediments exported by the world's major rivers are currently deposited on continental shelves (e.g., deltas and estuaries). Chapter 2 examines how the degree of barrier island segmentation affects abundance and source of carbon sequestered in Pamlico Sound throughout the mid-to-late Holocene. Total organic carbon sequestered in Pamlico Sound was calculated over the past 3500 years. Since the ultimate fate of TOC depends on its composition (e.g., whether it is labile or refractory), both OC and BC in sediments were quantified down-core. Results show that greater continuity of a barrier island chain significantly increased the amount of carbon sequestered in sediments. To our knowledge, this chapter provides the first quantitative estimate of the amount of carbon sequestered as a function of its composition since the mid-Holocene in any coastal system. The results of both chapters suggest that ENSO, NAO, eastern North Carolina temperature and precipitation, Atlantic storm activity, Outer Banks barrier island evolution, and coastal carbon sequestration were linked throughout the mid-to-late Holocene.