Holocene Evolution of a Drowned Tributary Estuary, Croatan Sound, North Carolina PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Holocene Evolution of a Drowned Tributary Estuary, Croatan Sound, North Carolina PDF full book. Access full book title Holocene Evolution of a Drowned Tributary Estuary, Croatan Sound, North Carolina by Greg L. Rudolph. Download full books in PDF and EPUB format.
Author: Greg L. Rudolph
Publisher:
ISBN:
Category : Croatan Sound (N.C.)
Languages : en
Pages : 474
Get Book Here
Book Description
Author: Greg L. Rudolph
Publisher:
ISBN:
Category : Croatan Sound (N.C.)
Languages : en
Pages : 474
Get Book Here
Book Description
Author: Stanley R. Riggs
Publisher:
ISBN:
Category : Coast changes
Languages : en
Pages : 238
Get Book Here
Book Description
Author: Stephen Boyd Benton
Publisher:
ISBN:
Category : Geology
Languages : en
Pages : 352
Get Book Here
Book Description
Author: Joseph T. Kelley
Publisher: Geological Society of America
ISBN: 0813724600
Category : Science
Languages : en
Pages : 190
Get Book Here
Book Description
"Sea level is rising, and yet Americans continue to develop beaches with little regard. In this volume, a group of coastal geologists discusses the startling saga of ten U.S. East and Gulf Coast shoreline communities (plus Puerto Rico and some western Europe strands) and the problems created by their inevitable interaction with natural processes in this highly dynamic geologic environment. The authors discuss the geologic context of the hazards of each site as the history of societal responses and their environmental impacts. Response to the natural coastal processes that threaten lives and buildings is carried out in a context of local, state and national politics with fixed short-term engineering solutions (beach replenishment, seawalls) generally favored over longer-term approaches (moving back, prohibition of seawalls). This essential GSA Special Paper foreshadows the impending rise of sea level and the myriad of shoreline responses and political controversies it will provoke."--Publisher's description.
Author: G. L. Giese
Publisher:
ISBN:
Category : Estuaries
Languages : en
Pages : 124
Get Book Here
Book Description
Tracings: 92.38.
Author: Andrew Lyman Dietsche
Publisher:
ISBN:
Category :
Languages : en
Pages : 152
Get Book Here
Book Description
Northern Core Sound is a shallow lagoonal estuary located behind the Outer Banks barrier islands of eastern North Carolina. Thirty-two vibracores and 155 km of chirp and boomer seismic data have been used to define the geologic framework and establish the Holocene evolution of this back-barrier lagoon. Vibracores have been logged for lithology, and sampled to establish the distribution and abundance of foraminifera. The lithostratigraphy and biofacies could not be directly correlated but when related to the seismic data, apparent patterns could be recognized. The Quaternary stratigraphic framework of North Core Sound consists of five depositional sequences, comprising transgressive, highstand, and falling stage systems tracts. Seismic reflections are prominent and are correlated to the sequence stratigraphic surfaces within Pamlico Sound defined by Mallinson et al. (2010). The late Pleistocene paleotopographic surface dips slightly seaward and is characterized by two or three fluvial channels correlating to modern embayments. These channels are separated by a paleotopographic high that extends from Cedar Island seaward. The channels run northeast in the north and southwest in the south creating two different paleo-environments. The paleotopographic high may have contributed to differing foraminiferal assemblages found within Holocene unit. The Holocene unit is characterized by high salinity estuarine deposits dominated by the foraminifera Elphidium excavatum and Ammonia parkinsoniana. Three very similar biofacies were defined with more abundant Ammonia parkinsoniana where salinities may have been slightly lower. Only a salt marsh facies was significantly different. The biofacies may also represent the two paleo-environments illustrated in the seismic data as one is mainly found to the north of the paleotopographic high and the other to the south. Two seismic reflections, H30 and H60, are interpreted as tidal ravinement surfaces and divide the Holocene into three parasequences. Lithologically the units are coarsening upward, which may be a result of the transgressing barrier island (Core Banks) or increased tidal energy related to inlet activity. Radiocarbon age estimates place the lower surface, H30, older than 600 cal y BP, suggesting that this erosional surface is related to the segmentation of the Outer Banks during the Medieval Warm Period or the Little Ice Age, as defined by other workers.
Author: G. L. Giese
Publisher:
ISBN:
Category : Hydrology
Languages : en
Pages : 202
Get Book Here
Book Description
Author: Kelli Moran
Publisher:
ISBN:
Category : Currituck Sound (N.C.)
Languages : en
Pages : 102
Get Book Here
Book Description
Coastal evolution is an increasingly important area of study, especially with the projected rise in sea level, increase in storm intensity, and population increases along the nation's coasts. In order to predict how the coastal environment will respond to these changes in the future, we need to first understand the evolution of coastal systems in the past. Here I address the late Holocene evolution of Currituck Sound, North Carolina, by examining time periods with different barrier island and inlet configurations interpreted from core data. Chirp seismic data and 13 vibracores have been used to interpret the Holocene development of this region. Four depositional units have been defined, based on lithofacies, biofacies, geophysical, and geochronologic data. The lowermost depositional unit (Unit I) is represented by quartz sand, barren of foraminifera, and is Pleistocene in age based on an OSL age estimate of 33.7 ka. Unit II consists of slightly muddy sand that fines upward to slightly sandy mud; it is barren of foraminifera, contains rooted horizons in several cores, and is interpreted as a fresh water swamp forest deposit (radiocarbon dating provide age estimates of ca. 4000 to 2800 cal y BP). Unit III is characterized by slightly sandy mud to mud containing a calcareous foraminiferal assemblage and oyster bioherms; these characteristics indicate a back-barrier estuarine environment with high salinity (ca. 25 to 35) due to open inlets in the barrier islands to the east. Radiocarbon age estimates for Unit IV range from ca. 1700 to 500 cal y BP. The topmost unit (Unit IV) is composed of sediment with variable composition, ranging from clean quartz sand to mud, and contains foraminiferal assemblages that are generally mixed calcareous/agglutinated at the base overlain by entirely agglutinated assemblages. This unit represents the modern (post- ca. 1827), mid- to low salinity (less than 10), back-barrier lagoon with no inlets open in the barrier island. Sediment and microfossil-based paleoenvironmental and geomorphic reconstructions, including variable numbers of inlets, have been used as input into the Delft3D hydrodynamic model to understand inlet related changes to tides and currents within the Sound. This modeling indicates that impacts of inlets are very localized and only inlets in the direct vicinity of Currituck Sound (i.e., between historic Caffey's Inlet and Kill Devil Hills) have a significant impact on the water levels and currents in the study area.
Author: Jeffrey J. Minnehan
Publisher:
ISBN:
Category : Albemarle Sound (N.C.)
Languages : en
Pages : 136
Get Book Here
Book Description
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.
Author: Caroline Faulkner Smith
Publisher:
ISBN:
Category :
Languages : en
Pages : 124
Get Book Here
Book Description
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.
