The Melungeons are a group of indeterminable origin living in the Blue Ridge Mountains of Southeastern Tennessee and Southwestern Virginia. This thesis describes characteristics of these tri-racial isolates and gives theories as to their mysterious origins. Being darker skinned, the Melungeons were pushed into more mountainous regions by European colonists in the early 1700’s. While multiple hypotheses exist as to the origin of the Melungeon people, there is no single theory that is accepted by all scholars. Dr. Brent Kennedy’s The Melungeons: The Resurrection of a Proud People, served as a catalyst for my Melungeon research. Kennedy is my cousin, and his book provided facts behind the family stories I recalled from childhood. It also linked me to other famous Melungeons such as Brandy Jack Mullins and Mahala Mullins. Although there are an abundance of stories and facts about my Melungeon heritage, there is also much history that has been lost. This thesis traces my Melungeon roots, following the family stories of N.B. Kennedy, Brandy Jack Mullins, Mahala Mullins, and Kenneth Kennedy. In order to fully understand these people and their stories, I not only researched their history, but I also visited the areas where they lived and died. In this manner, I was able to gain a better understanding my own family as well as the history of the Melungeons. A person’s past is pieced together through oral history, written records, fading pictures, and personal artifacts. Along with these methods, we as writers and researchers add a bit of our own thought and imagination to fill in the gaps of a person’s life. In this manner, personal mythology is created. This thesis ends with an example of one fictionalized story from my family surrounding the death of my uncle, Kenneth Kennedy.

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Xenolith-bearing orthogneiss of Amazonian affinity discovered in the Dellwood quadrangle in the Blue Ridge basement complex represents the oldest crustal component of the southern Appalachians (1.33 – 1.37 Ga: Quinn, 2012). New U-Pb zircon ages for migmatitic paragneiss of the Cartoogechaye terrane exposed in the Dellwood quadrangle reveal two unique detrital zircon age signatures that indicate either a local eastern Laurentian margin source or an exotic source. Detailed mapping, whole rock geochemistry, and U-Pb zircon geochronology were conducted to determine whether this exotic crustal component extends farther south into the Hazelwood 7.5” quadrangle. Lithological similarities exist between paragneisses in the Dellwood quadrangle and those in the Hazelwood quadrangle. However, the increase in proportion of leucosome and polyphase folding prevent direct correlation of lithologies between the areas. Whole rock major element compositions overlap the composition of basement orthogneisses. Zircon ages of six paragneiss samples reveal multiple detrital zircon age modes that are dominated by two Grenville modes at ~1050 and 1150 Ma. Minor zircon populations exist at ~450 – 480, 700 – 900, and 1300 – 1500 Ma. Age distributions and compositional trends are evidence that the protolith of the paragneiss in the Hazelwood quadrangle was Neoproterozoic rift sediments with a dominant Laurentian margin source.

The Grenville orogeny was a protracted (~200 m.y.) series of “hot” magmatic- metamorphic events that contributed to the growth of the Laurentian margin in the late Mesoproterozoic. The granites contain remarkably high Zr content, lack xenocrysts, and become zircon saturated at high temperatures, which are all unusual for felsic magmas. The “hot Grenville granite” hypothesis is tested and use of high-Zr granitoids as potential zones of crustal magma generation through: U-Pb geochronology and cathodoluminescence imaging to assess inherited zircon components; quantitative modeling of zircon crystallization history using rhyolite-MELTS; and Ti-in-zircon thermometry. U-Pb zircon ages for two samples from the Virginia Blue Ridge are 1168 ± 25 Ma (2209 ppm Zr; Tzr = 1032°C) and 1050 ± 13 Ma (918 ppm Zr; Tzr = 898°C). A sample from the NJ – Hudson Highlands has been dated at 1018 ± 11 Ma (1238 ppm Zr; Tzr = 960°C). These samples produce crystallization histories that range over higher temperatures (983–1060°C) than colder, low-Zr counterparts and contain Ti concentrations of 2 to 86 ppm. This analytical approach will further the understanding of zircon’s utility and limitations as a proxy in granite petrogenesis, and constrain thermal models that produced uncommon lithospheric conditions that led to widespread hot granite production at a unique period in Earth history.

The Cartoogechaye terrane (CT) is an enigmatic migmatite terrane within the Central Blue Ridge province of the southern Appalachians. Previous work identified exotic Pb isotope compositions within the CT (Quinn, 2012). More recent studies that mapped the extent of potentially exotic metaigneous lithologies yield U-Pb zircon ages consistent with a native Laurentian margin metasedimentary origin (Larkin, 2016). This study focused on the possible extent of similar lithologies in the Clyde quadrangle and provides further constraints on the crustal affinity of the CT. The Clyde quadrangle consists of four distinct lithologic packages: the CT, Ashe metamorphic suite, Great Smoky Group, and Grenville basement. Five samples within the Clyde quadrangle and one sample from Wayah Bald quadrangle were collected for detrital zircon (DZ) U-Pb geochronology and whole rock geochemistry for comparison similar anlayses from other bedrock units in the region. Dominant DZ age modes consist of the Grenville doublet (1050 Ma and 1150 Ma) or a modified version of it. Minor age modes exist at ~450 Ma, 600-750 Ma, and 1300-1550 Ma. Zircons for all but one sample display heterogeneous external and internal cathodoluminescence morphologies, consistent with a sedimentary protolith for the paragneisses. Whole rock compositions are consistent with weathering of and derivation from a local basement source. U-Pb age data are most consistent with an eastern Laurentian sedimentary provenance for five samples. The presence of 450-460 Ma grains is most consistent with high-grade Taconian regional metamorphism. The lack of a major Shawinigan age mode and zircon morphology for ca. 980-1050 Ma metamorphic zircons indicate that sample CLY16-1 is a syn-orogenic metasediment within the Grenville basement underlying the CT.

ABSTRACT The Central Blue Ridge sub-province of the southern Appalachian Mountains preserves an unique and complex geologic history. The Cartoogechaye terrane is the westernmost terrane of the Central Blue Ridge sub-province, and is characterized by extensive olistostromal sequences, including mafic-ultramafic massifs, isolated mafic units, and block-in-matrix structures of varying scales. This study investigates the genetic and tectonic relationships, and regional chemical and metamorphic trends of the amphibolitic rocks entrained within units of the Cartoogechaye and nearby terranes, toward constraining the origins of these regional sequences, and examining the rationale for the current Blue Ridge terrane designations. A distinct compositional variation exists between the northern and southern portions of the Cartoogechaye terrane, evident in the mafic rocks of the terrane. The amphibolite blocks and mega-blocks of the Willets-Addie mafic unit, in the northeastern portion of the Cartoogechaye terrane, indicate igneous rock protoliths of a calc-alkaline composition that are different from the mafic-origin amphibolitic massifs of the southwestern Cartoogechaye terrane (Ryan et al., 2005). Amphibolitic blocks of the Tathams Creek/Sylva area, immediately southwest of the Willets-Addie study site, show rare earth element systematics indistinguishable from the more mafic rocks in the Willets-Addie area, albeit with some chemical variation related most likely to variable migmatization of the rocks regionally. Mafic rocks in the adjoining Mars Hill terrane to the northwest show similar chemical trends, even though the Mars Hill terrane is recognized as different from the Cartoogechaye terrane, based on dating results from enclosing granitiods and migmatitic segregations. In the southwestern Cartoogechaye terrane, the Carroll Knob mafic complex preserves chemical signatures suggestive of ocean crustal origins, similar to the Buck Creek mafic-ultramafic suite (Berger et al. 2001, Peterson et al., 2009). However, the amphibolites in the Carroll Knob complex indicate pyroxene-rich cumulate and gabbroic protoliths consistent with an active oceanic magma system undergoing continuous magmatic replenishment and crystallization. West of the Carroll Knob complex, the Kimsey Bald mafic body includes amphibolites with protoliths comparable to the MORB-like, high-Ti amphibolites of the Buck Creek suite. The few amphibolite samples from the Lake Chatuge complex examined in this study also shows ocean crustal affinities, similar to those in the Buck Creek, Kimsey Bald, and Carroll Knob complexes. The chemical distinctions among these amphibolite suites, and the differences in the inferred crustal ages among their enclosing crustal units point to a possible boundary between the northern and southern regions of the Cartoogechaye terrane, one related either to likely crustal protoliths, or to a change in tectonic environment. The varied types of blocks comprising the Tathams Creek and associated Cartoogechaye units may indicate a transitional zone between the upper plate-derived accretionary sequences observed to the northeast and dominantly lower oceanic plate lithologies exposed in the southwestern extent of the terrane.

Identifying the crustal affinity of Grenville basement rocks in the Dellwood quadrangle, western NC, provides insight into the tectonic evolution of eastern Laurentia during Grenville orogenesis. U-Pb zircon geochronology of orthogneiss, augen gneiss, and mafic xenoliths in orthogneiss reveal magmatic pulses at 1130, 1180, and 1330 Ma and metamorphic episodes at 450 and 1040 Ma. Xenoliths in 1330 Ma orthogneiss are as old as 1382 Ma and represent the oldest component of Blue Ridge basement identified to-date. Feldspar Pb isotope values span a range between juvenile-Laurentian and southern-central Appalachian basement/Amazonia. Most Pb isotope data define an array consistent with crustal mixing between Laurentia and Amazonia, however, one xenolith has a unique Pb isotopic composition interpreted as Laurentian crust. Sm-Nd isotope data yield depleted mantle model ages ranging from 1.52 to 1.79 Ga (200 to 650 Ma older than their crystallization ages) indicating a broadly non-juvenile heritage for Dellwood basement. Three biotite gneiss samples contain detrital zircon grains derived from 1060, 1160, 1330, and 1750 Ma sources. Multiple magmatic zircon age populations, variable depleted mantle modelages, and regionally unique isotopic Pb signatures are evidence of protracted Grenville magmatism in the southern Appalachians involving both Laurentian and Amazonian crustal components.

Stream capture is a major driver of the retreat of the Blue Ridge Escarpment, but timescales of capture are not well understood. This study examines stream sediment geochemistry to establish a set of sediment source fingerprints which can be used to identify and date the capture of the Tallulah River. Statistical analyses show significant differences in U, Th, and certain REE enrichment. These differences result from variations in bedrock along the lengths of each river and a shift in relative stream powers after capture to favor mobilization or deposition of heavy elements. The observed differences should be sufficient to identify where Tallulah sediment appears in floodplains of the capturing Tugaloo River, facilitating future dating of the capture event. Understanding the timing of river capture will provide insight into the ongoing reshaping and redistribution of river systems and interactions of geomorphic processes in the continuing evolution of the southern Appalachian Mountains.

Observed stratigraphic variations within the Salem synclinorium in the Valley and Ridge Province of the southern Appalachians are part of a larger basinal setting. The basal conglomerate of the Ordovician Bays Formation is restricted to the limb of the synclinorium reflecting a regional trend of coarser sedimentation nearest the Taconic sediment source. Ordovician/Silurian and Silurian/Devonian unconformities have removed more section from the southern portion of the synclinorium which has been interpreted as evidence of a more landward setting for this area. Previous interpretations of these coarser sediments and unconformities theorized the synclinorium was a unique depositional basin active throughout Paleozoic time. The relationship between veins, fractures, slickensides, oblique-slip faults and thrusts in a riverbed exposure within the southwestern portion of the Salem synclinorium, offers a structural model for the Salem synclinorium. Thrusting induced extensional fractures and veins. Oblique-slip faults which cut the thrusts may have nucleated on these preexisting extensional features. On a larger scale, extensive secondary fracturing between faults may have produced the larger fault zones observed in the synclinorium. Although stratigraphic thickness variations within the synclinorium correspond to observed fold wavelength variations, faulting disrupts many of these folds and distorts the wavelength estimate. Faulting, not folding, is the dominant structural process. Ramp size and horse blocks are theorized to control fold wavelength within the Salem synclinorium. / M.S.

The Late Precambrian cover sequence in the Blue Ridge of central Virginia includes rocks of the Moneta Formation and the overlying Lynchburg Group. The Moneta Formation comprises arnphibolites, felsites and biotite gneisses that unconformably overlie the Grenville basement. The Lynchburg Group in central Virginia is divided into three formations. Lynchburg I is made up of massive to thick bedded coarse-grained feldspathic arenites and conglomerates, which are interpreted as slope-apron deposits. Lynchburg IT contains mainly medium to fine grained feldspathic arenites and graphitic schist (black shales) with subordinate conglomeratic rocks. These are believed to be channelized submarine fan turbidites formed in an anoxic environment. Lynchburg ill consists of fine to medium grained feldspathic quartz arenites and a minor amount of conglomeratic rocks, which are considered to be channelized submarine turbidites with a more open marine environment and wider shelf. Three metamorphic facies and two deformation events are recognized in the cover sequence of the study area. The current tectonic models tend to view most of the mafic-ultramafic rocks and the host sedimentary rocks of the Lynchburg as ophiolitic melange, thus creating a suture, of Precambrian to Ordovician age. Detailed field mapping shows that the Lynchburg Group does not have the characteristics of melange and the mafic-ultramafic rocks in it do not resemble ophiolite. Rather, the cover sequence is related to the Late Precambrian Iapetan rifting event. Some tectonomagmatic discriminant diagrams have been used to support the current tectonic model and they are considered one of the most important arguments for ophiolites. These diagrams were tested by plotting samples from Jurassic rift basalts-diabases of eastern North America (ENA). The ENA samples, as well as the post Grenville mafic rocks in the Blue Ridge, tend to plot outside the within-plate field. It is clear that geochemical data alone may give a wrong tectonic classification, and that a knowledge of field relations is of paramount importance for interpretation. / Ph. D.