• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 4
  • 2
  • 1
  • Tagged with
  • 9
  • 9
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Spatial and Temporal Landslide Distribution and Hazard Evaluation Analyzed by Photogeologic Mapping and Relative-Dating Techniques, Salt River Range, Wyoming

Rice, John B., Jr. 01 May 1987 (has links)
The distribution of landslide type and age was analyzed to determine the causes and timing of landsliding, and to assess landslide hazards in the study area. 1173 landslides and zones of landsliding were mapped on 1:15,840 scale air photos and designated by their style of movement and age. Slides were assigned to one of four age classes based on their degree of m orphologic modification visible on air photos. Relative dating (RD) methods previously applied to glacial deposits were used to refine and calibrate the age classification. Eleven RD para meters were measured on 21 rockslide and 19 glacial deposits. Cluster analyses were run on the RD data set. Slides assigned to Age-Classes 4, 3+, and 2 tend to cluster with probable Pinedale, early Holocene, and Neoglacial-age moraines respectively. Cluster analyses indicate poor age resolution by the RD method from approximately early Altithermal to early Neoglacial time. Landslide age cannot be resolved in this study to a finer degree by the RD method than by the morphologic (air -photo) method. However, cluster analyses generally confirm age assignments and absolute age estimates of the four landslide age classes, despite limitations of the RD method such as boulder spalling, and variations in lithology, deposit type, and elevation/climate between sampled deposits. The temporal distribution of landslides indicates that mass movements may have occurred rather uniformly throughout Holocene time, with slightly higher rates of sliding during post-Altithermal time due to climatic effects associated with Neoglacial advances. Spatial analyses indicate that landslides cover 73% of the Cretaceous section. Development, such as logging and road construction, could trigger landsliding in the Cretaceous section. Landslides account for 15% and 10% of the outcrop areas of the Paleozoic and Triassic-Jurassic sections respectively. Debris flows and slump-earth flows dominate sliding in both sections, with minor numbers of rockslides present. Debris flows pose the greatest hazard in both sections. Fine-grained stratigraphic units have the highest landslide densities in both sections. The previous event locations define areas most susceptible to future sliding.
2

Timber Circles, Henge Monuments and Stone Circles: A reassessment of the currently accepted chronologies.

Williamson, Richard A. January 2012 (has links)
The sequence of timber circle - henge monument - stone circle is widely accepted. This is in spite of the reality that the datable evidence and contextual data upon which this series is based has seldom been subjected to any real form of critical evaluation. The aim of this research was to determine whether this order could still be deemed tenable in light of contemporary research and the continued advances that have been achieved relating to the application of radiocarbon dating. The findings of this study demonstrated that sufficient contextual data exists to enable phases of construction to be identified. However rarely did these data appear to support the currently accepted chronologies. Indeed more commonly they alluded to an alternative series, one that demonstrated how some individual site sequences may have been previously misinterpreted. This study has also proven how methodological and interpretative weaknesses, relating to the use of radiocarbon dating, have created a quantifiable degree of accuracy between individual radiocarbon determinations and their ability to be reliably associated with the event or act that they have been used to date. These findings have not only cast sufficient doubt upon the reliability of the currently accepted chronologies for these three monumental forms but have also alluded to the existence of a far more appropriate sequence that conforms to the overall conclusions of this review far more convincingly. Accordingly a new series of timber circle(s) - stone circle - henge monument is proposed by this study.
3

As gravuras rupestres da bacia do baixo rio Urubu: levantamento e análise gráfica do sítio Caretas, Itacoatiara - Estado do Amazonas. Uma proposta de contextualização / The rock art of Lower Urubu River: survey and graphic analysis of Caretas site, Itacoatiara - Amazonas. A contextual approach.

Cavallini, Marta Sara 16 July 2014 (has links)
Este trabalho apresenta os resultados de uma pesquisa voltada à contextualização arqueológica do fenômeno da confecção das gravuras rupestres pré-coloniais na bacia do baixo rio Urubu (Estado do Amazonas). Com o objetivo de caracterizar o registro rupestre regional, foi desenvolvida uma pesquisa intensiva no sítio AM-IT-31 Caretas, portador da maior densidade e variabilidade formal de arte rupestre da área de estudo. O sítio foi abordado a partir do controle espacial dos petróglifos e dos demais vestígios arqueológicos. Sua documentação foi realizada de forma integral e sistemática e foi organizada em um banco de dados relacional, possibilitando a articulação entre diferentes classes de evidências. Para caracterizar a arte rupestre do ponto de vista de sua inserção na paisagem arqueológica, foi investigada a relação crono-cultural com o sítio cerâmico em matriz de terra preta AM-IT-30 Pedra Chata, espacialmente associado. A cronologia das gravuras foi relacionada à dinâmica de sedimentação fluvial; com três datações foi estabelecida a idade mínima dos petróglifos e foi proposto um modelo paleoambiental hipotético para inferir sua antiguidade máxima. Os resultados, embora preliminares, atribuem a formação do sítio ao Holoceno Recente, no âmbito das ocupações ceramistas da região. A análise do registro gráfico tem evidenciado elementos de homogeneidade, tanto no tema como também na apresentação gráfica dos petróglifos, que remetem a uma substancial coerência interna, apesar da variabilidade formal. / This thesis presents the results of research seeking to archaeologically contextualize the precolonial production of engraved rock art in the Lower Urubu River drainage (Amazonas State, Brazil). With the objective of characterizing the rock art of this region, I carried out an intensive research project at the site AM-IT-31 Caretas, which has the highest density and formal variability of rock art in the entire area. Spatial control of both the petroglyphs and other archaeological remains at the site was established to permit their complete and systematic documentation. The records were organized in a relational database, allowing for the analysis of the relationships between different sets of evidence. In order to characterize the placement of rock art within the archaeological landscape, I studied its chronological and cultural relationships with the adjoining archaeological site AM-IT-30 Pedra Chata where ceramics occur in a matrix of \"dark earth\". The chronology of the engravings has been correlated to the fluvial dynamics. Thanks to three dates a minimum age has been proposed for the petroglyphs and a paleoenviromental model suggests their maximum age. Preliminary results point to site formation during the late Holocene in synchrony with ceramic period occupations. The analysis of petroglyphs indicates some homogeneity in regard to themes and graphic representation. This suggest a internal consistency in design despite some formal variability.
4

New insights into old problems : the application of a multidisciplinary approach to the study of early Egyptian ceramic chronology, with a focus on luminescence dating

Hood, Amber Giles Eve January 2016 (has links)
This thesis takes a multidisciplinary approach to the study of ancient Egyptian ceramics by applying scientific dating techniques alongside more traditional methods. It is the first study to apply OSL dating to an Egyptian ceramic assemblage, and it has done so by developing the minimum extraction technique (MET), which has made it possible to use OSL to sample, and thus analyse, ceramics housed in museums. The MET is at present essential to the success of OSL dating of Egyptian ceramics, as the exportation ban on antiquities has prevented OSL analysis of field material. For this thesis, using this new sampling technique, OSL has been applied to several assemblages from the Predynastic to the Early Dynastic period. Ceramics from [ADD IN REVIEW ] have been examined, with three phases being established: late Naqada III, First Intermediate Period, and the mediaeval Islamic period. Absolute dates have been determined for each phase and, where comparison is possible, have been found in good agreement with the historical chronology. A set of vessels from Naqada, Ballas, and the Tomb of Djer at Abydos have been examined using OSL in conjunction with radiocarbon dating. Again, three phases of activity were discerned: late Naqada II, early Naqada III, and the first scientifically determined dates for a burning event in the Tomb of Djer (the New Kingdom). The thesis also demonstrates how OSL can be used as a relative dating technique by analysing a collection of Wavy-Handled ceramics and wine jars from Turah, finding that the OSL results agree well with the established relative chronology. Finally, this thesis has also examined the applicability of cladistic analysis to the study of Egyptian ceramics. Cladistics is a technique borrowed from the biological sciences which offers a complimentary way to examine the evolution of ceramic types and forms, in particular the development of beer and wine jars.
5

Systematics in Sileneae (Caryophyllaceae) – Taxonomy and Phylogenetic patterns

Eggens, Frida January 2006 (has links)
The focus for the first part of the thesis is on the systematics of species belonging to Silene subgenus Silene. Phylogenetic relationships are inferred from DNA sequences from both the plastid (the rps16 intron) and the nuclear (ITS, intron of the RPB2 gene) genomes. Silene section Rigidulae is shown to be non-monophyletic in its previous circumscription, but instead consisting of six separate clades, each correlated to the geographical distribution of the included species. The taxonomic consequences for each clade are discussed. One of the clades is recognized as a new section and described as Silene sect. Arenosae sect. nov. The morphological descriptions of the species are formalized using a novel implementation of the Prometheus Description Model. Two proposals are included in the thesis, one to reject the name Silene polyphylla L., which is a senior synonym to S. portensis L. Silene linearis Decne. is proposed for conservation against the rarely used S. linearis Sweet. Silene antirrhina, a weedy American annual, is strongly supported as sister to the Hawaiian endemic species of Silene, suggesting an American origin for these. Two of the endemics have evolved woodiness after introduction to Hawaii. In the second part of the thesis we use four nuclear DNA regions, (introns from RPA2, RPB2, RPD2a, RPD2b), and the chloroplast psbE-petG spacer. A framework is developed to evaluate different phylogenetic explanations for conflicting gene trees, where divergence times are used to discriminate among inter- and intralineage processes. The incongruences observed regarding the relationships among the three major lineages of Heliosperma are best explained by homoploid hybridization. The pattern regarding the origin of Heliosperma itself is more complicated and is likely to include several reticulate events. Two lineages have probably been involved in the origin of Heliosperma, one leading to Viscaria and Atocion and the other to Eudianthe and/or Petrocoptis.
6

As gravuras rupestres da bacia do baixo rio Urubu: levantamento e análise gráfica do sítio Caretas, Itacoatiara - Estado do Amazonas. Uma proposta de contextualização / The rock art of Lower Urubu River: survey and graphic analysis of Caretas site, Itacoatiara - Amazonas. A contextual approach.

Marta Sara Cavallini 16 July 2014 (has links)
Este trabalho apresenta os resultados de uma pesquisa voltada à contextualização arqueológica do fenômeno da confecção das gravuras rupestres pré-coloniais na bacia do baixo rio Urubu (Estado do Amazonas). Com o objetivo de caracterizar o registro rupestre regional, foi desenvolvida uma pesquisa intensiva no sítio AM-IT-31 Caretas, portador da maior densidade e variabilidade formal de arte rupestre da área de estudo. O sítio foi abordado a partir do controle espacial dos petróglifos e dos demais vestígios arqueológicos. Sua documentação foi realizada de forma integral e sistemática e foi organizada em um banco de dados relacional, possibilitando a articulação entre diferentes classes de evidências. Para caracterizar a arte rupestre do ponto de vista de sua inserção na paisagem arqueológica, foi investigada a relação crono-cultural com o sítio cerâmico em matriz de terra preta AM-IT-30 Pedra Chata, espacialmente associado. A cronologia das gravuras foi relacionada à dinâmica de sedimentação fluvial; com três datações foi estabelecida a idade mínima dos petróglifos e foi proposto um modelo paleoambiental hipotético para inferir sua antiguidade máxima. Os resultados, embora preliminares, atribuem a formação do sítio ao Holoceno Recente, no âmbito das ocupações ceramistas da região. A análise do registro gráfico tem evidenciado elementos de homogeneidade, tanto no tema como também na apresentação gráfica dos petróglifos, que remetem a uma substancial coerência interna, apesar da variabilidade formal. / This thesis presents the results of research seeking to archaeologically contextualize the precolonial production of engraved rock art in the Lower Urubu River drainage (Amazonas State, Brazil). With the objective of characterizing the rock art of this region, I carried out an intensive research project at the site AM-IT-31 Caretas, which has the highest density and formal variability of rock art in the entire area. Spatial control of both the petroglyphs and other archaeological remains at the site was established to permit their complete and systematic documentation. The records were organized in a relational database, allowing for the analysis of the relationships between different sets of evidence. In order to characterize the placement of rock art within the archaeological landscape, I studied its chronological and cultural relationships with the adjoining archaeological site AM-IT-30 Pedra Chata where ceramics occur in a matrix of \"dark earth\". The chronology of the engravings has been correlated to the fluvial dynamics. Thanks to three dates a minimum age has been proposed for the petroglyphs and a paleoenviromental model suggests their maximum age. Preliminary results point to site formation during the late Holocene in synchrony with ceramic period occupations. The analysis of petroglyphs indicates some homogeneity in regard to themes and graphic representation. This suggest a internal consistency in design despite some formal variability.
7

Phylogenetic Relationships of Silene sect. Melandrium and Allied Taxa (Caryophyllaceae), as Deduced from Multiple Gene Trees

Rautenberg, Anja January 2009 (has links)
This thesis focuses on phylogenetic relationships among some of the major lineages in Silene subgenus Behenantha (Caryophyllaceae) using DNA sequences from multiple, potentially unlinked gene regions from a large taxonomic and geographic sample. Both traditional phylogenetic analyses and a strategy to infer species trees and gene trees in a joint approach are used. A new strategy to optimize species classifications, based on the likelihoods of the observed gene trees, is presented. Silene latifolia, S. dioica and the other dioecious species previously classified in section Elisanthe are not closely related to the type of the section (S. noctiflora). The correct name for the group of dioecious species is section Melandrium. The chloroplast DNA data presented indicate a geographic, rather than a taxonomic, structure in section Melandrium. The nuclear genes investigated correlate more to the current taxonomy, although hybridization has likely been influencing the relationships within section Melandrium. Incongruence between different parts of the gene SlXY1 in two Silene lineages is investigated, using phylogenetic methods and a novel probabilistic, multiple primer-pair PCR approach. The incongruence is best explained by ancient hybridization and recombination events. A survey of mitochondrial substitution rate variation in Sileneae is presented. Silene section Conoimorpha, S. noctiflora and the closely related S. turkestanica have elevated synonymous substitution rates in the mitochondrial genes investigated. Morphological and phylogenetic data reject that the Californian S. multinervia should be treated as a synonym to the Asian S. coniflora, as has previously been suggested. Furthermore, none of the genes investigated, or a chromosome count, support the inclusion of S. multinervia in section Conoimorpha. Data from multiple genes suggest that S. noctiflora and S. turkestanica form a sister group to section Conoimorpha. The calyx nervature, which is a potential synapomorphy for S. multinervia and section Conoimorpha, may be explained either by parallelism or by sorting effects.
8

Taxonomy and Reticulate Phylogeny of Heliosperma and Related Genera (Sileneae, Caryophyllaceae)

Frajman, Božo January 2007 (has links)
Heliosperma (nom. cons prop.) comprises 15—20 taxa, most of them endemic to the Balkan Peninsula. DNA sequences from the chloroplast (rps16 intron, psbE-petG spacer) and the nuclear genome (ITS and four putatively unlinked RNA polymerase genes) are used to elucidate phylogenetic relationships within Heliosperma, and its position within Sileneae. Three main lineages are found within Heliosperma: Heliosperma alpestre, H. macranthum and the H. pusillum-clade. The relationships among the lineages differ between the plastid and the nuclear trees. Relative dates are used to discriminate among inter- and intralineage processes causing such incongruences, and ancient homoploid hybridisation is the most likely explanation. The chloroplast data strongly support two, geographically correlated clades in the H. pusillum-group, whereas the relationships appear poorly resolved by the ITS data, when analysed under a phylogenetic tree model. However, a network analysis finds a geographic structuring similar to that in the chloroplast data. Ancient vicariant divergence followed by hybridisation events best explains the observed pattern. The morphological and taxonomical diversity in the H. pusillum-group is possibly ecology-induced, and is not correlated with the molecular data. Phylogenetic patterns regarding the origin of Heliosperma are complicated, probably influenced by reticulate and sorting events. At least two ancient lineages have been involved in its evolution, one most closely related to Viscaria/Atocion and the other to Eudianthe/Petrocoptis. Atocion and Viscaria are sister genera, most species-rich on the Balkans, and including six/three species. Phylogenies do not support their traditional classification, and provide a framework for a taxonomic revision. Atocion compactum is found in three different positions in the chloroplast tree, and in a single clade in the nuclear gene trees. Using relative dates we demonstrate that hybridisation with subsequent chloroplast capture is a feasible explanation for the pattern observed. This, and other observed reticulate patterns, highlights the importance of hybridisation in plant evolution.
9

Zur pedologischen Relativdatierung glazialgeomorphologischer Befunde aus dem Dhaulagiri- und Annapurna-Himalaja im Einzugsgebiet des Kali Gandaki (Zentral-Nepal) / Pedological relative dating of glaciogeomorphological features from the Dhaulagiri and Annapurna Himalaya along the catchment of the Kali Gandaki (central Nepal)

Wagner, Markus 07 February 2007 (has links)
No description available.

Page generated in 0.1023 seconds