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  • 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

Geological And Morphological Investigations Of The Underground Cities Of Cappadocia Using Gis

Ayhan, Arda 01 December 2004 (has links) (PDF)
The purpose of this study is to investigate the effect of rock types and morphologic classes on the locations of underground cities existing in Cappadocia. To achieve this purpose four databases are created that contain related information of underground cities, present settlements, rock types and morphologic classes. Four main analyses are carried out using the data created fort the study. These analyses are: 1) Distance analysis to determine the distances between underground cities and present settlements, 2) Density analysis to inspect the areas where the underground cities are concentrated, 3) Distribution analysis to explore the spatial distribution of underground cities within the rock types and morphologic classes, and 4) Neighbourhood analysis to examine whether the underground cities within rock types and morphologic classes are located along or far inside the marginsof the polygons. The conclusions reached after the analyses are as follows: 1) The mean distance between two underground cities is about 4 km. 2) The mean distance between an underground city and the nearest present settlement is about 700 m. 3) Underground cities are concentrated in Derinkuyu-NevSehir-&Ouml / zkonak belt. Present settlements, on the other hand, are concentrated along Aksaray-Ortak&ouml / y-HacibektaS. 4) For the underground cities, pyroclastic dominant Neogene sequences are preferred whereas all other units are avoided. 5) In terms of morphology, the class defined as &ldquo / mesa&rdquo / is strongly preferred for underground cities. 6) Neither lithology nor morphology played a role in the site selection for present settlements. 7) Both for rock types and morphologic classes the underground cities are located along margins of the polygons.
2

Influence of bench geometries on rockfall behaviour in open pit mines

Musakale, Franklin Buana 16 November 2006 (has links)
Faculty of Engineering and Built Enviroment School of Mining Engineering 0315711f musakale@egoli.min.wits.ac.za / Rockfalls are a significant risk in open pit mines. Once movement of a rock perched on the top of a slope (bench) has been initiated, the most important factor controlling its fall trajectory is the geometry of the slope (bench). The best possible knowledge of rockfall trajectories and energies is important in order to determine accurate risk zoning and for the design and construction of adequate defence systems near the threatened areas. This study attempts to determine the influence of bench geometries, and the coefficient of restitution of rock, on rockfall behaviour. A study of literature was carried out to review previous studies and other relevant information on rockfalls and their analysis. The literature may be divided into two categories: experimental methods involving physical modelling, and computer models involving rockfall analyses using computers analysis methods. Rockfall computer simulation is considered to be applicable, quick to carry out and reproducible. The accuracy of the results depends on the knowledge of site conditions and slope geometry. The use of the Modified Ritchie criterion for the design of catch benches in open pit mines was also investigated. The assessment of bounce height, maximum run-out distance and kinetic energy achieved during the fall of rocks on the catch bench were the bases of the evaluation of the results obtained in this project. The computer program, Rocfall Version 4, was used for the purposes of the research. The following parameter variables were considered in the analyses: three types of rock; slopes with three stack configurations; four bench heights; and four bench face angles. The results show that, for all stack configurations and rock types, the maximum runout distance and maximum bounce height increase as functions of bench height at a specific bench face angle. A single bench configuration provides a maximum run-out distance of falling rocks larger than the value determined using the Modified Ritchie criterion for all rock types and bench face angles. Multiple bench stack configurations provide maximum run-out distances less than the value determined using the Modified Ritchie criterion only for the 90o bench face angle in all rock types; those with 60o, 70o and 80o bench face angle provide a larger maximum run-out distance. Therefore, the validity of the Modified Ritchie criterion for the design of catch bench widths in open pit mines with inclined benches must be questioned. According to Ritchie’s study (1963), rocks that fall in trajectory (free fall) seldom give high bounces after impact on a catch bench. This project shows that this finding is valid for rocks with low coefficients of normal restitution. Rocks with lower coefficients of normal restitution provide larger run-out distances with flatter bench face angles compared with rocks with higher coefficients. In contrast, rocks with higher coefficients provide larger run-out distances than those with lower coefficients for steeper angles. The consideration of the influence of geometry (shape) of falling rocks on rockfall behaviour showed that, for a flatter slope, as could logically be expected, the maximum run-out distance is greatest for rounder rocks and smallest for flatter slabby iv rocks. This is due to the fact that on a flatter slope, the mode of falling of rounder rocks is rolling down the slope. This mode provides essentially no resistance to motion, resulting in largest maximum run-out distance. In contrast, for long flat slabs, the mode of movement will be sliding, which results in a smaller maximum run-out distance. The maximum run-out distance as function of rock shape reduces as the normal coefficient of restitution increases. For all rock types, the maximum bounce height reduces as a function of the friction angle for flatter slopes. This is due to the fact that rocks are in contact with the slope during the rockfall. As the coefficient of normal restitution increases, an increase in the maximum bounce height results.
3

An Analysis Of The Relationship Between Settlements, Water Resources And Rock Types In Cankiri Province

Bayraktaroglu, Cuneyt 01 May 2005 (has links) (PDF)
This study introduces an approach that seeks a possible relationship between settlement locations, water resources and rock types. The method is applied to &Ccedil / ankiri province (central-north Anatolia) which covers approximately an area of 8380 km2. Three main data sets used in this study. These are settlement, water and rock type data.The methodology of the study is composed of five steps. The first step is the conversion of all water data into a standardized point data. Total number of point data for water is 23911 after this step. The second step is to find the distances between water resources and settlements. In the third step the densities of water resources and settlements are derived and then tested for the rock types in particular areas. The fourth step is the overlay analysis in which all three data sets are combined to find preferred and avoided regions of settlements in relation to water resources and rock types. In the last step all analyses are integrated to extract information on effect of two parameters on the selection of a site. The main conclusions derived from the analysis are that: a) the mean and median distances between settlements and water resources are, 285 m and 163 m respectively, b) there is a strong relationship between water resources and settlement area, c) old clastics is the mostly preferred rock type whereas the carbonate rocks are mostly avoided.
4

A STATISTICAL APPROACH FOR IDENTIFICATION OF CHEMICAL GROUPINGS OF ELEMENTS IN SWEDISH ROCKS WITH SPECIAL FOCUS ON ARSENIC AND SULPHUR

Frank, Erika January 2021 (has links)
Groundwater analyses have revealed high concentrations of the toxic element arsenic around Stockholm and Mälardalen, a problem that often is linked to high levels of arsenic in the bedrock and which could be escalated by the many construction projects in the same region. However, it is unknown what part of the bedrock is causing the contamination. The aim of this thesis is to identify the chemical elements that associate with arsenic and study how the rock types differ in their content of elements and compounds. The highest median concentration of arsenic is found in quartz-feltspar-rich sedimentary rock, while intrusive rock types reveal the lowest levels. Using cluster analysis, arsenic is placed in a group including nine other elements, to which the strongest correlations are found with antimony, bismuth and silver. A moderate correlation with sulphur is also observed. The associations between groupings of elements are analysed using measures of dependence, which reveal relatively strong associations. Dimension reduction and ordination techniques provide further insight to the typical appearances of elements and reveal two groups of similar rock types.
5

Banda Forearc Metamorphic Rocks Accreted to the Australian Continental Margin: Detailed Analysis of the Lolotoi Complex of East Timor

Standley, Carl Eldon 29 January 2007 (has links) (PDF)
Petrologic, structural and age investigations of the Lolotoi Complex of East Timor indicate that it is part of a group of thin metamorphic klippen found throughout the region that were detached from the Banda forearc and accreted to the NW Australian continental margin during Late Miocene to Present arc-continent collision. Metamorphic rock types are dominated by (in order of greatest to least abundance), greenschist, graphitic phyllite, quartz-mica schist, amphibolite and pelitic schist. Mineral, whole rock, and trace element geochemical analyses of metabasites indicate that protolith compositions are consistent with tholeiitic basalt and basaltic andesite with mixed MORB and oceanic arc affinities. Metapelitic schist compositions are consistent with mafic to intermediate oceanic to continental arc provenance. Geothermobarometric calculations show peak metamorphic temperatures in pelitic rocks range from 530°C to 610°C for garnet-biotite pairs and peak pressures of 5 to 8 kbar for garnet-aluminosilicate-quartz-plagioclase assemblages. Analyses of amphibole in amphibolites yield temperatures of 550°C to 650°C and pressures of 6 to 7 kbar. Lu-Hf analyses performed on garnet samples from two massifs in East Timor yielded four ages with a mean of 45.36 ± 0.63 Ma, which is interpreted to represent the approximate age of peak metamorphism. Detrital zircons from one amphibolite sample in East Timor yields a bimodal U-Pb age distribution of 560 Ma and 80 Ma, indicating deposition occurred after the 80 Ma closure of the zircon grains. The sequence of deformation as indicated by field measurements is similar to that reported from other klippen throughout the Timor region. Contact relationships with adjacent units indicate that the metamorphic terrane is in thrust contact with underlying Gondwana Sequence rocks. Overlying the metamorphic rocks are Asian affinity volcanic and sedimentary cover units found mostly in normal fault contact on the edges of Lolotoi Complex klippen. Geochemical, age, petrological and structural data imply the Lolotoi Complex formed part of the eastern Great Indonesian arc, which began to collapse in the Eocene, was incorporated into the Banda arc in the Miocene, and accreted to the Austrailian continental margin from Pliocene to Present.

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