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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

Spatial analysis of soil depth variability and pedogenesis along toposequences in the Troodos Mountains, Cyprus

Robins, Colin R. 17 August 2004 (has links)
In unstable landscapes, modern pedological research explores the role of soils as products and indicators of geomorphologic change. Understanding the dynamics of hill slope pedogenesis is especially important in regions with limited, poor, or threatened soil resources. The island of Cyprus, situated in the eastern Mediterranean, is claimed by many authors to exhibit signs of severe soil degradation and is a prime site for comparative soil geomorphologic research. This study strove to 1) identify the controls of soil genesis and landscape stability within the Troodos Mountains of Cyprus using image and GIS analysis; 2) compare toposequence data to expected soil thickness trends from traditional models of xeric soil toposequences prevalent in current scientific literature; and 3) develop a predictive model for hillslope pedogenesis based on measured soil properties within the field area. Study soils within the Troodos are thin, weakly developed Lithic and Typic Xerorthents formed in colluvium derived from fractured, igneous bedrock. Soil thickness was measured at 368 sites in seven transects across three watersheds in the Troodos, using interpretations of field profiles and image analysis of digital soil-bedrock profiles in photographed road-cuts along forestry paths. Soil thickness was compared through GIS and statistical analysis to landscape attributes derived from a 25-m DEM and other map data. Results indicate that lithology is the only factor of several studied to have a significant relationship with the variability of soil-profile thickness in the Troodos, and that soil thickness does not vary in a predictable manner across toposequences. These results, combined with differences between measured soil data and values predicted by the landscape stability model SHALSTAB, suggest that soil genesis in the Troodos is best described only within the context of a weathering-limited geomorphological system. Short-term disruptive processes such as forest fires, land sliding, tree throw, and raindrop impact, combined with long-term processes such as tectonic uplift and stream incision, are the most likely driving forces behind the rapid erosion of hill slope sediments and the weak development of Troodos hill slope soils. These findings have important implications for DEM-based, predictive soil mapping in weathering-limited geomorphologic systems. / Graduation date: 2005
2

Quaternary marine terraces on Cyprus : constraints on uplift and pedogenesis, and the geoarchaeology of Palaipafos

Zomeni, Zomenia 12 June 2012 (has links)
Numerous flights of Quaternary marine terraces are present around the island of Cyprus, in the Eastern Mediterranean. These terraces are a result of the global eustatic sea-level curve and local tectonism. Marine Isotope Stage (MIS) 5 through MIS 13 terraces are identified, mapped and dated. Palaeoshoreline elevation, an excellent indicator for a past sea–level, and new numerical geochronology are used to calculate an Upper Pleistocene uplift rate for various coastal sectors. Southwestern Cyprus presents the highest uplift rates of 0.35-0.65 mm/year with other sections suggesting uplift of 0.07-0.15 mm/year. This Upper Pleistocene tectonic signal is attributed to an active offshore subduction/collision system to the southwest of Cyprus, evidenced from the seismic activity offshore and the surface expression of a blind thrust fault in the Pafos region. Soil chronosequences and geology in southwestern Cyprus are studied in order to understand the Quaternary development on this uplifting landscape. Soil profile properties are used to calculate a profile development index (PDI), a method often applied to geomorphic surfaces as a relative dating method. Well-developed red and clayey soils occur in the coastal sector, on broad and low-angle surfaces, specifically on marine terraces and alluvial fans. Higher elevations of steep slopes consisting of carbonate and ophiolite lithologies host poorly developed soils. Results show variable PDI's on uplifted terraces, obscured by transported materials, active alluvial fan buildup and hillslope erosion. Calcium carbonate build-up in soil profiles in the form of nodular and laminar accumulations are used as another relative dating method. Geochronology of marine terraces is used as an age range approximation for carbonate stages. Geomorphologic mapping focuses on the southeastern part of the Pafos thrust fault, the only point on the landscape where this otherwise blind fault is exposed on the surface. This is the location of Palaipafos, an important Ancient polity, today the site of the village of Kouklia. Geoarchaeological study suggests little landscape change over the last 4000 years in the vicinity of the urban core of Palaipafos, this being attributed to bedrock and landscape resistance of its location, a plateau at 80 m amsl. Copper deposits in the Palaipafos hinterland had provided a valuable resource at one time. Soil and water resources continue to sustain agriculture.Tectonic uplift in this part of the Pafos thrust fault is estimated to be 2.1mm/year, considered, together with Late Holocene sea-level change responsible for the shifting locations and eventual abandonment of the Palaipafos harbor in the coastal lowlands. / Graduation date: 2013

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