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1
Dominy, Simon C. "The geology of the china clay deposits of Southwest England with particular reference to their chemical properties." Thesis, Kingston University, 1993. http://eprints.kingston.ac.uk/20351/.
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The geology and commercial properties of china clay deposits in Cornwall and Devon have been investigated in the field and by laboratory methods. Two deposits were studied, the Lower Bostraze pit on Land's End and the larger Lee Moor pit on southwest Dartmoor. These china clay deposits are hosted in biotite monzogranites which have been subject to a history of hydrothermal alteration. SEM and XRD studies show that extreme argillic alteration is characterised by total destruction of the feldspars which are replaced by a fine-grained assemblage dominated by kaolinite and secondary mica. Partial alteration leads to assemblages of secondary mica, smectite and kaolinite. Pervasive alteration leads to a reduction of bulk rock density as a result of the leaching of alkali-metals and silica from the system. Kaolinite forms euhedral to anhedral platelets with larger booklet or vermiform stacks. TEM work has revealed that the kaolinite populations are composed of a mixture of euhedral and anhedral crystallites, a low disorder clay will be composed of euhedral crystallites with a subordinate number of anhedral kaolinites. The stack and booklet forms are common at higher structural levels within the deposits and are probably formed under supergene conditions. Fluid inclusion studies indicate a complex pattern of fluid/rock interaction. Inclusion abundances provide a measure of the amount of fluid that has passed through the granite, the most intensely altered granites having the highest values. The inclusion populations in kaolinized granites are dominated by regular to irregularly shaped liquid-vapour and vapour-only inclusions that sometimes contain a phase identified by SEM-EDS as kaolinite. The earliest episode of fluid activity was responsible for the formation of hydrothermal sheeted vein swarms, breccias, microfracturing and pervasive phyllie alteration. These formed from high temperature, dominantly magmatic fluids from between 250 to > 400°C with moderate to high salinities (10 to 40 eq.wt. % NaCl). These fluids were followed by cooler < 100 to 200°C, less saline (< 13 eq.wt. % NaCl) meteoric fluids that were responsible for the first stages of kaolinization. A small number of low/moderate temperature (180-220°C) high salinity (25-35 eq. wt. % NaCl) inclusions were found which are most likely to represent the influx of basinal brines during wrench fault re-activation and thus played a role in the kaolinization process. Homogenization temperature and salinity signatures for weakly and intensely kaolinized granites are similar and suggest that the degree of kaolinization is controlled by the volumes of fluid that pervade the granites. Stable oxygen and hydrogen isotope studies show that the isotopic compositions of kaolinite plot close to the kaolinite weathering line, indicating growth/re-crystallization in a supergene environment. Evidence for the epithermal regime under which kaolinization took place is found in both pits where late quartz-filled cross-course veins contain a significant amount of silica, iron oxides and re-mobilized/re-crystallized kaolinite. Stable oxygen isotope analyses of cross-course vein quartz from Lower Bostraze pit supports the fluid inclusion data which suggest a low temperature epithermal environment of deposition. The flow of fluids through the granite was controlled by the intensity of fracture systems present. Both pits host sheeted vein swarms and breccias which acted as regions of enhanced permeability and are coincident with zones of intense kaolinization. Pre-granite wrench-faults were re-activated following granite emplacement and played an important part in providing zones of high permeability during kaolinization. Laboratory studies have shown that the commercial properties of paper coating clays are controlled by their mineralogy, which is determined by the precursor mineralogy of the granite and its hydrothermal history. The yellowness of a clay is related to the amount of iron oxide present either adsorbed onto the kaolinite surfaces or as discrete particles. In general terms the higher the yellowness values the lower the brightness values. Abrasion is related to the levels of quartz and feldspar present. Anomalously high abrasion values at Lee Moor have been shown by SEM to be due to the presence of silica coatings on kaolinite and K-feldspar laths from antiperthites. Viscosity is related to the levels of mixed-layer smectite/mica phases and smectite in the ultrafine fraction. Viscosity is also related in a complex way to the particle size and shape of kaolinites. An intensely altered granite will contain well-formed blocky crystallites which will have good viscosity values, weakly altered granite will contain smaller thinner particles the viscosity of which is poor. The zones of intense kaolinization around vein swarms are dominated by blocky, well-formed low disorder kaolinite crystallites which have good viscosity and brightness values. Partially altered granite contains less kaolinite and more mica and smectite. The kaolinite will be dominated by less well-formed high disorder crystallites which may be stained by iron oxides thus increasing yellowness.
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Bjornson, Jean. "Les glissements rétrogressifs de fonte de la rivière Willow, Territoires du Nord-Ouest, Canada: Caractéristiques sédimentologiques, distribution spatiale et temporelle." Thesis, University of Ottawa (Canada), 2003. http://hdl.handle.net/10393/26444.
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The Willow River (Richardson Mountains, N.W.T.) drainage basin is located at the western limit reached by the Laurentide ice-sheet during the Last Glacial Maximum (LGM). The icesheet covered the eastern fringe of the Mountains and deposited a lodgment till. The textural maturity and the lithology of the erratics indicate a distant origin to the till. During deglaciation, the retreating ice-sheet provided a supply of melt water to the aggrading permafrost. The resulting ice rich permafrost has been the host to two periods of thermokarst activity. The first, synchronous with the early Holocene warm period, led to an increase in active layer thickness and slope instability. The second, more recent, dates to the Little Ice Age and may have resulted from an increase in either fire frequency or intensity, or in modifications to the vegetation cover. Today, numerous active and inactive retrogressive thaw slumps can be seen throughout the drainage basin, but their distribution is restricted to the LGM. The slumps are polycyclic in nature and their headwall typically expose 2 units: the lodgment till (unit 1) overlain by a diamicton (unit 2) separated by a thaw unconformity. The latter is not associated to the paleo-active layer observed elsewhere in the Canadian northwest. Air photographs show an increase in thermokarst activity during the two last decades.
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Arpin, Sarah Marie. "Karst Hydrogeology of the Haney Limestone, South-Central Kentucky." TopSCHOLAR®, 2013. http://digitalcommons.wku.edu/theses/1253.
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South-central Kentucky has one of the world’s most intensively studied karstareas, with most work focusing on the Mammoth Cave System and related caves and aquifers. However, slightly higher in the stratigraphic section than Mammoth Cave, the Haney Limestone is a locally important but less well studied carbonate aquifer. This research provides the most comprehensive synthesis to date of the karst hydrogeology of the Haney Limestone of south-central Kentucky, focusing on the distribution and controls on cave and karst features developed within. In contrast to drainage systems within the major limestones below, joints are the most dominant control on passage development in the Haney Limestone within the study area and the orientation of these joints is consistent with that of regional joint sets. Bedding planes and the presence of insoluble rock at the base of the Haney also exert control on conduit development in the Haney Limestone. Most of the caves of the study area developed in the Haney Limestone are singleconduit caves that receive water through direct, allogenic sources. Cave entrances are frequently perennial spring resurgences and the presence of active streams suggests that the caves function within the contemporary landscape, acting as drains for localized recharge areas. The hydrology of the Haney Limestone plays an important, if localized, role in the regional hydrology of south-central Kentucky, integrated into the current system of surface and subsurface drainage of the regional karst landscape. Evidence supports the idea that caves of the Haney Limestone are, geologically, relatively recent phenomena. A majority of the cave passages in the study area are hydrologically active, the water resurging from the sampled springs is typically undersaturated with respect to limestone, and the caves in some case appear to be developed along potential stress release fractures associated with small, apparently young valleys. This suggests that caves in the Haney Limestone were not directly influenced by the incision of the Green River over vast periods, like Mammoth Cave, but that cave development is a largely contemporary process.
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Moore, Amy M. "Spatiotemporal Analyses of Child Pedestrian-Vehicle Incidents Occurring during School-Commuting Hours in Metro Atlanta from 2000 to 2007." Digital Archive @ GSU, 2011. http://digitalarchive.gsu.edu/geosciences_theses/35.
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From 2000 to 2007, the five core county area of Metropolitan Atlanta (Fulton, Dekalb, Clayton, Cobb and Gwinnett) experienced 1,871 incidents involving child pedestrians. Nearly one-third of these incidents occurred during school-commuting hours. This study examines the geospatial locations of these incidents, with regards to the location of all 647 public schools within the study area. A GIS is used to analyze the spatiotemporal arrangement of these incidents in order to find risk factors and patterns in the data. Aspects of the built environment are then considered in areas with higher frequencies of child pedestrian-vehicle incidents. A walkability assessment is conducted to assess risk factors involved in the increased incident frequencies in an area of Stone Mountain. A correlation with the location of parks, recreation centers and other destinations are found. Improvements and installation of crosswalks are suggested in order to improve safety and walkability of child pedestrians in these areas.
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Levy, Beth Michele. "High-Resolution Seismic Stratigraphy of the Ganges-Brahmaputra River System: Subaqueous Deltaic Progradation on the Bengal Shelf." W&M ScholarWorks, 1995. https://scholarworks.wm.edu/etd/1539617696.
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Lambert-Smith, J. S. "The geology, structure and metallogenesis of the world class Loulo-Bambadji Au district in Mali and Senegal, West Africa." Thesis, Kingston University, 2014. http://eprints.kingston.ac.uk/29998/.
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The 2.1 Ga Kedougou-Kenieba Inlier in West Africa hosts outstanding mineral wealth, with ~45 Moz of gold and 630 Mt of iron ore hosted along the Senegal-Mali Shear Zone (SMSZ). To the west of the SMSZ the Faléme’ Volcanic Belt (FVB). Detailed petrography and analysis of igneous rocks by solution lCP-MS and AES show that the FVB is comprised of calc-alkaline volcaniclastic sediments, lavas and plutonic rocks, hosts iron ore in a series of magnetite skam deposits. To the east of the SMSZ, the Kofi series is comprised of clastic sedimentary rocks and peraluminous granite plutons. Orogenic Au hosted in the Loulo-Bambadj i district of the Kofi Series (including the Gara, Yalea and Gounkoto mines) is spatially associated with epigenetic tourmaline alteration, while widespread albite alteration is associated with early stages of mineralisation in both the FVB and the Kofi Series. A >400 ppm boron soil anomaly along >100 km strike length of the SMSZ is related to widespread tourrnalinisation of sedimentary rocks in the Kofi Series. The Au deposits of the Kofi Series are characterised by a Fe-As-Cu-Au-Ag i REES-W-Ni-Te metal association. Ore assemblages are pyrite and arsenian pyrite dominated with accessory chalcopyrite, Ni-sulphides, scheelite and REE phosphates. Two distinct hydrothermal fluids were involved in Au mineralisation in the Kofi Series: 1) a moderate temperature (315-340 °C), low salinity (<10 wt. % NaCl equiv.), low density (31 gcm -3), HzO-COZ-NaCl-HZSiNz-CH4 fluid; and 2) a high temperature (up to 445 oC), hypersaline (~40 wt. % NaCl equiv.), high density (~1.3 gcm -3), H2O-CO2-NaCl+-FeCl2-B fluid. This hypersaline fluid has been interpreted as being sourced from crystallising magmatic bodies, new data presented here suggests otherwise. Stable isotope data (0, C and S from silicate, carbonate and sulphide minerals) indicate that volatiles involved in ore formation were generated through metamorphic devolatilisation reactions within the Kofi Series; this is interpreted to be the source of the low salinity fluid. Isotopically heavy delta 34 values (+25 %o) from diagenetic pyrite together with 11 B-enriched isotopic ratios in hydrothermal tourmaline (-4.6 to +19.8 %), measured by SIMS, suggest that the hypersaline fluid formed through dissolution of evaporite units formerly present in the Kofi Series. Furtheirnore, dating of magmatic zircons from nearby plutons by LA-ICP-MS shows a considerable time gap between magmatism at ~2100 Ma and mineralisation at ~2030 Ma. Fluid inclusion data from the Gounkoto deposit indicates that phase separation in the metamorphic sourced fluid was an important mechanism for ore deposition. In addition, discrete sections of the deposit exhibit evidence that partial mixing of the high salinity and low salinity end member fluids enhanced phase separation through retrograde boiling. The hypersaline fluid is widely distributed along the SMSZ, with increasing abundance toward the FVB in the west. Hypersaline inclusions at the Karakaene Ndi magnetite skam deposit in the FVB imply that the hypersaline fluid played a significant role in the development of the magnetite skarn deposit. The NaCl content allowed efficient transport of Fe to sites of ore formation in F6C120 complexes.
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Azmi, Azrin. "Late Triassic to early Jurassic microfossils and palaeoenvironments of the Waterloo Mudstone Formation." Thesis, University of Birmingham, 2018. http://etheses.bham.ac.uk//id/eprint/8517/.
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Northern Ireland Waterloo Mudstone Formation has received relatively little attention due to the scarcity of exposures and poor availability of subsurface records. The recent recovery of latest Triassic to Early Jurassic strata from boreholes permits further study of biostratigraphical and palaeoenvironmental using foraminifera and ostracods. The samples are from boreholes (Ballinlea-1, Magilligan and Carnduff-1) and exposures (White Park Bay, Tircrevan Burn, Larne, Ballygalley, Ballintoy and Kinbane Head). The age of the sections, established using foraminiferal biozonation ranges from latest Triassic (Rhaetian) to earliest Pliensbachian (JF9a). The assemblages recovered broadly similar to those elsewhere in NW Europe; European Boreal Atlantic Realm. The latest Rhaetian to earliest Sinemurian low diverse microfossil assemblages dominant by metacopid ostracods with occasional influx of opportunist foraminifera but gradually, foraminiferal abundances exceed the ostracods in the Early Sinemurian onwards with their highest diversity in the Late Sinemurian. The foraminiferal assemblages are dominated by foraminifera of the Lagenida, other groups include the Miliolida, Buliminida and Robertinida. Based on the microfossils, the sediments are considered to represent confined inner shelf environment in latest Rhaetian to Hettangian then gradually recovered to well-oxgenated, open marine deposits of outermost inner shelf to middle shelf in Early Sinemurian to Early Pliensbachian.
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Jaweesh, Mahmoud. "Correlations between fluviatile sandstone lithofacies and geochemical properties and their importance for groundwater contaminant transport." Thesis, University of Birmingham, 2018. http://etheses.bham.ac.uk//id/eprint/8170/.
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Reactive groundwater contaminant transport is dependent upon hydraulic and geochemical property distributions. The aim of this research was to determine, for an example fluvial sandstone: (i) the degree of correlation between geochemical property values and lithofacies (LFs); and (ii) the effect of the correlations on reactive solute transport. A 60 m core from the carbonate-cemented, red-bed Triassic Sherwood Sandstone Group was examined. Five fluvial LFs were identified, in fining upwards cycles from a channel lag sandstone (LF5) to a low energy mudstone (LF1). The main geochemical properties investigated were carbonate content, oxide content, sorption capacity, cation exchange capacity (CEC) and selectivity coefficient; Surface area and colour were also studied. There is a clear distinction in carbonate content, CEC, selectivity coefficient and Fe and Mn oxide content between LF1 and LF2, the ‘mud’ LFs, and the matrix of LF3, LF4 and LF5, the ‘sand’ LFs. In addition, the pellets change the bulk geochemical properties of the sand LF units. Modelling indicated that the pellets can affect solute mobility significantly. Selectivity coefficients show a possible depth zoning. Distribution parameter values obtained characterize the sequence for geochemical modelling and uncertainty estimation. Oxide coating thickness was estimated at about 100nm. CEC was found to be well-correlated with surface area. Colour/Fe/Mn content correlations suggest a possibility in future to use colour logging to indicate oxide content and possibly even surface area and CEC. As the sequence examined appears typical of many red-bed fluvial sequences, it is suggested that the findings may also be typical of other similar continental sandstones.
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Olivier, Bernard. "The geology and petrology of the Merelani tanzanite deposit, NE Tanzania." Thesis, Stellenbosch : University of Stellenbosch, 2006. http://hdl.handle.net/10019.1/1093.
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Thesis (PhD (Earth Sciences))--University of Stellenbosch, 2008.Tanzanite, a blue/violet gemstone variety of zoisite (Ca2Al2O.AlOH[Si2O7][SiO4]) is only produced in NE Tanzania. The only known locality is an approximately 7km2 deposit in the Merelani area. It is one of the most sought after gemstones in the world with an industry sales value of between hundred and fifty and two hundred million dollars per year. At the current production rates and estimated resources the tanzanite deposit has a life expectancy of around 20 years. Despite the economical and scientific importance as well as the geological uniqueness of the deposit very little research has been conducted on the geology and petrology of the deposit and the characteristics of tanzanite. The primary aim of the research summarised in this dissertation was to gain an understanding of the geological conditions that led to the formation of this unique variety of zoisite. In order to achieve this, a variety of geological disciplines were addressed including the lithostratigraphic setting, the deformational history, the metamorphic history and conditions, the geochemical and isotopic composition, the mineral chemistry as well as the physical and optical properties of the tanzanite. Extensive field work was conducted over a seven year period, which included surface and underground mapping, surface trenching, surface and underground core drilling, structural measurements and an intensive sampling programme. Various analytical techniques were used in order to petrologically and mineralogically investigate both the deposit and tanzanite itself, including optical microscopy, XRF analyses, laser-ablation ICP-MS, quantitative chemical analyses by means of the electron microprobe, XRD analyses, back-scattered electron microscopy, isotope analyses, fluid-inclusion studies, Vis/UV/NIR spectroscopy, IR spectroscopy, and EPR studies. This study revealed an intricate and complex geological history for the formation of tanzanite. The deposition of carbon-rich layers, formed during the development of a sequence of shallow shelf sediments consisting primarily of various organic carbon (δ13C between –22,85 ‰ and –26,74 ‰) -rich mudstone horizons and limestone beds is seen as the first phase of the mineralisation process. These Archaean sediments were deposited in a back- or fore-arc spreading basin. The organic carbon-rich mudstone layers acted as the first phase of vanadium accumulation in the stratigraphic sequence, and are intercalated with a material with a volcanic origin (metabasites), which most likely contributed to the enrichment of amongst others V. Early diagenetic processes were followed by an extended metamorphic and deformation (D1) history, reaching upper granulite facies conditions (10 – 12 kbar and 850 oC to 1000 oC) at ca. 1000 Ma. The high-grade metamorphic history was followed by multiphase retrograde deformation events (D2 and D3) that developed as a result of crustal uplift. The D2 event probably occurred between 850 and 600 Ma at P-T conditions estimated at between 8 to 7 kbar and 700 to 650 oC. A third stage of deformation (D3) resulted in the formation of overprinting structures and occurred during the later stages of the Pan-African (550 – 500Ma) event during amphibolite/greenschist facies conditions (7 to 6 kbar and 600 to 520 oC). The deformational history of the deposit played a critical role in the mineralisation processes. Of the four main deformation events identified, three played a critical role in the mineralisation process. The first event led to the development of early structural features as defined by F1, S1 and L1. This was followed by a multiphase D2 event consisting of three different orders of folding (F2a, F2b and F2c) and the formation of boudinage. The association between tanzanite and boudins as well as the stacking and multiple duplication of the boudinaged ore-zone through isoclinal folding resulted in multiple “ore-shoots”. These ore-shoots follow the plunge of the F2c fold closures and results in mine-able features within the ore-body. The third deformation event led to complex structural overprinting of the earlier fabric as observed in S3 and L3 and resulted in the deformation of the F2 structures through crosscutting F3 folds. Calc-silicate layers developed in the stratigraphic sequence as a result of metamorphic and metasomatic interaction between calcium enriched (boudinaged calc-silicates) and depleted horizons (graphitic gneisses) during a skarn-forming episode. V-rich green grossular garnet (tsavorite) crystallised in tension zones within and in proximity to the boudins during prograde metamorphism. Tanzanite mineralisation occurred during the retrograde stages at ca. 585 ± 28 Ma with P-T conditions estimated at ca. 5 to 6 kbar and 650 ± 50 oC. Two distinctive tanzanite-forming processes are distinguished. The first involves the formation of tanzanite as a result of retrograde reaction of grossular garnet. The second process involves the migration of V and Ca -enriched fluids along brittle shear zones to tension sites where fluids reacted with wall rock during a drop in P-T conditions to precipitate tanzanite. Fluid inclusion and stable-isotope studies concluded that the ore-forming fluids were derived from the dehydration of the metasedimentary sequence and consisted of a mixture of H2O, CH4, H2S and N2. Mineralogical investigation of tanzanite indicated that trace concentrations of vanadium within its crystals structure causes its blue / violet colour. It was proved that the vanadium originated from the abundant organically derived graphite within the deposit. Spectroscopic and EPR analyses revealed the importance of the Ti4+ / Ti3+ ratio within the crystal structure of tanzanite with regard to its colour characteristics. The heating of tanzanite results in a couple valence exchange reaction Ti 3+ + V 4+ → Ti 4+ + V 3+ which causes an increase the blue / violet colour of tanzanite. The research conducted led to the development of a successful geological model for the tanzanite mining and treatment activities in the Merelani area of NE Tanzania. As such the research contributed to the establishment of a successful tanzanite mine, based on sound geological principles, which may act as a role model for other gemstone mines worldwide.
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Miles, Luke G. "Global Digital Elevation Model Accuracy Assessment in the Himalaya, Nepal." TopSCHOLAR®, 2013. http://digitalcommons.wku.edu/theses/1313.
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Digital Elevation Models (DEMs) are digital representations of surface topography or terrain. Collection of DEM data can be done directly through surveying and taking ground control point (GCP) data in the field or indirectly with remote sensing using a variety of techniques. The accuracies of DEM data can be problematic, especially in rugged terrain or when differing data acquisition techniques are combined. For the present study, ground data were taken in various protected areas in the mountainous regions of Nepal. Elevation, slope, and aspect were measured at nearly 2000 locations. These ground data were imported into a Geographic Information System (GIS) and compared to DEMs created by NASA researchers using two data sources: the Shuttle Radar Topography Mission (STRM) and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER). Slope and aspect were generated within a GIS and compared to the GCP ground reference data to evaluate the accuracy of the satellitederived DEMs, and to determine the utility of elevation and derived slope and aspect for research such as vegetation analysis and erosion management. The SRTM and ASTER DEMs each have benefits and drawbacks for various uses in environmental research, but generally the SRTM system was superior. Future research should focus on refining these methods to increase error discrimination.
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Schannwell, Clemens. "Modelling ice dynamic sea-level rise from the Antarctic Peninsula Ice Sheet." Thesis, University of Birmingham, 2017. http://etheses.bham.ac.uk//id/eprint/7775/.
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The Antarctic Peninsula (AP) has been one of the most rapidly warming regions on this planet. This warming has been accompanied by major glaciological changes such as tidewater glacier retreat, ice-shelf retreat and collapse alongside acceleration of outlet glaciers in response to ice-shelf removal. As faster owing glaciers deliver more ice from the ice sheet's interior to the margins, the AP has been identified as an important contributor to global sea-level rise (SLR). However, comprehensible SLR projections of the AP induced by ice dynamics over the next three centuries are still lacking. In this thesis, numerical ice-sheet models are utilised to present scenario-based ice dynamic SLR projections for the AP.
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Singleton, Andrew G. "Analysing landslides in the Three Gorges Region (China) using frequently acquired SAR images." Thesis, University of Glasgow, 2014. http://theses.gla.ac.uk/5676/.
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Spaceborne Synthetic Aperture Radar (SAR) sensors obtain regular and frequent radar images from which ground motion can be precisely detected using a variety of different techniques. The ability to remotely measure slope displacements over large regions has many uses and advantages, although the limitations of an increasingly common technique, Differential SAR Interferometry (D-InSAR), must be considered to avoid the misinterpretation of results. Areas of low coherence and the geometrical effects of mountainous terrain in SAR imagery are known to hinder the exploitation of D-InSAR results. A further major limitation for landslide studies is the assumption that variable rates of movement over a given distance cannot exceed a threshold value, dependent upon the SAR image pixel spacing, the radar sensor wavelength and satellite revisit frequency. This study evaluates the use of three SAR image modes from TerraSAR-X and ENVISAT satellites for monitoring slow-moving landslides in the densely vegetated Three Gorges region, China. Low coherence and episodically fast movements are shown to exceed the measureable limit for regular D-InSAR analysis even for the highest resolution, 11-day interferograms. Subsequently, sub-pixel offset time-series techniques applied to corner reflectors and natural targets are developed as a robust method of resolving time-variable displacements. Verifiable offsets are generated with the TerraSAR-X imagery and the precise movement history of landslides is obtained over a period of up to four years. The capability to derive two-dimensional movements from sub-pixel offsets is used to infer a rotational failure mechanism for the most active landslide detected, and a greater understanding of the landslide behaviour is achieved through comparisons with likely triggering factors and 2D limit equilibrium slope stability analysis.
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Portenga, Eric W. "Assessments of human land use, erosion, and sediment deposition in the Southeastern Australian Tablelands." Thesis, University of Glasgow, 2015. http://theses.gla.ac.uk/6319/.
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Humans have interacted with their surroundings for over one million years, and researchers have only recently been able to assess the geomorphic impacts indigenous peoples had on their landscapes prior to the onset of European colonialism. The history of human occupation of Australia is noteworthy in that Aboriginal Australians arrived ~50 ka and remained relatively isolated from the rest of the world until the AD 1788 when Europeans established a permanent settlement in Sydney, New South Wales. The southeastern Australian Tablelands landscape, west of Sydney, has seemingly undergone drastic geomorphic change since European arrival. The introduction of European grazing practices reportedly led to the occurrence of deep erosional incisions, gullies, into valley bottoms and hillslopes, releasing sediment, which is subsequently deposited over downstream wetland environments – swampy meadows. This sediment is often called post-settlement alluvium (PSA); however, the age and genesis of PSA in Australia are debated. Questions regarding the geomorphic features and processes in the Tablelands remain unanswered because few studies quantify the timing of gully incision, PSA deposition, or the pre-human rate of landscape change. Erosion rates inferred from concentrations of in situ 10Be measured in fluvial sediment (n = 11) and bedrock outcrops (n = 6) range from 2.9–11.9 mm/kyr and 5.2–13.8 mm/kyr, respectively. The two sample populations are statistically indistinguishable, suggesting no relief has been generated since 600–110 ka. The overall erosion rate in the Tablelands is 7.5 mm/kyr, equal to long-term denudation rates integrated since ~20 Ma. Aboriginal Australians have been present in the Tablelands for at least 30 kyr, ~12–26% of the cosmogenic integration time, yet widespread Aboriginal fire use did not measurably affect landscape erosion until ~5.5 ka, in sync with increased charcoal in the sediment record. Portable optically stimulated luminescence (OSL) reader data from poly-mineral and poly-grain size samples collected from gully wall profiles of PSA and swampy meadow sediment show that swampy meadow environments were buried by PSA and that PSA is alluvium derived from upstream gully erosion. No relationships between bulk OSL and sample grain size or mineralogy exist, and inferences about bulk sediment mineralogy or grain size cannot be determined from portable OSL reader data. Large variability in adjacent PSA sample replicates, however, reveals incomplete sediment bleaching conditions during PSA deposition during floods. Greater bleaching efficiency is inferred from the small variability of bulk OSL data in the uppermost 10s of cm of PSA profiles. Measured concentrations of meteoric 10Be and bulk OSL in two PSA deposits in Birchams Creek show that initial gully incision eroded into weathered sandstone regolith and not swampy meadow environments, as previously believed. Initial gully incision was shallow (<15 cm) and PSA filled ponds in the lower reaches of the catchment. Continued erosion upstream led to a second depositional episode of PSA before headward gully incision from the mouth of Birchams Creek eroded through PSA deposits. Headward erosion of this gully created the continuous gully present at the site today. Initial gully incision was likely the result of livestock trampling in valley bottoms during droughts, creating localised slopes greater than the critical slope threshold required to erode the valley bottom. OSL burial ages of six PSA deposits collected throughout the Tablelands range from 195.1 ± 17.8 to 90.4 ± 8.9 a, corresponding to AD 1800–1932. The OSL burial ages are younger than European arrival in the Tablelands, and the term, PSA, is redefined as post-European settlement alluvium in Australia, recognising the earlier settlement of the region by Aboriginal Australians whose land use did not lead to PSA deposition. PSA burial ages agree with existing quantitative and anecdotal gully incision data. Contrary to previous assertions that gully incision began asynchronously in the Tablelands, three periods of synchronous gully erosion in localised areas within the Tablelands are recognized: 185 a, 158 a, and 94 a (AD 1828, 1855, and 1919, respectively) – in the southern, northern, and central Goulburn Plains, respectively. The AD 1828 and AD 1919 periods of gully incision correspond to the transition from drought-dominated climate regimes to flood-dominated regimes, and the AD 1855 period of gullying corresponds to a flood-dominated regime. Gully incision in the Tablelands is thus a result of European-introduced grazing practices, which primed the landscape for further erosion and degradation during climatic shifts. PSA deposits in the southeastern Australian Tablelands are some of the most recent examples of anthropogenic sedimentation in human history. The earliest preserved examples of PSA-type sediments are ~8,000 years old and found throughout the world. The establishment of an onset date for the Anthropocene is currently debated, and I believe the oldest PSA and PSA-type sediments around the world can define this modern epoch.
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Spahr, Paul Nathan. "Using Geovisualizations and GIS to Present Spatial-Temporal Water Withdrawals for Ohio and the Conterminous United States." The Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=osu1210894900.
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Mathers, Hannah. "The impact of the Minch palaeo-ice stream in NW Scotland : constraining glacial erosion and landscape evolution through geomorphology and cosmogenic nuclide analysis." Thesis, University of Glasgow, 2014. http://theses.gla.ac.uk/5302/.
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The British-Irish Ice Sheet (BIIS) is predicted to have deglaciated rapidly from ~ 18 ka, in response to rising sea level and temperature, similar forcings experienced by modern polar ice sheets. As the main conduits of ice mass loss, the reaction of ice streams to these forcings is thought to have been central in determining the mode and timing of this deglaciation. However, lack of understanding of ice stream influence on the glaciology and deglaciation of ice sheets limits confidence in ice sheet model predictions. NW Scotland is an area of the last BIIS predicted to have been dominated by ice stream onset conditions. This thesis presents results from a geomorphological and terrestrial cosmogenic nuclide (TCN) analysis study which resulted in the production of a composite ice-sheet thermal regime map and retreat chronology for the last BIIS in this region. Mapping and surface exposure dating suggest that the regional glaciology and landscape evolution was dominated by the presence of ice-stream onset zones during Greenland Stadial-2 (GS-2). Mountain top erratics were uplifted and transported to high elevation during GS-2, before 16.5 ka BP. By inference, mountain summits were covered by ice during maximal ice sheet conditions. The existence of sharp thermo-mechanical contrasts, developed in response to ice streaming, are proposed as the main controls on bedrock erosion and terrestrial sediment deposition. The interpretation of ‘trimlines’ in NW Scotland as englacial thermo-mechanical boundaries, is verified by the identification of ‘rip-offs’, a newly recognised geomorphic feature in the UK, and by quantitative demonstration of the increase in glacial erosion in the vicinity of these boundaries. Geomorphic and TCN data supports a conceptual model of thermal inversion following ice-stream cessation. The first description of ‘till tails’ in the UK provides insight into the glaciological organisation and thermal evolution of the BIIS. A dated (17.6 ka BP) terrestrial glacial limit on the north Sutherland coast indicates early ice retreat from the shelf and provides a minimum ii constraint on ice-stream cessation. This indicates rapid loss of ice extent and volume following shutdown of the Minch palaeo-ice stream. Major ice sheet reorganisation c. 15-16 ka BP is suggested by the correlation of some lateral margin ages with high elevation erratic deposition ages implying significant ice thinning and margin retreat prior to this time. Additionally, thinning of ~300 m is predicted for some areas prior to 14 ka BP.
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Bogren, Fredrik. "Evidence for birch forests and a highly productive environment near the margin of the Fennoscandian ice sheet in the Värriötunturit area, northeastern Finland." Thesis, Stockholms universitet, Institutionen för naturgeografi, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-170716.
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High-resolution records of early Holocene deposits are rare, and as a consequence reconstruction of terrestrial environments very soon after the deglaciation has often been difficult. In this study the palaeoenvironmental conditions of early Holocene (c. 10600-7500 cal. yr BP) are reconstructed in the Värriötunturit area of northeastern Finland, using evidence from plant macrofossils and pollen preserved in a lake sediment sequence retrieved from the small lake Kuutsjärvi. Special emphasis is put on the environment immediately following the deglaciation as the base of the sediment sequence is rich in minerogenic material interpreted to have been deposited by meltwater pulses from the retreating ice sheet. The abundance and variety of fossil remains in these early meltwater deposits provide evidence for a very productive ice-marginal environment in the area between the lake and the ice sheet, and the presence of tree-type Betula macro remains as well as high percentage values of tree-type Betula pollen suggests that a subarctic birch forest established just a few years after the deglaciation. In the following centuries the birch forest around the lake became rich in an under growth of ferns, and at c. 9400 cal. yr BP a transition into a mixed pine and birch forest took place. Due to absence of indicator plant taxa in the sediment it was not possible to reconstruct temperature conditions for any parts of the sequence in this study. However, the rapid colonisation of birch forests suggests that the climate was warm already during deglaciation, which is also in accordance with climatic conditions reconstructed for the early Holocene in the nearby Sokli area just 10 km away, as well as in other parts of Fennoscandia and Russia.
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Tennessee, State of. "Washington County Geographic Features." Digital Commons @ East Tennessee State University, 1986. https://dc.etsu.edu/rare-maps/8.
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This Washington County, Tennessee map includes geographic features including streams and mountain peaks, as well man made features such as highways, railroads, communities, and cemeteries. While the publication date is not included, it was received by the Documents, Law and Maps Department in 1986. However, due to the spelling of a few of the landmarks, the actual publication likely predates 1983. Some points of interest include the Veteran's Administration Mountain Home which is now the site of the Quillen College of Medicine and White Rock Ridge located where Buffalo Mountain Park would be established a decade later in 1994.https://dc.etsu.edu/rare-maps/1007/thumbnail.jpg
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Kaletsky, Kelly. "Measurement of the Effects of Food Preparation Activities on the Microclimate of the Snowball Dining Room Area of Mammoth Cave." TopSCHOLAR®, 1992. http://digitalcommons.wku.edu/theses/1734.
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The stability of Mammoth Cave’s microclimate has never undergone extensive investigation. The Snowball Dining Room area was chosen to measure the microclimate of the cave and to determine if food preparation, human presence and surface temperature variations alter this microclimate. Three portable weather stations containing a temperature / humidity probe, datalogger and microbarograph were placed in various locations along three passageways leading away from the dining room. Readings were taken 24 hours per day for four months. Plotting temperature readings in graph form show a correlation between temperature of the passageway and distance from the dining room.
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Kovarik, Johanna L. "A Composite Spatial Model Incorporating Groundwater Vulnerability and Environmental Disturbance to Guide Land Management." Scholar Commons, 2015. http://scholarcommons.usf.edu/etd/5863.
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Research has long recognized and studied the dynamics of groundwater processes. More recently, groundwater dependent ecosystems (GDEs) are being recognized for their diversity and vulnerability to anthropogenic impact. Groundwater in karst landscapes presents a distinctive situation where flow through the subsurface often moves rapidly on the scale of days and weeks as opposed to years or millennia in other systems. This distinctive situation of karst systems and their vulnerability to human impacts necessitate an integrated and multifaceted approach for the management of these important resources. However, development of such an approach is complicated by the difficulty of obtaining detailed data about the ecosystem, especially in remote areas of developing countries. Additionally, management difficulties related to political boundaries, jurisdictions, and land ownership can result in ineffective and inconsistent policies and practices across a single catchment. In order to address these issues, this dissertation creates a new composite model for groundwater dependent ecosystem (GDE) management in areas of karst development. Within this new composite model, the combination of the Karst Disturbance Index (KDI) and groundwater vulnerability mapping recognizes both human disturbance and how the physical nature of the karst will enhance this impact. These studies bridge the gap between science and management by connecting the final model to management strategies for a sub-catchment of the Rio la Venta watershed, the majority of which is within the Reserva de la Biosfera Selva el Ocote in Chiapas, Mexico. This composite model serves as an adaptable spatial tool for management planning and protection for all components of the karst environment.
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Thompson, James Kyle. "Station Exposure and Resulting Bias in Temperature Observations: A Comparison of he Kentucky Mesonet and ASOS Data." TopSCHOLAR®, 2014. http://digitalcommons.wku.edu/theses/1434.
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Station siting, exposure, instrumentation, and time of observations influence longterm climatic records. This thesis compared and analyzed temperature data from four Kentucky Mesonet stations located in Fayette (LXGN), Franklin (LSML), Clark (WNCH), and Bullitt (CRMT) counties to two nearby Automated Surface Observation Systems (ASOS) stations in Kentucky. The ASOS stations are located at Louisville International Airport (Standiford Field - KSDF) and at Lexington Airport (Blue Grass Field - KLEX). The null hypothesis states that there is no significant difference in temperature measurements between the two types of stations. To quantify the differences in temperature measurements, geoprofiles and the following statistical procedures were used: coefficient of determination (R2), coefficient of efficiency (E), index of agreement (d), root mean square error (RMSE), and mean absolute error (MAE). Geoprofiles were developed using GIS, and take into account elevation, slope, hillshading, land use, and aspect for each site to help better understand the influence of local topography. It was found that temperature differences could be related to the advancement of weather patterns, vegetation growth and decay, and changes in the landscape at the stations. KSDF consistently recorded higher temperatures than those at CRMT. The positive bias ranged between 0.27 and 2.41 ºC during the time period of September 2009 to August 2010. KLEX was found to be warmer or cooler, with temperature differences that ranged from -1.42 to 0.22 ºC for LXGN, LSML, and WNCH. The index of agreement at KSDF for mean hourly temperatures, when compared to the Bullitt County mesonet station, ranged from 0.88 to 0.99. Meanwhile, the index of agreement at KLEX was 0.96 to 1.00 when compared to the Franklin, Fayette, and Clark mesonet stations. KLEX recorded temperatures that were higher or lower compared to the Franklin, Fayette, and Clark mesonet stations. At the seasonal scale, fall and summer showed larger differences between the Mesonet and ASOS observations. KSDF consistently recorded higher temperatures ranging up to 2.41 °C during the summer. The index of agreement at KSDF in the fall, when compared to the Bullitt County mesonet station average temperatures, ranged from 0.89 to 0.95, while in the summer it was 0.88 to 0.96. The d index indicates a good agreement between ASOS and mesonet stations in winter. KLEX indicates that the index of agreement, RMSE, and MAE are best during winter for all three stations, while in the fall and summer the agreement was not as strong when compared to the Franklin, Fayette, and Clark mesonet stations. In summary, results indicate that the Kentucky Mesonet and ASOS temperature measurements show significant differences throughout the year; therefore, the alternative hypothesis is accepted. These differences are attributed to biases associated with ASOS observations, nearby artificial sources of heating, equipment/maintenance procedures, and land use and land cover at the site.
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Schillereff, Daniel. "Lake sediment records of flood frequency and magnitude." Thesis, University of Liverpool, 2015. http://livrepository.liverpool.ac.uk/2007561/.
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The recent spate of floods in many parts of Britain has stimulated substantial interest among scientists, policy makers and the public concerning contemporary trends in flood frequency and magnitude, in particular questioning whether these events exceed historical extremes. However, detecting a clear signal of recent intensification in the flood regime is hampered by the relatively short timescales covered by meteorological and river flow data. Lake sediment sequences have proven a valuable archive of historical flooding over centennial and millennial timescales elsewhere in Europe and globally, but this thesis presents one of the first attempts to extract flood histories from the sediments of lakes in Britain. It adapts a detailed field and lab-based approach to test the hypothesis that discrete layers can be distinguished from long sediment cores (1 – 3.5 m) that were probably deposited by high-magnitude floods based on their particle size and geochemical signatures. The programme of research was developed and applied at Brotherswater (River Eden catchment), northwest England, and then further tested at the Loch of the Lowes (River Tweed catchment), southern Scotland. A detailed literature review led to the creation of a conceptual model to guide field site selection, based on the catchment-lake configuration and hydrological regime of individual sites. Characteristics deemed critical include a high catchment:lake area ratio to maximise sediment availability, limited pre-lake sediment storage and an effective sediment conveyor, as well as simple lake bathymetry. The viability of µXRF scanning to characterise flood laminations within wet sediment cores was assessed in detail. A new method of calibrating geochemical concentrations where the water content varies substantially (50%) down-core based on x-ray scattering is described, and the first inter-comparison between different core scanners is performed. The analytical resolution of the ITRAX can reveal laminations too thin to manually sub-sample but the dataset can be noiser, especially after correction to the dry-mass basis. Caution should be used when interpreting ITRAX data at the sub -mm scale to ensure peaks and troughs represent real changes in sediment composition. Inspection of multiple sediment cores extracted along a delta-proximal to distal transect in Brotherswater, coupled with high-resolution (0.5 cm) particle size measurements revealed silt-dominated (90th percentile grain size (P90) ~ 16 µm) sediment matrices frequently punctuated by coarser-grained sand layers (P90 >100 µm) that are lighter in colour. These layers cannot be easily characterised geochemically, most likely due to the volcanic bedrock in the catchment, but constitute the stratigraphical signature diagnostic of repeated high-magnitude floods for the River Eden catchment. Sediment supply varied substantially through the late-Holocene at Brotherswater, complicating the particle size record. A normalisation approach was tested to remove the background trend and identify notable particle size peaks (>1 standard deviation from the longer-term moving window) and the similar profiles produced for three cores from Brotherswater suggests the technique has been able to produce a record of major floods in the Patterdale Valley spanning the last 1500 years. Geochemical profiles at Brotherswater are dominated by enhanced metal deposition during the last 300 years, especially Pb, which mimics and could be used as a surrogate for production data for the nearby Hartsop Hall Lead Mine. The down-core pattern of Pb deposition is strongly reproducible in twelve cores extracted from different parts of the lake and reveals reveals the pattern, rate and controls over sediment deposition, with post-1860 accumulation rates four times greater near the inflow. A coherent chronology that integrates short-lived radionuclide dating (137Cs, 241Am, 210Pb), 14C ages and the geochemical contaminant markers for Brotherswater reveals that the last millennium was characterised by flood-rich and flood-poor phases generally 50 – 100 years in duration. The timing of these phases is significantly correlated with annual precipitation reconstructions, indicating a link between rainfall and flood generation. Some temporal correspondence between flood occurrence and phases of the North Atlantic Oscillation is observed but the relationship frequently breaks down. At Brotherswater, flood deposits have been most frequent during the 20th Century but isolating the influence of human activity on the sediment record is challenging. Sixteen months of process monitoring at Brotherswater using sediment traps confirms the mechanics of sediment delivery and shows a strong continuity of current process to the late-Holocene sediment record. Particle size signatures were identified for a major winter flood, low-flow conditions and the regular flushing of the sediment system by successive low magnitude flood flows. Scaling the sediment trap data to an equivalent annual accumulation show how event delivery of coarse material may be masked by more regular fine-grained sedimentation through the year. The revealed anatomy of the annual sediment accumulation cycle has significant implications for palaeoflood research with process understanding at each site clearly a critical precursor to any sediment-based flood investigation. Laminations interpreted as palaeoflood deposits in the Loch of the Lowes sequence also exhibit prominent peaks in particle size but differ in colour and geochemical composition from Brotherswater, which highlights the importance of developing site-specific protocols for interpreting the sediment record. The coarse bands are much darker in colour and the Zr/Rb ratio appears to be an effective proxy of particle size in this case, with higher values reflecting coarser material. Preliminary chronological information suggest a finely-resolved palaeoflood record has been recovered extending approximately 350 years at the delta-proximal zone and perhaps twice as long in the central basin. The thesis demonstrates that particle size data, supported by appropriately calibrated geochemical analyses, can generate high-resolution flood stratigraphies from upland UK lakes and these span millennia, extending our understanding of regional flood frequency.
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Hutchison, Sean Taylor. "Eastern Deciduous Forest Phenology and Vegetative Vigor Trends From 2000 to 2013, Mammoth Cave National Park, KY." TopSCHOLAR®, 2013. http://digitalcommons.wku.edu/theses/1312.
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Global climate change is predicted to affect environmental systems at the midlatitudes, but the scope, severity, and outcomes of these impacts are yet to be fully understood. This study focuses on the implications of short-term climate variability for forests in central Kentucky. Using a Normalized Difference Vegetation Index (NDVI) calculated from MODerate-Resolution Imaging Spectroradiometer (MODIS) instrument data, the photosynthetic activity of vegetation at Mammoth Cave National Park (MACA) is tracked from 2000 to 2013. Three methods were employed to examine the changes and climate influences in vegetation over the study period: 1) aggregating the NDVI of the Park by year and by summer months (June, July, and August) and examining how these productivity trends could be influenced by precipitation and temperature fluctuations, 2) examining the trend of the NDVI at selected dates throughout the study period to detect phenological shifts around leaf-out and leaf-off, and 3) using a generalized vegetation classification of MACA to clip the imagery based on areas of similar vegetation and then testing correlations between those subsets and teleconnections. The results from the aggregated NDVI show there is an insignificant negative trend. A negative relationship between summer forest productivity at MACA and temperature was found, though more data are needed to rigorously validate this result. Changes in phenology indicate forest productivity is decreasing earlier each year throughout the study period. Finally, the Multivariate ENSO Index and the Pacific Decadal Oscillation index are shown to have significant positive correlations with the summer productivity of MACA during the study period.
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Broome, John D. "Simulation Modeling of Karst Aquifer Conduit Evolution and Relations to Climate." TopSCHOLAR®, 2008. http://digitalcommons.wku.edu/theses/36.
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ABSTRACT Karst regions of the world that receive relatively similar amounts of precipitation display a wide variety of landscapes. It has been suggested (Groves and Meiman, 2005) that climates exhibiting larger discrete storm events have more dissolving power and consequently higher rates of conduit growth than climates with more uniform precipitation distributions. To study this concept, a computer program “Cave Growth” was developed that modeled the growth of a cross-section of a cave passage under dynamic flow and chemical conditions. A series of 46 simulation datasets were created to represent different climatic conditions. These simulations had the same total annual discharge, but demonstrated a range of flow distributions quantified by use of a gamma distribution index, along with two special theoretical cases.
After simulating a year of conduit growth for each of the various flow distributions in a series of model runs, and repeating these sets of simulations for three different passage cross-section geometries, it was evident that the annual temporal distribution of flow did indeed impact the amount of cave growth. However, an increase in the “storminess” of the climate did not simply equate to more dissolution and thus conduit growth. Rather, the quantity and duration of surface contact between water and the conduit walls combined with dissolution rates to affect the total growth. The amount of wetted perimeter (contact between fluid and passage floor/walls) generated by specific conduit to capacity were shown to be very effective at growing the cave. Above this level, the dissolving power of additional water was essentially wasted. This investigation suggests that the maximum amount of passage flow levels depended upon the shape of the passage. Flow conditions that filled the growth occurs under flow conditions that result in the most wetted perimeter for the longest period of time at the highest dissolution rate.
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Steyn, Rochelle. "Modelling the architecture of distal sand-rich lobe deposits : an example from Fan 2, Skoorsteenberg Formation, Tanqua Karoo, South Africa." Thesis, Stellenbosch : University of Stellenbosch, 2009. http://hdl.handle.net/10019.1/2608.
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MScThesis (MSc (Earth Sciences))—University of Stellenbosch, 2009.
Fan 2, one of five submarine fan systems of the Tanqua fan complex in the south-western Karoo Basin, South Africa, is subdivided into Lower, Middle and Upper units. Here, detailed analysis of the internal architecture and distribution of lithofacies associations of Middle Fan 2 facilitated the 3-D visualisation of the sedimentological and stratigraphical changes towards the pinch-out. Middle Fan 2 is interpreted to be a lower-fan, sand-rich terminal lobe, comprising three sandstone-lobe elements, separated by two siltstone interlobe elements. It is fed by a distributary channel that is hypothetically positioned to the west-southwest of the study area. The sandstone-lobe elements pinch out downdip to the north-east and updip to the southsouthwest in the study area. The consecutive pinch out of lobe elements to the north-east indicates a progradational stacking pattern similar to the entire lobe complex. Palaeocurrent analysis and the interpretation of isopach maps indicate that the transport direction of Middle Fan 2 was in a north-easterly direction. The fringes of the lobe and the distribution of internal elements (channels, amalgamated sheets and sheets) show a finger-like geometry in plan-view, in contrast to simple radial-lobe bodies that are commonly envisaged.
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Johnson, Crystal. "Using Kriging, Cokriging, and GIS to Visualize Fe and Mn in Groundwater." Digital Commons @ East Tennessee State University, 2015. https://dc.etsu.edu/etd/2498.
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For aesthetic, economic, and health-related reasons, allowable concentrations of iron (Fe) and manganese (Mn) found present in drinking water are 0.3 mg/L and 0.05 mg/L, respectively. Water samples taken from private drinking wells in the rural communities within Buncombe County, North Carolina contain amounts of these metals in concentrations higher than the suggested limits. This study focused on bedrock geology, elevation, saprolite thickness, and well depth to determine factors affecting Fe and Mn. Using ArcGIS 10.2, spatial trends in Fe and Mn concentrations ranges were visualized, and estimates of the metal concentrations were interpolated to unmonitored areas. Results from this analysis were used to create a map that delineates the actual spatial distribution of Fe and Mn. The study also established a statistically significant correlation between Fe and Mn concentrations, which can be attributed to bedrock geology. Additionally, higher Fe in groundwater was concentrated in shallower wells and valley areas.
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Aly, Husein, and Gur Singh. "Värmesystem." Thesis, KTH, Byggvetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-173954.
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Rapporten handlar om att jämföra fyra olika värmesystem med varandra. Dessa värmesystem är bergvärmesystem, sjövärmesystem, markvärmesystem och akvifersystem. Strukturen på rapporten ser ut på följande: Först beskrivs varje systemför sig, alltså hur hela systemet fungerar och sedan beskrivs nackdelar samt fördelar för varje system. Vid val av rätt värmesystem är det olika för olika villor eftersom alla har olika förutsättningar. Vid diskussion jämförs dessa fyra värmesystem med varandra utifrån just dessa förutsättningar. De förutsättningar som jämförs med varandra om de olika systemen går att hitta under rubriken målformulering längre fram.This rapport is about evaluating four different heating systems. These systems are first, each system is described, how it works and then pros and cons with each system. Choosing the right heating system is different for different buildings since they all have different conditions. In the discussion these four systems are compared to each other considering all these conditions. The Conditions examined can be found in the beginning of the report.
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Hall, Veronica. "Addressing Water Resource Issues In Barbados Through An Isotopic and Atmospheric Characterization of Precipitation Variability." TopSCHOLAR®, 2014. http://digitalcommons.wku.edu/theses/1356.
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Numerous studies have analyzed isotopic variation of meteoric and dripwater in karst environments for paleoclimate reconstructions or aquifer recharge capacity. What is poorly understood is how the isotopic signal of δ18O and δ2H is transferred through the hydrologic cycle based upon storm type, frequency, intensity, and teleconnection activity in the tropical karst areas. At Harrison’s Cave, Barbados, a Hobo Onset event data logger was attached to a tipping bucket rain gauge to count the tips and record the total rainfall every 10 minutes. In the cave a Hobo data logger was used to record relative humidity and temperature at 10-minute intervals. Rainwater, dripwater, and stream water samples were collected at a weekly resolution and refrigerated before sample analysis. The study period was from July, 2012 to October, 2013, with data from the data loggers only until June, 2013 due to inability to reach the study site. The samples were analyzed using the Picarro Cavity Ring Down Spectroscopy Unit-Water L1102-I through laboratories at the University of Kentucky and the University of Utah. The samples were reported in per mil and calibrated. The teleconnection (NAO, AMO, and ENSO) and other atmospheric data were obtained from the Climate Prediction Center or the NOAA Earth System Research Laboratory-Physical Sciences Division. The weekly isotope signatures were linearly regressed against total rainfall for Harrison’s Cave and surface temperature with no statistically significant correlation, indicating the amount effect was not present at a weekly resolution. The amountweighted precipitation δ18O values were calculated on a monthly basis and compared to TRMM monthly rainfall and island-wide monthly rainfall, and a statistically significant negative correlation was found between both datasets. This confirmed that the amount effect dominates the island’s rainfall isotopic signature at a monthly resolution, and that specific atmospheric influences represented in weekly rainfall were less influential on a weekly basis. It is hypothesized that the variation in weekly rainfall is due to quick initiating, rain-out, and dissipation of convective storm systems over the island. In terms of evaporative influences, the samples do not deviate much from the Global Meteoric Water Line (GMWL), indicating minimal evaporation, which is typical for tropical locations. When the d-excess parameters were calculated, there were distinct variations with minimal evaporation occurring in the 2013 calendar year. This is attributed to coastal storm formation in the tropics.
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Kehrwald, Natalie Marie. "Low-latitude Ice Cores and Freshwater Availability." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1245169721.
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Dean, David James. "A River Transformed: Historic Geomorphic Changes of the Lower Rio Grande in the Big Bend Region of Texas, Chihuahua, and Coahuila." DigitalCommons@USU, 2009. https://digitalcommons.usu.edu/etd/378.
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Over the last century, the construction and management of large dams and stream-flow diversions, and periodic drought have resulted in significant declines in stream flow of the lower Rio Grande in the Big Bend region. Reductions in mean annual flow and peak discharge have resulted in channel narrowing by the formation of vertically accreting inset floodplains. Narrowing has been temporarily interrupted by infrequent large dam releases greater than 1000 m3/s that have temporarily widened the channel; however, after each of these events, narrowing has resumed. Prior to 1942, floods of this magnitude occurred approximately once every 4 years and maintained a wide sandy channel. Since 1942, they have occurred 4 times. The decline in frequency of these large floods has resulted in a channel approximately 50% narrower than in the 1940s. Since the most recent channel widening floods in 1991, the channel has narrowed between 35 and 50%. In two large floodplain trenches, we observed between 2.75 and 3.5 m of vertical accretion during the same period. Additionally, nearly 90% of bare active channel bars have been converted to vegetated floodplains. Since 1991, the cross section channel area at the Johnson Ranch gage has decreased by approximately 30%. The reduction in cross section area and the invasion of non-native vegetation have resulted in higher flood stages, flooding at lower discharges, and continued vertical accretion. Channel narrowing has negatively impacted the native and endemic aquatic ecosystem through the loss of ecologically important habitats such as backwaters, side channels, and low velocity portions of the channel. Reductions in cross section area and resultant increased flood stages have also endangered historic cultural sites within the Big Bend region. Restoration efforts are currently underway within the region without a clear understanding of these historical channel changes and why they occurred. Our reconstruction of historical channel changes shows that the most significant periods of channel narrowing occurred during drought and increased stream-flow management. Management practices also appear to have enabled the invasion of non-native riparian species, which promoted sedimentation, bank stabilization, and additional channel narrowing. In order to restore historical measures of channel width, management options include non-native vegetation removal, common low magnitude dam releases that provide flood disturbance and prevent vegetation establishment, and large dam releases in excess of 1000 m3/s that create and maintain a wide channel. Vegetation management is expensive; and time consuming, and managed dam releases are politically unpopular and expensive, however, without the management of non-native riparian species and reinstatement of portions of the historical flood regime, ecological restoration will be difficult.
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Steinberg, Rebecca M. "Predicting Post-Mining Hydrologic Effects of Underground Coal Mines in Ohio throughMultivariate Statistical Analyses and GIS Tool Building." Ohio University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1555429886192267.
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Webster, James William. "Radon Contamination of Residences in a City Built Upon a Karst Landscape Bowling Green, Warren County, Kentucky." TopSCHOLAR®, 1990. http://digitalcommons.wku.edu/theses/1682.
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The United States Environmental Protection Agency (EPA) estimates that 8 to 12% of U.S. homes have radon concentrations that equal or exceed 4 picocuries per liter (pCi/l). A statewide screening of Kentucky by EPA resulted in an average residential radon concentration of 2.8 pCi/l with 17% of the homes at or above 4 pCi/l. EPA requires routine monitoring and maintenance or worker health records in mines and caves having radon daughter concentrations at or above 0.30 working levels (WL).
Bowling Green is a city located in a karst region of south central Kentucky. Residents of Bowling Green have been subjected to various environmental hazards that are closely linked with the landscape. Of particular concern has been the recurring problem of chemical fumes rising from contaminated caves and collecting in buildings.
The author has recorded radon daughter concentrations in excess of 5 WLs in caves beneath Bowling Green. A preliminary screening of residential radon concentrations in Bowling Green resulted in an average concentration of 25.8 pCi/l. Two of the test results were above 100 pCi/l and were recorded in homes that were known to have a history of fume problems. These results spurred this thesis which addresses the magnitude of residential radon contamination in Bowling Green and its association with the karst landscape.
The investigation involved radon daughter testing in Bowling Green caves and residential radon testing. A total of 84 measurements were conducted in order to establish a working average residential radon concentration for the city. Twelve other tests were performed in buildings known to have a history of chemical fume problems. The resulting average residential radon concentration was 9.06 pCi/l. First floor measurements averaged 4.73 pCi/l, and basement measurements averaged 22.92 pCi/l. The overall average for buildings with a history of fume problems was 35.15 pCi/l with first floors and basements averaging 29.75 and 57.40 pCi/l respectively. Forty-six percent of the homes comprising the sample population equaled or exceeded 4 pCi/l.
The results of the investigation indicate that: Bowling Green Caves sometime have radon daughter concentrations far in excess of 0.30 WL. The average residential radon concentration for Bowling Green exceeds the average for Kentucky obtained by EPA. The percentage of houses that have radon concentrations at or above 4 pCi/l for the study area exceeds the estimated national average of 8 to 12% and the statewide average.
The author suggests that insufficient data was collected to determine whether radon concentrations in Bowling Green homes with a history of chemical fume problems are higher than for the city as a whole.
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Wilder, Jason. "Modeling malaria transmission risk using satellite-based remote sensing imagery a five-year data analysis in Democratic People's Republic of Korea : a thesis presented to the Department of Geology and Geography in candidacy for the degree of master of science /." Diss., Maryville, Mo. : Northwest Missouri State University, 2007. http://www.nwmissouri.edu/library/theses/WilderJason/index.htm.
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Thesis (M.S.)--Northwest Missouri State University, 2007.The full text of the thesis is included in the pdf file. Title from title screen of full text.pdf file (viewed on January 25, 2008) Includes bibliographical references.
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Conley, Gary D. "Examining the Cover and Composition of the Successional Vegetation Mosaic of Pre-SMCRA Mined Landscapes in Southeast Ohio." Ohio University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1357751096.
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Salyer, Melanie. "An evaluation of the economic and environmental impacts of coal mining Flat Gap, Pound, Wise County, Virginia, as case study : a thesis presented to the Department of Geology and Geography in candidacy for the degree of Master of Science /." Diss., Maryville, Mo. : Northwest Missouri State University, 2006. http://www.nwmissouri.edu/library/theses/SalyerMelanie/index.htm.
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Thesis (M.S.)--Northwest Missouri State University, 2006.The full text of the thesis is included in the pdf file. Title from title screen of full text.pdf file (viewed on January 25, 2008) Includes bibliographical references.
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Nedvidek, Daniel C. "Evaluating the Effectiveness of Regulatory Stormwater Monitoring Protocols on Groundwater Quality in Urbanized Karst Regions." TopSCHOLAR®, 2014. http://digitalcommons.wku.edu/theses/1407.
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Non-point pollution from stormwater runoff is one of the greatest threats to water quality in the United States today, particularly in urban karst settings. In these settings, the use of karst features and injection wells for stormwater management results in virtually untreated water being directed into the karst aquifer. Currently, no policies exist specifically to provide water quality protections to karst environments. This study utilized a combination of karst stormwater quality data, along with survey data collected from MS4 Phase II communities, and an analysis of current federal, local, and state water quality regulations, to assess the need for karst-specific water quality regulations. Water quality data indicate that significant levels of contamination are mobilized during storm events, and often are directed into the karst system via Class V injection wells. Survey data collected from MS4 stakeholders in the karst regions of Kentucky indicate stakeholders are generally unable to explain local karst regulations or the steps taken to develop them. This confusion comes in part from insufficient progress on evaluation criteria available for the MS4 Minimum Control Measures (MCMs). Karst waters are often placed into the legal “gray zone” due in part to differences in definitions of key terms in state and federal regulations. This study recommends the development of regulations specific to karst waters at the state and federal levels through either the adaptation of existing or creation of new policies, which place an emphasis on the integration of water quality monitoring and karst education.
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Baca, Kira J. "Environmental Impacts on the Development and Dune Activity of Oxbow Lake along the Southwest Coast of Lake Michigan at Saugatuck, Michigan USA." University of Toledo / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1365161018.
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Russell, Jr Scot Allan. "Analysis of Fresh Water Resources at the Line Hole Well Field, San Salvador Island, the Bahamas." TopSCHOLAR®, 2010. http://digitalcommons.wku.edu/theses/164.
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A major economic constraint in the Bahamas, and other small carbonates islands world-wide, is the lack of fresh water resources. To combat these socio-economic problems on San Salvador Island I sought to gain a more detailed understanding of the extent, behavior, and controls on the island’s fresh-water lens. DC electrical resistivity tomography and time-series geochemical data are used to study the fresh water lens at the Line Hole well field. Electrical Resistivity profiles are used to image the extent of fresh water resources. Time-series geochemical data provide information on the behavior of the fresh water resources as a function of time.
The inversion models of the electrical resistivity profiles illustrate a fresh water lens less than 3 meters thick on average. The mixing zone is diffuse in nature, and substantially thicker than the fresh water lens. The geochemical results corroborate the fresh water lens dimensions predicted by the electrical resistivity model. In addition, mixed semi-diurnal and spring/neap tidal cycles are the primary control on the water level. Statistical analysis of specific conductance and temperature illustrate a positive and negative correlation with water level, respectively. Analysis of precipitation with respect to water level and geochemistry indicate low effective recharge rates during the period of study.
The current state of the water resources at the Line Hole well field is strained. Despite moderate levels of freshening since the termination of pumping in December 2006; the system continues to be in a state of disequilibrium. The problem is compounded by abnormal thickening of the mixing zone due to communication of the well field with the ocean, and a limited volume of fresh water. In conclusion, the two techniques used in conjunction provide a non-invasive method of estimating fresh water resources in this type of setting. Conversely, the high RMS and L2 values for the electrical resistivity models and limited time-series data create a high level of uncertainty in the interpretation of results.
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Erasmus, Lelandi. "Virtual reconstruction of stratigraphy and past landscapes in the West Coast Fossil Park region." Thesis, Link to the online version, 2005. http://hdl.handle.net/10019/1640.
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Able, Anthony. "Karstification of the Pennyroyal Plain Behind the Retreating Chester Escarpment: Warren, Simpson & Logan Counties, Kentucky." TopSCHOLAR®, 1986. http://digitalcommons.wku.edu/theses/1211.
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Hydrogeologic investigations were conducted on the drainage systems of an area of the Pennyroyal sinkhole plain of south central Kentucky. The degree of karstification of five area streams was studied to develop an understanding of the evolution of drainage as the landscape changes from a sandstone caprock plateau to a limestone sinkhole plain. The Chester Upland, capped by the Big Clifty Sandstone, possesses predominantly surface drainage and the Pennyroyal Plain, formed on Mississippian limestones, possesses considerable subsurface drainage. As the Chester Upland Escarpment retreats and surface streams are onto the limestones, the streams evolve to become subsurface streams. The five streams observed in the study (all flowing on limestones) demonstrated less karst development close to the Chester Escarpment and more karst development with increasing distance from the escarpment. Sediments derived from the escarpment and plateau blanket the stream beds thus perching the streams and preventing chemically aggressive water from forming karst solution features in the limestones. The streams farther away from the escarpment are removed from the sediment source and are therefore able to downcut into the limestone and invade the subsurface to become cave streams.
Lithologic investigation of limestones exposed in stream beds revealed that minor resistant units can act to diminish downcutting and maintain short sections of surface flow. The stream investigated was not flowing on a perching layer, but instead was held on the surface by a stratigraphic control (spillover layer) that prevented subterranean stream invasion.
Dye traces conducted on groundwater flow in the sinkhole plain revealed that the area drainage pattern is changing as surface streams invade the subsurface and that integration between drainage basins is taking place. Stream piracy and stream diversion are occurring in the subsurface causing alteration of the existing topographic drainage divides that developed before the surface streams invaded the subsurface.
A general model is presented which shows the evolution of surface drainage to subsurface drainage, as the Chester Escarpment continues its northwestward retreat.
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Pollack, Gerald D. "Timing and Characterization of the Change in the Redox State of Uranium in Precambrian Surface Environments: A Proxy for the Oxidation State of the Atmosphere." unrestricted, 2008. http://etd.gsu.edu/theses/available/etd-12052008-125923/.
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Thesis (Ph. D.)--Georgia State University, 2008.Title from file title page. Eirik J. Krogstad, committee chair; Andrey Bekker, committee co-chair; W. Crawford Elliott, Timothy E. LaTour, committee members. Description based on contents viewed Aug. 27, 2009. Includes bibliographical references (p. 207-219).
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Wikel, Geoffrey L. "Variability in Geologic Framework and Shoreline Change: Assateague and Wallops Islands, Eastern Shore of Virginia." W&M ScholarWorks, 2008. https://scholarworks.wm.edu/etd/1539617877.
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Lyles, Frank. "Climate Change Adaptation for Southern California Groundwater Managers: A Case Study of the Six Basins Aquifer." Scholarship @ Claremont, 2017. http://scholarship.claremont.edu/pomona_theses/172.
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Groundwater has been very important to the economic development of Southern California, and will continue to be a crucial resource in the 21st century. However, Climate Change threatens to disrupt many of the physical and economic processes that control the flow of water in and out of aquifers. One groundwater manager, the Six Basins Watermaster in eastern Los Angeles and western San Bernardino Counties, has developed a long-term planning document called the Strategic Plan that mostly fails to address the implications of Climate Change, especially for local water supplies. This thesis presents an in-depth analysis of the Six Basin Watermaster’s Strategic Plan as a case-study of how groundwater managers can improve their planning assumptions to better prepare for Climate Change. It begins with a brief history of how Southern California’s environment influenced the development of the institutions that manage the Six Basins’ groundwater, then provides a physical description of the aquifer itself. The current scientific literature on Climate Change’s expected impacts on California water supplies are summarized, and the implications of these impacts for basin management are highlighted. The Strategic Plan’s projects are evaluated and critiqued in light of these insights, including a need for the Strategic Plan to: explicitly consider Climate Change in its planning assumptions, use decision-making frameworks that account for uncertainty, and prepare for more frequent droughts and floods in the future. Climate Change will have important effects on how Southern California’s groundwater is managed, and the Six Basins Strategic Plan should be revised to better account for these impacts.
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Nordlund, Christer. "Det upphöjda landet : vetenskapen, landhöjningsfrågan och kartläggningen av Sveriges förflutna, 1860-1930." Doctoral thesis, Umeå universitet, Historiska studier, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-56808.
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Taking the establishment of Ice Age theory as its point of departure, the present dissertation examines aspects of geological, plant geographical and archaeological research on shoreline displacement conducted in Sweden during the period 1860-1930, and the significance of this research for the perception of "the Swedish landscape" and its post-glacial history. The research is analyzed on three levels under the rubrics "The Highest Shoreline and the Ancylus Lake", "The Question of Land Elevation", and "Charting Swedens Past", respectively. Taken together, these levels capture the varying perceptions and exchanges of opinion of the nature of shoreline displacement and the contexts in which they were applied. The present study is conducted via a theoretical and methodological approach where both the ideas and the practices of science are studied: activities in the field and at the various institutions (primarily the Swedish Geological Survey, its museum and the Geological Society of Stockholm); arguments and hypotheses presented in artides and handbooks, including visual images, diagrams and maps; social networks, career paths and controversies. Particular attention is paid to the relationship between science and nationalism, and comparisons are made with research conducted in an imperialist context. Ice Age theory helped initiate research whose purpose was to discover how the Swedish naturai and cultural landscape carne into being. The foremost task of geology became studying geographic evolution during the Quaternary epoch, how the land had "risen from ice and water". Plant geography studied how and whence plant life had migrated and how vegetation had evolved under the influence of biological, geological and climatological factors. In a similar manner, archaeologists studied the migration and dissemination of mankind during the StoneAge. When natural scientists primarily used "natural landmarks" as its source material, archaeologists relied on "archaeological finds", which were invested with scientific value but also became symbols of national collective memory. Through this survey, national identity was unifìed with the territory itself and its evolutionary history. Knowledge about shoreline displacement became significant for geology, plant geography and archaeology, which in turn encouraged interdisciplinary collaboration, but also locked the researchers into a similar way of thinking about the nature of shoreline displacement. According to this "thought style", the phenomenon was first and foremost the result of the vertical movement of the land rather than movement in the ocean surface. Up until the 1870s, the Ice Age was thought to have been followed by one single subsidence and elevation; during the 1880s, two such land oscillations; three during the 1910s and by the 1920s, five. Only toward the end of the 1920s did Swedish researchers begin to accept a multi-factor explanation, which succeeded in finally subverting the reigning thought style. According to this explanation, shoreline displacement was not solely the result of changes in the land or the sea, but of both.digitalisering@umu
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Heyman, Jakob. "Glacial geology of Bayan Har Shan, northeastern Tibetan Plateau." Licentiate thesis, Stockholm University, Department of Physical Geography and Quaternary Geology, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-7507.
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The paleoglaciology of the Tibetan Plateau is still largely unexplored, despite its importance for regional and global climate reconstructions. In this thesis a comprehensive glacial geological record is presented from an extensive part of the northeastern Tibetan Plateau centred on the Bayan Har Shan. Glacial reconstructions for this region range from restricted mountain glaciers through the intermediate-size regional-scale Huang He ice sheet to a plateau-scale Tibetan ice sheet. To provide a robust basis for glacial reconstructions, this thesis provides conclusions based on two principle methods, remote sensing and field studies. The remote sensing of a 90 m resolution digital elevation model and 15- and 30 m resolution satellite imagery renders a detailed data set with complete spatial coverage of large- and medium-scale glacial landforms, and large-scale plateau geomorphology. Observations from fieldwork campaigns add detailed point information for the distribution of glacial deposits. Geomorphological glacial traces such as glacial valleys, glacial lineations, marginal moraines, meltwater channels, and hummocky terrain occur frequently in elevated mountain areas, indicating former alpine-style glaciations. Glacial deposits in the form of till, erratic boulders, and glaciofluvial sediments are common in areas with mapped glacial landforms, but also beyond, in areas lacking large-scale glacial landforms. For extensive plateau areas in-between formerly glaciated mountain blocks, there is a striking absence of glacial landforms and sediments, indicating that these areas, perhaps, never were ice covered. Interestingly, glacial deposits occur further away from the mountain blocks than the large- and medium-scale glacial landforms, indicating insignificant erosion beneath the maximum ice covers close to their margins.
The large-scale geomorphology of the northeastern Tibetan Plateau is characterised by a low-relief plateau surface with glacial valleys in elevated mountain blocks and marginal steep V-shaped valleys. This geographical distribution indicates a dominance of glacial erosion in the elevated mountain areas and a dominance of fluvial erosion along the steep plateau margins, dissecting a relict plateau surface. The outline of the relict plateau surface mimics the proposed outline of the Huang He ice sheet, suggesting that the inferred ice sheet may represent a misinterpreted relict surface with scattered glacial traces.
In conclusion, the glacial geology examined in the Bayan Har Shan region is consistent with paleo-glaciers of varying extent restricted to elevated mountain areas. Even though extensive icefields/ice caps were centred on discrete mountain areas, there is no indication that these ice masses merged but rather that they were separated from each other by unglaciated plateau areas. The presented glacial geological record will be used in further studies towards a robust paleoglaciological reconstruction for the northeastern Tibetan Plateau.
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Link, Adam John. "Identifying Potential Patterns of Wildfires in California in Relation to Soil Moisture using Remote Sensing." Bowling Green State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu158646328387007.
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Kemp, Matthew L. "Characterizing the Depositional History of Three Ponds, Bath Nature Preserve, Bath, Ohio." University of Akron / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=akron1270834695.
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Van, Brabant Reid. "Lacustrine sediment records of debris flow activity, northwestern British Columbia and southwestern Yukon Territory." Thesis, University of Ottawa (Canada), 2004. http://hdl.handle.net/10393/26791.
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Lacustrine sediment records were used to examine debris flow magnitude and frequency at two sites in northwestern Canada. A rod-driven piston corer was used to collect four lacustrine sediment cores from Mount Aramis Lake, Yukon Territory (YT) and five from Three Guardsmen Lake, British Columbia (BC).
Nine layers deposited in the Lacustrine sediment of Mount Aramis Lake over an estimated 3400 to 3800 yrs and ten layers deposited in Three Guardsmen Lake over an estimated 3000 to 3500 yrs are inferred to be due to debris flows. However, these layers represent the minimum number of events because lacustrine sediments only contain a record of debris flows with sufficient energy to reach the lake. Variations in the sedimentary structure of the debris flow layers between the sites could not be attributed to differences in debris flow magnitude and frequency resulting from local variations in slope gradients, debris supply, or precipitation.
The lacustrine, terrestrial, and climatic evidence indicates that lower precipitation at Mount Aramis may result in higher magnitude, lower frequency debris flows. Conversely, higher precipitation at Three Guardsmen Mountain may cause lower magnitude, higher frequency debris flows. However, these are preliminary conclusions and further research regarding the relationship between precipitation regime, debris supply, and debris flow magnitude and frequency is required.
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Barrett, Kelly A. "Identifying Building Sites in Summit County, Colorado: Geography, Geology, and GIS." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1238024467.
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Pachos, Alexander. "An Empirical Study of Cave Passage Dimensions Using Augmented Radial and Longitudinal Survey Data." University of Akron / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=akron1221760340.
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Basagic, Hassan J. "Quantifying Twentieth Century Glacier Change in the Sierra Nevada, California." PDXScholar, 2008. https://pdxscholar.library.pdx.edu/open_access_etds/2239.
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Numerous small alpine glaciers occupy the high elevation regions of the central and southern Siena Nevada, California. These glaciers change size in response to variations in climate and are therefore important indicators of climate change. An inventory based on USGS topographic maps (l :24,000) revealed 1719 glaciers and perennial snow and ice features for a total area of 39.l5 ±7.52 km2. The number of 'true' glaciers, versus non-moving ice, is estimated to be 118, covering 15.87 ± 1.69 Km2. All glaciers were located on north to northeast aspects, at elevations >3000 m. Historical photographs, geologic evidence, and field mapping were used to determine the magnitude of area loss over the past century at 14 glaciers. These glaciers decreased in area by 31% to 78%, averaging 55%. The rate of area change was determined for multiple time periods for a subset of seven glaciers. Rapid retreat occurred over the first half of the twentieth century beginning in the 1920s in response to warm/dry conditions and continued through the mid-1970s. Recession ceased during the early 1980s, when some glaciers advanced. Since the 1980s each of the seven study glaciers resumed retreat.
The uniform timing of changes in area amongst study glaciers suggests a response to regional climate, while the magnitude of change is influenced by local topographic effects. Glacier area changes correlate with changes in spring and summer air temperatures. Winter precipitation is statistically unrelated to changes in glacier area. Headwall cliffs above the glaciers alter the glacier responses by reducing incoming shortwave radiation and enhancing snow accumulation via avalanching.