Karakalpakstan, Uzbekistan, has faced water scarcity and low water during several years as a consequence of Uzbekistan’s extensive irrigation of cotton fields. The environmental status of the Mejdurechye Reservoir, which is the largest in the lower Amudarya Delta, is therefore of great local importance. This thesis quantifies pollutant mass flows through the reservoir, concidering for instance salt, DDT and Lindane (HCH). Surface water flow paths through Mejdurechye Reservoir are also conceptualized in order to provide suggestions for future a possible monitoring program. Results show that chloride concentrations have decreased during July 2007-2008 with at least 10% in spite of a large specific evaporation and a reservoir volume reduction of at least 60%. The most important implication of this is that pollutants in the reservoir cannot have been subject of evapoconcentration during this period. DDT and Lindane have on the other hand increased with up to 50000% in concentration and 20000% mass compared to measurements dating back to 2002. A rough age estimation of DDT shows that the DDT has been mobilized recently. The results of this thesis may prove valuable when forming environmental policy plans and setting up future monitoring programs.

Understanding the link between the Sun and climate is vital in the current incidence of global climate change, and 10Be in natural archives constitutes an excellent tracer for this purpose. As cosmic rays enter the atmosphere, cosmogenic isotopes like 10Be and 14C are formed. Variations in solar activity modulate the amount of incoming cosmic rays, and thereby cosmogenic isotope production. Atmospherically produced 10Be enters natural archives such as sediments and glaciers by wet and dry deposition within about a year of production. 10Be from natural archives therefore provides information on past solar activity, and because these archives also contain climate information, solar activity and climate can be linked. One remaining question is to what degree 10Be in natural archives reflects production, and to what extent the local and regional environment overprints the production signal. To explore this, 10Be was measured at annual resolution over the last 600 years in a Greenland ice core. Measurement potentials for these samples benefited from the development of a new laboratory method of co-precipitating 10Be with niobium. To diversify geographic location and archive media type, a pioneer study of measuring 10Be with annual resolution in varved lake sediments from Finland was conducted, with samples from the entire 20th century. Pathways of 10Be into lake sediments are more complex than into glacial ice, inferring that contemporary atmospheric conditions may not be recorded. Here, it is shown for the first time that tracing the 11-year solar cycle through lake sediment 10Be variations is possible. Results also show that on an annual basis, 10Be deposition in ice and sediment archives is affected by local environmental conditions. On a slightly longer timescale, however, diverse 10Be records exhibit similar trends and a negative correlation with solar activity. Cyclic variability of 10Be deposition persisted throughout past grand solar minima, when little or no sunspot activity was recorded. 10Be levels indicate that although solar activity has been high during the 20th century, levels are not unprecedented in the investigated 600 years. Aerosol 10Be/7Be values indicate possible influence of stratosphere-troposphere exchange on isotope abundance and the production signal.

A Quaternary perspective on the paleoceanographic evolution of the central Arctic Ocean has been obtained in this PhD thesis by studying sediment cores from all of the Arctic’s major submarine ridges and plateaus. The included cores were mainly recovered during the Healy-Oden Trans-Arctic expedition in 2005 and the Lomonosov Ridge off Greenland expedition in 2007. One of the main thesis objectives is to establish whether different sediment depositional regimes prevailed in different parts of the central Arctic Ocean during the Quaternary and, if so, establish general sedimentation rates for these regimes. This was approached by dating key cores using the decay of the cosmogenic isotopes 10Be and 14C, and through stratigraphic core-to-core correlation using sediment physical properties. However, the Arctic Ocean sea ice complicated the use of 10Be for dating because a solid sea ice cover prevents the 10Be isotopes from reaching the seafloor, resulting in too old ages. Dating using 14C is also complicated due to uncertain marine reservoir age corrections in the central Arctic Ocean. The core-to-core correlations show five areas with different depositional regimes; the northern Mendeleev Ridge and Alpha Ridge, southern Mendeleev Ridge, Morris Jesup Rise, Lomonosov Ridge and Yermak Plateau, listed in the order of increasing sedimentation rates from ~0.5cm/ka to ~4.8 cm/ka. A detailed study of the relationship between sediment bulk density and grain sizes suggests a strong link between variations in clay abundance and bulk density. Grain size analysis of a Lomonosov Ridge core show that fine silt and clay dominates the interglacials, possibly due to increased suspension freezing of these size fractions into sea ice and/or nepheloid transport. Sediments younger than the marine isotope stage (MIS) 7 generally contain more coarse silt, attributed to a regime shift during the Quaternary with increased iceberg transport into the central Arctic Ocean from MIS 6 and onwards. / At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: In progress. Paper 4: In progress. Paper 5: In progress. Paper 6: In progress.

Tephrochronology, or the dating and correlation of stratigraphic sediment sequences by the use of tephra, is a dating method that has been much refined in the last decade. This refinement has enabled the detection of cryptotephra, which has expanded the known distribution of different tephras. At the site Lake Mulakullegöl in the southwest of Sweden, three distinct tephra horizons have been detected, of which two have been geochemically identified. The identified tephras are the Vedde Ash (ca 12,000 cal. yrs BP) and the Hässeldalen Tephra (ca 11,500 cal. yrs BP), both of Icelandic origin. These tephras were deposited during the middle of the Younger Dryas Stadial and the Younger Dryas/Preboreal transition, respectively. The Vedde Ash is one of the most widespread tephras of Icelandic provenance, while the Hässeldalen Tephra so far only has been found at two sites in southeastern Sweden, prior to the current study. A third, unidentified, tephra was also detected. Based on the stratigraphic position, this tephra might be the Borrobol Tephra, which has been dated to ca 14,400 cal. yrs BP. This might indicate that warming had not yet occurred in this part of Sweden. The extended known distribution of especially the Hässeldalen Tephra, but also the Vedde Ash, has enabled a higher potential for correlations between different records deposited during the Last Glacial/Interglacial transition.

In quantitative palaeoecology modern species-environmental relationships can be statistically modelled, and recent development has made the calibration models more statistically robust. These models are used to transform fossil assemblages to quantitative estimates of past environmental conditions. The aim of this thesis is to infer Holocene temperatures from fossil pollen data sampled from lakes in central and southern Sweden. This reconstruction is done by using a north-European pollen-climate calibration model, which was extended with 37 modern pollen samples from the southern deciduous vegetation zone in Sweden within this project. A statistical method is used for deriving the pollen-climate calibration model, weighted averaging partial least square (WA-PLS) method. The long term trends in pollen inferred temperatures from this study reflect low, but rapidly rising temperatures in the early-Holocene, a trend that was temporarily interrupted by a cool period about 8500 cal yr BP, but continued after 8000 cal yr BP. A Holocene thermal maximum (HTM) with temperatures roughly 2°C higher than at present was recorded about 7000 cal yr BP and by 4000 cal yr BP pollen inferred temperatures starts to decline. In order to create a more comprehensive picture of past climate patterns in the investigated area inferred temperatures from this study are compared with independent palaeorecords, a stable oxygen isotope record for moisture variability (paper I) and chironomids for summer temperature (paper II). Taken all together, these records reflect a coherent Holocene climate pattern which also is supported by several studies from Scandinavia and the north Atlantic region. Pollen inferred temperatures and the moisture record are indicating markedly dry, continental climate conditions in southern Sweden during the HTM possibly as a result of reorganisations in regional atmosphere circulations. The local observations in this study of regional climate events, such as the cold period at about 8200 cal yr BP and the dry period at about 7000 to 4000 cal yr BP are of particular interest because they suggest that vegetation in the study region has responded sensitively both to long-term climatic trends and more transient climate events.

Länge har landskapets alla olika processer påverkat och påverkar landskapets utseende och utveckling. Landskapet är i en ständig naturlig förändring, en förändring som är kontinuerlig i tid och rum. Dess strukturer och former är ofta idag avlagringar från istider och processer som skedde för länge sedan och har genom dessa hjälpt människan förstå jordens utveckling. Människan är villkorslöst beroende av landskapet med dess resurser och utnyttjar dem i en allt större utsträckning. Många av resurserna vi utnyttjar har alla sin grund i landskapets geologi. Människans påverkan på landskapet är så pass stor att landskapet med alla dess former och avlagringar hotas om de inte beaktas. För att effektiv kunna anpassa brukande och annan användning av naturens resurser krävs förståelse för landskapets grundstrukturer, geologiska processer och deras resultat. För att i framtiden fortsätta kunna ha kännedom om landskapets bildning och historia och andra samhällsrelevanta faktorer som miljö och vatten är det viktigt att införa de geovetenskapliga värdena i all slags samhällsplanering. När geovetenskapliga värden glöms bort och enbart natur, kultur, friluftslivsvärden etc. sätts i fokus var för sig, förloras helhetssynen. Eftersom de geovetenskapliga värdena är en förutsättning för dessa värden är de ett viktig, idag nästan outnyttjat verktyg för att sammanfoga sektoriella värden till en helhetssyn. I denna studie har en vägplanering valts ut för att illustrera denna brist, där en inventering av studieområdet samt en analys av den valda vägplaneringens rapporter och miljökonsekvensbeskrivningen gjorts. Studien visar att man beaktar värden sektoriellt och oftast objekt för objekt. Helhetssynen på landskapet saknas nästan helt. De geovetenskapliga egenvärdena beaktas inte alls och det verktyg för helhetssyn som geovetenskapen erbjuder används inte alls. / Landscape processes such as erosion and weathering have for very long time shaped and reshaped the landscape. The continuously natural changes of the landscape will never stop. Today its structures and shapes are historical deposits and have helped humans to understand Earth’s history. Humans are unconditionally dependent on Earth’s resources and will continue being so for an unforeseeable future. Human development such as infrastructure alters an unnatural landscape where the natural landscape with all its forms and deposits are threatened to disappear if not protected from exploitation. To continuing understanding Earth’s history in the future and to developing ecological areas, it’s important to introduce the geological values in all types of society planning. When geological values are forgotten or disregarded and ecological values get the majority of attention you loose the bigger picture. Instead a more holistic view is needed that accounts for all natural values. In this study, a path plan has been selected to illustrate this short supply, where an inventory of the study area and an analysis of the selected path plan’s reports and environmental impact assessment have been made. The results from the study indicate that objects are considered object by object and observe the geoscientific values ​​more durable and it’s often unclear how the geological values are affected.

Isolating the climatic mechanisms driving Holocene geomorphic change and deciphering the role of landscape change in prehistoric cultural processes both require well-dated and relatively continuous alluvial chronologies. This study presents a centennial-scale, latest Pleistocene and Holocene chronology based on alluvial fan, floodplain, groundwater-discharge, and volcanic deposits for the Carrizo Wash watershed, a Little Colorado River headwater drainage on the southeastern Colorado Plateau. More than 200 radiocarbon dates provide chronometric control. The age of Zuni Salt Lake volcanic eruptions was re-evaluated using radiocarbon and luminescence dating. Two eruptive phases ~13.3 ka and ~11.8 ka suggest closely spaced, monogenetic events. These terminal Pleistocene ages for the eruptions are significantly younger and substantially more precise than previous argon method ages. Sediment exposed in modern arroyos is dominated by middle Holocene (~7.1–4.9 ka) alluvium in valley contexts, whereas piedmont alluvium dates primarily to the late Holocene (~4.3–2.7 ka). Extensive prehistoric channel entrenchment occurred ~4.9 and 0.8 ka. Localized incision occurred ~1.9 and 1.2 ka, and possibly ~7.5 and 2.7 ka. Extended drought typically preceded arroyo cutting, and entrenchment was associated with increased climate variability, major shifts in precipitation amount or seasonality, and reduced flooding. Accelerated valley and piedmont aggradation appears related to increased flooding and runoff associated with reduced vegetation cover during periods of low effective moisture resulting from enhanced North American Monsoon circulation and weak ENSO conditions. Conversely, slow or stalled deposition appears connected to reduced flooding and runoff fostered by denser vegetation during times of increased effective moisture caused by enhanced El Niños and increased winter precipitation. Ground-water discharge deposits at Cienega Amarilla indicate that spring discharge was greatest and water tables most elevated ~2.3–1.6 ka. Spring discharge appears to reflect variations in El Niño frequency and intensity and the resultant variations in winter precipitation. Study results suggest that predicted increased drought and enhanced or delayed monsoons associated with modern climate change could initiate accelerated erosion of upland areas and increased flooding in southern Colorado Plateau headwater tributaries. Archaeological implications include temporal biases associated with surface site distributions and changing viability of floodwater and water-table farming over time.

The Greys River fault is the easternmost active normal fault associated with Basin and Range extension in the lntermountain seismic belt. It is a north south trending normal fault, located in the Sevier-age fold and thrust belt of western Wyoming , and bounds the west side of the Wyoming Range . The fault is at least 54 km long , and juxtaposes Permo-Pennsylvanian Wells Formation against various Triassic formations . Throw ranges from 100-1000 m. Seismic reflection data suggest that the Greys River fault is a listric normal fault that soles into the Darby thrust at depth. The fault offsets late Quaternary deposits on the west flank of the Wyoming Range. These deposits were mapped and differentiated on the basis of provenance and weathering characteristics. Four sets of moraines were identified in the study area. The moraines segregated into a local four-fold relative age sequence based on topographic position and relative dating parameters. The four-fold relative age sequence was correlated to Blackwelder's original Rocky Mountain glacial chronology. The most extensive glacial deposits were correlated to the late Pinedale glacial advance. Alluvial deposits associated with the Pinedale glacial cycle also contain evidence for late Quaternary faulting on the Greys River fault. Maximum vertical surface displacements of late Quaternary deposits range from 8.6 m in Blind Bull Creek to 8.3 m in Box Canyon, 25 kilometers to the south. Between these points, vertical surface offset ranges from 3 to 8.2 meters. Three trenches were excavated in a late Pinedale alluvial terrace complex in Sheep Creek across a 7.5-meter scarp, a 3.1-meter scarp, and a 7.5-meter scarp-graben. The trenches revealed evidence for two paleoseismic displacements, the ages of which were constrained by eight radiocarbon dates. The most recent event involved a maximum displacement of 4.5 meters and occurred between 2110 +/- 60 and 2910 +/- 60 14C years BP. The earlier event was associated with a maximum observed displacement of 3.2 meters and occurred between 5080 +/- 60 and 5310 +/- 60 14C years BP. The moment magnitudes for these events, calculated from displacement and surface rupture length , range from Mw = 6.9 to 7.4 for both events. Scarp heights indicate an uplift rate of 1.11 mm / year. If the late Pinedale alluvium is 14,000 years old, then it appears no events occurred between 14,000 yr BP and 5310 14C yr BP, and two events have occurred between 5310 14C yr BP and 2110 14C yr BP. Such irregular recurrence interval is typical for normal faults in the Basin and Range and makes long-term prediction difficult.

<p>Extensive assemblages of glacial erosional features are commonly observed on bedrock outcrops in deglaciated landscapes. There is considerable debate regarding the origins of many subglacial erosional landforms, due to a relative paucity of detailed data concerning these features and a need for improved understanding of the subglacial processes that may form them. This study presents detailed documentation and maps of assemblages of glacial erosional features from select field sites throughout the Great Lakes basins. The characteristics and spatial distribution of p-forms exposed on variable substrates at the Whitefish Falls, Vineland, Pelee Island and Kelleys Island field sites were investigated in order to determine the mode of p-form origin to identify significant spatial and temporal variability in subglacial processes operating at these locations. Observations from this work suggest that p-forms evolve through multiple phases of erosion, whereby glacial ice initially abrades the bedrock surface, leaving behind streamlined bedrock highs, striations and glacial grooves. Subsequent erosion by vortices in turbulent subglacial meltwater sculpts the flanks of bedrock highs and grooves into p-forms. These forms are subjected to a second phase of subglacial abrasion that ornaments the sinuous, sharp rimmed features with linear striae. The presence of multi-directional (‘chaotic’) striae at some sites suggests erosion by saturated till may contribute to, but is not essential for p-form development. Investigation in the Halton Hills region of Ontario focused on modeling bedrock topography in order to delineate the extent and geometry of buried bedrock valleys thought to host potential municipal significant aquifer units. Various approaches to subsurface modeling were investigated in the Halton Hills region using a combination of primary data (collected from boreholes and outcrop), intermediate data collected through aerial photography and consultant reports, and extensively screened low quality data from the Ontario Waterwell Database. A new, ‘quality weighted’ approach to modeling variable quality data was explored but proved ineffective for the purposes of this study, as differential weighting of high and low quality data either over-smoothed the model or significantly altered data values. A series of models were interpolated and compared using calculated RMSE values derived from model cross-validation. The preferred bedrock topography model of the Halton Hills region had the lowest RMSE score, and allowed identification of three major buried bedrock valleys systems (the Georgetown, Acton and 16 Mile Creek buried valleys) which contain up to 40 – 50 m of Quaternary infill. These valleys were likely carved through a combination of fluvial and glacial erosion during the late Quaternary period, and their orientation may be influenced by pre-existing structural weaknesses in the bedrock. Future work on subglacial erosional landforms should focus on the temporal scale in which subglacial processes, through association with other subglacial landforms and dating methods.</p> / Master of Science (MSc)

<p>In the Kisumu District, Kenya, unreliable rainfall pattern has been identified as one of the main causes for poverty in rural areas. The negative effects of such unreliable patterns could be mitigated through improved water resource management and planning. However, estimates of current (and future) water availability will likely differ depending on whether managers draw upon data gathered at a local-scale or regional-scale. This is particularly important in developing regions where, due to lack of data availability, managers are often limited in their choice of data resolution. This study investigates the potential effect of spatial resolution of data on water management and planning by comparing hydro-climatic trends in local-scale data with trends in regional-scale data. The influence of adopting local-scale versus regional-scale data is further demonstrated by estimate the storage requirements of proposed irrigation ponds for farmers in the Orongo village of the Kisumu District located in Kenya, Africa. Results indicate a low correlation between local and regional hydro-climatic trends. Data spatial scale directly influences water resources management leading to a 300% difference in estimated storage requirement for the average farmer.</p>