The Quaternary geology of Chatham Island has been investigated using several different techniques, including: tephrochronology, mineralogy, palynology and stratigraphy; in an attempt to draw together a Quaternary history for the Island. The Quaternary record of Chatham Island comprises mainly deposits from terrestrial environments, predominantly thick blanket peats and aeolian sand, all of which range from latest Castlecliffian to Haweran/Recent in age. Quaternary deposits that demonstratably predate this age range (i.e. > Oxygen Isotope Stage 12) have not been recognised anywhere on the Island. Their absence is, at this stage, attributed to a major marine transgression across much of the northern and central portions of the Island during Oxygen Isotope Stage 11. Two rhyolitic tephra produced during two of the largest eruptions from the Taupo Volcanic Zone are present on Chatham Island. The 27.1 ka Kawakawa Tephra is well preserved across most of the Island, occurring within most pre-Holocene sequences. The 345 ka Rangitawa Tephra, not previously recognised on Chatham Island, is found in a few scattered coastal locations where older, late Castlecliffian sediments are preserved. In the absence of any other forms of radiometric age control these two tephras have provided the principal means for time control within and between stratigraphic sequences on the Island. Palynology has been used predominantly to determine climatic conditions at the time of sediment accumulation. Palynological investigations of seven sections of peat deposits have also demonstrated that cyclic changes in vegetation patterns have occurred throughout the Quaternary on Chatham Island. However these changes have not been as significant as those that occurred on mainland New Zealand over the Quaternary. It is concluded that this indicates climatic deterioration during glacials may not have been as pronounced on Chatham Island as on the mainland. Marine terraces created during former high sea level stands are preserved in several areas on Chatham Island. Quaternary terrace surfaces ranging in age from Last Interglacial (OIS 5e) to OIS 11 occur at heights of 3-5 m, 9 – 10 m, 16 m, 20 m and 30 - 40 m above sea level. An exhumed surface of Late Pliocene age occurs at 7 – 14 m a.s.l.. Terrace ages have been determined using cover-bed stratigraphy, and in particular the presence or absence of tephra marker beds. Height-age relationships of marine terraces have been used to develop preliminary rates of tectonic uplift on Chatham Island. The resulting values range between 0.01 – 0.13 mm/yr and are very low compared with more tectonically active areas of mainland New Zealand. However, there is considerable variation in these rates across Chatham Island, indicating that the tectonic history of the Island over the Quaternary may be complex. This thesis has also demonstrated that considerably more work is required to fully understand the Quaternary history of Chatham Island. In particular, better numerical age control on key deposits; more detailed, high-resolution pollen records from key locations; and obtaining stratigraphic records from a greater range of locations. This is particularly so for the southern uplands where older records are virtually inaccessible due to a thick blanketing of post-glacial peat deposits.

The Vanadium bromide (V/Br) flow cell employs the Br3-/Br- couple in the positive and the V(II)/V(III) couple in the negative half cell. One major issue of this flow cell is bromine gas formation in the positive half cell during charging which results from the low solubility of bromine in aqueous solutions. Bromine complexing agents previously used in the zinc-bromine fuel cell were evaluated for their applicability in V/Br flow cell electrolytes. Three quaternary ammonium bromides: N-ethyl-N-methyl-morpholinium bromide (MEM), N-ethyl-N-methyl-pyrrolidinium bromide (MEP) and Tetra-butyl ammonium bromide (TBA) were studied. It is known that aqueous bromine reacts with quaternary ammonium bromides to form an immiscible organic phase. Depending on the number of quaternary ammonium bromides used and the environmental temperature, the second phase formed will either be solid or liquid. As any solid formation would interrupt the flow cell operation, potential formation of such kind has to be eliminated. Stability tests of simulated V/Br electrolyte with added quaternary ammonium bromides were carried out at 11, 25 and 40 oC. In the absence of bromine, the addition of MEM, MEP and TBA were found to be stable in V/Br electrolytes. However, in the presence of bromine, solid formation was observed in the bromine rich organic phase when the V/Br electrolyte contained a single quaternary ammonium bromide (QBr) compound. For V/Br electrolytes with binary or ternary QBr mixtures containing TBA, the presence of bromine caused a viscous polybromide phase to form at room temperature and the release of bromine gas at higher temperature. Only a binary mixture of MEM and MEP formed a stable liquid organic phase between 11 ?? 40 oC. In this study it was found that V/Br electrolytes containing a binary QBr mixture (0.75M) of MEM and MEP gave the best combination that formed an orange oily layer in the presence of bromine without solidification between 11 ?? 40oC. Furthermore, it was found that samples of V/Br electrolytes containing a ternary QBr mixture, are less effective in bromine capturing if the total QBr concentration was less than 1 M at 40oC, where bromine gas evolution was observed. From electrochemical studies of V3+/V2+, it was found that the addition of MEM and MEP had a minimal effect on the formal potential of the V3+/V2+ couple, the V2+/V3+ transfer coefficient and the diffusion coefficient of V3+. Therefore, MEM and MEP can be added to the negative half-cell of a V/Br flow cell without major interference From linear sweep voltammetry, the kinetics of the Br-/Br3- redox couple was found to be mass transfer controlled. After the addition of MEM and MEP mixture, the exchange current density was found to decrease from 0.013 Acm-2 to 0.01 Acm-2. On the other hand the transfer coefficient before and after MEM and MEP addition was found to be 0.5 and 0.44 respectively. Since the kinetic parameters were not significantly affected by the addition of MEM and MEP mixture, they can be added to the positive half-cell of the V/Br flow cell as bromine complexing agents. The electrochemical studies of both V3+/V2+ and Br-/Br3- showed the addition of MEM and MEP has minimal interference with the redox reactions of the vanadium bromide flow cell. This thesis also investigated the effect of MEM and MEP addition on the cell performance of a lab scale V/Br flow cell using two different membranes (ChiNaf and VF11). Flow cell performance for 2 M V3.7+ + 0.19 M MEM + 0.56 M MEP electrolytes utilising ChiNaf membrane at 10 mAcm-2 produced an energy efficiency of 59%, and this decreased to 43% after 15 cycles. For the static cell utilising VF11 membrane, the addition of MEM and MEP reduced the energy efficiency from 59.7% to 43.4%. It is believed that this is caused by the mass transfer controlled Br-/Br3- couple in the complexed positive half-cell solution. Therefore, uniformity between the organic and aqueous phase is important for flow cells utilising electrolytes with MEM and MEP. Finally, the polarization resistance of a lab scale V/Br flow cell utilising ChiNaf membrane and 2 M V3.7+ electrolytes was found to be slightly higher during cell charging (3.9 cm2) than during the discharge process (3.6 cm2), which is opposed to that in the all-vanadium redox cell.

"February 2004" / Includes bibliographical references (leaves 216-227) / Each accompanying profile sheet is named and numbered individually. / xvi, 245 leaves : ill. (some col.), maps (col.), charts ; 30 cm. + 1 location map ( 22 x 30 cm. folded to 22 x 15 cm.) + 4 geologic profiles ( 56 x 100 cm. folded to 20 x 29 cm.) ; in pocket inside back cover. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, School of Earth and Environmental Sciences, Discipline of Geology and Geophysics, 2004

<p>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.</p>

<p>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.</p><p>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.</p>

<p>Kongsfjordhallet is situated at 79° N on the North coast of Kongsfjorden, Spitsbergen.The landscape shows a large diversity of landforms and sediments and the aim of thisstudy has been to investigate the spatial distribution and temporal differences betweenthese landforms.The most prominent landform is interpreted as a lateral moraine dividing the area fromsoutheast to northwest. This is probably a sign of a standstill during the deglaciation ofan ice-sheet glacier tongue filling the fjord. The valley-glaciers at Kongsfjordhallet haveadvanced after this event and left end moraines on top of the lateral moraine. Largeamounts of meltwater have eroded parts of the Kongsfjordhallet, creating several fossilmeltwater channels that dissect the landscape. Erratic boulders of mainly gneiss type arescattered all over the landscape, as high up as 500 m a.s.l. In addition to the erraticboulders, a lot of allochthonous material is found incorporated in local material,especially as a diamict interpreted as till that covers large parts of Kongsfjordhallet.The till can likely be correlated to one of the diamict units in the cliff sections at theKongsfjordhallet coast. At present, two large ravines drain the area, moving water fromthe glaciers to the ocean and a beach is developing in the Southeast part of the area dueto ocean transgression. Landforms from two glacial events are found, one regional andone local. An episode of high sea-level as well as fluvial and mass-wasting activity afterthe deglaciation is also recorded. The formation of the landforms in the area is believedto be after the Last Glacial Maximum and into the Holocene, but no absolute dates areavailable.</p> / SciencePub

<p>This thesis focuses on responses in raised bogs to changes in the effective humidity during the Holocene. Raised bogs are terrestrial deposits that can provide contiguous records of past climate changes. Information on and knowledge about past changes in climate is crucial for our understanding of natural climate variability. Analyses on different spatial and temporal scales have been conducted on a number of raised bogs in south-central Sweden in order to gain more knowledge about Holocene climate variability.</p><p>Peatlands are useful as palaeoenvironmental archives because they develop over the course of millennia and provide a multi-faceted contiguous outlook on the past. Peat humification, a proxy for bog surface wetness, has been used to reconstruct palaeoclimate. In addition measurements of carbon and nitrogen on sub-recent peat from two bogs have been performed. The chronologies have been constrained by AMS radiocarbon dates and tephrochronology and by SCPs for the sub-recent peat.</p><p>A comparison between a peat humification record from Värmland, south-central Sweden, and a dendrochronological record from Jämtland, north-central Sweden, indicates several synchronous changes between drier and wetter climate. This implies that changes in hydrology operate on a regional scale.</p><p>In a high resolution study of two bogs in Uppland, south-central Sweden, C, N and peat humification have been compared to bog water tables inferred from testate amoebae and with meteorological data covering the last 150 years. The results indicate that peat can be subjected to secondary decomposition, resulting in an apparent lead in peat humification and C/N compared to biological proxies and meteorological data.</p><p>Several periods of wetter conditions are indicated from the analysis of five peat sequences from three bogs in Värmland. Wetter conditions around especially c. 4500, 3500, 2800 and 1700-1000 cal yr BP can be correlated to several other climate records across the North Atlantic region and Scandinavia, indicating wetter and/or cooler climatic conditions at these times. Frequency analyses of two bogs indicate periodicities between 200 and 400 years that may be caused by cycles in solar activity.</p>

<p>In order to explore site formations and reconstruct environmental development in Medieval and Post-Medieval towns, urban occupational strata in Norrköping and Karlstad were studied according to biostratigraphy, sedimentology and pedology. New field procedures including continuous pilot sampling, parallel archaeological and geological stratigraphic interpretation, and on-site analysis of plant macrofossils were developed and applied at archaeological excavations in both towns. Representation of both disciplines in the field during excavations greatly contributed to more complete field interpretations.</p><p>Stratigraphical analyses indicate that geological processes have been active in both towns, and reveal similarities in site formation. The earliest proto-urban phase is represented by the presence of dark earths, formed by the combination of alluvial processes and cattle tramping. Alluvial processes were common in Karlstad due to the flooding of the river delta, and in Norrköping due to the sloping topography. Both situations were enhanced by human activity, which caused drainage problems. A significant change in composition and origin of house foundation fill was also noted. The oldest foundations contained fine-grained material of local origin in contrast to younger foundations, which contained coarser material, sometimes of regional origin. This is interpreted as a professionalisation of the urban building tradition, which in Norrköping occurred during the 16th century and in Karlstad during the 18th century. Site formations of urban strata are regulated by three major factors: deposition, post-depositional soil formation and erosion/truncation, which all may occur both culturally and naturally.</p><p>Plant macrofossil analyses in Norrköping and Karlstad resulted in a fossil record with a total amount of 203 and 169 different types of plant species and taxa respectively. The records indicate that site formation processes seem to have been inhibited during wintertime. The results also confirm the idea of the early Scandinavian towns as rural, also during the Post-Medieval time. The finds of cultural plants in Karlstad indicate 18th century cultivation of Fragaria moscata and 17th century import of Pimento officinalis. In Norrköping remains of beer additives confirm that the tradition of combining Humulus lupulus and Myrica gale disappeared after the 15th century, but also indicate a the use of Filipendula ulmaria as a beer addative. Finds of seeds from Nicotiana rustica suggests that tobacco cultivation occurred in Norrköping 1560-1640, which is some decades earlier than known so far in Sweden.</p>

<p>This thesis investigates architectures for multiplying elements in Galois rings of the size 4^m, where m is an integer. </p><p>The main question is whether known architectures for multiplying in Galois fields can be used for Galois rings also, with small modifications, and the answer to that question is that they can. </p><p>Different representations for elements in Galois rings are also explored, and the performance of multipliers for the different representations is investigated.</p>

<p>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.</p>