2 10 656 https://theses.otagogeology.org.nz/files/original/c7570259e401f1aaaa72bad3c2556341.pdf 732e1fda88d764b4aa9dc9d0804fb079 Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource Geology theses OU Geology thesis Thesis or dissertation completed by University of Otago Geology students Author last name Last name of the Author Giacalone Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? PhD Advisers Who supervised/advised this student White, James D.L. Scott, James M. Abstract The Abstract for this thesis Swinburn Volcanic Complex is the remnant of a Miocene volcano, forming part of the Dunedin Volcanic Group (~ 24 - 9Ma), on the South Island of New Zealand. It is part of the Waipiata Volcanic Field, and its basalts are distinct from most others in that field. New analyses of Swinburn rocks, which have only very few mantle nodules, are compared with other new data from peridotite-bearing basanites collected from different volcanic rocks of Dunedin Volcanic Group. Swinburn basaltic rocks are geochemically and isotopically different than any other rock so far described from the intraplate Waipiata Volcanic Field or the Dunedin Volcanic Complex. I have identified geochemical and isotopic affinities (e.g. high 207Pb/204Pb trend together with lower trace element concentrations) of Swinburn rocks with those formed from Cretaceous basaltic magmas elsewhere in Zealandia and the Hikurangi Plateau. Percolation processes have: a) metasomatized the lithosphere, leaving strong geochemical imprints (e.g. carbonatite, OIB and HIMU-like), b) locally modified the thermal gradient c) produced metasomatic cumulates (amphibole-bearing veins and/or pyroxenites) which have major and trace-element compositions suitable for the mantle source that fed the Dunedin Volcanic Group. Within the footprint of this Group, Swinburn Volcanic Complex is an anomaly. Under the Swinburn Complex, percolating fluids interacted with one part of the lithospheric mantle that had been already metasomatized by Cretaceous melts. The combination of Cretaceous and Miocene percolation through the same mantle domain formed the distinctive geochemistry of Miocene Swinburn magmas. Petrographic and geochemical differences among samples from Swinburn also reveal that more than one batch of magma was involved in the formation of the complex. By combining field evidence with new geochemical data, two effusive eruptions or eruptive periods are inferred, separated an episode of magma intrusion. Reversed polarity of the magnetic field at the time of Swinburn effusion and intrusion activity was identified by paleomagnetic analysis. A magnetometer survey suggests the presence of several buried features. There are pegmatitic domains in the Swinburn basaltic rocks. Compaction of a crystal mush, together with the buoyant separation of residual melt rich in dissolved volatiles, is interpreted as the main mechanism driving the upward movement of Swinburn segregation domains and the formation of those segregation veins and domains. Results of this multidisciplinary analysis of the Swinburn Volcanic Complex, based on petrographic, mineralogical, geochemical and geophysical investigations are summarised below. 1) Older pyroclastic rocks, and the majority of the exposed vesicular lavas, represent the first activity of the complex, whereas younger pyroclastic products and a lava exposed in the western part of the complex (G7) formed during the last event. 2) The Swinburn body was emplaced during two effusive events by the intrusion of two batches of magma with similar composition. The higher amount of magnetic minerals forming the rocks of the Main body explains the inhomogeneous magnetic signal showed by my newly produced 3D magnetic map of the area. The association of magnetic profiles with cross sections unveiled several buried features such as a fault, possible thickness variations in the body, and places where Quarry and Main rocks overlap. 3) Compaction together with the buoyant rise of volatile-rich residual melt are interpreted to have been the main mechanisms driving upward movement of segregated residual liquids to form pegmatitic domains and veins. Compaction of the lower and central parts of the emplaced magma body caused dilatation and tearing in the upper crystallising front, which were filled by residual liquid to form segregation veins. 4) The concentration of major and trace elements is similar for plagioclases and clinopyroxenes crystallised near the top and bottom of the body but different for mineral crystallised near the mid-level of it. These differences reflect slower cooling of the interior of the body, furthest from basal and top cooling surfaces. The comparison of Swinburn features with those of volcanoes elsewhere worldwide sheds light on processes that regulate the origin of melts, and formation of segregation products during cooling of emplaced magmas. Following the main aim to determine the volcanic evolution and processes of the Swinburn Volcanic Complex and how it impacts on the wider volcanological perspective, this study demonstrates that even inside a broadly monogenetic volcanic field, individual volcanic complexes may be products of multiple eruptions. They can preserve significant local heterogeneities and magma source regions distinct from those of most volcanoes in the field. OURArchive handle The handle from the Otago University Research Archive (OURArchive) https://ourarchive.otago.ac.nz/handle/10523/8768 OURArchvive access level Open Access Department The department where the student is studying primarily. Geology Thesis description Number of pages, maps, CDs, etc. 245 Pages A4 Named locality Named locality describing the field area location. Swinburn Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource Swinburn Volcanic Complex, Central Otago, New Zealand Creator An entity primarily responsible for making the resource Giacalone, Emanuele Date A point or period of time associated with an event in the lifecycle of the resource 2018 Identifier An unambiguous reference to the resource within a given context 2018Giacalone biotite geochemistry geophysics greenschist magmatism Miocene Otago Schist Swinburn Volcano Waipiata Zealandia https://theses.otagogeology.org.nz/files/original/dc5288529176a6f60244af5c62bcb4fe.pdf fc4cc34490646f9dd3be42e1382f9398 Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource Geology theses OU Geology thesis Thesis or dissertation completed by University of Otago Geology students Location WKT (WGS84) The location stored in WKT (WGS84) format MULTIPOLYGON (((169.798292031391 -43.5293028095617,170.341206105389 -43.2440135055566,170.43216699032 -43.3127983353413,169.865109514897 -43.6045274335989,169.798292031391 -43.5293028095617))) Author last name Last name of the Author Williams Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? PhD Advisers Who supervised/advised this student Toy, V.G. Smith, S.A.F. Abstract The Abstract for this thesis The dynamic propagation of an earthquake rupture will generate inelastic deformation within its surrounding medium, culminating in the development of a fault damage zone. These are heavily fractured volumes of rock that flank the fault core, where the majority of displacement has been accommodated. Using the example of the Alpine Fault, I assess the mechanical and chemical processes associated with fault damage, which strongly condition the short and long term evolution of a fault. Approximately 70% of the oblique-dextral motion between the Australian and Pacific plates on the South Island of New Zealand is localised onto the Alpine Fault. A continuous record of its damage zone extending <30 m above its principal slip zones (PSZs) is provided by core recovered during the first phase of the Deep Fault Drilling Project (DFDP-1). A combination of visual core descriptions, X-ray and neutron tomographic core scanning, and X-ray diffraction demonstrate that the damage zone is epitomised by gouge-filled ‘phyllosilicate-enriched’ fractures. These contain a soft fine-grained fill, which have a relatively low density but are hydrogen-rich. Their bulk composition reflects both wear of the surrounding rock and phyllosilicate mineralisation during hydrothermal alteration. Fracture density in DFDP-1 core and field transects does not increase with proximity to the PSZs, but does systematically vary with lithology. By reorienting core sections with respect to geographically referenced borehole televiewer logs of the DFDP-1 boreholes, the true orientations of 637 fractures was obtained. Combined with field observations, these results indicate that damage zone fractures occupy a wide range of orientations. This reflects variable stress states adjacent to the Alpine Fault, which are generated by a fault trace that is non-planar in the near-surface, and non-optimally orientated with respect to the regional stresses at depth. The mechanical anisotropy of the foliated mylonites that host the damage zone cannot strongly influence fracturing. In field transects, broadly-oriented fractures are confined to within 50-150 m of the Alpine Fault, and this is the best estimate of damage zone width along its central section. This width is comparable to elsewhere along-strike. Therefore, the Alpine Fault is considered to be embedded within a tabular localised damage zone, as documented in other structurally mature crustal-scale faults. Petrological and scanning electron microscopy demonstrate that gouge-filled fractures extend to the micron scale where calcite, chlorite, K-feldspar and muscovite veins are also present. These veins and fractures form in a cyclic manner that may be operative throughout the Alpine Fault’s seismogenic zone. The documentation of some veins that cross-cut cataclasite textures requires that strain localisation from the 10-20 m thick Alpine Fault cataclasites to its 10-50 cm thick PSZ gouges must occur at depths <2-5 km. This study has sampled the Alpine Fault damage zone late in its cycle of stress accumulation. Within this period, micro and macro-scale fracture healing has occurred at distances <25 m of the PSZs. A combination of fluid over-pressures and unhealed damage elsewhere permit a Low Velocity Zone around the Alpine Fault. OURArchive handle The handle from the Otago University Research Archive (OURArchive) <a href="http://hdl.handle.net/10523/7360">http://hdl.handle.net/10523/7360</a> OURArchvive access level Open Access Department The department where the student is studying primarily. Geology Named locality Named locality describing the field area location. West Coast Thesis description Number of pages, maps, CDs, etc. 255 Pages A4 Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Identifier An unambiguous reference to the resource within a given context 2017Williams Creator An entity primarily responsible for making the resource Williams, Jack Nicholas (Jack) Date A point or period of time associated with an event in the lifecycle of the resource 2017 Title A name given to the resource The damage zone of New Zealand Subject The topic of the resource Structural Geology Alpine Fault Damage zones DFDP Fault healing Fault structure fractures https://theses.otagogeology.org.nz/files/original/57e00179957dc3c5a10d33062a463699.pdf 317e0a92009b8e549b0cc0d8040c2d00 Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource Geology theses OU Geology thesis Thesis or dissertation completed by University of Otago Geology students Location WKT (WGS84) The location stored in WKT (WGS84) format MULTIPOLYGON (((169.007357194797 -44.4801048617569,168.852891876841 -44.7153959537916,168.644939480572 -44.8819889426719,168.53059861996 -44.8789917767537,168.652743501904 -44.4707082049925,169.007357194797 -44.4801048617569))) Author last name Last name of the Author Wellnitz Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? PhD Advisers Who supervised/advised this student Scott, J.M. Palin, J.M. Abstract The Abstract for this thesis In this thesis the chemistry and textures of void-filling hydrothermal carbonate and associated altered metamorphic and lamprophyric rock in western Otago, New Zealand, were studied. With this information a detailed model of the mobility behaviour of various elements is established. Conduits for CO2-bearing fluids were faults, joints, folds and, in the northernmost part of the study area, volcanic diatremes. The southernmost study area lies in the Shotover Valley, where many of the larger fault zones are auriferous. Throughout the studied area, many larger faults, including the gold-bearing ones, strike W to NW. In addition to these faults, there are also structures (i.e. veins and fold hinges) that trend northwards. The formation of most of the structures happened in the Oligocene -Miocene andwas closely connected to the movements along the newly forming Alpine Fault and reverse movements along the Moonlight Fault. Adjacent to the fluid conduits, the wall rock has been extensively altered. This alteration is especially obvious in greenschist and the altered rock has a pale creamy colour due to the replacement of various metamorphic phases (epidote, chlorite, actinolite) mostly by Fe-bearing carbonate and phyllosilicates. In quartzo-feldspathic greyschists the same metamorphic minerals as in greenschist are unstable in response to the incoming CO2-bearing fluid. However, as those minerals are less abundant in greyschist, the alteration is less obvious. Textural and chemical data of the individual metamorphic and hydrothermal minerals forming during replacement were obtained using SEM, microprobe and LA-ICP-MS. The hydrothermal minerals replacing metamorphic minerals describea diverse array of mineral textures, which give insight into relative solubility of the different mineral phases. The replacement reactions also attest to mobility and immobility of the different major and trace elements. For example, in the breakdown of epidote in rocks which contain metamorphic muscovite, Al is mobilised potentially in F-OH complexes and transported away from the original epidote site, whereafter carbonate forms. In cases where there is no muscovite in the rock, epidote is replaced by muscovite, hence resulting in local loss of Ca. At the same time, the REE of this epidote are also mobilised on microscopic scale (µm to mm) as the growing muscovite cannot accommodate the REE in its crystal structure. These REE are then incorporated in the ankerite replacing the chlorite. On a macroscopic scale (cm to m), Sr, Ba, Rb, K and Cs show the largest mobility during the hydrothermal alteration (sometimes up to 20 times enrichment in the altered rock compared to the unaltered rock) and are often brought into the rock by the hydrothermal fluid. The REE and Al, on the other hand, do not show any signs of mobility at thatscale. Overall, of all elements in alteration-sensitive metamorphic minerals, only titanium is shown to be immobile throughout, also on µm scale. In addition to carbonate forming in the hydrothermal alteration halo around fluid conduits, carbonate is also a common void-filling mineral, such as fractures and vesicles. The chemical composition of these carbonates shows that the different elements are controlled by various factors. Contents of Ca, Sr, Mg, Fe, Mn and according ratios show that these elements can travel metres to tens of metres in the fluid before they are precipitated in carbonate. REE contents and patterns in the carbonate are the product of the interplay between fluid- and rock-dominated processes; in cases were only little rock needs to be leached to form the carbonate, the REE patterns are very similar to the wall rock. In cases where relatively large rock volumes need to be leached to provide the main components of the void-filling carbonate, the REE content of the carbonate is dominated by fluid-controlled processes and the REE patterns reflect the relative solubility of the different REE in the fluid. Radiogenic isotopic compositions (Nd, Sr) of void filling carbonates and wall rock show that Nd and Sr in the carbonates travel different distances in the fluid conduit; Nd isotopic ratios show that the bulk of the LREE are transported for short distances in the fluid passing through the void (cm to dm), whereas Sr isotopic ratios confirm that Sr can be for transported many meters by the aqueous fluid. Stable isotope data (C, O) in conjunction with assessing the regional geological and tectonic settings permitted to reconstruct the history and sources of the fluids in the studied areas; after taking temperature effects on isotope fractionation and relative sample locations into account, it is concluded that two main fluid types were present in the studied area. One of these is a mixture of meteoric and magmatic components, while the other fluid interacted extensively with the metamorphic rock in Western Otago, but was most likely originally meteoric-derived water. Only in the volcanic diatremes is there indication that these two fluid types mix. Outside the diatreme, the isotopic composition of the carbonate give evidence that only the second mentioned fluid type was present, including in the auriferous structures and there is no indication that the gold-bearing and magmatic system had any connection to each other OURArchive handle The handle from the Otago University Research Archive (OURArchive) <a href="http://hdl.handle.net/10523/7300">http://hdl.handle.net/10523/7300</a> OURArchvive access level Open Access Department The department where the student is studying primarily. Geology Named locality Named locality describing the field area location. Southern Alps Thesis description Number of pages, maps, CDs, etc. 257 pages A4 Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Identifier An unambiguous reference to the resource within a given context 2017Wellnitz Creator An entity primarily responsible for making the resource Wellnitz, Anne Katrin (Katrin) Date A point or period of time associated with an event in the lifecycle of the resource 2017 Title A name given to the resource Carbonate alteration associated with lamprophyres and orogenic gold, Southern Alps, New Zealand Subject The topic of the resource Igneous geology Metamorphic geology Alteration Carbonate Fluid gold Lamprophyres New Zealand radiogenic isotopes Rare Earth Elements stable isotopes https://theses.otagogeology.org.nz/files/original/68a46294e55cb886bd88475e18d74f51.pdf 07c784ae8768a4815d20675e91886b19 Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource Geology theses OU Geology thesis Thesis or dissertation completed by University of Otago Geology students Author last name Last name of the Author Vaughan Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? PhD Advisers Who supervised/advised this student Prior, D.J. Abstract The Abstract for this thesis Ice is ubiquitous on Earth and on the outer planets and satellites of the solar system. Ice is an important geologic material, and is a critical contributor to global climate and sea-level models. Understanding and modelling the dynamic behaviour of the glaciated regions on earth and in the outer solar systems requires an intimate knowledge of the mechanisms that control the mechanical behaviour of ice polycrystals. During dynamic events, such as rapid heating or ice-shelve collapse, much of the response of ice sheets is governed by its internal deformation, that is, the ductile flow behaviour of the ice. Ductile flow in ice is primarily controlled by temperature and the arrangement of ice crystals into crystallographic preferred orientations (CPO), which both have a dramatic effect on flow rates and mechanical anisotropy. Seismic field surveys provide a window into the regional characteristics of ice sheet flow, via the relationship between CPO and polycrystal elastic anisotropy. That is, CPO effects the velocity of elastic waves travelling at different directions through a textured polycrystal. CPO geometry in ice evolves as a function of deformation conditions such as temperature and the stress field. Thus, elastic anisotropy can be used to interpret mechanical anisotropy, an important parameter for predicting long-term ice sheet behaviour. Here, we present the results of several un-confined uniaxial compression experiments on cylinders of isotropic polycrystalline ice under controlled temperature and displacement-rate conditions. The deformed material was characterised in real-time by measuring ultrasonic time-of-flight in-situ during ductile creep, and post-deformation using cryo electron backscatter diffraction to characterise the final microstructure. Resonant ultrasound spectroscopy measurements were made on cylinders of synthetic isotropic ice polycrystals, to determine the relationship between temperature and the elastic and anelastic characteristics that govern wave propagation in ice. At high homologous temperatures (-5°C), uniaxial shortening gives rise to a CPO cone girdle, where the c-axes of the individual crystals become aligned into an orientation 30-50° from the shortening direction. The evolution of this CPO is controlled primarily by strain-energy driven grain boundary migration, where grains in orientation favourable for slip on the basal planes grow at the expense of those in hard slip orientations. Grains in hard basal slip orientations deform by non-basal slip on pyramidal planes. Rapid weakening occurs in the samples around 3% strain, and corresponds to the formation of a network of grains well oriented for basal slip. Through in-situ measurements of elastic wave velocity evolution, we observe that changes in ultrasonic velocity anisotropy can be used as a continuous proxy for CPO evolution, quantifying the relationship between velocity anisotropy and fabric strength. Resonant ultrasound measurements show that elastic wave velocity is strongly sensitive to temperature in ice polycrystals, as are the components of the elasticity tensor. These measurements reveal that compressional wave speeds and intrinsic attenuation are most sensitive to temperature, which we attribute to liquid phases on ice grain boundaries associated with pre-melting conditions. OURArchive handle The handle from the Otago University Research Archive (OURArchive) <a href="http://hdl.handle.net/10523/7159">http://hdl.handle.net/10523/7159 </a> OURArchvive access level Open Access Department The department where the student is studying primarily. Geology Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Identifier An unambiguous reference to the resource within a given context 2017Vaughan Creator An entity primarily responsible for making the resource Vaughan, Matthew James Hatfield (Matt) Date A point or period of time associated with an event in the lifecycle of the resource 2017 Title A name given to the resource The creep behaviour, and elastic and anelastic properties of polycrystalline ice Subject The topic of the resource Rock Deformation Anelasticity anisotropy CPO creep deformation Ductile EBSD Elasticity Fabric MIcrostructure Polycrystalline slip-systems Velocity https://theses.otagogeology.org.nz/files/original/e85e8c9fe7d80858c4e21de3fd56adba.pdf 128149cf1aa08f62c84c5b56eda712a6 Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource Geology theses OU Geology thesis Thesis or dissertation completed by University of Otago Geology students Location WKT (WGS84) The location stored in WKT (WGS84) format MULTIPOLYGON (((174.516292314169 -80.7113702485974,170.914290973674 -80.6857239691589,170.772115898609 -79.9224712681925,174.638031600643 -79.9844705027868,174.516292314169 -80.7113702485974))) Author last name Last name of the Author van Haastrecht Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? MSc Advisers Who supervised/advised this student Gorman, A.R. Ohneiser, C. Abstract The Abstract for this thesis The Ross Ice Shelf (RIS) is the largest ice shelf in the world. It buttresses ice flow from both the East Antarctic Ice Sheet (EAIS) and the West Antarctic Ice Sheet (WAIS). Today the RIS does not appear to be retreating or advancing. Understanding what controls the ice shelf’s stability, and how it may respond to future warming and oceanic change is vital, as its collapse would accelerate global sea level rise. Understanding the rates at which physical processes occurred in the past during ice shelf and ice sheet retreat can improve our models for future climate change. This study aimed to answer two main research questions: first, to characterise seafloor bathymetry and substrates in the vicinity of a future hot water drill site and make informed decisions concerning seafloor coring/sampling locations, and second, to characterise the roughness of the ice shelf’s basal surface. Field work was conducted during the 2015/2016 Antarctic field season as opposed to the 2014/2015 season, after a one year delay due to logistical constraints. As a result, this study focussed on reprocessing previous data, survey design, and modelling, conducted prior to data collection in Antarctica. The preliminary work involved a comparative study between conventional spiked geophone data and snow streamer on data previously collected on the McMurdo Ice Shelf (MIS), and a detailed survey design for the November 2015 survey. Synthetic shot records were generated to test the effect of ice thickness variations. The snow streamer and weight drop seismic source data acquisition system were an effective method of data collection on the RIS. This combined system allowed for rapid data collection, and facilitated the collection of 45.8 km of multichannel seismic reflection data. The seismic data are interpreted to reveal two seismic facies, separated by an erosion surface, of at least 180 m thickness. The upper seismic facies is characterised by two cycles of high-amplitude, mostly continuous, horizontal strata, and the lower facies is characterised by irregular, discontinuous, dipping strata. The two seismic facies and erosion surface are interpreted to reflect the change in glaciation regime that occurred in the late Pliocene (approximately 3 Ma), where the lower sedimentary packages consists of sediments deposited under a warmer, wet-base regime and overlying sediments that were deposited by colder, dry-base glaciers. It is unlikely that deeper bedrock structures were imaged in this study. From the seismic data alone, it is recommended that any future hot water drill site locations are positioned close to the South Pole Overland Traverse (SPOT) road and the 2015 season base camp. The basal ice interface was not imaged distinctly in this study, likely due to the interference of surface waves and the presence of marine ice. It lies within as a seismically opaque zone in the upper 200 ms, after which the signal changes character to low- to moderate-amplitudes in the water column. It is hypothesised that this is due to either the presence of marine ice, surface waves obscuring the reflection, or a combination of the two. The RIS data also display a relatively strong intra-ice multiple (modelled in the synthetic shot records), and contain strong surface waves, which were a significant aspect of the shot records. Due to the nature of collecting data close to the end of this study, several processing and analysis options still need to be investigated for these data including, but not limited to, better analysis of the surface waves and of the intra-ice multiple characterise ice properties, and calculations of reflection and transmission co-efficient values derived from the intra-ice multiple and seafloor. OURArchive handle The handle from the Otago University Research Archive (OURArchive) <a href="http://hdl.handle.net/10523/7032">http://hdl.handle.net/10523/7032</a> OURArchvive access level Open Access Department The department where the student is studying primarily. Geology Named locality Named locality describing the field area location. Ross Ice Shelf Antarctica Thesis description Number of pages, maps, CDs, etc. 173 pages A4 Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Identifier An unambiguous reference to the resource within a given context 2017van_Haastrecht Creator An entity primarily responsible for making the resource van Haastrecht, Laurine Nathalie (Laurine) Date A point or period of time associated with an event in the lifecycle of the resource 2017 Title A name given to the resource Vulnerability of the Ross Ice Shelf: Seismic Site Characterisation and Drilling Recommendation Subject The topic of the resource Geophysics Ross Ice Shelf seismic survey snow streamer https://theses.otagogeology.org.nz/files/original/4cf8d43a4eb126535c97786789553cea.pdf 7304c147774e9250aa0993949ee7e8f7 Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource Geology theses OU Geology thesis Thesis or dissertation completed by University of Otago Geology students Location WKT (WGS84) The location stored in WKT (WGS84) format MULTIPOLYGON (((170.01732476684 -46.2522487078296,169.986529340236 -46.2347707468098,170.196091498041 -46.0448322899835,170.233040363231 -46.0582359272952,170.01732476684 -46.2522487078296))) Author last name Last name of the Author Taylor-Silva Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? MSc Advisers Who supervised/advised this student Stirling, M.W. Abstract The Abstract for this thesis My thesis documents the first-ever paleoseismic trench investigation of the Akatore Fault, which has long been considered the most active fault to exist near Dunedin City. Two trenches were excavated across the fault in order to investigate the late Quaternary activity (timing, magnitude and recurrence of large ground rupturing earthquakes). Trenching investigations at Big Creek and Rocky Valley have concluded that there have been three ground-rupturing earthquakes in the Holocene. An antepenultimate event has been constrained between 10,400 ± 1,700 and 1,326 ± 22 cal. yr BP, while, the penultimate and most recent events have been constrained between 1,326 ± 22 and 776 ± 22 cal. yr BP. These events resulted in 5 m of dip slip, hence 1 - 2 m of surface displacement per event, which may to have produced earthquakes with moment magnitudes 6.8 - 7.4. Further studies at Taieri Mouth provided information on the longer term behaviour of the Akatore Fault. We estimated only 2 – 3 m of scarp development since the 125 ka marine terrace was formed. Since the Big Creek trench results indicated similar displacements achieved over three Holocene earthquakes, it is plausible that the scarp development has happened by way of these same three Holocene events. This would imply that there has been no activity along the Akatore Fault for a long period prior to these Holocene events i.e. little to no movement between 125,000 – 10,000 cal. yr BP. Furthermore, the Holocene slip rate along the Akatore Fault is significantly greater than the long term slip rate. This suggests the fault does not act in a characteristic fashion. It has an episodic / irregular behaviour. Similar behaviours have been determined for other Otago faults, which is problematic for forecasting future earthquakes. If inception of uplift along the Akatore Fault occurred ~1 Ma, the implied long-term slip rate is such that the fault may not yet have slipped enough in these Holocene events to accommodate the accumulated slip over the previous ~110 ka. The Akatore Fault needs to become the focus of a time-dependent seismic hazard calculation for Dunedin. OURArchive handle The handle from the Otago University Research Archive (OURArchive) <a href="http://hdl.handle.net/10523/7488">http://hdl.handle.net/10523/7488</a> OURArchvive access level Open Access Department The department where the student is studying primarily. Geology Named locality Named locality describing the field area location. Taieri Mouth East Otago Thesis description Number of pages, maps, CDs, etc. 184 pages A4 Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Identifier An unambiguous reference to the resource within a given context 2017Taylor-Silva Creator An entity primarily responsible for making the resource Taylor-Silva, Briar Date A point or period of time associated with an event in the lifecycle of the resource 2017 Title A name given to the resource Akatore Fault; Reverse Fault; Fault Trenching; Holocene; Paleoseismology; East Otago; New Zealand Subject The topic of the resource Earthquake Geology Akatore Fault east Otago Fault Trenching Holocene New Zealand Paleoseismology Reverse Fault https://theses.otagogeology.org.nz/files/original/d4d06c5c9345c095b6cb9ba405b1fb1c.pdf 0da3fa631abc646eb41ac3d74bd75217 Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource Geology theses OU Geology thesis Thesis or dissertation completed by University of Otago Geology students Location WKT (WGS84) The location stored in WKT (WGS84) format MULTIPOLYGON (((-110.326873029723 35.1091344486426,-110.318230781959 35.1214432048754,-110.301394402982 35.112238115349,-110.290255505864 35.0951927799335,-110.303058835885 35.0945087871119,-110.326873029723 35.1091344486426))) Author last name Last name of the Author Re Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? PhD Advisers Who supervised/advised this student White, J.D.L. Ort, M. Abstract The Abstract for this thesis Many populated areas in the world (e.g., Flagstaff, AZ; Auckland, NZ; Mexico City, MEX) lie within active monogenetic volcanic fields that typically contain small volcanic cones and explosive maar craters formed over the course of a single eruptive cycle. Although much work has focused on the eruptive behaviour of monogenetic volcanoes, little geological information exists about their subsurface development and how the movement of magma through Earth’s shallow crust modulates the location and style of hazardous volcanic eruptions. Determination of the dynamics of magma intrusion and the transition from a coherent magma's ascent to its explosive fragmentation is crucial to our understanding of the controls on explosive versus effusive eruptive behaviour, thus to better evaluation of risks in a certain area. This study aims to determine the processes and relative timing of activity that took place below the ground surface of the deeply-eroded but well-preserved Jagged Rocks Complex, a cluster of monogenetic volcanoes within the Miocene Hopi Buttes Volcanic Field in northeastern Arizona, by combining detailed structural mapping, volcanological observation, paleomagnetic and geochemical analysis. The Jagged Rocks Complex, exposed at ~ 350 m below the pre-eruptive surface, comprises a well-preserved intrusive network, including dikes, sills and inclined sheets, associated with different type of fragmental bodies including buds, pyroclastic massifs and a diatreme, that represent different extents of shallow-depth fragmentation. These exposures at the Jagged Rocks Complex provide an excellent natural laboratory for examining the subsurface record of volcano initiation, and for constraining interpretations of processes controlling upward migration of magma from intrusion to eruption. This multidisciplinary approach allows an investigation at different levels from the source region to the surface, and aims to shed the light on the processes that regulate eruptions not only within monogenetic volcanic fields but also within small basaltic volcanoes in general. OURArchive handle The handle from the Otago University Research Archive (OURArchive) <a href="http://hdl.handle.net/10523/7358">http://hdl.handle.net/10523/7358</a> OURArchvive access level Open Access Department The department where the student is studying primarily. Geology Named locality Named locality describing the field area location. Arizona USA Thesis description Number of pages, maps, CDs, etc. 273 pages A4 Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Identifier An unambiguous reference to the resource within a given context 2017Re Creator An entity primarily responsible for making the resource Re, Giuseppe (Peppe) Date A point or period of time associated with an event in the lifecycle of the resource 2017 Title A name given to the resource Evolution and dynamics of a monogenetic volcanic complex in the southern Hopi Buttes Volcanic Field (AZ, US): magma diversion and fragmentation processes at the Jagged Rocks Complex Subject The topic of the resource Volcanology Basaltic Conduit diatreme Dike Feeder Hopi Buttes Monogenetic volcano https://theses.otagogeology.org.nz/files/original/40619c3286d9edb8d245714002bffd36.pdf 9fe3de378391b7aab72618dbff57f2e1 Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource Geology theses OU Geology thesis Thesis or dissertation completed by University of Otago Geology students Location WKT (WGS84) The location stored in WKT (WGS84) format MULTIPOLYGON (((171.951066336025 -42.3392437657565,171.945269977672 -42.3401437250807,171.932645245355 -42.3269689228649,171.932483457731 -42.3213439037579,171.938960362076 -42.3180680379941,171.954485088648 -42.3345093104671,171.951066336025 -42.3392437657565)),((171.907811478265 -42.2198398151223,171.902042032984 -42.2197847303217,171.888666886462 -42.2092188751299,171.890640984123 -42.2063070331894,171.893632442448 -42.2056925470364,171.907865676327 -42.2166949227961,171.907811478265 -42.2198398151223))) Author last name Last name of the Author Malloch Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? MSc Advisers Who supervised/advised this student Craw, D. Abstract The Abstract for this thesis Orogenic gold deposits are a source of arsenic (As) and antimony (Sb), in the sulphides arsenopyrite and stibnite respectively. Weathering of these deposits releases As and Sb into the environment but it is ore processing that can concentrate naturally occurring As to Sb to toxic percentage levels. Gold recovery by mercury (Hg) amalgamation and cyanidation results in the addition of metals (zinc (Zn), lead (Pb) and Hg)) and chemicals (cyanide) that can also be concentrated during processing to high levels that exceed national guidelines. Through the practice of crushing and milling during processing, fine (< 500 ?m) metal-rich particles are produced that are easily transported by rain splash and wind, and easier to inhale and ingest. This study examines three historic processing sites in the Reefton Goldfield, New Zealand that operated prior to the 1950s when legislation was not in place requiring the remediation of a site after closure. These abandoned processing sites contain historic relics that are of an interest to the Department of Conservation (DOC) to preserve on these heritage sites, as well as containing high metal processing residues that are a potential environmental concern. Of the three sites presented in this study, the toxic As(III) arsenolite in the Edwards roaster at the Alexander processing complex poses the highest hazard. The extreme As levels (in excess of 35 wt% As) are the result of ore roasting to release refractory gold from sulphides, and these extreme As levels are seen at other historic processing sites where the ore was roasted. Crystalline efflorescences inside the Edwards roaster may indicate that As vapours permeated the structure during roasting and are now a point source for As. Ore roasting has also concentrated other metals (Sb, Hg) in the roaster to high levels. High metal levels on the three sites studied are largely sequestered by the formation of secondary iron arsenate and iron oxide minerals. Any dissolved metals leaving the sites are diluted by high regional rainfall. The weathering of sulphides, concentrated by ore processing, has resulted in the localised production of acid but lime added during processing, as well as carbonates in the Greenland Group host rocks, neutralises the acid so there is no acid mine drainage (AMD). There is no significant increase in dissolved metals downstream from the Alexander processing complex, with most metals below detection limits and all metals well below the New Zealand drinking water standards. Previous site investigations into historic processing sites in the Reefton Goldfield, and this study, highlight the importance of undertaking a thorough investigation of metal distribution, speciation and mobility before deciding on a site remediation plan. Ranking of a site for remediation should take into account its land use and future land use, as well as visitor numbers and levels of exposure. On the basis of the processing residue’s mineralogy and geochemistry at the three sites presented in this thesis, it is recommended that due to the remoteness of these sites and low visitor numbers, that they are a low priority for remediation. OURArchive handle The handle from the Otago University Research Archive (OURArchive) <a href="http://hdl.handle.net/10523/7047">http://hdl.handle.net/10523/7047</a> OURArchvive access level Abstract Only Department The department where the student is studying primarily. Geology Named locality Named locality describing the field area location. Alexander Mine West Coast Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Identifier An unambiguous reference to the resource within a given context 2017Malloch Creator An entity primarily responsible for making the resource Malloch, Kirstine Date A point or period of time associated with an event in the lifecycle of the resource 2017 Title A name given to the resource The Environmental Legacy of Historic Gold Processing in the Reefton Goldfield Subject The topic of the resource Environmental Geology Alexander mine amalgamation arsenic arsenolite Golden Lead mine lead mercury ore roasting pharmacolite yukonite zinc https://theses.otagogeology.org.nz/files/original/48572e4d61711ae8b65345e14aad2f84.pdf 7161d97d9bf6331b7bf4380fe1e78fe6 Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource Geology theses OU Geology thesis Thesis or dissertation completed by University of Otago Geology students Location WKT (WGS84) The location stored in WKT (WGS84) format MULTIPOLYGON (((-18.4711923145008 63.5416956421709,-18.9703197424945 63.50349596139,-19.1271883627211 63.813963623143,-18.6280609347274 63.8517463583428,-18.4711923145008 63.5416956421709))) Author last name Last name of the Author Gorny Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? PhD Advisers Who supervised/advised this student White, J.D.L. Gudmundsson, M.T. Abstract The Abstract for this thesis Large scale subglacial eruptions are enigmatic. Their eruption and emplacement dynamics are not well understood due to the incompleteness of preserved units. The Snæbýlisheiði unit, south Iceland, forms a ca. 27 cubic km elongate, flat-topped ridge of volcaniclastic debris coupled with and intruded by coherent basalt and represents a large-scale subglacial basaltic fissure eruption, where both the eruption and ridge growth occurred subglacially. It is preserved in its entirety from the eruption site stretching over 34 km towards the modern day coastline. Snæbýlisheiði differs from typical Icelandic subglacial deposits in being elongate perpendicular to the controlling rift direction reflecting the high eruption rates and the overlying glacier slope at the time of eruption. Investigation of the source area reveals voluminous volcaniclastic debris encased by and complexly intruded into by coherent basalt; I infer early and continuing production of pyroclastic deposits with near-synchronous emplacement of peperitic intrusions. Volcaniclastic debris accumulated at the eruption site and prograded towards the present coastline by deposition in an enlarging drainage network. Deposition took place both in migrating and converging tunnels and during short intervals of sheet flow during outbreak floods. The main body of the deposit is characterized by complexly bedded volcaniclastic debris coupled with and intruded by a longitudinally extensive basalt sheet. The deposits result from an intricate depositional and intrusive history, with a longitudinally extensive internal basalt sheet comprising complex and irregular coherent bodies with dikes, apophyses, horns, tendrils, and lobate fingers that extend into the surrounding host debris. Peperitic margins, where dynamic mingling or quench fragmentation occurred, are common. The basalt sheet fed higher-level intrusions through irregular apophyses as it propagated down-flow to produce the multilevel intrusions exposed today. During propagation the coherent basalt sheet concentrated into gently meandering and locally bifurcating conduits having sheet-lobe extensions. This channelized or conduit-concentrated magma propagation was very thermally and mechanically efficient, insulating the molten basalt and hence reducing rheological changes from cooling. This efficiency is reflected by the intrusions’ propagation more than 34 km from the source area or eruption site with little change to overall intrusion morphology. The sheet forms apophyses and tendrils into the overlying sediment where it dynamically mingled to form extensive peperitic textures. In places, apophyses locally intersected the sediment-water interface and shed clasts into flowing water. These “contorticlasts” have “rolled-up” forms encasing matrix-forming debris. The main body of the intrusion propagated through the host in a channelized fashion, gently meandering within the edifice, with thin sheet-like extensions along the margins. Tendrils and apophyses extending from the main body extended into the overlying host, where they experienced enhanced cooling and frictional interactions resulting in efficient brittle fragmentation. The resulting fragments are typically angular, dense, and glassy medium lapilli to coarse ash sized and make up the bulk of the distal deposits. Where apophyses remain attached to the basal intrusion the margins fragment in the ductile regime forming fluidal-type fragments. Bed contacts are sharp to diffuse, locally erosive, indicating deposition from traction or/and high-concentration flows. Shedding of contorticlasts into bedload beneath flowing water requires that their source intrusions shoaled, hence implying the voluminous intrusions would have also been transferring heat into the water with only a thin, deforming clastic blanket to reduce the heat flux into water and hence overlying ice. As the eruption is influenced by the ice, the ice is influenced by the eruption. The vast amounts of heat release during fragmentation will melt ice above the fragmentation zone. Using simplified ice mechanics and thermodynamic principles the total volume of ice melted can be calculated for a subglacial volcano of any type. For the Snæbýlisheiði unit, the thermal model was constructed to consider the consequences of the formation of the unit based on field and other observational data. The thermal model for the extent of ice melted by the emplacement of the Snæbýlisheiði unit combined with field observations and dissolved volatile contents in matrix glass suggests that the eruption likely occurred during the PreBoreal or Younger Dryas stadials. This is the first description of a complete unit formed by a large-scale subglacial basaltic fissure eruption. OURArchive handle The handle from the Otago University Research Archive (OURArchive) <a href="http://hdl.handle.net/10523/7031">http://hdl.handle.net/10523/7031</a> OURArchvive access level Abstract Only Department The department where the student is studying primarily. Geology Named locality Named locality describing the field area location. South Iceland Thesis description Number of pages, maps, CDs, etc. 791 pages A4, 2 A1 maps in back pocket folded Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Identifier An unambiguous reference to the resource within a given context 2017Gorny Creator An entity primarily responsible for making the resource Gorny, Carolyn Fine (Carolyn) Date A point or period of time associated with an event in the lifecycle of the resource 2017 Title A name given to the resource The Origin of Lava-Hyaloclastite Sheets, South Iceland Subject The topic of the resource Volcanology Dalsheidi Eruption dynamics Fissure eruption Glaciofluvial Glaciovolcanism Glass microtextures Ice melting Iceland Intrusions Juvenile clast microtextures lava-hyaloclastite sheets Lithofacies analysis Magma fragmentation Magma-water interactions Particle analysis Peperite Pipe-flow Sida Group Slurry Subglacial eruption Subglacial sediment transport/deposition Surtseyan eruption Thermal model Tholeiitic basalt Vesicle number density volatiles Volcano-ice interactions https://theses.otagogeology.org.nz/files/original/39a80828e576af74783e07ebe0ee72e5.pdf 8c363235f7544d968baf950d13c9cf89 Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource Geology theses OU Geology thesis Thesis or dissertation completed by University of Otago Geology students Location WKT (WGS84) The location stored in WKT (WGS84) format MULTIPOLYGON (((168.827632428016 -46.2806964200463,168.771173631899 -46.2779040142391,168.48019576634 -45.8435402817495,168.876108763784 -45.6275267591134,168.945749828871 -45.6502675100504,169.275065995524 -45.9830076577298,168.827632428016 -46.2806964200463))) Author last name Last name of the Author Gard Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? MSc Advisers Who supervised/advised this student Lee, D.E. Fordyce, R.E Abstract The Abstract for this thesis Chatton Formation, is a late Oligocene (Duntroonian (27.3–25.2 Ma) to Waitakian (25.2–21.7 Ma)) unit comprising fossiliferous shallow marine sandstones, sandy siltstones, greensands, grainstones and conglomerates. The formation was studied at thirteen localities in Southland and southwest Otago, from north to south: Thompson’s Farm (Freshford), Muddy Terrace (Freshford), Coalbrook, Wendon Valley School, Wendon Creek, Wendon Valley, Balfour Quarry, Chatton, Charters Road Slump, Copelands Pit, Cosy Dell Pit, Hedgehope Stream and Brydone. Exposures are generally thin with one to two facies exposed making correlations between sections difficult. Thin sections of sandstones and conglomerate lithic clasts show sediment was derived from local sources that include the Caples, Maitai and Murihiku basement terranes and possibly the more distal Rakaia Terrane. Fossils, especially molluscs, are well preserved and some faunas have a high diversity of species (e.g. n>360 at Cosy Dell) owing to the preservation of aragonitic shells. Molluscan faunules have both life and death components and assemblages appear to be somewhat localised and facies controlled with the exception of families Glycymerididae, Pectinidae, Carditidae, Veneridae, Turritellidae, Calyptraeidae, Naticidae and genera Limopsis, Austrofusus and Amalda which are widespread. Shellbeds represent a wide variety of depositional environments from storm, mass flow or transgressive lag deposits for clast-rich beds to quiet waters with next to no bottom currents for greensands with shells in near-life position. The formation was almost certainly deposited during a transgressive systems tract. Autecology of fossils with close living relatives revealed that water depth was less than mid sublittoral (100 m) and was often much shallower. The locally derived sediment, shallow water taxa (including the brackish potamidid Pyrazus) and the observation that many sites have abundant vascular plant debris indicates that emergent land was present in the field area throughout the late Oligocene. Dating of the Chatton Formation using age ranges of foraminifera and molluscs reveals that the formation gets younger in southward and westward directions. Localities are of Duntroonian age in the north and Waitakian in the south and west of the field area. This evidence coupled with dating of the underlying lower Gore Lignite Measures and Pomahaka Formation, indicates that there was a rapid, relatively short-lived transgression of the Chatton Sea forming a shallow seaway during the late Duntroonian. This seaway rapidly regressed in the Waitakian, possibly due to falling global sea levels coupled with rapid influx of sediment caused by the prograding river system that deposited the overlying upper Gore Lignite Measures. OURArchive handle The handle from the Otago University Research Archive (OURArchive) <a href="http://hdl.handle.net/10523/7230">http://hdl.handle.net/10523/7230</a> OURArchvive access level Abstract Only Department The department where the student is studying primarily. Geology Named locality Named locality describing the field area location. Southland Thesis description Number of pages, maps, CDs, etc. 210 pages A4 Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Identifier An unambiguous reference to the resource within a given context 2017Gard Creator An entity primarily responsible for making the resource Gard, Henry James Leonard (Henry) Date A point or period of time associated with an event in the lifecycle of the resource 2017 Title A name given to the resource Sedimentology, paleoecology and paleogeography of the shallow marine Chatton Formation, southern New Zealand Subject The topic of the resource Paleontology Chatton Formation Duntroonian late Oligocene New Zealand paleoecology paleogeography