1 10 30 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/9ab157748022883d669156956347c62c.pdf 3f094b4597fa4ccf1fa11b47cf62cb55 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 (((174.070746110104 -42.097846706775,174.354811926306 -41.725481753094,175.0229096855 -41.4743803795098,175.182786764833 -41.635287225184,175.298698689571 -41.656856048084,175.786393378181 -41.4345819385547,176.220194151376 -40.9848036585385,176.816067254341 -41.7147376789169,175.521928819304 -42.2842059042345,174.284381302374 -42.3381111532636,174.070746110104 -42.097846706775))) Author last name Last name of the Author Fraser Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? PhD Advisers Who supervised/advised this student Gorman, A.R. Pecher, I. Abstract The Abstract for this thesis The Pegasus Basin off the east coast of New Zealand's North Island is a frontier basin that hosts a large gas hydrate province. The basin has a large amount of faulting, which has lead to the creation of many interesting and unique accumulations of gas hydrates. In 2009/2010, petroleum industry standard 2D seismic data were acquired across the basin by New Zealand Petroleum and Minerals (a New Zealand government agency) to generate interest in exploration of this basin for conventional oil and gas. This seismic data set presents an unique opportunity to examine the basin's gas hydrate systems with the aim of determining the economic potential of the gas hydrates in the basin while improving our understanding of how observed gas hydrate features were formed. The seismic data were reprocessed to optimise the imaging of features related to gas hydrates. When the data were examined, there were numerous gas hydrate features found, so only a selection are presented in this thesis. With the assistance of seismic attributes, Bottom Simulating Reflections (BSRs) and blanking zones are examined. High-density velocity analysis is used to characterise areas of hydrate (higher velocity) and free gas (lower velocity). The high-density velocity analysis proved to be a very effective technique for examining the structure of gas migration chimneys. Two of the most interesting features identified in the data set include a blank dome shape with a gas chimney at its centre and a text book hydrate/free gas phase reversal that is examined in detail using amplitude vs offset (AVO) and inversion analysis techniques. The model for fluid flow and how the free gas from a chimney at the centre of the blanking zone is converted to hydrate is discussed. The hydrate and free gas phase reversal that is observed was formed by localised fluid flowing from depth into the gas hydrate stability zone (GHSZ). As the BSR becomes shallower, the sea floor deepens at this location. Without a localised fluid flow, the BSR would increase in depth with the increasing depth of the sea floor. Gas hydrate saturation and volumetric analyses were performed for one target. Concentrations were determined using empirical saturation formulae, confirming a potential target. The question of how much gas hydrate potentially is present in the basin, is discussed based both my work and that of others. OURArchive handle The handle from the Otago University Research Archive (OURArchive) <a href="http://hdl.handle.net/10523/7372">http://hdl.handle.net/10523/7372</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. Pegasus Basin Hikurangi Margin Thesis description Number of pages, maps, CDs, etc. 289 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 2017Fraser Creator An entity primarily responsible for making the resource Fraser. Douglas 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 Seismic characterisation of hydrate and shallow gas systems associated with active margin sediments and structures in the Pegasus Basin, Hikurangi Margin, New Zealand Subject The topic of the resource Geophysics gas hydrates Pegasus Basin Seismic https://theses.otagogeology.org.nz/files/original/24bab10fbed5c5ad08b7217ba43042d8.pdf 5157f0cb7ecf8172be4a9f18aba8a874 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 (((171.303052248729 -44.9961429029632,171.711890051056 -45.2063152292055,171.619362892389 -45.2985952492034,171.229720706335 -45.0664819568099,171.303052248729 -44.9961429029632))) Author last name Last name of the Author Abbey Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? MSc Advisers Who supervised/advised this student Gorman, A.R. Abstract The Abstract for this thesis Submarine canyons are well documented, both around New Zealand and globally, but questions remain around the processes involved in their formation and evolution as well as around how their morphology reflects their developmental history. The Waitaki Canyon, located at the edge of the passive Otago Shelf in the Canterbury Basin, southeast New Zealand, presents an opportunity to investigate the near-surface features associated with a shelf-indenting submarine canyon using high-resolution seismic data. One such high-resolution survey was conducted in early 2015, collecting approximately 270 km of boomer seismic data in a high-density survey pattern centred at the head of the Waitaki Canyon. Approximately 40 km2 of the seafloor bathymetric data was also collected during that cruise. These data were analysed, along with approximately 100 km of boomer seismic data from a previous survey in the area and a selection of lower resolution seismic data from surveys conducted by the hydrocarbon industry, to investigate the subsurface structures in the vicinity of the Waitaki Canyon for evidence of changes in the canyon’s morphology throughout the Quaternary Period. South of the Waitaki Canyon, a large (several kilometres across) asymmetrical system of infilled paleochannels is intersected by a canyon-parallel survey line and canyon-perpendicular lines. Several high-order sequence boundaries are identifed throughout the survey area, and a region of seafloor depressions is observed on a ridge near the head of the canyon. Seismic reflections from the outer parts of the across-shelf survey lines are generally conformable, and do not show evidence of significant lateral migration of the canyon’s point of incision. The preferred interpretation of the stratigraphy and structures imaged in the data is that they represent the poorly preserved upper reaches of a series of paleochannels that had their heads somewhere west of the present canyon head and curved, or kinked, in very shallow S-shapes to rejoin the present path of the canyon. The canyon-parallel survey line thus intersects this kink and then approximately follows the centreline of the infilled channel, resulting in an asymmetric subsurface feature. The more recent symmetrical features are interpreted as non-axial tributaries or vestigial remains of this larger paleochannel. OURArchive handle The handle from the Otago University Research Archive (OURArchive) <a href="http://hdl.handle.net/10523/7400">http://hdl.handle.net/10523/7400</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. Waitaki Canyon Thesis description Number of pages, maps, CDs, etc. 142 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 2017Abbey Creator An entity primarily responsible for making the resource Abbey, Cameron James (Cam) 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 Waitaki Canyon - An investigation of the Late Quaternary development of a shelf-indenting submarine canyon using high-resolution boomer seismic data Subject The topic of the resource Geophysics Canterbury Basin canyon geophysics Otago shelf Quaternary submarine canyon Waitaki https://theses.otagogeology.org.nz/files/original/185061ddc0df61ee4af2b71affb671f4.pdf 5550c8160d0d4a4cf560a0991bdd89c6 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 (((170.38748098797 -43.265149244074,170.424934473365 -43.2659990625108,170.422899020371 -43.3141954428501,170.385416011598 -43.3133442005652,170.38748098797 -43.265149244074))) Author last name Last name of the Author Lepine Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? MSc Advisers Who supervised/advised this student Gorman, A.R. Abstract The Abstract for this thesis The glacio-fluvial sediments of the Whataroa Valley contain a geological record of environmental change that occurred as the valley was filled by sediments following the retreat of Pleistocene glaciers. This record is greatly affected by the significant motion that has occurred on the Alpine Fault over the same period. The Alpine Fault is the boundary between the Pacific and Australian tectonic plates, with uplift along the fault giving rise to the formation of the Southern Alps. For much of its length, the trace of the Alpine Fault is covered in sediments, so its precise position is not known. A series of hammer and weight drop seismic reflection lines collected in 2011, 2013 and 2015 image the sediments of the Whataroa Valley overlying the (presumably) glacially carved basement. This thesis uses these high-resolution seismic data for three purposes: 1) characterisation of sedimentary strata deposited in the valley while contributing to the multidisciplinary dataset characterising site 2 of the Deep Fault Drilling Project, 2) constraining the position of the Alpine Fault near surface trace on the coastal plain and 3), comparing and contrasting two different seismic sources that been used in data acquisition. The WhataDUSIE 3D survey conducted in 2011, consists of seven separate profiles on the eastern side of the Whataroa River on the hanging wall of the Alpine Fault. Each of these profiles was approximately 750 m in length, with a receiver spacing of 4 m and a shot spacing of 8 m. This survey was aimed at characterising the sedimentary strata in the Whataroa Valley in 3D. The Whataroa 2013 survey consists of four profiles totalling approximately 3 km in length. Geophone spacing was 5 m with shot points located between every second geophone (at a spacing of 10 m). Two of these profiles (4 and 5) were collected on the coastal plain running approximately perpendicular to the Alpine Fault. These lines were collected in an attempt to image the Alpine Fault in the near surface sediments. The other two profiles (1 and 2) lie on a river terrace and are orientated parallel to the Alpine Fault, and perpendicular to the valley wall. These two profiles characterise the sediments in the lowe r section of the Whataroa Valley and were collected as part of a larger data set for characterisation of the DFDP-2 drill site. The Whataroa 2015 survey was a re-shoot and extension of line 5 of the Whataroa 2013 survey. It made use of a weight drop seismic source and had a shot spacing of 10 m, with a 5 m receiver spacing. A comparison between the hammer seismic source and weight drop seismic source showed that while the frequencies of both sources were similar, the weight drop seismic source produced five times the energy and was a more repeatable source, leading to better quality data. Results of this study identified five main seismic facies, and the depth to basement within Whataroa Valley at the DFDP-2 drilling location. Offset reflections were also identified in the vicinity of the Alpine Fault surface trace. The sedimentary strata in Whataroa Valley have been divided into four facies: fluvial gravels (facies 1), Pleistocene marine sediments (facies 2), Pliocene marine sediments (facies 3) and a transition to basement (facies 4). Facies 5 represents a sudden change in signal strength in the northern sections of lines 4, 5 and 7. Within the marine and most recent glacio-fluvial deposits are offset reflections that do not propagate to the surface. These reflections have been interpreted to represent old Alpine Fault surface traces with offsets on the order of 10 to 25 m. There is a strong signal strength change identified in lines 4 and 7 that coincides with the proposed location of the Alpine Fault surface trace. Basement was only conclusively observed i n lines 1 and 2, occurring at a depth of 240 m near the DFDP-2 drill site. This was confirmed by rock cuttings from the borehole itself. OURArchive handle The handle from the Otago University Research Archive (OURArchive) <a href="http://hdl.handle.net/10523/6768">http://hdl.handle.net/10523/6768</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. Whataroa Valley West Coast Thesis description Number of pages, maps, CDs, etc. xiv, 153 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 2016Lepine Creator An entity primarily responsible for making the resource Lepine, Patrick Rafe Wadworth (Patrick) Date A point or period of time associated with an event in the lifecycle of the resource 2016 Title A name given to the resource Shallow Seismic Survey of the Whataroa Glacial Valley in the vicinity of the Alpine Fault, Westland Subject The topic of the resource Geophysics Alpine Fault DFDP Shallow Seismic https://theses.otagogeology.org.nz/files/original/3e7e9d4d4618847e75546af375722f37.pdf 886eb1e5f0b4c0cc5a5fbbe562692a68 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 (((169.803081781456 -44.1599965354529,169.89584575211 -44.1577932769353,169.912344443123 -44.247327558642,169.982143852039 -44.2820659801661,169.934064587607 -44.3393808826585,169.799308174647 -44.2785136990548,169.803081781456 -44.1599965354529))) Author last name Last name of the Author Krause Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? MSc Advisers Who supervised/advised this student Gorman, A.R. Abstract The Abstract for this thesis In a New Zealand first, a multi-channel hydrophone streamer has been used in conjunction with a boomer source to seismically image post-glacial sediments in the floor of Lake Ohau, Mackenzie Basin, adjacent to the Southern Alps, New Zealand. By integrating this dataset with existing geophysical data in a three-dimensional framework, a seismic stratigraphy has been defined, which, when combined with geological data will help develop a better understanding of climate variability in New Zealand since the retreat of glacier from the Ohau valley at the end of the last ice age. Lake Ohau exhibits sedimentary units typical of deglaciation and subsequent post-glacial deposition. The seismic stratigraphic units correspond to changing depositional environments; ice-contact and sub-glacial outwash and till; pro-glacial glacio-lacustrine meltwater deposits; post-glacial lacustrine deposits, are defined from the six seismic facies identified. Further- more, Lake Ohau exhibits multiple deformation structures, in particular, a landslide caused by catastrophic slope failure soon after the Ohau glacier had receded. Further structures present are multiple gravity flows, originating from the Ben Ohau range and slump deposits present along the eastern margin. Natural gas is a common and widespread feature within the Ohau stratigraphy and indicates the change from a pro-glacial to a post-glacial depositional regime. The results reveal that Lake Ohau has recorded the process of de-glaciation since the Last Glacial Maximum, with no active faulting, thus providing an excellent, undisturbed sedimentary record of the last ?18,000 years, when combined with well-hole control. This study allowed comparison of the different seismic surveys, demonstrating that CHIRP and multi-channel seismic data, respectively, provide quality images of high resolution and good depth penetration. OURArchive handle The handle from the Otago University Research Archive (OURArchive) <a href="http://hdl.handle.net/10523/7029">http://hdl.handle.net/10523/7029</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. Lake Ohau Canterbury Thesis description Number of pages, maps, CDs, etc. xvi, 147 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 2016Krause Creator An entity primarily responsible for making the resource Krause, Michael Anthony (Mike) Date A point or period of time associated with an event in the lifecycle of the resource 2016 Title A name given to the resource Characterising change in post-glacial climate using seismic imaging of Lake Ohau sediments Subject The topic of the resource Geophysics Paleoclimatology geophysics Lake Ohau paleoclimate Seismic seismic stratigraphy https://theses.otagogeology.org.nz/files/original/f8ca7e802ec374e8a838fabae6a720be.pdf 47f1f877b1a3a7bc0fcc7654e09e8897 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 (((170.517052682067 -45.8981924221679,170.498483884105 -45.8863561920674,170.514216864362 -45.8700294905412,170.556144002159 -45.8623611434089,170.602896841589 -45.8214381727438,170.618916303892 -45.8131999863651,170.625210283952 -45.7933265865297,170.703566935237 -45.7754009800494,170.72019984987 -45.7681134761579,170.740562129658 -45.7694707605913,170.734408411591 -45.7869718471385,170.716624478748 -45.8056695029933,170.679345831581 -45.8177780357334,170.677873420324 -45.8367998850659,170.648877805233 -45.8457325027839,170.609058461018 -45.8525264841923,170.599160556188 -45.8766097578685,170.566725301227 -45.8854491222552,170.536106187645 -45.8838400463155,170.517052682067 -45.8981924221679))) Author last name Last name of the Author Flectcher Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? BSc(Hons) Advisers Who supervised/advised this student Riesselman, C.R. Gorman, A.R. Abstract The Abstract for this thesis The sedimentary units that line the floor of Otago Harbour contain a rich geological record of past environmental changes and catastrophic events, like earthquakes and floods that may have affected the region. While the surface geology of the region around Otago Harbour has been well studied, very little is known about the units and structures that lie beneath. These subsurface features hold vast amounts of geological evidence which can be used to determine the origin of and processes controlling, the harbour, offering insight into possible hazards the future might hold. A total of 23 harbour-crossing seismic lines were collected between Taiaroa Head an the Leith Canal covering the majority of Otago Harbour. These lines were processed and refined to produce cross sections of the harbour, imaging from the upper sediments right down to the bedrock. The resulting data were then used to produce a 3D model of the paleovalley’s bedrock contact, as well as allowing the identification of major depositional horizons within the sediment. From this modelling and analysis, interpretations related to sedimentary time scales, erosional processes and faulting were made. The paleovalley 3D model showed far deeper depths (upto 160m) than imaged by previous studies, as well as providing evidence to support a time scale for the erosional valley’s formation. Evidence such as the merging of multiple small channels and shallowing paleovalley depths near the centre of the harbour, indicated a paleovalley formed by the erosion of two rivers out from a paleowatershed, situated above today’s Portobello Peninsula and Quarantine and Goat Islands. The 3D model also allowed a calculation of a stored sediment volume which exceeded previous estimates by ~37%. The harbour cross sections supported correlation of past depositional events with major sea level rise on two possible time scales (Pleistocene and Post Glacial). These same depositional horizons also exhibited possible offsets and slumping which sets the foundations for future studies into possible faulting in the harbour. Many of these findings provide insight into the possible future of Otago Harbour, constraining possible transgressional rates as well as identify indicators of a possibly active fault, both which could have a significant impact in terms of hazard assessments and the overall sustainability of Dunedin’s coastal setting. Department The department where the student is studying primarily. Geology Named locality Named locality describing the field area location. Otago Harbour Dunedin Thesis description Number of pages, maps, CDs, etc. 145 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 2016Fletcher Creator An entity primarily responsible for making the resource Fletcher, Patrick T. Date A point or period of time associated with an event in the lifecycle of the resource 2016 Title A name given to the resource The geological evolution of Otago Harbour: a high-resolution seismic reflection study Subject The topic of the resource Geophysics Sedimentology Controlled source seismology https://theses.otagogeology.org.nz/files/original/8edce1270ee9bf43a2942fd65ad45ecf.pdf 9c84c0a9022da3a992b12ee94ead9716 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 POLYGON ((170.614049517661641 -45.949554100034938,170.760494851073446 -46.043012833490131,170.725929991760438 -46.135203730806282,170.541156819792349 -46.207579980975247,170.41619407450213 -46.092897465911165,170.614049517661641 -45.949554100034938)) Author last name Last name of the Author McLachlan Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? MSc Advisers Who supervised/advised this student Wilson, G.S. Gorman, A.R. Abstract The Abstract for this thesis A seismic survey was collected between March and October 2013 using the RV Polaris II on the inner‐mid Otago continental shelf. The survey included ~200 km of high resolution single channel boomer seismic, CHIRP and side scan sonar as well as piston cores which were collected on the October cruise. The study area is ~25 x 10 km and is located ~10 km off the city of Dunedin where the shelf is ~40 km wide with a low gradient to the shelf break at ~120 m water depth. The majority of the profiles collected are shore normal with three tie lines linking them. The survey was set up to investigate the origin of the Saunders Ridges, which are an anomalous set of ridges in the study area. It had been previously suggested that they are the result of an overstepping event during a rapid sea level rise and meltwater pulse 1A has been proposed as the causal event. The results of this study are inconclusive; however the preliminary evidence suggests that an overstepping event is the probable cause of the ridges and the depth at which the ridges occur suggests that the sea level rise event may have been meltwater pulse 1b, which occurred ~9.5 ka. The evolution of the last three sea level cycles on the Otago continental margin was determined and shows a regressive transgressive stratigraphic stacking pattern. Sequence 2 is only observed as an incised channel in two of the profiles; otherwise it is unknown in the study area. A difference in the stratigraphic stacking pattern over the profiles in the study area and a previously collected profile ~30 km to the north, Osterberg’s (2001) profile, has been investigated. Sequence 3 in the study area has an unusually thick transgressive systems tract when compared to the equivalent sequence in Osterberg’s profile, which has a thick regressive systems tract. The difference in stratigraphic stacking patterns has been attributed to a change in the hydraulic regime and sedimentation patterns between over the course of the Late Quaternary. The Holocene highstand sand wedge migrates northeastwards up the littoral zone ~190 km from the Clutha River by longshore transport. However, on the mid shelf a proposed eddy on the down‐current side of the Otago Peninsula that was operational during the highstand is the most likely cause for the limited extent of the sand wedge on the mid shelf, which is restricted to ~60 m north of the Clutha River mouth. During lowstand this would not be present allowing for sediments to be transported unimpeded north on the Otago continental shelf, creating a sediment supply for Osterberg’s region during the highstand‐regressive phase. During the transgressive phase of sequence 3 a coastal plain would have been present in the study area draining the ancient Water of Leith which could have provided the increased sediment supply for the thick transgressive systems tract. This shows that the investigation of hydraulic regime and longshore transport as well as point source of sediment play an important role in determining the development of the stratigraphic stacking patterns. OURArchive handle The handle from the Otago University Research Archive (OURArchive) <a href="http://hdl.handle.net/10523/6026">http://hdl.handle.net/10523/6026</a> OURArchvive access level Open Access Department The department where the student is studying primarily. Marine Science Geology Named locality Named locality describing the field area location. Otago continental shelf Saunders Ridges Thesis description Number of pages, maps, CDs, etc. xiv, 192 pages, A4, some A3 foldouts, some bigger foldouts 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 2015McLachlan Creator An entity primarily responsible for making the resource McLachlan, Christine Jane Date A point or period of time associated with an event in the lifecycle of the resource 2015 Title A name given to the resource A seismic and sedimentological investigation and evolution of the Otago continental shelf and the Saunders Ridges demonstrating the role of longshore drift Subject The topic of the resource Geophysics Sedimentology Longshore drift Otago continental shelf Saunders Ridges Seismic https://theses.otagogeology.org.nz/files/original/7121c0db178e957697271db94a596143.pdf af69f9b3f70b40a125fa081ccb8f7d5d 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 Kadada Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? PGDipSci Advisers Who supervised/advised this student Gorman, A.R. Abstract The Abstract for this thesis Since 1976, the Great South Basin has undergone exploration for hydrocarbons. Eight exploratory wells have explored various structural highs within the basin. The basin was delineated by 30,000 km of 2D seismic data in the early 1970s to early 1980s, conducted by a number of New Zealand and international companies. In 2006 a new survey consisting of 3110 km of high resolution seismic tied the available wells off the SE coast of the South Island. Since then OMV New Zealand and other partners have collected more detailed data including a 3D seismic survey in 2012. The aim of this study is to analyze and evaluate the source rocks and gas shows in the Great South Basin and to assess the extent of the source rocks in the seismic data. This includes an examination of seismic data surrounding the Kawau-1A well to evaluate the development of structural closure that would be instrumental in forming a potential trap. Numerous sets of well data have been adapted and generated from the original composite logs prepared by companies such as Hunt to identify coal deposit intervals, thicknesses and occurrences and their subdivisions relative to age. The logged data, and in particular the coal intervals were correlated. Gas show intervals were evaluated in new sets of adapted well sections and the geochemistry measurements of total organic matter were plotted for eight wells. The coal source rock was then correlated in the seismic lines between the Tara-1 and Toroa-1 wells. Stratigraphic markers were picked on 13 seismic lines in the area of Kawau-1A, and data were mapped for four seismic markers in the Cretaceous, Paleocene, Miocene and Eocene. Another. 50 seismic lines were examined to discover the distribution of gas chimneys/volcanoes. IHS Kingdom software was used for generating the horizons and the contour maps. The results of the analysis show that the thickest coal source rock exists at Tara-1. The source rock correlations in the seismic lines are limited to a small area surrounding the well. Gas chimneys or small sediment volcanoes are found in many lines, particularly with high frequency near Toroa-1. Kawau-1A displays good closures developed at the top of the Cretaceous and Paleocene. Department The department where the student is studying primarily. Geology Named locality Named locality describing the field area location. Otago University Thesis description Number of pages, maps, CDs, etc. 71p 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 2015Kadada Creator An entity primarily responsible for making the resource Kadada Talal Khalid (Talal) Date A point or period of time associated with an event in the lifecycle of the resource 2015 Title A name given to the resource Assessment of Source Rock Distribution from Well and Seismic Data in the Great South Basin Subject The topic of the resource Geophysics Great South Basin https://theses.otagogeology.org.nz/files/original/5618d6f92d4dfd3e735b7a4557f306f3.pdf eb649742c83fdc21f12b22ee0d49c1c1 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 (((180.0 -44.339562710309906,178.642311413012322 -44.335253643114314,178.614551266778079 -43.764996330785578,180.0 -43.770672694190807,180.0 -44.339562710309906)),((172.437795548386504 -46.226325799176706,170.956219220779843 -46.20943619974814,171.074125411950234 -45.18267442813459,172.367596856769353 -45.159056922324673,172.437795548386504 -46.226325799176706)),((174.235065676561049 -44.334767485195819,173.518248259879925 -44.340269274720178,173.487607941161571 -43.844918705194296,174.30335489562475 -43.819468426881102,174.235065676561049 -44.334767485195819)),((-180.0 -43.770672694190765,-179.807242288648126 -43.771462447569967,-179.764229615031809 -44.340311004463089,-180.0 -44.339562710309878,-180.0 -43.770672694190765))) Author last name Last name of the Author Hillman Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? PhD Advisers Who supervised/advised this student Gorman, A.R. Pecher, I. Moy, C. Abstract The Abstract for this thesis Seafloor depressions are widespread on the present-day continental slope along the south-east coast of New Zealand's South Island. The depressions appear to be bathymetrically constrained to depths below 500 m and above 1100 m. Similar depressions observed on the Chatham Rise are interpreted to have formed as a result of gas hydrate dissociation, primarily due to the correlation of the depth range to the predicted gas hydrate stability zone in the region. This lead to the hypothesis that a similar origin can be applied for the depressions investigated in this study. However, this investigation has found limited geophysical or geochemical evidence to support this hypothesis. The objective of this study is to examine whether a causal relationship can be established between potential mechanisms of depression formation and observations based on existing and newly acquired data. This has been done using newly acquired data from the R/V Sonne, R/V Polaris II and R/V Tangaroa, in combination with existing data sets from previous surveys in the region. A combination of multiple geophysical survey techniques have been utilised in this study to conduct the first detailed investigation of these structures. Multibeam bathymetry and backscatter have been used to produce high resolution maps of the seafloor geomorphology and to carry out automated supervised segmentation of substrate classes. Sediment samples and underwater images have been used to ground truth substrate classifications. Sediment samples have also been used to conduct geochemical analysis to assess whether evidence of paleogeochemical methane is present. Subsurface profiles in the form of multichannel boomer seismic, parasound seismic, 2D and 3D seismic lines have been used to investigate underlying structural controls such as polygonal fault systems and understand the stratigraphic framework of the seafloor depressions. Although the results of our analysis do not preclude that the seafloor depressions formed as a result of gas hydrate dissociation, neither does our geophysical or geochemical evidence support the theory. Therefore, we propose that an alternative mechanism may have been responsible for the formation of these structures. The morphometric variability of the seafloor depressions on the Otago Shelf and Chatham Rise indicates that either these structures were formed as the result of the influence of multiple mechanisms, or that they formed at different times and are at different stages in formation. Based on the evidence presented in this study, we propose that the interaction of multiple mechanisms is the most likely explanation for the formation of these seafloor depressions. Multiple mechanisms have played a role in the formation of these structures, including fluid and / or gas venting, groundwater flux and subsurface structural controls. We propose that the primary mechanism of formation for the smaller seafloor depressions is groundwater flux related to artesian seepage of meteoric groundwater, however this mechanism cannot fully explain the formation of the giant structures observed on the Central Chatham Rise. We therefore propose that in this area gas venting from hydrates or other sources may have been a factor. Subsequent to their initial formation the seafloor depressions have been modified and maintained by the action of regional oceanic currents. OURArchive handle The handle from the Otago University Research Archive (OURArchive) <a href="http://hdl.handle.net/10523/5612">http://hdl.handle.net/10523/5612</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. Chatham Rise Canterbury Basin 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 2015Hillman Creator An entity primarily responsible for making the resource Hillman, Jess Irene Tsahai Date A point or period of time associated with an event in the lifecycle of the resource 2015 Title A name given to the resource Investigation of seafloor depressions east of New Zealand Subject The topic of the resource Geophysics backscatter bathymetry Canterbury Basin Chatham Rise gas hydrates geomorphology methane multibeam New Zealand Otago Submarine Canyon Complex pockmarks seafloor depressions Seismic https://theses.otagogeology.org.nz/files/original/7672ce430b39c6b99de82ae112a7a4f8.pdf ac5f73578c5ff7f9e3d88828a86d14c7 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 POLYGON ((170.2406113602338 -45.752754865914653,170.286167593748729 -45.753370537614913,170.285230837798963 -45.786689425434872,170.239670984917382 -45.785597026416852,170.2406113602338 -45.752754865914653)) Author last name Last name of the Author Bowie Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? PGDipSci Advisers Who supervised/advised this student Gorman, A.R. Lee, D.E. Abstract The Abstract for this thesis In 2007, airborne geophysical surveys identified four sub-circular features presenting high magnetic intensity near Hindon, 25 km NW of Dunedin, within the Miocene Waipiata Volcanic Field (WVF). Similar magnetic anomalies within the WVF are associated with maar-diatreme structures, e.g., Foulden Maar or Gladsmuir diatreme. Subsequent excavations produced evidence that at least two of the basins contain extremely fossiliferous laminated diatomite and/or carbonaceous mudstone, deposited in former maar-lakes. Surface exposure is very limited, which means that geophysical surveys (ground-based magnetic, microgravity and seismic) are essential for accurately representing the size, depth and sediment infill. The large magnetic susceptibility of the basaltic diatreme allows for ground-based magnetic surveys to accurately characterise the size and extent of all four structures. It was found that these structures extend over an area of 16 km2 and are individual anomalies probably related to the same magma source. The relative density of rock within the maar complex then allowed for microgravity surveys to be conducted. Schist typically has a density of 2.73, basalt 2.77, volcanic breccia 2.19 and diatomite 1.53 g/cm3. The relatively low density of diatomite in the subsurface produces a negative anomaly that has been characterised by a Worden Gravimeter survey. Two maars have yielded negative anomalies related to a thickness of diatomite in the subsurface. The final geophysical method was a seismic survey conducted in Maar One. The seismic plot has revealed the thickness and lithologies of the sediment infill within Maar One. This has clarified that at least one of these deposits is a suitable candidate for full coring and paleoenvironmental studies, as at Foulden Maar some 25 km to the northwest. An integrated geophysical interpretation of Maar One has indicated that 160 to 190 m of laminated sediment is present within Maar One. Seismic and microgravity surveys have allowed for selection of an appropriate location to recover this maximum thickness. These two methods provide a generally consistent interpretation of basin thickness (although the thickest locations lie 150 m apart in the two models. A site between these points is most suitable for a drill core to be located. The Foulden core yielded 127 m of diatomite, enabling the reconstruction of a 100,000- year-long terrestrial record of climate, fossil biodiversity and ecosystems. A potential 190 m core of diatomite at Hindon suggests this record could be extended and improved. New samples of volcanic rock have been selected for radiometric dating to confirm the early Miocene age established by preliminary palynological biostratigraphy. Department The department where the student is studying primarily. Geology Named locality Named locality describing the field area location. Hindon Maar Hindon East Otago Thesis description Number of pages, maps, CDs, etc. xvi,149 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 2015Bowie Creator An entity primarily responsible for making the resource Bowie, Elliot Date A point or period of time associated with an event in the lifecycle of the resource 2015 Title A name given to the resource Geophysical Characterisation of the Hindon Maar Complex Subject The topic of the resource Geophysics geophysics Hindon Maar maar