1 10 22 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/d3fc6493a25094a8fc4ad66f3586ab27.pdf fd6fbacdc75d5de676eb34208efa777d 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 (((165.459024571345026 -78.260975887577573,165.930153403187717 -78.275458748374291,165.880470623272714 -78.384796163202211,165.32149895585971 -78.358351090289432,165.459024571345026 -78.260975887577573)),((163.391037909385147 -78.228595263547234,163.887357474306356 -78.243236626491793,163.784154488444841 -78.350120025240315,163.240067291074126 -78.322582660464377,163.391037909385147 -78.228595263547234)),((159.226884147374847 -78.499508349075626,159.985105885787448 -78.550457251856272,159.699927940592261 -78.766278258193182,158.840943766587714 -78.705339607664101,159.226884147374847 -78.499508349075626))) Author last name Last name of the Author Anderson Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? MSc Advisers Who supervised/advised this student Wilson, G.S. Abstract The Abstract for this thesis Retreat of the Antarctic ice sheets since the Last Glacial Maximum (LGM) has been associated with sea-level rise and ocean warming on the ice sheet margins, but the significance and relative contribution to eustatic sea-level rise since this time has been difficult to quantify. This thesis presents new constraints for the timing and retreat of the Skelton Glacier in the Ross Embayment and grounded ice in the Ross Sea, the Ross Sea Ice Sheet (RSIS). Using two nunataks, Escalade and Tate peaks as a gauge for past ice sheet levels, glacial geologic evidence and ¹⁰Be and ²⁶Al cosmogenic-nuclide exposure ages provide new and direct constraints on the past extent and timing of retreat of the Skelton Névé over the Late Quaternary. Glacial geological and geochronological evidence from Escalade and Tate peaks show that between 288 ka and 40.3 ka, the ice surface experienced slow deflation, lowering from ≥1431 to 1363 metres above sea level (masl). Ice in the southern Skelton Névé lowered by ~50 m between 40.3 ka and ~13.6 ka. Records from the eastern margin of Escalade Peak indicate the ice surface of the Skelton Névé was between 50 and 106 m higher than present during the LGM. The ice surface elevation remained close to its maximum ice level prior to 17.2 ka and has thinned by at least 50 m to the present-day level since ~13.6 ka. Thinning continued after 8.7 ka, and likely reached the present-day ice level ~2 - 3 ka. This lateglacial-Holocene ice-surface lowering is asynchronous from other sites in the Transantarctic Mountains where increased snow accumulation has been reported to have caused thickening up glacier in the early to mid-Holocene. ¹⁰Be exposure ages from large (>1 m) boulders in southern McMurdo Sound show that the RSIS had an ice surface elevation ~520 masl on the eastern side of Mount Discovery during the LGM and the onset of deglaciation was ~13.1 ka. The ice surface lowered from ~520 to 234 masl between 13.6 ka and 9.3 ka; and from 234 masl to the present ice shelf between 9.3 ka and 6.6 ka. This late-glacial and Holocene chronology from southern McMurdo Sound is consistent with other records in the Ross Embayment, and implies the RSIS experienced rapid retreat during the early to middle Holocene. These results suggest that the majority of ice sheet thinning and retreat in the Skelton Névé and in southern McMurdo Sound began just after meltwater pulse 1A (MWP-1A), a period of abrupt sea-level rise of up to 20 m that occurred between ~14.7 ka and 14.3 ka. Thus, it is unlikely that the RSIS and outlet glaciers from the East Antarctic Ice Sheet (EAIS) that drain into the Ross Embayment made a significant contribution to eustatic sea-level rise at this time. From the distribution and petrography of glacial deposits and the retreat chronology in southern McMurdo Sound a two-stage ice flow model for McMurdo Sound was reconstructed: (1) Prior to ~18 ka an expanded Koettlitz Glacier lobe of ice owed north and northeast through the Brown Saddle during the LGM and coalesced with northward owing ice from the Ross Sea. (2) Retreat of the Koettlitz Glacier and perhaps other outlet glaciers then accommodated westward and northward ice flow north of Brown Peninsula, fed from grounded ice in the Ross Sea. These findings reveal that components of both the EAIS and West Antarctic Ice Sheet (WAIS) that drained into the Ross Sea contributed to lateglacial-Holocene sea-level rise. However, it is likely to be in response to warming of the Southern Ocean and sea-level rise from the retreat of the Northern Hemisphere ice sheets and the outer margins of the Antarctic. OURArchive handle The handle from the Otago University Research Archive (OURArchive) <a href="http://hdl.handle.net/10523/5613">http://hdl.handle.net/10523/5613</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. Antarctica McMurdo Sound Ross Sea Thesis description Number of pages, maps, CDs, etc. xii, 215 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 2015Anderson Creator An entity primarily responsible for making the resource Anderson, Jacob Thomas Herd (Jacob) 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 Late Quaternary ice sheet thinning and retreat in southern Victoria Land, Antarctica Subject The topic of the resource Paleoclimatology Antarctica Exposure dating Holocene Last Glacial Maximum McMurdo Sound Ross Sea Skelton Glacier https://theses.otagogeology.org.nz/files/original/416e1af17372cfd0096cb577d3e37e4d.pdf 8163ebe43a3bf9a55dbec78b5424e98e 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 (((-70.842533829626547 -27.455542812226064,-71.092097543623439 -27.466143739655447,-71.080213557242644 -26.977439096352633,-70.783113897722515 -26.977439096352633,-70.842533829626547 -27.455542812226064)),((-70.438478292679093 -23.596356314795017,-70.723693965818484 -23.64015683276104,-70.711809979437675 -22.926577418999052,-70.390942347155871 -22.926577418999052,-70.438478292679093 -23.596356314795017))) Author last name Last name of the Author Tapia Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? PhD Advisers Who supervised/advised this student Wilson, G.S. Gorman, A.R. Abstract The Abstract for this thesis The late Neogene evolution of the Antarctic ice sheet is argued to have been relatively stable since the middle Miocene in response to progressive tectonic and palaeoceanographic isolation of the continent. The primary data set used to support the stability theory is the marine <5180 record. However, the stable isotopic system does not allow discrimination between water temperature and ice volume/ eustatic sea level controls. In this thesis, calibration of the global sea level record is proposed from three different continental margin marine records (Chile, New Zealand and Antarctica). Five late Neogene, shallow marine records from two main locations of northern Chile (Mejillones Peninsula and Caldera), are investigated in order to compare them to the existing Antarctic and New Zealand marine sedimentary records. The aim is to find common sea level components that are presumably glacial in origin. Magnetostratigraphic models are integrated with biostratigraphic and radiometric data to construct high- resolution chronologies for the studied sections. Sedimentology and sequence stratigraphic studies reveal facies associations of continental shelf and submarine fan environments in the Chilean records. Textural and faunal variations indicate that coarsening and fining up of the successions are due to shallowing and deepening of the continental margin, respectively. Paleomagnetic studies indicate that the northern Chile marine sediments retain a three component remanent magnetization: a low unblocking temperature (Tb), recent thermo viscous component; an intermediate Tb component which is the primary detrital magnetization; and a high Tb component, considered to be diagenetic in origin. Rock magnetism studies indicate that the magnetic carriers of remanence are most likely to be detrital magnetite, hematite, titanomagnetite and/or low titanium maghemite. The chronologic models constrain: Caleta Herradura section between 18.5 and 4.7 Ma, with two unconformities (16.2-14.9 and 8.9-7.3 Ma); Tiburon Basin lower section between 4.2 and 2.8 Ma; Bahia lnglesa succession between 7.5 and 4.2 Ma, with one unconformity (5.5-5.1 Ma); Quebrada Playa Chorrillos section between 7.23 and 6.03 Ma, with two unconformities (7.1-6.74 and 6.44- 6.26 Ma); and the Quebrada La Higuera section between 15.52 and 14.2 Ma., with two unconformities (15.04-14.9 and 14.72-14.58 Ma). Correlation of the northern Chile records with the Wanganui Basin (New Zealand), the AND-1B core (Antarctica) and the oxygen isotope curve reveals that: 1) During the mid- late Miocene, cyclothems from Caleta Herradura, Quebrada La Higuera and AND-1B core are likely to be controlled by sea level variation with orbital periodicities of eccentricity and obliquity; 2) During the late Miocene- early Pliocene, cyclothems from Bahia Inglesa, Caleta Herradura, Quebrada Playa Chorrillos, Wangafmi Basin and AND-1B are likely to be controlled by sea level fluctuation with orbital frequencies of eccentricity and obliquity; 3) During the early- late Pliocene, cyclothems from Tiburon Basin, Rangitikei, Tangahoe and AND-1B core are likely to be controlled by sea level change with orbital periodicities of obliquity, and; 4) between 3.2 and 2.9 Ma, records from the three continental margins showed synchronous, high- amplitude sea level fluctuations interpreted to represent phases of climatic deterioration of greater extent, implying an variable behavior of the Antarctica ice sheet . OURArchive handle The handle from the Otago University Research Archive (OURArchive) <a href="http://hdl.handle.net/10523/4113">http://hdl.handle.net/10523/4113</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. Chile New Zealand Antarctica Thesis description Number of pages, maps, CDs, etc. xiv, 370, LXVI pages : illustrations, maps ; 30 cm. 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 2013Tapia Creator An entity primarily responsible for making the resource Tapia Orellana, Claudio Andrés Date A point or period of time associated with an event in the lifecycle of the resource 2013 Title A name given to the resource Calibrating the Southern Hemisphere Glacio-Eustasy Record Subject The topic of the resource Marine Geology Antarctica Chile Eustasy magnetostratigraphy Neogene New Zealand Sea Level sedimentology https://theses.otagogeology.org.nz/files/original/9947d3dd766f1b51154c09dab3614a9e.pdf c442be68c846ae5e6cd0e388b2dacf03 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 Ohneiser Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? PhD Advisers Who supervised/advised this student Wilson, G.S. Abstract The Abstract for this thesis The Pliocene period is an attractive geological analogue from which to study the future behaviour of the cryosphere because global temperatures and atmospheric CO2 were inline with what is projected in the coming decades. A Pliocene succession recovered beneath the McMurdo Ice Shelf revealed repeated collapses of the West Antarctic Ice Sheet during the Pliocene period. This conflicts with geomorphic records from the Transantarctic Mountains, which have been used to argue for continued polar conditions since the middle Miocene. The New Harbour drill cores were examined because they contain Plio- Pleistocene sediments that were deposited in deep fiords located within the Transantarctic Mountains only a few kilometres from geomorphic records that were used to argue for stable polar conditions. New paleomagnetic age models were constructed for the core successions from AF and thermal demagnetisation of 559 specimens. Environmental magnetic records, which are sensitive indicators of the terrestrial climate evolution, were constructed for the drill core successions. In a parallel study, a database of the magnetic mineralogy of southern Victoria Land basement and cover rocks was compiled. The database was used to construct a model of the source to sink evolution of magnetic minerals and to identify how the modern climate is expressed in the offshore environmental magnetic records. The new age models indicate that the Taylor Glacier was thick and dynamic during latest Miocene and earliest Pliocene and that it retreated after 4.69 Ma. Maghemite and pure magnetite cycles between ∼4.9 Ma and ∼4.6 Ma in sediments are coherent with advance and retreat history of the Taylor Glacier. The presence of maghemite may indicate paedogenesis during interglacial periods under warmer and wetter conditions than today. Glaciers in the Taylor and Ferrar fiords retreated after ∼4.4 Ma resulting in the deposition of fine-grained sediments with very low magnetic concentrations. Magnetic mineralogy cycles are in phase with the benthic δ18O record and an up-core increase of coercivity may indicate greater input of terrigenous sediment by rivers. Evidence of terrestrial soil formation and ice-free fiords conflicts with the nearby contemporaneous geomorphic records used to argue for persistent hyper arid, modern style polar conditions. Significant unconformities after ∼4.2 Ma indicate a dynamic environment which agrees with the terrestrial geomorphic records of expansion of EAIS glaciers. Grounded eastern sourced ice entered New Harbour at 2.6 Ma and the appearance of paramagnetism in sediments may indicate a shift to a modern style climate and the onset of strong katabatic winds. A shift to sand dominated lithologies after ∼1.2 Ma indicates deposition in ice-dammed lakes during glacial maxima. Environmental magnetic behaviour of these sediments is identical to the behaviour of modern sediments from southern Victoria Land. The new chronologies of New Harbour successions demonstrate coherence between the emplacement age of the geomorphic features and unconformities in the drill cores, which were both caused by expansion of EAIS glaciers during the mid Pliocene. However, indications from New Harbour successions of much warmer than present conditions and deep, ice-free fiords conflict with contemporaneous evidence from the Dry Valleys of hyper polar conditions. It is possible that the geomorphic records are not sensitive indicators of climate evolution. OURArchive handle The handle from the Otago University Research Archive (OURArchive) <a href="http://hdl.handle.net/10523/2195">http://hdl.handle.net/10523/2195</a> OURArchvive access level Open Department The department where the student is studying primarily. Geology Named locality Named locality describing the field area location. New Harbour Antarctica Thesis description Number of pages, maps, CDs, etc. xxxiv, 419 p., [5] folded sheets : ill. (some col.), maps ; 30 cm. + 1 DVD (4 3/4 in.) 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 2012Ohneiser Creator An entity primarily responsible for making the resource Ohneiser, Christian. Date A point or period of time associated with an event in the lifecycle of the resource 2012 Title A name given to the resource Late Neogene evolution of the Antarctic cryosphere as derived from paleo- and environmental- magnetic studies of New Harbour drill cores Subject The topic of the resource Sedimentology Antarctica CIROS DVDP Environmental magnetism Ferrar Neogene New Harbour paleomagnetism Pliocene Taylor https://theses.otagogeology.org.nz/files/original/748412a34b31c94fc0438d5eca2350c0.pdf f48bdb017bf5c136773d23c88b330046 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 Paulsen Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? MSc Advisers Who supervised/advised this student Cooper, A.F. Abstract The Abstract for this thesis Mt Morning is a 2723 m high, undissected, mainly basanitic volcano with trachytic and phonolitic assemblages. It is located 92 km southwest of Scott Base, at the foothills of the Royal Society Range. Rocks of the Erebus Volcanic Province, a part of the McMurdo Volcanic Group, are exposed on two ridges on the northern flank of the mountain, the western Riviera Ridge and the eastern Hurricane Ridge. Several pyroclastic deposits were mapped on Mount Morning, most of them monomict. However, one outcrop of a poorly bedded lapilli tuff, on the upper slopes of Riviera Ridge, contained a great diversity of lithic clasts. These clasts include phonolites, basanites, basement rocks and crustal xenoliths. This deposit was chosen as study area because of the range of clasts that provides a lithological cross-section through Mount Morning, from basement to phonolites. Volcanic rocks include basanite and phonolites clasts, phonolite flow stratigraphically underlying the lapilli tuff, and glass shards from the eruption depositing the lapilli tuff. These rocks are derived from the main eruptive sequence on Mount Morning. The phonolites show a variety of fractionating stages, which is interpreted to be due to crystal fractionation, and possibly re-incorporation of fractionated crystals in a zoned magma chamber during eruption. The glass-shards represent the most evolved phonolitic magma reported from the mountain. The phonolites are thought to have been derived from crystal fractionation from the basanite magmas. Crustal xenoliths found have a variety of origins. Crustal xenoliths include; nepheline syenites that show the same chemical characteristics as the phonolites; a syenite derived from a silica saturated sub-volcanic complex; and a biotite gabbro that has its origin outside the McMurdo Volcanic Group. The biotite gabbro is derived from a hydrous magma, possibly of an arc origin. A fenite xenolith was also found as a clast in the lapilli tuff. It is a result of alkali metasomatism of a granitic protolith, possibly beneath Mount Morning. Fenitisation has not been reported from southern Victoria Land before. The protolith, possibly a granite outcropping at the base of Riviera Ridge, similar to the Granite Harbour Intrusives from the Transantarctic Mointains, is made up of quartz, alkali feldspar, plagioclase feldspar and mica, all of which have been altered to varying degrees by fenitising fluids rich in Na (with some K). Along the edges of the grains, plagioclase and alkali feldspar have altered, quartz has dissolved, and mica has been both recrystallised and been replaced by Na-rich members of pyroxene, amphibole, and both Na and K rich phases of feldspar. The presence of anastomosing veins crosscutting a plagioclase feldspar grain indicates the presence of a strong acid, possibly hydrofluoric acid (HF). Fluorine has been found as fluorite in a xenolith from the lapilli tuff, and this is an indicator of a fluorine environment beneath Mount Morning. Department The department where the student is studying primarily. Geology Named locality Named locality describing the field area location. Antarctica Mount Morning Thesis description Number of pages, maps, CDs, etc. ix, 169 leaves : ill. (chiefly col.), col. maps ; 30 cm + 1 CD-ROM (4 3/4 in.) 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 2007Paulsen Creator An entity primarily responsible for making the resource Paulsen, Hanne-Kristin. Date A point or period of time associated with an event in the lifecycle of the resource 2007 Title A name given to the resource Lithological cross section through Mount Morning, Antarctica : a story told from xenolithic assemblies in a pyroclastic deposit Subject The topic of the resource Lithostratigraphy Petrology Volcanology pyroclastic deposits xenoliths https://theses.otagogeology.org.nz/files/original/d59c9ec78c5480a1931d6b49b0419893.pdf 7af170bed3d708823dbf9881e88d908c 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 ((166.504243443131173 -78.304870235822406,166.118671614482025 -78.307956731074682,166.11338772136034 -78.250217432958465,166.49553126832916 -78.247161801360178,166.504243443131173 -78.304870235822406)) Author last name Last name of the Author Timms Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? MSc Advisers Who supervised/advised this student Wilson, G.S Abstract The Abstract for this thesis Conflicting reconstructions exist for Last Glacial Maximum (LGM) ice configurations in McMurdo Sound, yet climatic modelling studies such as the landmark CLIMAP11 investigation, are critically reliant on ice sheet reconstructions in this region. In more recent reconstructions, there is disagreement over grounding line position, ice flow directions, ice surface contours and chronology of ice sheet retreat. The most significant divergence occurs in the region surrounding southern Black Island, which in turn hosts a significant glacial and geological cover that has been little studied. Fifteen days were spent mapping striated basement, geomorphic features, sediment/ erratic distribution and collecting samples on four diamict-covered, bedrock promontories at the southern end of Black Island. Petrographic, petrological and geochemical analyses were carried out on erratic and bedrock samples. Grain size analyses were undertaken to better characterise the diamict cover. Two new units, Cape Beck Phonolite (Cbp) and Cold Bluffs Tephriphonolite (Cbt), belong to the Erebus volcanic lineage and are the most evolved units of the Black Island volcanic complex. An 40Ar/39Ar age range of 1.8–1.7 Ma was obtained from Cbp lava flows, providing a maximum age constraint for deposition of glacial material. Mapped geomorphic features are a product of both glacial erosion and periglacial weathering processes, with the latter predominant during recent times. Several newly defined glacial facies are defined by two drift units. Cape Beck Drift is not a correlative of the Ross Sea Drift (RSD), and is believed to be a more antiquated Quaternary deposit. Younger drift is considered to be the Last Glacial Maximum response to ice fluctuations in Southern McMurdo Sound (SMS). Drift composition and distribution and glacial striae on Cbp indicate an ice sheet was grounded in SMS when the Cape Beck Drift was deposited. Granite erratics and glacially polished bedrock, proxies for ice elevation, mark the minimum height of the ice sheet at 590 m a.s.l., indicating that it completely overrtopped southern Black Island. The glacial reconstruction presented in this study was constrained by the orientations of 150, previously unrecorded, glacial striae and the distribution of key erratics in the Cape Beck Drift, which support northerly trending ice flow of the main lobe of the SMS ice sheet. This flow direction is antipodal to those presented by the CLIMAP reconstruction and its derivatives. The discrepancies between RSD reconstructions and the reconstruction of this study, highlight the need to re-assess the glacial deposits in the McMurdo Sound region that have been ascribed a LGM age, and are assumed to be related to most extensive configuration of the Antarctic Ice Sheet. Department The department where the student is studying primarily. Geology Named locality Named locality describing the field area location. McMurdo Sound Antarctica Thesis description Number of pages, maps, CDs, etc. xiv, 150 p. : ill., maps ; 30 cm. + 1 CD-ROM (4 3/4 in.) and 3 maps. 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 2006Timms Creator An entity primarily responsible for making the resource Timms, Carolyn Jean. Date A point or period of time associated with an event in the lifecycle of the resource 2006 Title A name given to the resource Reconstruction of a grounded ice sheet in McMurdo Sound : evidence from Southern Black Island, Antarctica Subject The topic of the resource Geomorphology ice sheets https://theses.otagogeology.org.nz/files/original/1137e53431cd28e90c97ea378ff145ab.pdf e123b03139df4aaf6ab09cf55d73855c 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 ((169.89189280301062 -72.329024702780401,168.889484360565831 -76.88581828016612,159.835239364604917 -76.168738850084225,163.010490925529155 -71.674030375809309,169.89189280301062 -72.329024702780401)) Author last name Last name of the Author Johnston 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 Fifty-two kilometres of of multi-channel seismic reflection data were acquired from the southern McMurdo Ice Shelf in preparation for future drilling as part of the Antarctic Drilling (ANDRILL) programme. These data provide the first opportunity to test existing hypotheses for basin evolution in this region. The seismic survey was acquired atop rvllO to rv220 m of floating ice and extended across ablation and accumulation zones of the ice shelf. Seismic processing included: datum static corrections to account for changes in the nature of the near-surface firn layer, and changes in the surface elevation across the survey area; residual static corrections to account for near surface ice shelf irregularities; and predictive deconvolution to suppress ice and firn layer multiples. A model for the ice shelf thickness was incorporated into the interval velocity model during depth conversion to ensure that the ice shelf structure did not impose non-static shifts on the seismic section. Within the depth converted seismic sections, several N to NE trending normal faults offset acoustic horizons by up to rv 150 m within the lower part of the section, and form a broad east-dipping, half-graben structure. These structures are interpreted as the southern extension of the ( early-Mesozoic to present) Terror Rift. The rift is offset slightly to the west beneath the SMIS, which may have been facilitated by an accommodation zone. This latest episode of rifting is associated with up to rv500 m of strata beneath the SMIS, which contrasts with the rvlOOO m thick succession recorded to the north of Ross Island (Fielding et al., 2005). This difference suggests that the field area is located at the tip of the rift basin, within a basin-linking accommodation zone where subsidence is less significant and erosion is more pronounced. The rift succession can be seperated into two main packages: a dislocated (?)earlyMiocene syn-rift package; and a relatively undeformed, post-rift package, seperated by a high amplitude syn-rift unconformity. The post-rift package infills the rift topography, and drapes over the graben system. Throughout this stage, basin evolution was also influenced by minor Neogene volcanic flexure, indicated by tilted strata and an ang~ lar unconformity. Neogene volcanism has also exerted a more direct effect, indicated by the presence of three volcanic features within the profiles, and thick successions of associated igneous material. Glacial erosion has also played an important role and is indicated by erosional horizons and glacio-geomorphic features within the sedimentary package and on the seafloor. The orientation of glacio-geomorphic features on the seafloor indicates an approximately NW direction for ice flow during recent ice sheet grounding events. These grounding events have probably removed the plio-pleistocene iii - •:". 'I succession from this area. Underlying the early-Miocene rift succession, reflectivity is low and acoustic horizons are dislocated. This unit may represent rift strata from an earlier Paleogene rift episode or may be acoustic basement. Support for the earlier rift episode is provided by the occurance of Eocene fossiliferous erratics around the margin of the SMIS, which has lead other workers to suggest that strata of this age may underly the SMIS and be uplifted within the footwall of a normal fault (Stilwell and Feldmann, 2000; Wilson, 2001). The structural setting revealed by the SMIS seismic reflection profiles is consistent with this hypothesis. Department The department where the student is studying primarily. Geology Named locality Named locality describing the field area location. Antarctica McMurdo Sound Thesis description Number of pages, maps, CDs, etc. xvi, 230 p. : ill. (some col.), 5 diag., maps ; 30 cm. + 1 CD-ROM (4 3/4 in.); 5 sheets (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 2006Johnston Creator An entity primarily responsible for making the resource Johnston, Lisa. Date A point or period of time associated with an event in the lifecycle of the resource 2006 Title A name given to the resource Cenozoic basin evolution beneath the Southern McMurdo ice shelf, Antarctica Subject The topic of the resource Map Cenozoic basin analysis ice sheets https://theses.otagogeology.org.nz/files/original/183f25ae6244f06dbfede7aa7a750a2f.pdf 52be272c141708915360c98fa89efcb7 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 Gue?gan Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? MSc Advisers Who supervised/advised this student White, J.D.L. Abstract The Abstract for this thesis The Middle Jurassic Kirkpatrick flood basalts and comagmatic Ferrar intrusions exposed in the Transantarctic Mountains represent a major pulse of tholeiitic magmatism, and together constitute the Ferrar Large Igneous Province of Antarctica. At Coombs Hills, the exposed Ferrar intrusions consist of numerous dykes and sills representing a complex plumbing system. This work examines the mode of dyke propagation and magma flow within different dykes present within, and on the edge of, a vent complex, enriching our understanding of magma transport and shallow intrusion conditions within Large Igneous Provinces generally. A tentative scaling relationship analysis has been applied to the dyke population of Coombs Hills from study of aerial photographs. This preliminary study shows a heterogeneous distribution of dykes, both spatially and in terms of orientation, within the area. The length-frequency distribution of dykes follows a power-law distribution, but the physical significance of these observations is not yet known. Field mapping, plus detailed observation and description of dykes' geometry in the field produced one of the main datasets of this study. Dykes exposed at Coombs Hills are highly segmented. The mechanisms inferred for segmentation suggests either a system of preexisting segmented country-rock fractures in some areas, or variations in the orientation or intensity of the principal stresses along the propagation paths. En-echelon arrays of dyke segments are considered to have formed by breakdown of a parent crack in response to spatial or temporal rotations of the remote principal stresses, and mostly show a sense of dextral offset in the field. Bridging structures and en-echelon dykes array reflect a predominantly vertical flow within the area. There are differences in the inferred flow patterns and dyke geometry between the dykes that intrude the well r) . layered but isotropic Beacon sandstone versus dykes intruding the poorly stratified ---------~ Mawson lapilli tuff. These differences may reflect a meandering flow in the poorly stratified Mawson compared to a more straightforward one within the sandstone, and may reflect the poor consolidation inferred for the recently deposited Mawson at the ---~-----~ time of dyke intrusion. The structural analysis reveals two distinct sets of dyke trends, subperpendicular to each other. The country rock fractures in the area present the same geomorphologic aspect as the dykes' walls and their orientations follow similar subperpendicular trends as those identified for the dykes. The fractures are found in prolongation of dykes and are here interpreted to have formed during an early stage of dyke propagation and in the absence of significant stresses other than the magmatically induced ones. The characteristic sub-perpendicular dyke and fracture trends observed suggest that the "background" stress field was an effectively triaxial stress field with strains and fractures generated only by vertical movement and pressure on the host rock. Anisotropy of Magnetic Susceptibility (AMS) analyses have been done on 80 samples collected from the field area. This analysis reveals the importance, when investigating the flow direction within volcanic rocks of considering and removing the magnetic remanent component from the bulk magnetic susceptibility measured on the sample. Unfortunately the degree of anisotropy measured for most samples was consistently very low and did not allow determination of extensive and characteristic flow directions within dykes and within the whole area. The AMS analysis, however, still suggest a sub-horizontal flow direction within the massive basaltic cliff of the area, suggesting it to be a major (more than 300 m wide) sill; this is interesting, because the inner, western contact of the sill with the vent complex is subvertical. The petrographical and geochemical observations indicate that the intrusions are basaltic andesite in terms of T AS classification, with little variation among samples. The geochemical results suggest the dykes intruded the Beacon sandstone first, before minor fractional crystallisation reduced the compatible element abundance in the magma that was subsequently emplaced as the massive sill (basaltic cliff) intrusion. The model of emplacement proposed for Coombs Hills intrusion is comparable to the observed system exposed at Mt Grant where both vertical and horizontal intrusive sheets, as well as inclined ones, are linked together as record of a complex magma distribution system. Department The department where the student is studying primarily. Geology Named locality Named locality describing the field area location. Coombs Hill Antarctica Thesis description Number of pages, maps, CDs, etc. v, 188 page + appendices; A4, 1 map (~A2), CD 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 2006Guegan Creator An entity primarily responsible for making the resource Emilie B. M. Guégan (Emilie Benedicte Montaine), 1983- Date A point or period of time associated with an event in the lifecycle of the resource 2006 Title A name given to the resource Shallow intrusion conditions in a flood-basalt province : the story from dykes and a sill offshoot along the contact between a vent complex and country rock : Coombs Hills, Ferrar Province, Antarctica Subject The topic of the resource Volcanology Map Dykes Ferrar intrusions Flood Basalt Intrusion https://theses.otagogeology.org.nz/files/original/88d22aead830fb492b5d58c32571d794.pdf 3485554f000f218ae65b5295b48b480c 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 Ross Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? PhD Advisers Who supervised/advised this student White, J.D.L. Abstract The Abstract for this thesis The Jurassic Ferrar large igneous province of Antarctica contains significant mafic volcaniclastic deposits, underlying the Kirkpatrick flood basalts. In South Victoria Land, the mafic volcaniclastics are referred to as the Mawson Formation. At Coombs Hills, the Mawson is interpreted as filling a large vent complex, which was re-examined in detail to better understand vent-forming processes. Two contrasting types of cross-cutting volcaniclastic bodies were found in the complex, both of which are interpreted to have been forcefully emplaced from below into existing, non-consolidated debris. The first type consists of country rock-rich lapilli-tuff pipes. These are interpreted as fossilized remnants of subterranean debris jets which originated when phreatomagmatic explosions occurred near the walls or floor of the vent complex, causing fragmentation of both magma and country rock. The second type of cross-cutting body consists of basalt-rich tuff-breccias and lapilli-tuffs, some of which could have been generated by explosions taking place within pre-existing basalt-bearing debris, well away from the vent walls. Other basalt-rich zones, accompanied by domains of in situ peperite and coherent basalt, are inferred to have originated by less violent processes. At nearby Allan Hills, the Mawson can be divided into two informal members, m1 and m2. Member m1 is exposed only at central Allan Hills, consists essentially of sedimentary material from the underlying Beacon Supergroup, and is interpreted as a ::::;180 m-thick debris avalanche deposit. Most megablocks in m1 were derived from the late Triassic Lashly Formation, parts of which were probably only weakly consolidated in the Jurassic. Sandstone breccias dominate volumetrically over megablocks within the deposits. This indicates pervasive and relatively uniform fragmentation of the moving mass, and probably reflects the weak and relatively homogeneous nature of the material involved. The avalanche flowed into a pre-existing topographic depression carved into the Beacon sequence, and flow indicators reveal a northeastward movement. Sparse globular basaltic megablocks suggest that Ferrar intrusions played a role in triggering the avalanche. Member m2, which is exposed at both central and southern Allan Hills, consists predominantly of metre-thick basaltic volcaniclastic layers that fall into three broad categories: (1) poorly sorted, coarse lapilli-tuff and tuff-breccia; (2) block-rich layers; (3) tuff and fine lapilli-tuff. The former type is interpreted as the deposits of high-concentration pyroclastic density currents (PDCs), probably formed during the collapse of phreatomagmatic eruption plumes. Occasional block-rich layers probably were formed by both ballistic fall from local vents and pyroclastic flows, and the finer-grained layers were probably deposited by dilute PDCs. Dilute, moist turbulent currents were also likely responsible for the generation and deposition of large (::::;4.5 cm) rim-type accretionary lapilli. The thick layers are locally underlain by or interbedded with thin tuff ring-style volcaniclastic layers, and all the layers are underlain and invaded by basalt-rich tuff-breccias and lapilli-tuffs. Department The department where the student is studying primarily. Geology Named locality Named locality describing the field area location. Coombs Antarctica Allan Hills Antarctica Victoria Land south Thesis description Number of pages, maps, CDs, etc. 1 v. (various pagings) : ill., maps ; 30 cm. 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 2005Ross Creator An entity primarily responsible for making the resource Ross, Pierre-Simon. Date A point or period of time associated with an event in the lifecycle of the resource 2005 Title A name given to the resource Volcanology of the Mawson Formation at Coombs and Allan Hills, South Victoria Land, Antarctica Subject The topic of the resource Volcanology lapilli - tuffs mafic volcaniclastics Mawson Formation vent-forming processes https://theses.otagogeology.org.nz/files/original/cf9d95c66fc9abf46c648fea32b25f04.pdf 22d0e578d62f626c2bd8c48c832dc4c7 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 ((170.65608753074946 -77.562057616076615,169.925001679483756 -78.648782917432698,164.13705178231271 -78.408168273440168,165.349204115465511 -77.346396867272929,170.65608753074946 -77.562057616076615)) Author last name Last name of the Author Clifford Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? MSc Advisers Who supervised/advised this student Wilson, G.S. Abstract The Abstract for this thesis global environmental change. Such changes are of particular concern in West Antarctica the world's largest marine ice sheet (the West Antarctic Ice Sheet, WAIS) could cause m global sea level rise, should it collapse. Many studies have, therefore, focused on the largest ice shelves buffering the WAIS from the oceans (the Ross and Ronne-Filchner ice ves). However, an understanding of the dynamics and stability of these large ice shelves is 'ted by their inaccessibility and the complex behaviour of the ice streams and glaciers that them. Conversely, the McMurdo Ice Shelf (MIS) at the north-west edge of the Ross Ice (RIS) has dimensions of only 100 x 50 km and is relatively accessible, making it a good 'ILIV''"'H'"~~ analogue for the glacial processes of the RIS. uH,...,~,J~v5,·,.., data for the northern MIS are abundant and show that this part of the ice shelf is fed by the RIS, the Ross Island glaciers and the Koettlitz Glacier. In contrast, the present glaciologic regime of the southern MIS (SMIS; between the volcanic landmasses of Black Island, Mount Discovery and Minna Bluff) has mainly been inferred from limited spot measurements published over 30 years ago (Swithinbank, 1970). The SMIS is distinctive in that glacial deposits are preserved at its margins and on its surface, providing evidence for former ice shelf and ice sheet activity in southern McMurdo Sound. Consequently, there is potential to evaluate how an ice shelf responds to environmental change, as, on the SMIS, the preserved glacial deposits can be interpreted in terms of active processes that can be readily measured within the confines of a comparatively small area. The major motivation for the present research has been to determine the present glaciologic regime of the SMIS by compiling data-sets relating to its physiography and flow characteristics, with which former inferences can be tested and vulnerability of the ice shelf to climate change can be assessed. Geophysical data (GPS, ground-penetrating radar, seismic, aeromagnetic and gravity surveys) were acquired on the SMIS over three consecutive austral summers (2002/03-2004/05) in conjunction with ANDRILL site investigations. These data have been compiled with morphometric analyses (satellite images, aerial photographs and field observations) to identify: (i) surface accumulation/ablation areas, (ii) ice surface elevation, (iii) ice shelf thickness, (iv) horizontal flow velocities, (v) pinning points/grounding zones (vi) areas of marine ice accretion and, (vii) active sediment transport processes. iii The results show that south-westerly katabatic winds deposit snow and sediment in the surface accumulation area south of Black and White islands, where surface elevation is highest (>-20 m ellipsoid height) and the ice shelf is thickest (190 ± 10 m). Surface elevation and ice thickness decrease towards the south (Minna Bluff) and west (Moraine Strait), where the katabatic winds are strongest, and cause surface ablation. The flow pattern follows the same directional trend, indicating that it is driven by gravitational creep. Flow is regulated by frictional resistance at grounding zones, located at the landmass margins and below a midshelf ice rise, where a seamount intersects the base of the SMIS. The horizontal flow velocities (~2-7 m a-1) are up to two orders of magnitude lower than those observed on the adjacent RIS and northern MIS and there is negligible input from these ice shelves. This indicates that the SMIS is an independent ice shelf characterized by its wind-driven glaciologic regime and thus is not an analogue for the neighbouring RIS. In addition, the SMIS is buffered from potential collapse by the MIS and the surrounding land masses, and, therefore, will not respond to climate change in the same way as the exposed ice shelves that surround the rest of the continent. Department The department where the student is studying primarily. Geology Named locality Named locality describing the field area location. McMurdo Ice shelf southern Antarctica Thesis description Number of pages, maps, CDs, etc. xiii, 238 p. : ill., maps (some fold.) ; 30 cm. + 1 CD-ROM. 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 2005Clifford Creator An entity primarily responsible for making the resource Clifford, Andrew E. (Andrew Eliot) Date A point or period of time associated with an event in the lifecycle of the resource 2005 Title A name given to the resource Physiography, flow characteristics and vulnerability of the Southern McMurdo Ice shelf, Antarctica Subject The topic of the resource Geomorphology ice sheets