1 10 656 https://theses.otagogeology.org.nz/files/original/0e4952d5def095a175ceffba2c451eb2.pdf fad502307302a080e6cd1c2259fb0eb4 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 Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? MSc Abstract The Abstract for this thesis Current meter experiments on the inside of Harington Bend (Lower Otago Harbour) during a neap tide demonstrated that the mean flow was ebb dominant, concentrated in an east-southeast direction with a maximum velocity of 0.58 m/ s. Flood values reached 0.47 m/ s and were concentrated in a west to southwest direction. Sediment entrainment was likely to occur only at the height of an ebb tide for the duration of the experiment. Current meter determined velocities were supported by the geomorphology of the Aramoana tidal flats. Water temperature varied between 5 95-6.97°C, the water column being cooled by the tidal flats irrespective of the diurnal atmospheric temperature cycle. Salinity, and density ranges were 34.865-35.377 %a and 1.0273-1.0278 g/ cm3 respectively, values that appear anomalously high when compared with ocean data and other salinities obtained in the harbour. The bedforms in the Lower Otago Harbour are summarised on map one in the map pocket. Bedform wavelength ranges from ripples, approximately (27 cm) up to long period (60 m) sandwaves with heights seldom reaching above 1 m.The majority of sandwaves in the harbour are flood orientated at all stages of the tide and show little evidence of reorientation within a tidal cycle. Regions of three dimensional, scoured areas are noted as well as plane beds on the outside of shipping channel bends. High resolution sub bottom profiling equipment has enabled the recognition of a number of (Holocene?) reflectors distinguished by their height below mean sea level. A reflector (R2) at 20 m below M.S.L. is relatively continuous occurring from Taiaroa Head to Pulling Point, with occasional areas of localised acoustic opacity and is correlated with an 8 m thick gravel layer (in the northern end of the field area). In the vicinity of Dowling Bay, the R2 reflector becomes noticeably discontinuous and is more likely to represent the bottom of a mud wedge. There was no definitive seismic evidence for Dowling Bay Formation (Tertiary) under the harbour, during this study. Deep volcanic (basement) reflectors are reported from near Port Chalmers (80 m below M.S.L.) and also in the cross channel area close to Aramoana (85 m below M.S.L.). Slightly offshore from Port Chalmers, the Port Chalmers Breccia appears as a rough channelised topographical surface overlain by young (Holocene) reflectors. The contact between Careys Bay Basalt and the Port Chalmers Breccia appears as a sharp transition. Borehole data reveal the presence of significant sub surface muds, possibly exposed to erosion in the shipping channel, at depths greater than 12-15 m. The environment of formation of these muds is interpreted as a barrier enclosed lagoon, as at Hoopers Inlet today. The discovery of extant crab concretions containing Macrophthalmus hirtipes, (Jacquinot) a burrowing mud crab and Cancer novae zealandiae in Port Chalmers muds at a depth of 15-18 m below mean sea level suggests a rapid burial event during barrier enclosure. The burial was probably the result of a catastrophic rainfall event and the resulting high levels of terrestrial derived sedimentation. 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. vi, 216 p. : ill. (some col.), maps ; 30 cm. Author last name Last name of the Author Cournane Advisers Who supervised/advised this student Landis, C.A. | Koons, P.O. Keywords Seismic profiling Lower Otago harbour 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 Seismic and oceanographical aspects of lower Otago Harbour Date A point or period of time associated with an event in the lifecycle of the resource 1992 Subject The topic of the resource Marine geology Creator An entity primarily responsible for making the resource Cournane, Steve Lower Otago harbour. Seismic profiling https://theses.otagogeology.org.nz/files/original/5f2bc6b0db044b3c2745438e4800abf1.pdf 8dadf29da60103db3f920a7405d1c093 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 ((171.141993295569534 -43.765957880366102,171.127225220069732 -43.752018963448187,171.147016256960001 -43.749661629394389,171.164890693597584 -43.756203465908939,171.182954471912808 -43.770189975952796,171.189934449726593 -43.783998554506027,171.166435988809894 -43.786303863846456,171.141993295569534 -43.765957880366102)) Author last name Last name of the Author Fittall Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? BSc(Hons) Advisers Who supervised/advised this student Campbell, J.D. Abstract The Abstract for this thesis An area lying on the west side of the middle reaches of the Rangitata River is mapped and described. Basement Torlesse terrane rocks,·cretaceous conglomerate and Mount Somers Volcanics, an infaulted block of Tertiary sediments, and Quaternary Glacial outwash and alluvium are all present in the area. The basement Torlesse terrane rocks are subdivided into two facies, massive sandstone facies and siltstone facies for mapping purposes. The massive sandstone facies dominates throughout the area. The massive sandstone facies consists of sequences dominated by thick bedded massive sandstones with interbedded siltstone, occasionally graded, amalgamated and showing water escape structures. The massive sandstones are inferred to be of sediment gravity flow origin, deposited from sandy high density turbidity currents. The siltstone facies is subdivided into laminated siltstone and graded siltstone subfacies. These thin bedded laminated or graded siltstone sequences are treated as mappable where they are more than 10m thick. The siltstone beds are inferred to have been deposited from dilute turbidity currents. Measured sections are interpreted in terms of depositional environment. In terms of a submarine fan model the massive sandstone facies is inferred to be upper mid-fan distributory channel deposits and the siltstone facies interchannel deposits. Mineralogically the sandstones are lithic - arkoses and arkoses. The Torlesse terrane sediments are first cycle erosion products. The detrital mineralogy and the internal structures of quartz grains indicate a volcano-plutonic arc source terrane. Development of cleavage is well documented in these sandstones. A Middle Triassic to Permian-? Carboniferous age range is assigned to these rocks using petrographic trends defined by MacKinnon (1980). Three phases or folding are recognised, an initial macroscopic phase, Which is folded into a subregional isoclinal syncline which in turn is gently folded. An axial planar cleavage is developed in the isoclinal subregional syncline. A regional fault, inferred to have both Rangitata Orogeny and Kaikoura Orogeny movement, passes through the area. The Torlesse terrane basement has been subject to prehnite-pumpellyite facies metamoiphism locally reaching the pumpellyite-actinolite facies. Overlying the Torlesse on an angular unconformity is a lense of conglomerate, inferred to be fluviatile in origin. Overlying this conglomerate and lying directly on the Torlesse terrane basement by onlap, is the Mount Somers Volcanics consisting or a lower sequence of andesitic flows and an upper sequence or rhyolitic flows. Differentiation trends indicate that fractional crystallization was acting on the magma. The large volume or rhyolites and the presence or quartz xenoliths out or equilibrium with the surrounding magma may indicate assimilation or basement rocks as an important process. Xenoliths in the andesite also contain an anomalously Al-rich orthopyroxene. A transgressive sequence or Tertiary sediments is infaulted on the eastern border or the area. A zone of very low sedimentation is present within the upper parts or the Tertiary sequence. Glacial outwash also adhering to the slopes in some places, and alluvium cover the valley floors. Department The department where the student is studying primarily. Geology Named locality Named locality describing the field area location. Rangitata Valley Thesis description Number of pages, maps, CDs, etc. 142 leaves : 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/. Title A name given to the resource Geology of the mid Rangitata Valley Creator An entity primarily responsible for making the resource Fittall, Alan Matthew. Date A point or period of time associated with an event in the lifecycle of the resource 1982 Identifier An unambiguous reference to the resource within a given context 1982Fittall Subject The topic of the resource Map Metamorphic geology Sedimentary petrology Quaternary geology Structural geology Cretaceous Torlesse Supergroup https://theses.otagogeology.org.nz/files/original/766e0c42eaf45d2dbfad0aabc950e4df.pdf 0bd6125d9fd91011588b1c88929983a0 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 ((167.864041996000083 -45.996994626999935,167.863345847000119 -46.00451000399994,167.837204366000037 -46.003174422999962,167.820547991000012 -46.002319221999983,167.816739627000061 -46.002124123999977,167.819069958000114 -45.977970358999983,167.786756198000035 -45.976782788999969,167.790258830000084 -45.938431369999932,167.791076567000118 -45.929469774999973,167.791856768000116 -45.920916728999941,167.829181750000089 -45.92257782799993,167.84672885800012 -45.923354770999936,167.892861828000036 -45.92538615899997,167.892456088000017 -45.930466614999943,167.891996082000105 -45.936261414999933,167.88998188000005 -45.961556069999972,167.88910050000004 -45.97262892599997,167.866386939000108 -45.971619845999953,167.864041996000083 -45.996994626999935)) Author last name Last name of the Author Arifin Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? MSc Advisers Who supervised/advised this student Norris, R.J. Campbell, R.M. Abstract The Abstract for this thesis Early Oligocene to middle Miocene sedimentary rocks of the western Ohai district are mapped, subdivided into lithostratigraphic units. The geology structures are interpreted, based on field evidence and aerial photo study. Tertiary strata are folded and faulted, in the east of the study area they are faulted against the Twinlaw basement. Two major sedimentary sequences are recognized; a transgressive sequence represented by the Orauea Mudstone, the Birchwood Lower, Middle and Upper Members, and a regressive sequence represented by the Rannock Siltstone, the Feldwick Formation, the Reipihi Formation and the Lentile Formation. The relation between these two sequences is gradational. Evidence of hard ground submarine erosion occurs in the lower part of Feldwick Formation during deposition of the regressive sequence. The sedimentology of the Birchwood Middle Member is described in terms of submarine fan, a middle-fan depositional environment is interpreted to this Member. A biofacies analyses of benthonic and planktonic foraminiferal assemblages (after methods of Phleger and of Vella) is used to assist further the interpretation of depositional environments. Clay fractions of the fine-grained sediments were analysed by X-ray diffraction methods, and show that mixed two or three layers clay mineralogy is predominant in most of the samples analysed. Petrographic analyses of sandgrade sediments in the Birchwood Middle Member permit the conclusions that the main provenance of terrigenous components are plagioclase-rich intrusive and volcanic rocks of the Takitimu and Longwood massifs. The rocks of Feldwick Formation are described and grouped into lithofacies. Local variations in sea-floor relief and several transport mechanism involved during the deposition of Feldwick Formation in inner shelf environments are interpreted by megascopic and microscopic characteristics of the lithofacies. Petrographic analyses of some specimens of the Reipihi and the Lentile Formations suggest that two main provenances can be identified, i.e. a schist provenance and a granite provenance, and that these vary in relative importance within the formation. Department The department where the student is studying primarily. Geology Named locality Named locality describing the field area location. Birchwood Ohai Thesis description Number of pages, maps, CDs, etc. 148 leaves : 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/. Title A name given to the resource Tertiary geology of Birchwood area, near Ohai : South Island, New Zealand. Date A point or period of time associated with an event in the lifecycle of the resource 1982 Identifier An unambiguous reference to the resource within a given context 1982Arifin Creator An entity primarily responsible for making the resource Arifin, Maximon Shah, 1947- Subject The topic of the resource Map Lithostratigraphy Sedimentology clay analysis foraminifera biofacies paleoecology https://theses.otagogeology.org.nz/files/original/4c608658f9e0ba677218e7e895515394.pdf eeca980a0a10ab9e146e741388c45f2b 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 Anderson Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? BSc(Hons) Advisers Who supervised/advised this student Landis, C.A. Reay, A. Abstract The Abstract for this thesis Beach and offshore sediments were systematically sampled and studied during this work. Textural studies resulted in both on and offshore sediments being modelled by mixing of two modes, a fine modern modal population and a coarse relict modal population. The modern mode is analogous for beach and offshore sediments, the relict mode is finer in the beaches than offshore. This fining is due to abrasion and drowning of coarser clasts by the transgressing sea. With the use of a microprobe, detrital grains were analysed and compared to analyses of minerals from inferred source areas. Appraisal of all textural, mineralogical and chemical data results in definition of the nature of the sources of the Kakanui sediments. Green hornblende and hypersthene are inferred to be derived from the rocks of the Waiau catchment or gabbroic bodies of southern New Zealand. Epidote and MnO rich garnets are derived from the Haast Schist Group. Brown hornblende, enstatite, spinel, clinopyroxene and pyrope garnet are derived from erosion of mantle derived material contained in the Kakanui Mineral Breccia or associated vents. A vent is concluded to occur approximately 4km offshore. Two sources for glauconite were concluded. Sediment from the Waianakarua River and coastal erosion of the Gees Greensand at Gees Point. Titanaugite are concluded as being derived from the Dunedin and associated alkalic volcanics of East Otago. Department The department where the student is studying primarily. Geology Named locality Named locality describing the field area location. Kakanui Otago north Thesis description Number of pages, maps, CDs, etc. v. 180 p. ill. Photos. 30 cm. Location WKT (WGS84) The location stored in WKT (WGS84) format POLYGON ((170.88 -45.17, 170.92 -45.17, 170.92 -45.21, 170.88 -45.21, 170.88 -45.17)) 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 Beach and Continental Shelf Recent Sedimentation of the Kakanui District, North Otago. Identifier An unambiguous reference to the resource within a given context 1982Anderson Creator An entity primarily responsible for making the resource Anderson, SG Date A point or period of time associated with an event in the lifecycle of the resource 1982 Subject The topic of the resource Marine geology Sedimentary petrology Sedimentology Mineralogy beach sediment shelf sediment https://theses.otagogeology.org.nz/files/original/3f19a801659262b9551a86dd3a71bb8a.pdf 12d0b93d9d246505d2133d3704f1db22 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 ((168.462727735000044 -46.730259451999984,168.552406605000101 -46.73348425599994,168.547053688000119 -46.809635908999951,168.547048378000113 -46.809703277999972,168.45793118600011 -46.806536944999948,168.46263629200007 -46.730255980999971,168.462727735000044 -46.730259451999984)) Author last name Last name of the Author Webster Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? BSc(Hons) Advisers Who supervised/advised this student Coombs, D.S. Abstract The Abstract for this thesis Ruapuke Island lies to the north-east of Stewart Island in Foveaux Strait. The area mapped consists mainly of dioritic rocks with small amounts of older gabbro and hornblende hornfels. A region of heterogeneous diorite is formed by partial assimilation of hornblende hornfels by dioritic magma. Trondhjemite, hornblende gabbro, granodiorite dykes and pegmatite veins have been examined and mapped where size permits. Metamorphosed flows, dykes and volcanic sediments of the hornblende hornfels, and the gabbro pluton, are correlated with the Brook Street and Eglington volcanics, probably forming part of an extensive Permian volcanic arc. Diorite and hornfelsic rocks are cut by basic dykes of hornblende-andesite composition, some of which have been intruded into hot dioritic magma. Field relations and petrography suggest that diorite emplacement may have taken place in more than one phase. Intrusive activity probably extended from late Permian into the Triassic. Devereux, McDougall and Watters (1968) have dated a tonalite from South Point by potassium-argon mineral dating at 217 m.y.s. Whole rock chemical analyses and mineral analyses of Ruapuke rock types have been compared to published analyses of Stewart Island and South Island contemporary rocks. OURArchive handle The handle from the Otago University Research Archive (OURArchive) <a href="http://hdl.handle.net/10523/3919">http://hdl.handle.net/10523/3919</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. Ruapuke Island Thesis description Number of pages, maps, CDs, etc. 149 p. : ill. (xome col.), 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/. Title A name given to the resource The geology of Ruapuke Island Creator An entity primarily responsible for making the resource Webster, J. G. (Jennifer Gaye) Date A point or period of time associated with an event in the lifecycle of the resource 1981 Identifier An unambiguous reference to the resource within a given context 1981Webster Subject The topic of the resource Map Metamorphic geology Igneous petrology Anglem Complex diorite hornblende hornfels https://theses.otagogeology.org.nz/files/original/e01ae11e858f479159eb953dc63d060c.pdf 21b6bafd2c4dbf485047b9f2f7410730 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 Situmorang Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? MSc Advisers Who supervised/advised this student Landis, C.A. Campbell, J.D. Abstract The Abstract for this thesis Late Quaternary sediments in Shag Point and south Oamaru have been investigated. The Hillgrove Formation and loess deposits are distributed consistently throughout the coastal area. The lower part of the Quaternary sequence, Hillgrove basal gravel, consists predominantly of greywacke gravels and m1nor sands and silts. Two ecologic groups of macrofauna are recognised, intertidal and subtidal species. Intertidal species are Melagraphia aethiops., Micrelenchus tenebrosus., Cellana genera and the subtidal fauna consists primarily of Ostrea lutaria. This study clearly shows that paleoecology of these Quaternary sediments has close similarities with ecology of the modern fauna. Foraminifera paleoecology is in agreement with macrofauna and indicates shallow water environment. The restricted shallow water benthic foraminiferids, Notorotalia zelandica and Elphidium charlottensis are recorded abundantly. Paleoclimatic interpretations from planktic foraminiferids and Nonionella flemingi suggest a cold climate during deposition perhaps slightly cooler than mean sea temperature in present day. This evidence in conjunction with several radiocarbon 14C dates of shells (>45,000 yr.B.P.) and stratigraphic relationship with overlying sediments (loess deposits), suggest the Hillgrove basal gravel was deposited in Otiran Glaciation under interstadial conditions. The upper part, Hillgrove loose sand, is massive 1n exposure, always shows a gradational boundary with overlying sediments, and an absence of cross-bedding, suggesting a possibly beach origin. On the other hand sedimentological analyses including granulometric study and SEM investigation on quartz texture show strong evidence for an eolian origin. Loess deposits were classified into several types according to stratigraphic relations, macrofeatures and sedimentological analysis. The loess BI, moderately hard silt loam, shows conspicuous jointing pattern distinctively high proportion of green-hornblende, and is texturally coarser than other loesses. Heavy mineral study, particularly through ZTR index (Zircon-Tourmaline-Rutile) implies the presence of "intrastratal solution" in heavy minerals. This reflects the increase of maturity in older loess deposits. This might be associated with diagenetic features on the surfaces of quartz grains as quartz crystal growth, solution pits and adhering particles. Clay minerals have been observed in loess however it was not possible to distinguish between loess horizons on the basis of their clay minerals. Allogenic clays are presumed to consitute most of the loess, these are obviously of illite and kaolinite. Minor authigenic kaolinite is also present. Study of grain orientation in loess deposits gains two source paleowind directions, the central Otago and eastern Otago continental shelf. This interpretation accord with heavy mineral's provenance. Mineralogically the loess deposits are usually homogeneous, with angular monocrystalline quartz predominant. Feldspar consists mainly of plagioclase whilst potassium feldspar was found in minor quantity. Heavy minerals in loess are distinctive from other sediments (e.g. Hillgrove Fm, Recent sediments), phyllosilicate heavy minerals are in high percentages. In beach studies, grain slze analysis and dispersal pattern of some heavy minerals suggest longshore transport of beach material in a northwards direction. Furthermore it also noticed that the Shag River supplies considerable amounts of beach material to the Shag Point beaches, more obvious in phyllosilicate heavy minerals. Department The department where the student is studying primarily. Geology Thesis description Number of pages, maps, CDs, etc. 245 p. : illl. (some col.) ; 30 cm. Named locality Named locality describing the field area location. Shag Point Oamaru 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 Studies of late quaternary sediments Shag Point and South Oamaru coastal areas, South Island, New Zealand. Subject The topic of the resource Micropaleontology Quaternary geology Sedimentology Creator An entity primarily responsible for making the resource Situmorang, Mangatas. Date A point or period of time associated with an event in the lifecycle of the resource 1981 Identifier An unambiguous reference to the resource within a given context 1981Situmorang allogenic clay clay Hillgrove Formation quartz https://theses.otagogeology.org.nz/files/original/7fa6b51ef0ff06c097a12e8b7cae2321.pdf 367be1ed6a192eaf915c74dc6cad2dfe 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 Named locality Named locality describing the field area location. Annear Creek Thesis description Number of pages, maps, CDs, etc. 118 p. : ill. (some col.), 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/. Title A name given to the resource Geology of Annear Creek. Subject The topic of the resource Map Igneous petrology Metamorphic geology Sedimentary petrology Creator An entity primarily responsible for making the resource Pillai, D. D. L. (Deirdre Dhana Lakshmi) Date A point or period of time associated with an event in the lifecycle of the resource 1981 Identifier An unambiguous reference to the resource within a given context 1981Pillai detrital pyroxenes Trabeculatia https://theses.otagogeology.org.nz/files/original/064a9a53f196cd9491e1c1f9a882ca6a.pdf deac61f514a421745ac82b5e9c9cb50b 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 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 of the east branch, Eglinton River. Subject The topic of the resource Map Creator An entity primarily responsible for making the resource Kelsey, Philip I. (Philip Ian) Date A point or period of time associated with an event in the lifecycle of the resource 1981 Identifier An unambiguous reference to the resource within a given context 1981Kelsey Dun Mountain Ophiolite melange https://theses.otagogeology.org.nz/files/original/d9b750ebe884a6d1f77a3623dedcba3d.pdf 14833ea6574c9fa483ddfc9da3105cb4 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 Verolino Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? PhD Advisers Who supervised/advised this student White, James D. L. Schipper, C. Ian Abstract The Abstract for this thesis Shallow to emergent basaltic subaqueous explosive eruptions, here referred as Surtseyan, are a source of pyroclastic material expelled from subaqueous vents and transferred to the water column and atmosphere. They can threaten coastal communities in different ways. One of these is through the generation of pyroclastic density currents travelling over water once the eruption becomes subaerial, and which may be preceded or accompanied by eruption-fed currents moving along the sea/lake floor; another potential danger offered by these eruptions is from the subaerial eruption, which can deliver hot fragments locally and abrasive ash over hundreds or thousands of km2. Both for their potential hazard, and to better understand the mechanics of such eruptions as one class of volcanic thermodynamics, these volcanos have been the subject of significant investigations for more than 50 years, particularly since the start of the Surtsey eruption in 1963. One approach for studying the early stages of these eruptions is through analysis of their proximal, edificebuilding deposits, but these are commonly either inaccessible (under water) or poorly preserved by the time they are exposed subaerially. The sites selected for this work, Pahvant Butte, Utah, and Black Point, California, USA, overcome these limitations. These volcanos were formed in the late Pleistocene by eruptions at hundred meter depths in the giant former Lake Bonneville and Lake Russell respectively. The water is now drained and all the deposits (both edifice-forming and at medial distances on the old lake floors) are easily accessible and maintain a good level of preservation. This allowed me to investigate the eruption dynamics and conduit conditions of these volcanoes, potentially extendable to other Surtseyan volcanoes. The combination of field-based work, granulometry, geochemical analysis of majorelements (glass, minerals and melt inclusions) and dissolved-water content of tephra glass, and particle tomography allow me to reconstruct the pre-eruptive and syn-eruptive dynamics for Pahvant Butte and Black Point. Overall, the results suggest that the explosivity of these two monogenetic volcanoes was mainly driven by hydromagmatic explosions, with gas expansion only playing a secondary role. Inferred eruption dynamics are consistent with those inferred by previous authors, and the eruptions yielded ash dispersed both by eruption-fed density currents subaqueously, and subaerially by wind. This study demonstrates that eruption-fed density currents generated prior to eruptive emergence can travel up to > 20 km on a nearly horizontal lake floor (i.e., Pahvant Butte), even in early stages of the subaqueous eruption. In this work, it is shown that geochemistry can be a powerful tool for correlating edifice-building tephra with ash deposited in proximal/medial locations, based on the magma evolution recorded in the glass. Another way to study shallow subaqueous explosive eruptions is through experimental investigation. I carried out underwater experiments at bench scale to investigate the behaviour of particles transferred to the water column from underwater explosive bursts. In the natural counterpart, there are two different types of particles involved in the explosions, juvenile particles, directly produced by the magma fragmentation, and non-juvenile particles (sea/lake floor sediments or country rock sediments). The former ones are initially dry, while the latter are wet, and these conditions were investigated independently during the experiments. The results show that these two conditions impart different particle behaviours. Wet particles are better coupled with tank water than are dry particles, and this behaviour can be associated with a more efficient transfer in nature from eruption bursts into eruption-fed subaqueous currents. Keywords western USA, Surtseyan eruptions, Lake Bonneville, Lake Russell, Mono Lake, Pahvant Butte, Black Point OURArchive handle The handle from the Otago University Research Archive (OURArchive) http://hdl.handle.net/10523/8772 OURArchvive access level Open Access Department The department where the student is studying primarily. Geology Thesis description Number of pages, maps, CDs, etc. 270 pages A4 Named locality Named locality describing the field area location. Pahvant Butte and Black Point, Western USA 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 Surtseyan volcanism: case studies from Pahvant Butte and Black Point, Western USA Subject The topic of the resource volcanism Creator An entity primarily responsible for making the resource Verolino, Andrea Date A point or period of time associated with an event in the lifecycle of the resource 2019 Identifier An unambiguous reference to the resource within a given context 2019Verolino Black Point garnet zone Lake Bonneville Lake Russell Mono Lake Pahvant Butte Pounamu Ultramafics Surtseyan eruptions western USA https://theses.otagogeology.org.nz/files/original/8f855864fd4e7859573ea86af2a098c2.pdf fe4826353f29448ce1f177e2abd188cf 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 Mannering Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? MSc Advisers Who supervised/advised this student Ohneiser, Christian Abstract The Abstract for this thesis The Antarctic ice sheets are sensitive to changes in ocean temperature and are predicted to retreat in the coming centuries. Geological reconstructions of ancient ice margin retreat can offer insights into the potential future rates of change. However, a lack of well-dated sedimentary records near the ice margin in the Ross Sea has restricted the reconstruction of ice sheet retreat since the Last Glacial Maximum and the subsequent oceanographic changes. Paleomagnetic studies are capable of providing the precise age control required for paleoclimate reconstruction from marine sedimentary successions and also enable correlation between geographically distant records, enabling comparisons to be made on both regional and global scales. The study of magnetic grains within sediment (environmental magnetism) can provide additional insights into changing oceanographic conditions and can be used to reconstruct changing terrestrial erosion rates and sediment delivery patterns. This thesis discusses the paleomagnetic study of four sedimentary cores: RS15- LC100; RS15-GC101; RS15-GC102; and RS15-GC107. The cores were recovered from the Drygalski and Glomar Challenger basins on the Ross Sea continental shelf, and further offshore on the abyssal plain by the Korean Polar Research Institutes’ vessel the R/V Araon, in 2015. They are located in regions with greatly varying depositional and oceanographic environments, and range in age from Holocene to mid-late Pleistocene. Paleomagnetic and environmental magnetic studies are sparse in this region, with a lack of well constrained age models. U-channel subsamples were measured at the Otago Paleomagnetic Research Facility (OPRF) in a 2G Enterprises superconducting magnetometer. Each sample underwent alternating field (AF) demagnetisation, and the data analysed on orthogonal component vector plots. Puffin Plot software was used to determine the Characteristic Remanent Magnetisation (ChRM) of the sediment and to produce a magnetostratigraphy. In addition, magnetic mineral studies (hysteresis, IRM, FORC and TDMS) were carried out in order to create a record of the environmental magnetism. Paleomagnetic age models based on secular variation or relative paleointensity were not able to be constructed for RS15-LC100, RS15-GC101, and RS15-GC102, due to the lack of a coherent ChRM. The ChRM records for RS15-LC100 in particular were entirely unable to have a magnetostratigraphy produced due to significant variations in magnetisation direction down the entire core. These cores are likely be Holocene in age and will rely on radiocarbon dating to produce an age model. Rock magnetic data indicates that magnetite is the dominant remanence carrying mineral, with potential indicators of the diagenetic magnetic mineral greigite present in some cores which may contribute to the poor data quality. A paleomagnetic age model was successfully constructed for RS15-GC107. Downcore variation in ChRM inclination aligned with the calculated Geocentric Axial Dipole inclination and the magnetostratigraphy that was correlated with the geomagnetic polarity timescale. Because biostratigraphic constraints were unavailable two age models were produced. Both models contain the Brunhes-Matuyama reversal boundary, with the preferred model, which results in the least varying sedimentation rate placing the boundary (C1n - C1r.1r, 0.774 Ma) at approximately 530 cm down core. This model also places the upper boundary of the Jaramillo chron (C1r.1r - C1r.1n, 0.990 Ma) at approximately 725 cm, and the lower boundary of the Jaramillo chron (C1r.1n - C1r.2r, 1.071 Ma) at approximately 775 cm. Calculated sedimentation rates varied between 0.68 cm/kyr and 0.72 cm/kyr. Small quantities of IRD are present throughout the core, as evidenced by discrete intervals with poor quality of demagnetisation data. TDMS and FORC analyses did not indicate the presence of greigite or other minerals that may carry a CRM. Keywords New Zealand, Ross Sea, Antarctica, Magnetostratigraphy, RS15-LC100, RS15-GC101, RS15-GC102, RS15-GC107, Paleomagnetism, Environmental Magnetism, Age Model, Drygalski Basin, Glomar Challenger Basin, Brunhes-Matuyama, Reversal OURArchive handle The handle from the Otago University Research Archive (OURArchive) http://hdl.handle.net/10523/9900 OURArchvive access level Open Access Department The department where the student is studying primarily. Geology Thesis description Number of pages, maps, CDs, etc. 165 Pages A4 Named locality Named locality describing the field area location. Ross Sea, Antarctica 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 Magnetostratigraphy and Environmental Magnetism of the RS15-LC100, RS15-GC101, RS15-GC102, and RS15-GC107 cores from the Ross Sea Subject The topic of the resource Paleomagnetism Creator An entity primarily responsible for making the resource Mannering, Henry Date A point or period of time associated with an event in the lifecycle of the resource 2020 Identifier An unambiguous reference to the resource within a given context 2020Mannering Age Model alluvial gold Antarctica Brunhes-Matuyama Cretaceous stratigraphy Drygalski Basin Environmental magnetism Glomar Challenger Basin gold magnetostratigraphy New Zealand paleomagnetism Reversal Ross Sea RS15-GC101 RS15-GC102 RS15-GC107 RS15-LC100