1 10 2 https://theses.otagogeology.org.nz/files/original/32b14e467b6d10a30212a661b52e1d55.pdf 01f7ab807449b3de71fb5ac23d471292 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 Andrews Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? PhD Advisers Who supervised/advised this student White, J.D.L. Valentine, G. Abstract The Abstract for this thesis In recent decades, major fieldwork studies have greatly advanced our knowledge of maar-diatreme systems, the second most common type of volcano; despite this, much of the interpretation is strongly debated. My original contribution to volcanological research is twofold: firstly, successfully simulating maar-diatreme systems using analogue experimentation in order to determine the processes that generate them; secondly, using mathematical modelling to produce a predictive model for their total energy release during an eruption. This study uses a tripartite, quantitative approach: (1) bench-scale experiments are used to generate simulated maar-diatreme volcanoes and examine their eruption and depositional processes; (2) these are qualitatively compared and quantitatively scaled to both field-scale experiments and natural maar-diatreme volcanoes; and (3) the 1886 maar-forming Rotomahana eruption is used as a case study for a new thermodynamic model which gives a first-order calculation of the cumulative energy change during the event. This study finds that maar-diatreme volcanoes can form through both ascending and descending blast series; multiple types of diatreme can form depending on the blast pattern. Debris jets responsible for the genesis of such systems are two-tier processes: the crater excavation and upward entrainment processes are temporally segregated. The behaviour of the explosively generated cavities, the preservation potential of the system architecture, and the stratigraphic partitioning of blast energy are controlled by mathematical relationships between blast depth and energy. Comparing the simulated volcanoes’ sedimentological architecture to natural examples reveals additional information regarding their eruption history and depositional processes. Data produced by the thermodynamic modelling of the 1886 Rotomahana event corroborates with both fieldwork studies and direct observations, and reveals the eruption was overwhelmingly dominated by a thermal component; this predictive model is hypothetically applicable to similar volcanic systems. A new conceptual model of maar-diatreme formation is conceived based on a synthesis of the findings of this thesis. OURArchive handle The handle from the Otago University Research Archive (OURArchive) <a href="http://hdl.handle.net/10523/5716">http://hdl.handle.net/10523/5716</a> OURArchvive access level Open Access Department The department where the student is studying primarily. Geology Thesis description Number of pages, maps, CDs, etc. 321 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 2015Andrews Creator An entity primarily responsible for making the resource Andrews, Robin George 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 Approaches in Experimental Volcanology: Bench-Scale, Field-Scale and Mathematical Modelling of Maar-Diatreme Systems Subject The topic of the resource Volcanology bench-scale experiments Experimental Volcanology field-scale experiments maar-diatreme volcanoes mathematical modelling phreatomagmatism https://theses.otagogeology.org.nz/files/original/721ea0ad9f3b4cc12f12062ee57478a3.pdf 2fb85b3def21e818552944d540fd5c8a 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 ((170.845821911633834 -45.355973015372307,170.87170887119035 -45.350266282770164,170.883647607033794 -45.374304531726061,170.859848784774414 -45.37814781914598,170.845821911633834 -45.355973015372307)) Author last name Last name of the Author Andrews Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? PGDipSci Advisers Who supervised/advised this student White, J.D.L. Abstract The Abstract for this thesis Eocene explosive submarine volcanism on the East Otago shelf is reported and discussed. Surtseyan lapilli tuff deposits with maximum stratigraphic thicknesses of at least 175 m record the existence of a volcano that built into storm wave base and may have emerged. A diverse range of large clast types, including schist xenoliths and dike fragments, show that the lapilli tuff was produced through a variety of fragmentation processes including Fuel-Coolant Interaction. Additionally, irregular shaped clasts exhibiting possible fluidal deformation indicate that magma was ejected from the vent while still molten. Stratigraphy also indicates that the volcano experienced two periods of major activity with a relatively quiescent interval between. Though widespread slumping and possible sector collapse have rendered accurate reconstruction of the volcano nearly impossible, orientations of dikes and data from two measured stratigraphic sections indicate that a large island near the centre of the field area may have been the vent. Both basalt and clastic dikes are emplaced in lapilli tuff at Moeraki. The basalt dikes are commonly banded with alternating layers of high and low vesicularity; these textures indicate formation through repeated injection of magma. The innermost bands of the dikes are often discontinuous and pinch out in fold hinges, indicating syndeformational emplacement. Irregular intrusions of basalt also occur at Moeraki and may be large intrusive pillows. The clastic dikes at Moeraki exhibit three textures; porcelainite breccia, mudstone breccia and mudstone. Though mudstone dikes occur discretely on one beach, a progression of all three occurs in association with basalt dikes at another locality. The dikes there grade from basalt through porcelainite to mudstone and indicate formation of clastic dikes as a result of explosive brecciation of sedimentary rocks. The brecciation is generated by the phreatomagmatic interaction of hot basalt dikes with wet low permeability mudstones. Numerical modelling of this process is presented. Department The department where the student is studying primarily. Geology Named locality Named locality describing the field area location. Moeraki Peninsula Thesis description Number of pages, maps, CDs, etc. 141 leaves : ill. (some col.), maps ; 30 cm. + 1 CDrom. 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 2001Andrews Creator An entity primarily responsible for making the resource Andrews, Benjamin J. (Benjamin James) Date A point or period of time associated with an event in the lifecycle of the resource 2001 Title A name given to the resource Physical volcanology of Moeraki Peninsula Subject The topic of the resource Volcanology volcanism