https://theses.otagogeology.org.nz/files/original/7c9ba31d068b472e6589e0114f81e63a.pdf dbbea262e86972a3c1ce3391771fae43 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 ((176.637176364569257 -38.06589282132169,176.620366085807575 -38.06736589198146,176.619419395834797 -38.05428587136263,176.636527691491267 -38.052803761732413,176.637176364569257 -38.06589282132169)) Author last name Last name of the Author Murphy Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? BSc(Hons) Advisers Who supervised/advised this student Landis, C.A. Abstract The Abstract for this thesis The mapped region encompassing the Haunui Valley covers 32 km2 and is situated on the western margin of the Taupo Volcanic Zone, 12 km southwest of Rotorua. Six formations are identified. The oldest formation is the densely welded, quartz poor Waiotapu Ignimbrite which is stratigraphically overlain by phreatoplinian, pyroclastic flow and plinian eruptives of the non-welded, crystal poor Onuku Breccia. The oldest phase of Haparangi Rhyolite extrusion follows these, and is represented by the Horohoro Rhyolite Dome. Onlapping and overlying this, is the Korokoro Ignimbrite, an ignimbrite formation newly proposed in this thesis. The youngest pyroclastic flow formation is the voluminous quartz-rich Mamaku Ignimbrite forming the Mamaku Plateau. A period of lake sedimentation produced the Huka Group in the Guthrie Graben from 42 000 yrs B.P. until 20 000 yrs B.P. after which a series of plinian tephra formations were deposited. Laboratory work involves several aspects. Firstly, correlations of ignimbrite formations to areas outside the Haunui Valley are presented, based on mineralogy and stratigraphy. Secondly, grainsize analyses and scanning-electron-microscope data are used to investigate the phreatoplinian nature of the Onuku Breccia. Thirdly, previously unestablished characterisation of ignimbrite formations in terms of recrystallization zones are presented. Finally, petrographic modal analyses are compared to XRF major element chemical analyses in vertical sequences of ignimbrite formations. The results are inferred to reflect compositional zonation of the magma chambers involved, by convection-driven thermogravitational diffusion. The Haunui Valley is delineated by a tectonic rim, inferred to be associated with Holocene anticlinal warping of the Mamaku Plateau. Two other major faults are present. The oldest is the northerly trending Pokaitu Fault, which represents post-Korokoro Ignimbrite tectonism. The youngest fault is the probably recent active, northeasterly trending Horohoro Fault and its subparallel, discontinuous derivatives. Department The department where the student is studying primarily. Geology Named locality Named locality describing the field area location. Haunui Valley Thesis description Number of pages, maps, CDs, etc. 104 leaves : 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/. Identifier An unambiguous reference to the resource within a given context 1983Murphy Creator An entity primarily responsible for making the resource Murphy, Linda (Linda Susan) Date A point or period of time associated with an event in the lifecycle of the resource 1983 Title A name given to the resource Geology of the Haunui valley, central North Island Subject The topic of the resource Map Igneous petrology Lithostratigraphy ignimbrite Korokoro Ignimbrite Onuku Breccia