1 10 3 https://theses.otagogeology.org.nz/files/original/bc7e7857b8ff868f18c0aa69cf747990.pdf bf79c5bb399ccf0ad3f5893227e55cd4 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 ((171.702609656633854 -42.307575747619474,171.741187669028562 -42.304788952346208,171.858434629636577 -42.371424977278323,171.863670086089087 -42.401857872611309,171.826932466995856 -42.406491686098697,171.705897196851993 -42.335134553056832,171.702609656633854 -42.307575747619474)) Author last name Last name of the Author Ritchie Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? BSc(Hons) Advisers Who supervised/advised this student Scott, J.M. Abstract The Abstract for this thesis This report describes the first field descriptions, mineralogy, quantitative P-T-t conditions of the Greenland Group in the Waipuna Valley, Westland. The Greenland Group in this area has been subdivided into four groups (I-IV) based on textural and mineralogical features. Group I rocks contain detrital textures and chlorite zone greenschist facies mineralogies. The rocks increase in grade to Group IV amphibolite facies gneisses and migmatites. Quantitative estimates on the conditions of deformation range from 420 C in Group I, through to 670 C in the Group IV gneisses. Group III rocks, however, contain the most informative mineral assemblages. Group III rocks contain an assemblage comprising andalusite-staurolite-biotite-quartz-oligoclase-Fe-oxide (M2) overprinted by biotite-sillimanite-muscovite-quartz and plagioclase (M3). These assemblages suggest that they formed under a relatively high geothermal gradient. The timing of the latest phase of metamorphism has been constrained by the U-Th-Pb dating of monazite, which is texturally controlled and grew at 108 1 Ma. Monazite growth may have coincided with the imposition of deformation fabrics, such as recrystallisation of quartz. The Waipuna Valley Greenland Group has been intruded by a suite of granitic dykes, stocks and plutons, here named Upper Grey Granites. The granite geochemistries indicate correlation with the nearby Rahu Suite magmatism. This interpretation is corroborated by U-Pb zircon ages which reveal mid Cretaceous emplacement between 111 and 105 Ma. Early granites (111 Ma, intruding Group III and IV Greenland Group) have deformation textures continuous with the their host rock. The youngest granite (105 Ma) intrudes Group I Greenland Group and there is a biotite hornfels assemblage developed in the aureole. The field, metamorphic and geochronological characteristics of theWaipuna Valley Greenland Group and Upper Grey Granites are interpreted to represent a rocks on either side of Cretaceous ductile detachment fault, here named the Waipuna Shear Zone. Group I and II Greenland Group represent upper plate portion, whereas the Group III gneisses and Group IV migmatites represent the lower plate. Although mylonitic rocks are exposed, the detachment surface is not. Nevertheless, the overall relationships described for the Waipuna Shear Zone are strikingly similar to those of the nearby Paparoa Metamorphic Core Complex, which has been interpreted as having formed during continental extension immediately prior to opening of the Tasman Sea. The rocks of the Waipuna Valley extend the known extent of Cretaceous shearing. In addition, the evidence for Cretaceous amphibolite facies metamorphism and dehydration of the mid crust, directly south of the Reefton Goldfield, may have significant implications for the timing of mineralisation. Department The department where the student is studying primarily. Geology Named locality Named locality describing the field area location. Waipuna Valley North Westland Thesis description Number of pages, maps, CDs, etc. viii, 137 pages A4, map in back pocket 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 2013Ritchie Creator An entity primarily responsible for making the resource Ritchie, Tom 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 Metamorphism and Plutonism in the Waipuna Valley, North Westland Subject The topic of the resource Metamorphic Geology geochronology Greenland Group Waipuna shear zone https://theses.otagogeology.org.nz/files/original/a832c6fa12df379eb506c2cd03dc544c.pdf edae67be149a258fadfd05e6fad8b8c9 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 Ritchie Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? BSc(Hons) Advisers Who supervised/advised this student Toy, V.G. Abstract The Abstract for this thesis Pseudotachylytes produced during coseismic slip are ubiquitous within the rocks of the Alpine Fault zone, New Zealand. Pseudotachylytes from three principal host rocks are described and characterised from field and petrographic observations. The pseudotachylytes range from ~ 1 mm thick in Alpine Schist-derived mylonites to ~1 cm thick in Western Province-derived augen mylonites and cataclasites. Depth estimates based on field and petrographic relationships divide the differently hosted pseudotachylytes into two broad groups that formed during seismic rupture in the upper crust of the Alpine Fault zone: 1) relatively low volume pseudotachylytes forn1ed in Alpine Schist-derived mylonites at- 8 km depth, where shear stress was relatively low, during low magnitude events just below the brittle-ductile transition; and 2) voluminous pseudotachylytes formed at shallower levels of- 2-5 km, where shear stresses were high, in Western Province granitoid-derived augen mylonites and cataclasites during higher magnitude events. Bulk-rock powder X-ray Fluorescence (XRF) of host rocks and Electron Microprobe Energy Dispersive Spectroscopy (EMP-EDS) spot analysis on pseudotachylyte matrices reveal that relative to their host rocks, the Alpine Fault pseudotachylytes are depleted in SiO? and enriched in Al?O?, alkalis and metallic oxides. This is interpreted to be the result of preferential inclusion of hydrous, ferromagnesian mineral phases and to a lesser extent feldspar into the melt, and the exclusion of quartz from the melt. The preferential selection relationship in part controls the voluminous nature of pseudotachylytes within retrogressed host rocks containing high proportions of hydrous, ferromagnesian minerals. Size analysis of the clasts within the pseudotachylytes reveals power law size-frequency distributions that are modified in the finer fraction of the clasts, suggesting pervasion of friction melt depleted the fine fraction of precursor ultracataclasites by incorporation into the melt phase by uniform rim melting. OURArchive handle The handle from the Otago University Research Archive (OURArchive) <a href="http://hdl.handle.net/10523/2709">http://hdl.handle.net/10523/2709</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. Alpine Fault Thesis description Number of pages, maps, CDs, etc. 82 leaves. Ill. Photos. Diagms. 30 cm.CD-ROM (4 3/4in.) 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 2009Ritchie Creator An entity primarily responsible for making the resource Ritchie, Samuel D. (Samuel David) Date A point or period of time associated with an event in the lifecycle of the resource 2009 Title A name given to the resource Alpine fault pseudotachylytes Subject The topic of the resource Structural geology Alpine Fault Alpine Schist Pseudotachylytes https://theses.otagogeology.org.nz/files/original/7fc4bf042fcd566fe8fa506ac0bc2cc1.pdf 411a97794ac1519129e16d23e378ad82 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 ((168.136389871000119 -44.549316192999981,168.136500927000043 -44.547328584999946,168.137730873000123 -44.525433721999946,168.139145524000014 -44.500265283999966,168.14074877500002 -44.480455230999951,168.156126872000073 -44.481137147999959,168.183640747000027 -44.482354082999962,168.220490729000062 -44.483976018999954,168.219767023000031 -44.492879246999962,168.216953335000085 -44.527467901999955,168.216848393000078 -44.528757113999973,168.214124729000105 -44.562195749999944,168.208090869000102 -44.561930717999985,168.163680955000018 -44.559983949999946,168.135677880000117 -44.558747266999944,168.136389871000119 -44.549316192999981)) Author last name Last name of the Author Ritchie Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? PGDipSci Advisers Who supervised/advised this student Landis, C.A. Abstract The Abstract for this thesis Sedimentary rocks of upper Permian Bryneira Group exposed in the Central Bryneira Range, Pyke Valley have been mapped and described in detail. The five lowermost Bryneira Group formations outcropping in this region form a distinctive 2.4 km thick sedimentary pile, disconformably underlain to the east by Humboldt Group volcanic rocks, and in faulted contact with Eocene-Oligocene Tertiary sediments, and Alabaster Group volcanic rocks to the west. The Bryneira sediments are interpreted as having been deposited in an arc-trench gap basin by a variety of offshore sedimentological processes. The basal unit, Upukerora Formation, consists of a 25-50 m sequence of coarse breccias which were eroded off a nearby submarine volcanic scarp. This unit passes abruptly upward into a 1 km thickness of turbidity-current deposited Howden Limestone (Trabeculatia prism limestone), with distinctive interbeds of green volcanogenic sandstone. The overlying, more quartzo-feldspathic sandstones and siltstones of Annear Formation (260 m), were deposited partly from sediment-carrying bottom contour currents (derived from a more silicic terrane to the south), and partly from downslope turbidity deposition. Both the Howden and Annear Formations are divided into two members on lithological grounds (BH1 and BH2), (BA1 and BA2). Annear Formation grades upward into an 1180 m thickness of Key Summit Volcanogenic Sandstone, which is overlain by 100 m of grey thinly laminated siltstones of Tapara Formation, most of which is interpreted as contourites. Low-grade Prehnite-Pumpellyite to Lawsonite-AlbiteChlorite facies metamorphic mineral assemblages are developed representing regional-burial metamorphism in the mid-late Mesozoic. A complete range of lithologies~ from siltstones to boulder conglomerates, is found within the Annick Group Tertiary beds which are derived from volcanic rocks of Alabaster Group and plutonic rocks perhaps of the McKay Intrusives. Structurally, the majority of Bryneira Group sediments are overturned, forming the eastern limb of the near isolc1inal Key Summit Syncline which appears to plunge both to the north and to the south from a 'high' in the Bryneira Range. The Hollyford Fault Zone downfaults most of the west limb, forming a graben which provided a basin for Mid-Tertiary sedimentation. Department The department where the student is studying primarily. Geology Named locality Named locality describing the field area location. Bryneira Range Thesis description Number of pages, maps, CDs, etc. 76 leaves : ill. (some col.), 2 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 1980Ritchie Creator An entity primarily responsible for making the resource Ritchie, Duncan David. Date A point or period of time associated with an event in the lifecycle of the resource 1980 Title A name given to the resource Geology of the Central Bryneira Range. Subject The topic of the resource Map Sedimentary petrology Structural geology Bryneira Group Key Summit Syncline