1 10 27 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 https://theses.otagogeology.org.nz/files/original/57e00179957dc3c5a10d33062a463699.pdf 317e0a92009b8e549b0cc0d8040c2d00 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 (((169.007357194797 -44.4801048617569,168.852891876841 -44.7153959537916,168.644939480572 -44.8819889426719,168.53059861996 -44.8789917767537,168.652743501904 -44.4707082049925,169.007357194797 -44.4801048617569))) Author last name Last name of the Author Wellnitz Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? PhD Advisers Who supervised/advised this student Scott, J.M. Palin, J.M. Abstract The Abstract for this thesis In this thesis the chemistry and textures of void-filling hydrothermal carbonate and associated altered metamorphic and lamprophyric rock in western Otago, New Zealand, were studied. With this information a detailed model of the mobility behaviour of various elements is established. Conduits for CO2-bearing fluids were faults, joints, folds and, in the northernmost part of the study area, volcanic diatremes. The southernmost study area lies in the Shotover Valley, where many of the larger fault zones are auriferous. Throughout the studied area, many larger faults, including the gold-bearing ones, strike W to NW. In addition to these faults, there are also structures (i.e. veins and fold hinges) that trend northwards. The formation of most of the structures happened in the Oligocene -Miocene andwas closely connected to the movements along the newly forming Alpine Fault and reverse movements along the Moonlight Fault. Adjacent to the fluid conduits, the wall rock has been extensively altered. This alteration is especially obvious in greenschist and the altered rock has a pale creamy colour due to the replacement of various metamorphic phases (epidote, chlorite, actinolite) mostly by Fe-bearing carbonate and phyllosilicates. In quartzo-feldspathic greyschists the same metamorphic minerals as in greenschist are unstable in response to the incoming CO2-bearing fluid. However, as those minerals are less abundant in greyschist, the alteration is less obvious. Textural and chemical data of the individual metamorphic and hydrothermal minerals forming during replacement were obtained using SEM, microprobe and LA-ICP-MS. The hydrothermal minerals replacing metamorphic minerals describea diverse array of mineral textures, which give insight into relative solubility of the different mineral phases. The replacement reactions also attest to mobility and immobility of the different major and trace elements. For example, in the breakdown of epidote in rocks which contain metamorphic muscovite, Al is mobilised potentially in F-OH complexes and transported away from the original epidote site, whereafter carbonate forms. In cases where there is no muscovite in the rock, epidote is replaced by muscovite, hence resulting in local loss of Ca. At the same time, the REE of this epidote are also mobilised on microscopic scale (µm to mm) as the growing muscovite cannot accommodate the REE in its crystal structure. These REE are then incorporated in the ankerite replacing the chlorite. On a macroscopic scale (cm to m), Sr, Ba, Rb, K and Cs show the largest mobility during the hydrothermal alteration (sometimes up to 20 times enrichment in the altered rock compared to the unaltered rock) and are often brought into the rock by the hydrothermal fluid. The REE and Al, on the other hand, do not show any signs of mobility at thatscale. Overall, of all elements in alteration-sensitive metamorphic minerals, only titanium is shown to be immobile throughout, also on µm scale. In addition to carbonate forming in the hydrothermal alteration halo around fluid conduits, carbonate is also a common void-filling mineral, such as fractures and vesicles. The chemical composition of these carbonates shows that the different elements are controlled by various factors. Contents of Ca, Sr, Mg, Fe, Mn and according ratios show that these elements can travel metres to tens of metres in the fluid before they are precipitated in carbonate. REE contents and patterns in the carbonate are the product of the interplay between fluid- and rock-dominated processes; in cases were only little rock needs to be leached to form the carbonate, the REE patterns are very similar to the wall rock. In cases where relatively large rock volumes need to be leached to provide the main components of the void-filling carbonate, the REE content of the carbonate is dominated by fluid-controlled processes and the REE patterns reflect the relative solubility of the different REE in the fluid. Radiogenic isotopic compositions (Nd, Sr) of void filling carbonates and wall rock show that Nd and Sr in the carbonates travel different distances in the fluid conduit; Nd isotopic ratios show that the bulk of the LREE are transported for short distances in the fluid passing through the void (cm to dm), whereas Sr isotopic ratios confirm that Sr can be for transported many meters by the aqueous fluid. Stable isotope data (C, O) in conjunction with assessing the regional geological and tectonic settings permitted to reconstruct the history and sources of the fluids in the studied areas; after taking temperature effects on isotope fractionation and relative sample locations into account, it is concluded that two main fluid types were present in the studied area. One of these is a mixture of meteoric and magmatic components, while the other fluid interacted extensively with the metamorphic rock in Western Otago, but was most likely originally meteoric-derived water. Only in the volcanic diatremes is there indication that these two fluid types mix. Outside the diatreme, the isotopic composition of the carbonate give evidence that only the second mentioned fluid type was present, including in the auriferous structures and there is no indication that the gold-bearing and magmatic system had any connection to each other OURArchive handle The handle from the Otago University Research Archive (OURArchive) <a href="http://hdl.handle.net/10523/7300">http://hdl.handle.net/10523/7300</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. Southern Alps Thesis description Number of pages, maps, CDs, etc. 257 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 2017Wellnitz Creator An entity primarily responsible for making the resource Wellnitz, Anne Katrin (Katrin) 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 Carbonate alteration associated with lamprophyres and orogenic gold, Southern Alps, New Zealand Subject The topic of the resource Igneous geology Metamorphic geology Alteration Carbonate Fluid gold Lamprophyres New Zealand radiogenic isotopes Rare Earth Elements stable isotopes https://theses.otagogeology.org.nz/files/original/011e6971550e2e3b1824ee81a27cef0b.pdf b02baef117c29e26352eadb125687ccf 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 (((171.906889677648 -41.8981119820802,171.985343292508 -41.8988320454063,172.096642805904 -41.94551555725,172.012738375843 -42.1078198899358,171.958609430256 -42.1302174999423,171.866632766476 -42.1179077549911,171.851215815353 -42.0677128784645,171.906889677648 -41.8981119820802))) Author last name Last name of the Author Robinson Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? PGDipSci Advisers Who supervised/advised this student Scott, J.M. Abstract The Abstract for this thesis The conditions of metamorphism have been determined through a contact aureole within the interbedded argillites and greywackes of the Greenland Group in Larry River and Brown Creek, north Westland, New Zealand. These rocks were metamorphosed at greenschist facies during folding. The emplacement of a granitoid into the Greenland Group rocks, the 378-370 Ma Dunphy Granite, produced a contact aureole that overprints the original regional metamorphic conditions. The highest grade assemblages, from next to the granite, comprises quartz, muscovite, chlorite, oligoclase and biotite. Ti-in-biotite geothermometry suggests peak metamorphism to have been 654 ± 24°C. This represents hornblende hornfels facies. Moving away adjacent to the Dunphy Granite the hornblende hornfels facies grades to albite-epidote facies, which comprises quartz, muscovite, chlorite and albite. Greenland Group rocks at the contact experience metasomatism with the granite. On the Greenland Group side of the contact there is only minor oligoclase, less biotite and an enrichment in apatite, quartz and muscovite. On the granite side there is a lack of oligoclase and K-feldspar, but an enrichment in muscovite and apatite. The Caledonian Mine in the Larry River valley is located in the north most point of the Reefton Goldfield. Gold is found in recrystallised quartz veins with sulphitic stylolitic veins. There are two mineralising phases identified. The first phase of mineralisation formed hydrothermal quartz veins associated with initial As-Fe-Pb-Cu-Au-S enrichment. Hydrothermal fluid producing gold-bearing quartz veins is assumed to have meteoric origins or have been produced by metamorphic dehydration reactions at depth. The second phase is separated by a brittle fracturing event and involved Pb-Mo-S rich fluids, possibly with magmatic origins. The Caledonian Mine deposit contained significant amounts of gold, but the economic potential is unknown as historic reports suggest a fault truncates mineralisation. The most precise date of mineralisation to date has been inferred, based on field relationships and SEM-EDS analysis, to have occurred after pluton emplacement and contact metamorphism of the host Greenland Group, <370 Ma. Department The department where the student is studying primarily. Geology Named locality Named locality describing the field area location. Reefton West Coast Thesis description Number of pages, maps, CDs, etc. 132 pages A4, 3 maps and sections, SEM-EDS and XRD data 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 2016Robinson Creator An entity primarily responsible for making the resource Robinson, Bryce Date A point or period of time associated with an event in the lifecycle of the resource 2016 Title A name given to the resource Contact aureole formation adjacent to the Dunphy Granite, Westland, and implications for Reefton Goldfield Au mineralisation Subject The topic of the resource Economic Geology Contact Metamorphism Dunphy Granite gold https://theses.otagogeology.org.nz/files/original/1689b5a9c2ce3c3bf23abfb0b0755667.pdf 368bf8b4ba242179fb7288a7bce59d6e 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 ((170.363343925000095 -45.677738555999952,170.363342507000084 -45.677770029999976,170.363324848000047 -45.678233217999946,170.203418739000085 -45.674492338999983,170.203431676000037 -45.674155054999972,170.203435572000103 -45.674006607999956,170.203446572000075 -45.673709789999975,170.203448940000044 -45.67366033199994,170.2036999500001 -45.666270803999964,170.203728444000035 -45.665407246999962,170.202522899000087 -45.665378877999956,170.178030688000035 -45.664799768999956,170.142849419000072 -45.600745822999954,170.208853985000019 -45.602407127999982,170.337510127000087 -45.605532020999931,170.366386611000053 -45.606215769999949,170.36594673500008 -45.616639051999982,170.365552884000067 -45.625965109999981,170.363364384000079 -45.677284429999986,170.363357902000075 -45.677428311999961,170.363343925000095 -45.677738555999952)) Author last name Last name of the Author MacKenzie Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? MSc Advisers Who supervised/advised this student Norris, R.J. Department The department where the student is studying primarily. Geology Named locality Named locality describing the field area location. Barewood Thesis description Number of pages, maps, CDs, etc. viii, 173 p. (some folded) : ill. (some col.), maps ; 30 cm. Abstract The Abstract for this thesis The historic Barewood Mining Area comprises an important gold and tungsten deposit in east Otago, New Zealand. Numerous gold and scheelite-bearing quartz vein systems are hosted within several well defined subparallel normal faults which crosscut the regional flatlying schistosity at approximately 50°-70°. The faults are traceable for several kilometres and strike northwest subparallel to the predominant lineation direction and the axes of regional macroscopic folds. The faults lie on the lower limb of a large macroscopic recumbent fold and dip subperpendicular to its axial surface. Correlation of the Barewood faults with regional northwest trending normal faults suggests formation in the mid to late Cretaceous during the later stages of schist uplift. A complex history of fault movement is recorded by quartz vein textures and slickenside lineations. Vein textures are indicative of a mesothermal mineralising environment significantly above the brittle-ductile transition. Mineralisation occurred within quartzofeldspathic sediments derived from the Torlesse Terrane and are classified Textural Zone IV. Hydrothermal alteration extends no more than a few metres from individual veins and is characterised by silicification and kaolinisation of altered host rock. Geochemical XRF analyses reveal significant additions of Si02, K20, Ba and Rb with the dilution of most other major and trace elements. Gold, tungsten, arsenic and antimony are the main elements indicative of mineralisation and are thought to have been transported in the mineralising fluid. Quartz vein textures record a succession of brecciation and mineral deposition events. Gold, scheelite and sulphide distribution is concentrated in zones of repeated fracturing where textural overprinting is highest. Native Au commonly occurs as free blebs in quartz veins. Fe-sulphides ± Au are associated with replacement textures in altered schist inclusions. Enhanced permeability created by repeated fracturing of wall rock and pre-existing vein material is thought to have contributed significantly to fluid-rock interaction and thus the concentration and deposition of metals. Arsenopyrite geothermometry, combined with fluid inclusion temperature and density determinations, yields an estimate of 325°± 60°C and 2 ± 1 kbars for the conditions of Barewood mineralisation. A mineralising fluid of low apparent salinity (1-2 wt.% equiv. NaCl) is indicated by fluid inclusion studies. The carbon and oxygen isotope composition of mineralised vein carbonate from Barewood and its calculated fluid composition suggest equilibration with metamorphic rocks, and is consistent with a metamorphic source for the mineralising fluid. Stibnite-bearing quartz veins at the Hindon Antimony Mine are hosted in a series of subparallel moderately dipping reverse faults and steeply dipping extensional fractures. The fault zone comprises a complex thrust system at low angle to S2, and dips 30°- 40° SE. Significant postmetamorphic deformation of host schist, evidenced by local steepening of schistosity, 25°- 60° SE, is confined to the immediate mine area. Stibnite is the predominant sulphide at the Antimony Mine and the main indicator of mineralisation. The most significant mineral deposition occurred in zones of localised extension within the thrust system and in late stage crosscutting extension veins. Vein textures are quite different from those observed at Barewood and are more suggestive of an epithermal environment. Fluid inclusion studies indicate a mineralising fluid of significantly higher salinity than Barewood (3.5-5.0 wt.% equiv. NaCl) and a minimum mineralising temperature of approximately 200°C. 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 1990MacKenzie Creator An entity primarily responsible for making the resource MacKenzie, Douglas James. Date A point or period of time associated with an event in the lifecycle of the resource 1990 Title A name given to the resource Gold, tungsten, and antimony mineralisation at Barewood, east Otago, New Zealand Subject The topic of the resource Metal-ore deposits antimony Barewood gold Haast Schist Group Otago Region Taieri River tungsten Waipiata Igneous Formation https://theses.otagogeology.org.nz/files/original/d5ede32fbd2fa3d736cbd25f9f5b3ba6.pdf 0f5e608165159ae38f8135c33bde6ce4 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 ((171.880595031720304 -42.127729991917725,171.893774311229606 -42.126428070975187,171.908555876473656 -42.126855592022544,171.906323098572074 -42.139416143324375,171.901092679509446 -42.141939711828954,171.880552946389031 -42.141026256121279,171.878953096002903 -42.139151961045954,171.879133589909372 -42.134364064327038,171.880595031720304 -42.127729991917725)) Author last name Last name of the Author Stick Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? BSc(Hons) Advisers Who supervised/advised this student MacKenzie, D. Scott, J.M. Abstract The Abstract for this thesis The Reefton Goldfield produced over 67 tonnes of hard rock gold from 84 mines between 1870 and 1951, making it one of New Zealand’s richest goldfields. Reaching a depth of 692 m, the Energetic gold mine, in the Crushington group of mines was the third largest producer. Hosted in Greenland Group metasediments, the mine produced 208,992 ounces of gold during operation between 1870 and 1927 when it closed due to an underground collapse This report details the first comprehensive study of the Energetic mine and the surrounding Greenland Group host rocks. The Energetic shear zone hosts the Energetic mine on the eastern limb of the NE-striking Globe Hill Anticline. The shear zone comprises two variably mineralised faults that host three main quartz reefs. One NE-striking fault is controlled by both local bedding and cleavage whereas the other (NNW-striking) is controlled primarily by cleavage. The formation of these faults was the result of an ENE-WSW shortening direction, oblique to the local bedding but perpendicular to the NNW-striking, cleavage controlled fault. Alteration surrounding the Energetic shear zone is asymmetric to the west, most noticeably through As and S concentrations obtained through geochemical analysis of the RDD0048 drillcore. This alteration appears to be lithologically controlled to argillite. The argillaceous units were preferentially sheared and their relative impermeability compared to greywacke units prevented fluids from migrating into and altering the surrounding host rock to the east. Early hydrothermal fluids migrated into the wall rocks and altered carbonate spots in argillaceous units from ankerite to siderite proximal to mineralised zones. This compositional change is the most reliable exploration vector at the Energetic mine. Associated with this phase was the formation of wall rock sulphides that due to continual shearing were deformed and had antitaxial strain shadows form around them. The main stage of gold mineralisation along the Energetic shear zone is associated with dark grey quartz and stylolitic veins that contain pyrite. These veins are hosted in and cut early ductiley deformed quartz lodes. These veins and later crosscutting veins are more brittle in nature and indicate mineralisation along the shear zone may have been prolonged. Brittle structures have overprinted earlier ductile structures and are now the most prominent feature of mineralised rocks. The mineralised rocks are highly deformed and a succession of mineralised veins cut the rocks. Pressure solution effects are commonly associated with both ductile and brittle structures and show the prolonged nature of deformation along the shear zone. Department The department where the student is studying primarily. Geology Named locality Named locality describing the field area location. Reefton Thesis description Number of pages, maps, CDs, etc. 155p 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 2015Stick Creator An entity primarily responsible for making the resource Stick, George Nicholas, 1992 (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 A structural, paragenetic and geochemical study of the Energetic gold mine, Reefton Goldfield, New Zealand Subject The topic of the resource Geochemistry Metamorphic geology Metamorphic petrology Mineralogy Ore deposits Alteration Buller Terrane deformation Energetic Mine Energy Dispersive Spectroscopy (EDS) gold Greenland Group Greenschist Facies metamorphism mineralisation Orogenic gold quartz veins Reefton goldfield Reefton Group shear zones https://theses.otagogeology.org.nz/files/original/2decafb0df1eb62e2b135dc999d6e04d.pdf beb7e122ccf8374875fde66788de9aba 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 ((171.805374862809884 -42.196242566958638,171.93739778661805 -42.196588440737941,171.940308195905743 -42.32910292096863,171.799127321466614 -42.322945467334939,171.805374862809884 -42.196242566958638)) Author last name Last name of the Author Shand 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 The Big River South – St George deposits are hosted within Sunderlands lode series, in the south east of the Reefton Goldfield. Macroscopic folds flank both deposits. Three bedding parallel faults host the auriferous quartz reefs at each deposit, with the central reef being the principal ore zone. These reefs are offset by later E-W trending faults. There are also several auriferous quartz stockworks surrounding the mines. The primary ore type comprises large recrystallised quartz veins with sulphitic stylolites. These veins host visible gold. Lower concentrations of gold have been identified within mineralised greywacke adjacent to the lode, whilst a lower permeability may have prevented mineralisation within argillitic horizons. Fault valve behaviour along with a variable fluid composition has resulted in a complicated paragenetic sequence of mineralisation. However, there appear to be three dominant ore-forming stages. Initially Au, As, Fe, Sb and Pb were deposited in large white quartz veins, then subsequently concentrated into irregular vein-parallel stylolites. It is inferred that this initial fluid has been produced through metamorphic dehydration reactions at depth. Subsequently an influx of Cu, Mo and Pb overprinted the initial mineralisation during deformation. This fluid may have been generated throughout the second phase of metamorphism known from the Greenland Group. Shallow Cu-Mo-bearing porphyry intrusions known from the area could possibly provide a plausible source candidate for these base metals. Following this, supergene enrichment of mineralised greywacke within the alteration halo may have occurred, and locally enriched the Au. In summary, the Big River South – St George deposits both host significant gold mineralisation; however, the sporadic occurrence of gold means the mines are unlikely to contain the high Au grades of other locations in the goldfield. Department The department where the student is studying primarily. Geology Named locality Named locality describing the field area location. Reefton Westland Thesis description Number of pages, maps, CDs, etc. 112p some A3 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 2015Shand Creator An entity primarily responsible for making the resource Shand, Fraser Charles Grant, 1992 (Fraser) 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 Structural controls and paragenesis of the Big River South Subject The topic of the resource Geochemistry Metamorphic geology Metamorphic petrology Ore deposits Petrology Big River gold OceanaGold Reefton goldfield https://theses.otagogeology.org.nz/files/original/0d85f58ff1f293308a5fa885f0a17930.pdf 805a3d237beef1894c4a218e82f22fda 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 ((170.645418025022138 -45.8543595686372,170.65557341305086 -45.853568278082541,170.659573268470922 -45.860580375008972,170.649137052263995 -45.863152338060637,170.642373124419606 -45.861083921473536,170.645418025022138 -45.8543595686372)) Author last name Last name of the Author Fleming Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? PGDipSci Advisers Who supervised/advised this student MacKenzie, D. Abstract The Abstract for this thesis Gold was first discovered on the southern slopes of Harbour Cone on the Otago Peninsula in 1872. Initial sampling of mineralised rocks in the Battery Creek area returned 4.6-33.7 g/t gold. A subsequent study describes a pyrite-bearing syenite with up to 2.55-21.8 g/t gold. More recent investigations failed to find any significant mineralised rocks. In this study the Battery Creek area is mapped in detail and the exposed rock units are described along with the locations of the historic workings which include a shaft and several small adits. Lithological units in Battery Creek formed as a product of Miocene volcanism in (21-10 Ma). The main volcanic unit that blankets the area are tuffaceous layers and dolerite deposits. Three hydrothermally altered and mineralised units were identified. These are an unexposed syenite, that is cut by a narrow (20 cm wide) fracture zone and containing disseminated pyrite that have replaced the primary igneous kaersutite phenocrysts; a pyroclastic lapilli tuff layer with pumice lapilli that have been replaced by pyrite and a dolerite with a fine network of narrow pyrite-bearing veinlets. Laser Ablation Inductively Coupled Mass Spectrometry of the mineralised dolerite and lapilli tuff were analysed for trace elements and confirmed the presence of pyrite in these rocks, however, neither samples were enriched in gold. Two small grains of gold up to 0.2 mm across were recovered by sluicing approximately 50 cubic litres of gravel from Battery Creek 70 metres downstream from the old shaft. This suggests that the pyrite-bearing rocks in the old workings and the catchment area upstream are the most likely source for the Battery Creek gold. Department The department where the student is studying primarily. Geology Named locality Named locality describing the field area location. Battery Creek Otago Peninsula Dunedin Thesis description Number of pages, maps, CDs, etc. ix, 97 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 2015Fleming Creator An entity primarily responsible for making the resource Fleming, James Armstrong (James) 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 Characterisation of Gold Bearing Lithologies, Battery Creek, Otago Peninsula, New Zealand Subject The topic of the resource Exploration Geology Battery Creek gold Hydrothermal alteration https://theses.otagogeology.org.nz/files/original/8d67f50f02de365aa98b130dd7aa9fd8.pdf 162e7c43bf18e60349c0510b50ed69b4 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 ((172.720715606122013 -41.0531463765194,172.819863327854279 -41.052890961980104,172.815562664355696 -41.092751433143683,172.716554001543926 -41.093154460720861,172.720715606122013 -41.0531463765194)) Author last name Last name of the Author Phillips Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? MSc Advisers Who supervised/advised this student Craw, D. Abstract The Abstract for this thesis Gold mineralisation at Sams Creek occurs within an under-explored region with a rich history of alluvial gold prospecting dating back to at least the 1850s. Gold at Sams Creek is structurally hosted by sheeted veins and irregular fractures in an A-type peralkaline microgranite dike which extends 7km along strike and is up to 60 meters in thickness. The deposit was first discovered by CRA Exploration and was then further explored by OceanaGold, currently in a joint venture with MOD Resources. The majority of exploration has been conducted in the “Main Zone” including over 120 diamond drill holes. At least three stages of hydrothermal activity have altered the dike including the precipitation of late arsenopyrite veins, and lesser amounts of pyrite, sphalerite, galena, and gold. Scanning Electron Microscopy (SEM) is used to show that gold occurs as an alloy with silver (~80-85% Au) as small growths (up to 40 μm) with pyrite and base metal sulphides. These phases are primarily found cementing and in-filling fractured and brecciated arsenopyrite (the most abundant “ore mineral”). A reduced assemblage characterises the unaltered peralkaline microgranite dike which undergoes its first alteration (T1) under relatively oxidizing and ductile conditions during a late magmatic stage. Later, structurally controlled vein-related alterations (T2, T3, & T4), tied to regional deformation, occur under reduced and brittle conditions. Microstructural deformation during these stages is primarily characterised by a combination of extensional and shear related features. This study isolates geochemical enrichments related to specific alteration and vein assemblages from analysis of a targeted, independent sample set collected for this research. Using exploration generated assays, from 1 m half-core sampling a kilometre of vertical relief, this study also defines spatial distributions and variations in geochemical signatures throughout the deposit scale. A Au-As-Sb assemblage is anomalous over the full scale of the deposit, and zoning patterns of Ag, Pb, and Zn are observed throughout the full range of elevations sampled. Most notably, Ag increases with elevation, while Pb and Zn increase with depth. Mo is also relatively elevated at depth. Hydrothermal zircons first reported by Nazimova (2012) occur as clusters and stringers of <1-15μm anhedral crystals along grain boundaries of arsenopyrite and within the same micro fractures which gold grains occupy. These zircon are interpreted as forming from hydrothermally dissolved and reprecipitated zirconium present in the unaltered Sams Creek Dike. Zircons also occur in un-mineralised samples as larger ellipsoidal to faceted individual grains associated with primary mafic minerals and are interpreted as magmatic in origin. These zircons are up to ~25μm in size and many grains exhibit a spongy dissolution(?) texture. OURArchive handle The handle from the Otago University Research Archive (OURArchive) <a href="http://hdl.handle.net/10523/5119">http://hdl.handle.net/10523/5119</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. Sams CreeK NW Nelson Thesis description Number of pages, maps, CDs, etc. xiv, 177 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 2014Phillips Creator An entity primarily responsible for making the resource Phillips, Markham Date A point or period of time associated with an event in the lifecycle of the resource 2014 Title A name given to the resource Geochemistry & Timing, Sams Creek Gold Deposit NW Nelson, New Zealand Subject The topic of the resource Geochemistry Exploration Geology exploration geochemistry Geology gold Hydrothermal Zircon Northwest Nelson Sams Creek U-Pb Dating https://theses.otagogeology.org.nz/files/original/0327a2fe669e280d3833a4c7e8249f5b.pdf 26b873cccc26690cb198514393062928 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 (((168.451224660724904 -44.885898033364391,168.393783591749468 -44.883590800942457,168.401627872702107 -44.852468047135432,168.459188203246185 -44.852870628255161,168.451224660724904 -44.885898033364391)),((168.911755815476226 -44.798070303351658,168.899281276576318 -44.917188240482815,168.746940966482981 -44.910177645629553,168.759482258347845 -44.794413468896266,168.911755815476226 -44.798070303351658)),((171.916010761828943 -42.250280043141132,171.889992922875564 -42.250635086608682,171.889603128360449 -42.238100068707311,171.916014349335171 -42.238201758443743,171.916010761828943 -42.250280043141132)),((171.899277154527425 -42.163255769324884,171.898684573549104 -42.175259918662931,171.882938502706537 -42.174392794247062,171.882553225204816 -42.163523004393006,171.899277154527425 -42.163255769324884))) Author last name Last name of the Author Druzbicka Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? PhD Advisers Who supervised/advised this student Craw, D. Pope, J. Abstract The Abstract for this thesis Mining activities inevitably result in changes to the environment and have the potential to cause negative impacts. This work investigates and emphasises the role of geology as the primary control on the environmental issues related to mining activities, whether current or historic. The knowledge and understanding of geological and geochemical factors associated with a particular deposit is crucial in ensuring the prevention and/or minimisation of the environmental impacts of mining operations. Such knowledge is essential for the responsible environmental management of mines. The research presented in this thesis is applied in nature and focuses on mesothermal and associated placer gold deposits located in the South Island of New Zealand. Arsenic and antimony are two metalloids commonly associated with mesothermal deposits, where they are mainly present as minerals arsenopyrite and stibnite, respectively. The mobilisation of these metalloids from deposits is facilitated by near-neutral pH and the greenschist facies rocks hosting mesothermal deposits are characterised by generally high acid neutralising capacity thanks to the presence of carbonate minerals. Arsenic and antimony are known for their toxicity at low levels (e.g. < 0.01 mg/L in water) and therefore their elevated concentrations in waters and solid mine residues and soils are the main environmental concerns with regards to the mining of mesothermal deposits. The presence of metalloids has been studied as part of this work in both active as well as historic mining settings in four different locations. At the active Globe Progress mine in the West Coast, metalloid signatures of mine waters were found to have evolved from Sb/As < 1 to above 1 suggesting that the mobilisation of antimony has proportionally increased with regards to arsenic over the course of over two years since the mine’s opening. The impact of metalloids on aquatic fauna was investigated in a long-term field study and not enough evidence was gathered to suggest their involvement in the decrease in the ecosystem’s health which was found more likely to be attributable to the repeated increased turbidity events in the receiving stream. The choice of mining methods as well as climate as a factor in determining the environmental aspects is also recognised here with the change in mining method from underground to open cast being responsible for the change in the type of ore mined and therefore also the related metalloid signatures. An historic mining processing method of roasting of sulphide-rich ore (especially in an Edwards roaster including an As saving system) was found to influence the mobility of metalloid-bearing mine residues governed by the presence of soluble arsenolite and immobilisation of metalloids through the formation of relatively stable secondary minerals at sites where no roasting in the Edwards roaster has been performed in the past. For example, immobilised As and Sb-bearing residues at the Big River mine were found to contain up to ~20 wt% As and 3.5 wt% Sb. The presence of localised acidic pH conditions was recognised as an important control on the immobilisation of metalloids, ensuring the stability of some of the secondary mineral phases (e.g. scorodite). Turbidity or suspended solids load in waters has been a major environmental issue in New Zealand since the beginning of mining operations in the country. Even though the problem is widely-recognised, not much is known with regards to what controls the levels of turbidity produced and their rates of settling. The geological factors recognised as important in the study of five paleoplacer deposits from Central Otago include the abundance of clay minerals, which is partially dependant on the presence of altered basement rocks in the Central Otago setting as well as the mode of transport and deposition of the sediments. Additional physical factors such as the level of cementation of a deposit were also found to be an important control on turbidity production and dissipation. The appropriate management of active mine sites is crucial in ensuring that the activities are performed in as safe a manner as possible from the environmental point of view. Today, modern mines operate extensive environmental management and monitoring systems and actively work towards improving the existing schemes. The evaluated waste rock management system at the Globe Progress mine, designed to help keep the metalloids on site and prevent their release via waters percolating through waste piles, was found to be working well. Overall, the system correctly categorises waste rocks into two types depending on their predicted arsenic content, and therefore their level of environmental sensitivity, followed by correct handling and storage in appropriate waste piles. The management of historic sites involves the evaluation of their environmental impact on the local environment which should also include an assessment of any potential health and safety risks with regards to the visiting public, which is not always considered at historic sites in New Zealand. In addition, a potential conflict between historical preservation and environmental management has been recognised. On the other hand, the widely-perceived conflict between mining and conservation values has been demonstrated to not always be the case with examples of unique saline habitats forming at two historic placer mining sites in Central Otago. The natural rehabilitation of these sites was found to contribute to the enhancement of the sites’ long-term biodiversity suggesting that natural succession may be important for the establishment of stable and robust ecosystems. OURArchive handle The handle from the Otago University Research Archive (OURArchive) <a href="http://hdl.handle.net/10523/4915">http://hdl.handle.net/10523/4915</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. West Coast Globre progress mine South Island Central Otago Thesis description Number of pages, maps, CDs, etc. xxvi, 2 Parts, 560 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 2014Druzbicka Creator An entity primarily responsible for making the resource Druzbicka, Joanna Barbara (Asia) Date A point or period of time associated with an event in the lifecycle of the resource 2014 Title A name given to the resource Geological controls on environmental impacts and management strategies for mined mesothermal and placer gold deposits Subject The topic of the resource Environmental Geology environmental gold mesothermal metalloids mining placer https://theses.otagogeology.org.nz/files/original/8199aab14f138b54dcfb8693265bde2b.pdf f81ac76ffb59d7629b93a464de823189 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 ((169.359776841146925 -45.259080422426123,169.347242996690483 -45.440877800715739,169.07632715220754 -45.432475295790731,169.088081758988864 -45.250084752184293,169.359776841146925 -45.259080422426123)) Author last name Last name of the Author Stephens Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? BAppSci(Hons) Advisers Who supervised/advised this student Craw, D. MacKenzie, D. Abstract The Abstract for this thesis Six structurally controlled gold deposits are hosted within two different structural blocks in the Old Man Range area. The mineralised lodes are hosted in normal faults which cut steeply across the host schistosity. In the East structural block, mineralised faults and the prominent joint set strike northwest and cut steeply across greenschist facies TZ III Caples Terrane schist. In the West structural block, mineralised faults and prominent joint sets strike east-west and cut steeply across upper-greenschist facies TZ IV Wanaka lithologic association schist. These structural blocks are separated by the regional scale Old Man Fault. Orientation of hard rock gold deposits is closely linked to the prominent joints in host schist surrounding the deposits. Mineralised lodes formed along ~1m wide normal fault zones. They are discontinuous but can be traced for up to ~150m, with variable thickness along strike. The lodes comprise brecciated silicified schist and hydrothermal quartz breccia, and minor quartz veins with abundant arsenopyrite. Open cavities with euhedral quartz crystals are common. Euhedral arsenopyrite occurs in quartz and silicified schist clasts within mineralised zones. Gold occurs as micro-particulate blebs in partly oxidised arsenopyrite, and as coarser free grains within quartz, micaceous laminae, micro-faults, and micro-shears within mineralised rock. Hydrothermal alteration is minor, comprises addition of Si, Au and As, and extends only a few centimetres from the mineralised lodes. Mineralisation may have occurred within a few kilometres of the surface during mid-Late Cretaceous extension (~106-101Ma), with estimated formation temperatures between 200-350°C. The mineralised structures within the Old Man Range area are similar to other shallow level, post-metamorphic Otago gold deposits. Magnetic, magnetite bearing greenschist has a high magnetic response and can be successfully mapped using total magnetic intensity surveys over the Old Man Range area. Electromagnetic (EM) surveys can be used successfully to map post-metamorphic faults within the Old Man Range area, where they show up as linear conductive anomalies. These geophysical surveys are a useful tool for geologic mapping. However, there is no direct link between the geophysical features and gold mineralisation within the Old Man Range. Department The department where the student is studying primarily. Geology Named locality Named locality describing the field area location. Old Man Range Otago Thesis description Number of pages, maps, CDs, etc. v, 112 pages A4 map in back pocket A1 OURArchive handle The handle from the Otago University Research Archive (OURArchive) <a href="http://hdl.handle.net/10523/7295">http://hdl.handle.net/10523/7295</a> OURArchvive access level Open Access 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 2013Stephens Creator An entity primarily responsible for making the resource Stephens, Samuel (Sam) 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 Characterisation of Gold Mineralisation and Geophysical aided Geologic Mapping in the Old Man Range, Central Otago, New Zealand Subject The topic of the resource Ore Deposits EM gold Magnetics schist veins