1 10 9 https://theses.otagogeology.org.nz/files/original/21c369eb2726a2107014b55c7f42234a.pdf 9082638b7eebbe587e6b92e6acea6594 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 (((170.454624258042 -45.4655465354816,170.492232871253 -45.4665575501279,170.491638928032 -45.483751567299,170.453112926024 -45.4821840430224,170.454624258042 -45.4655465354816))) Author last name Last name of the Author King Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? BSc(Hons) Advisers Who supervised/advised this student MacKenzie, D. Abstract The Abstract for this thesis Lot's Wife was first discovered in 1890 and mined sporadically until 1904, pro- ducing 2002 oz Au. The deposit is an orogenic vein system that is hosted in upper greenschist facies, textural zone four (TZ4), Otago Schist and is lo- cated 11 km southeast of OceanaGold (NZ) Ltd0s currently active Macraes gold mine. The vein system consists of three main, subparallel, mineralised quartz veins, the Bonanza No. 1, Bonanza No. 2 and Zedd lode, which were mined historically in a system of shallow pits and at least one shaft sunk to a depth of 45 m on Bonanza No. 1. The quartz veins are hosted within a series of NW-striking normal faults that cut the relatively at, metamor- phic foliation at 50 to 70. Warping of the schist, up to 4 m, next to the faults is consistent with a normal sense of displacement. Although outcrop is poor arsenic soil geochemistry outlines a continuous strike length of at least 4 km. Hydrothermal quartz in the veins and silicified host schist next to the faults is typically euhedral with prismatic faces and locally infills open cavities. Arsenopyrite and pyrite occur along the margins of the veins, often in association with rutile. SEM-EDS analysis of sulphides has not identified any mineralisation in the fractures of grains, indicating only one mineralising generation of hydrothermal uid. Host schist within the fault zone is cataclas- tically deformed and cut by brittle shears with characteristic brown Fe-oxide staining. Shears contain hydrothermal muscovite, sulphides and ankerite, lo- cally cutting the quartz veins and cataclasites. Sulphides extend up to 20 cm from the veins. SEM-EDS analysis failed to find any micro-particulate gold in the limited samples of sulphides, however some micron-size free gold grains were observed in quartz vein material and in micaceous layers in schist next to the veins. Fluid inclusions within quartz crystals shows little variation in size and indicates the mineralising uid did not undergo boiling. Previous work at Bonanza indicate homogenization temperatures in the range 175C to 270C. Data obtained supports conclusions that mineralisation occurred from an immiscible uid at approximately 1 kbar, at a depth of between 3 and 6 km. Mineralisation at Lot's Wife is correlated with the approximate time that Barewood and Nenthorn mineralised veins formed. This was during late stage extensional exhumation of the high grade core of the Otago Schist belt, 112 - 100 Ma. Department The department where the student is studying primarily. Geology Named locality Named locality describing the field area location. East Otago Thesis description Number of pages, maps, CDs, etc. 85 pages A4, digital appendix-one spreadsheet 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 2016King Creator An entity primarily responsible for making the resource King, Alastair 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 Structure and mineralisation at Lot's Wife, East Otago, New Zealand Subject The topic of the resource Economic Geology mineralisation quartz veins SEM https://theses.otagogeology.org.nz/files/original/f5cc77cc64d8e790b1fb065244349860.pdf 9b12c00415da53d6f0b29f52a3938748 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 ((169.449001255111398 -45.233334970424167,169.446825321401917 -45.278995759185221,169.381480173370534 -45.277417866292026,169.39850970053277 -45.232228257690274,169.449001255111398 -45.233334970424167)) Author last name Last name of the Author Yeo Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? MSc Advisers Who supervised/advised this student Craw, D. Mackenzie, D. Scott, J.M. Abstract The Abstract for this thesis A zone of brittle faults, hosted within the Otago Schist occurs along the NE- trending margin of the Manuherikia valley in Central Otago. The faults were initiated in the Cretaceous with predominantly normal sense of motion. Some faults have been reactivated as reverse structures since the Miocene, offset- ting gold-bearing Cenozoic sediments. Quaternary reactivation has resulted in stepped topography adjacent to the Manuherikia River. Cretaceous fault activity was accompanied by hydrothermal fluid flow and minor alteration of fault rocks and adjacent wall rocks. There are three different styles of faulting within the Tucker Hill area: narrow E-W orientated silicified zones, wide NE-SW orien- tated silicified cataclasite zones, and carbonate-rich, orange-stained zones. The narrow E-W oriented silicified zones have 5-10 cm wide silicified cataclasites along the fault plane, and these dominate the southern end of the area. Some of these zones host veins with euhedral crystals of calcite and quartz. These nar- row zones have a wide range of orientations, often show cross-cutting relation- ships with other faults and are traceable for only short distances (<100 m) along strike. Farther north in the area, wide resistant, silicified slabs of cataclasite, be- tween 2-4 metres across, form resistant ridges across topography. These zones are well exposed, with prominent fault planes containing slickenlines which pre- dominately show a dip-slip sense of motion. These large resistant faults range from moderately to steeply dipping and are largely orientated NE-SW. Inferred fault zones are prominently orange-stained where Fe-rich calcite has been al- tered to limonite, and form easily-eroded lower topographic features within the area such as gullies or saddles between ridges. These inferred fault zones are often associated with remnant Miocene, Dunstan Formation sediments. Some of the inferred zones occur along the same strike as the wide silicified catacla- site zones. Scattered pyrite occurs in some silicified rocks, and there are low but anomalous levels of arsenic and gold in some fault rocks. Two morphologically distinct types of Otago Schist basement have been described at Tucker Hill. The southern section contains a TZIII ”slabby” schist, whereas the northern section has a TZIV ”folded” schist. OURArchive handle The handle from the Otago University Research Archive (OURArchive) <a href="http://hdl.handle.net/10523/6138">http://hdl.handle.net/10523/6138</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. Manuherikia Fault Zone Alexandra Central Otago Thesis description Number of pages, maps, CDs, etc. xiv, 120 pages A4, A1 map in back pocket folded 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 2015Yeo Creator An entity primarily responsible for making the resource Yeo, Samantha Louise (Sam) 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 Structurally Controlled Hydrothermal System in the Manuherikia Fault Zone, Alexandra, Central Otago Subject The topic of the resource Metamorphic geology Metal-ore depsoits Fault Zone mineralisation Otago Schist 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/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/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 https://theses.otagogeology.org.nz/files/original/40ef0c57f9beb5b8d0a507bd2d8c6db8.pdf 44da873a847ab7cae97e7b763485995b 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 Smith Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? BSc(Hons) Advisers Who supervised/advised this student Scott, J.M. MacKenzie, D. Abstract The Abstract for this thesis The South Reefton Shear Zone (SRSZ) is a 11km long mineralised shear zone in the Reefton Goldfield. The SRSZ strikes parallel to the fold hinges of the pervasive tight folds in the Reefton Goldfield. In outcrop the SRSZ is defined by a zone of discrete brittle shears and a close association with sulphide and carbonate minerals. A shear sense obtained from rotated carbonate and sulphide porphyroclasts, shows the SRSZ had an oblique sinistral movement, east side down in its current position. Upon comparison with regional tight folds the SRSZ appears to have been rotated since its formation, and was initially a reverse oblique shear zone. Shearing may have begun during the tight folding event, between layers that progressively steepened, or after the tight folding event along the axial planar cleavage of tight folds. A possible paragenesis for mineralisation of the SRSZ begins during diagenesis or early metamorphism of the Greenland Group when traces elements, including Au and As concentrated in mud layers and formed framboidal and small euhedral arsenian pyrite (SF1). Shearing on the SRSZ began and focused hydrothermal fluids, enriched in trace elements that have been released from metamorphic reactions at depth and in the surrounding rocks. This second stage of mineralisation (SF2) formed the euhedral disseminated grains of arsenopyrite and arsenian pyrite which is abundant in the southern portion of the SRSZ. In a later event, parts of the SRSZ were hydrothermally brecciated and stibnite was deposited, SF3. The age of the SRSZ can not be well constrained, but must have formed after deposition of the host Greenland Group rocks (490 Ma) and finished before the unmineralised Reefton Group was deposited (Devonian). Compared with structures in the Reefton Goldfield shearing occurred during or just after the tight folding event which formed the pervasive tight fold seen around the Reefton Goldfield (D2 of Maw (2000)). Department The department where the student is studying primarily. Geology Named locality Named locality describing the field area location. Reefton goldfield Thesis description Number of pages, maps, CDs, etc. 112 p. : 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/. Identifier An unambiguous reference to the resource within a given context 2011Smith Creator An entity primarily responsible for making the resource Smith, James Andrew. Date A point or period of time associated with an event in the lifecycle of the resource 2011 Title A name given to the resource Structure and geochemistry of the South Reefton Shear Zone, Reefton Goldfield Subject The topic of the resource geochemistry gold Greenland Group mineralised shear zone Reefton goldfield https://theses.otagogeology.org.nz/files/original/2783491e875dae62cbbaea079d97e528.pdf 0743ebf8cee49186d3970591cf98e4f9 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 ((171.889084457509199 -42.238243702536231,171.9157039405018 -42.238021884604812,171.916129039198239 -42.250655142031015,171.889512601450207 -42.250400502527846,171.889084457509199 -42.238243702536231)) Author last name Last name of the Author Rayner Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? BSc(Hons) Advisers Who supervised/advised this student Mackenzie, D. Abstract The Abstract for this thesis The Reefton Goldfield produced over 67 tonnes of gold between 1870 and 1951 and was the largest gold producer on the West Coast of the South Island of New Zealand. Current Mining operations run by Oceana Gold Limited commenced in 2007 at the Globe-Progress deposit. Mining currently operates in four open cut pits; the Globe-Progress, General Gordon, Empress and Supreme and is expected to produce 455,000 ounces of gold over 7 years. The Big River deposit was mined historically between 1882 and 1942, producing over 130,000 ounces of gold at an average grade of 34 g/t. Gold was recovered from a number of quartz rich reefs which were successfully worked with some grades reported as high as 63.7 g/t. The ore body was not exhausted however and although Big River was one of the largest producers in the goldfield there is no good description on the style and distribution of mineralisation. The Big River deposit is hosted within the Big River Shear Zone (BRSZ), which is hosted on the limb of the Big River anticline. Early quartz veins, deposited during/ soon after peak metamorphism (~400°C) were deformed in association with the regional folding of the goldfield, which produced upright N-NE trending folds (F2). The quartz veins accommodated deformation through dynamic recrystallisation at temperatures of ~355°C, with a flow stress of 83.9 ± 25 Mpa. Continued deformation is marked by the transition from ductile-brittle deformation of quartz veins below temperatures of 280°C. Brecciation of quartz veins is associated with the deposition of acicular arsenopyrite seams, pyrite veins and disseminated pyrite + arsenopyrite ± gold. Further decrease in deformation temperature resulted in the brecciation of pyrite veins and deposition of galena and ankerite veins with associated sericite wallrock alteration. Pyrite vein deformation also resulted in symmetric micro-folding of veins associated with a pressure solution crenulation cleavage formation (S4) with axial plane-parallel white calcite veins. The calcite veins were deformed at temperatures between 250°C and 200°C, with a differential stress of 239 Mpa. Chalcopyrite-sphalerite-pyrite bearing calcite veins were deformed at temperatures below 180°C, with a differential stress of 196 Mpa. Late stage gold + arsenopyrite + stibnite in-filled at shallow crustal levels associated with the exhumation of the BRSZ. Fine–grained disseminated gold is associated with acicular arsenopyrite and pyrite hosted within breccia zones. Visible gold is inter-grown with arsenopyrite with associated stibnite which infill fractures. Cu-Pb-Zn ± Mo + Ag anomalies indicate a magmatic fluid component at some stage during the evolution of the BRSZ (371Ma?) Early regional compression of Big River produced shear zone hosted mesothermal gold deposits with associated pyrite and arsenopyrite, hosted within upright to steeply inclined folds. As regional deformation continued, early structures were reactivated and new structures formed at new orientations discordant to previous structures. It is possible an influx of magmatic hydrothermal fluids associated with the rapid intrusion of the Karamea suite produced a relatively late stage of epithermal-style gold–stibnite ± Mo mineralisation. Late stage mineralisation (arsenopyrite + stibnite + gold) was introduced at shallow levels during Cretaceous exhumation. 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. 165 pages : illustrations, maps ; 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 2011Rayner Creator An entity primarily responsible for making the resource Rayner, Anthony James Date A point or period of time associated with an event in the lifecycle of the resource 2011 Title A name given to the resource Structural geology and paragenesis of the Big River shear zone, Reefton goldfield, South Island, New Zealand Subject The topic of the resource Map Structural geology Reefton goldfield shear zone. Structural geology https://theses.otagogeology.org.nz/files/original/4aa1c0f4ba660f9d80328f4506c689e4.pdf f880c6be46d9fe9ab2d5b74164c089e6 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 Henne Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? BSc(Hons) Advisers Who supervised/advised this student MacKenzie, D. Abstract The Abstract for this thesis The Fiddlers Flat section is a steep gorge cut into basement rocks and Tertiary sediment cover by the Manuherikia River downstream of Falls Dam in Central Otago, New Zealand. The river section exposes little-metamorphosed Torlesse Terrane sediments and their metamorphic equivalent, the Otago Schist with textural grades I, IIA, liD and Ill. Sediments overlying the Miocene unconformity that cut into the basement schist host a famous vertebrate fossil locality. The project uses field observations, petrography and geochemistry to produce a detailed structural section through the Otago schist margin exposed along the Fiddlers Flat section. This provides a structural setting for the aforementioned Miocene fossil locality and tests the hypothesis that argillite serves as a precursor to gold-bearing schist such as that which hosts the Macraes mine. The study area is ideal for this, because it contains all the typical structural characteristics of the metamorphosed Torlesse Terrane and provides a section showing a gradual increase in textural zone towards higher metamorphic grade Otago Schist in the SW. The geochemical composition of pelitic rocks from all textural zones at Fiddlers Flat, compared to unmineralised schist from Macraes and Oturehua, suggests that the unmineralised schist is Torlesse-derived. The geochemical comparison of Fiddlers Flat mineralised pelitic rocks with mineralised schist from Macraes identified some correlation but clearly indicated that Macraes rocks underwent an additional alteration process and/or mineralisation. Furthermore, Fiddlers Flat meta-pelites display two features characteristic of nearby gold-deposits: (1) post-metamorphic ankeritic alteration associated with argillitic material is similar to hydrothermal alteration occurring at Oturehua and (2) the high graphite content is similar to that found in Macraes intrashear schist. However, Macraes graphite is post-metamorphic while graphite at Fiddlers Flat was added pre- or syn-metamorphic and has distinctly higher values (up to 11.91 wt.%). Observations of changes in the textures and the amount of pyrite and graphite with increasing strain are used to make inferences about possible protolith-hydrothermal fluid interactions. 111 ,, ' il ! I The results of this study highlight that structural and chemical properties of rocks are important for post-diagenetic Au-mineralisation. These properties include (1) high permeability and (2) graphite enrichment. Two lithologies at Fiddlers Flat have these properties: a sheared TZ IIA meta-pelite and a pyrite-rich TZ liB meta-pelite. Both lithologies localise graphitisation, sulphidation, ankeritic alteration and tectonic deformation. The occurrence of graphitised TZ IIA rock and ungraphitised TZ IIA rock within a single complex tectonosome is the first genetic link between lithologies altered by graphite. Argillaceous rocks at Fiddlers Flat are structurally weak and chemically highly reactive and therefore more favourable for hydrothermal alteration than any other lithology observed. Data presented in this dissertation suggest that the protolith of Macraes mineralised micaceous schist may be genetically related to argillites of the Torlesse Terrane and that a complex interplay ofprotolith-fluid interaction is necessary in order to precipitate minerals. Department The department where the student is studying primarily. Geology Named locality Named locality describing the field area location. Manuheriikia River Thesis description Number of pages, maps, CDs, etc. ix, 195, [14] 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/. Identifier An unambiguous reference to the resource within a given context 2010Henne Creator An entity primarily responsible for making the resource Henne, Anicia Ingrid Date A point or period of time associated with an event in the lifecycle of the resource 2010 Title A name given to the resource Structural evolution of the north-eastern Otago schist margin, New Zealand Subject The topic of the resource Petrology geochemistry gold Otago Schist Torlesse Terrane https://theses.otagogeology.org.nz/files/original/532f127a9c8bc9fd9295f7781f6031a9.pdf c111fac0a35904a2d5a4258c7e4cadf5 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 Mackie Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? BSc(Hons) Advisers Who supervised/advised this student Craw, D. Mackenzie, D. Palin, J.M. Abstract The Abstract for this thesis North Rough Ridge is a northeast trending Quaternary asymmetric antiform which folds the regional unconformity of the Otago Schist and overlying sediments. The schist foliation of the ridge is a dome like structure, formed by several postmetamorphic generations of deformation. Historically mined gold bearing veins occurring near Oturehua lie at the northern end of the ridge. The host rock is lower greenschist facies textural zone m schist, which has interlayered laminated and massive lithologies. Approximately 50 veins occur in the vein swarm, with northwest strike, commonly at 3200 but with a range of orientations 275 - 324°. The veins formed in extensional sites along - 1 m wide normal fault zones and are steeply dipping, mainly to the northeast. Individual vein fault zones can be traced from- 50- 650 m, with variable thickness along strike. Vein thicknesses typically range from a few mm- 20 cm over 1-5 m along strike, with the greatest thickness seen- 1 m where fault zones steepen. Early Cretaceous mm - cm scale kink folds with northwest trending axes, subparallel to vein strike, occur in adjacent schist and are cross-cut by the mineralised veins. Quartz veins preferentially formed in weak kink folded schist. The quartz in the veins is dominated by intergrown quartz crystals and schist fragments, and some cavities with prismatic quartz crystals occur locally. Euhedral arsenopyrite occurs in quartz veins and impregnates immediate host rock up to 10 cm from veins. Arsenopyrite rich fault gouge of around 1 cm thick envelopes some veins. Veins and minor replacement of schist by ankerite and local silicification occur in host rocks, particularly in laminated lithologies. Gold occurs in sulphides and as < 0.5 mm free grains in the quartz veins. Gold analyses up to 75 ppm have been obtained from spot samples, and arsenopyrite grains have gold contents up to 1031 ppm. A broad alteration zone tens of metres wide comprising pyrite and ankerite surrounds the mineralised zones. Mineralisation occurred at - 293 - 350 °C. The mineralised structures at Oturehua appear to be similar to well-defined Otago quartz vein swarms such as seen at Nenthorn and Barewood, and have few similarities with the shallowdipping mineralised shear zone at Macraes mine. Department The department where the student is studying primarily. Geology Named locality Named locality describing the field area location. Oturehua Thesis description Number of pages, maps, CDs, etc. v, 122, [5] leaves, : col. 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/. Identifier An unambiguous reference to the resource within a given context 2008Mackie Creator An entity primarily responsible for making the resource Mackie, Claire. Date A point or period of time associated with an event in the lifecycle of the resource 2008 Title A name given to the resource Structure and mineralisation of gold-bearing quartz veins at Oturehua, Central Otago, New Zealand Subject The topic of the resource Mineralogy Structural geology Metal-ore deposits gold-bearing quartz quartz