1 10 1 https://theses.otagogeology.org.nz/files/original/a35c4d7120ba6360e3d4b4843a9c1a88.pdf 31bfb8c8d76f1213e08788d52f012aaf 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 ((169.866396627725351 -45.133923088606338,169.871963387087959 -45.124429863111018,169.892429392666003 -45.128561705121918,169.87646731121842 -45.162065329313592,169.852559779917243 -45.156049465566348,169.866396627725351 -45.133923088606338)) Author last name Last name of the Author Stewart Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? PGDipSci Advisers Who supervised/advised this student Craw, D. McKenzie, D. Abstract The Abstract for this thesis A set of more than 30 mineralised normal faults and associated fractures cuts upper greenschist facies textural zone 4 Otago Schist between the North Rough Ridge and Rough Ridge drainage divides near Garibaldi Diggings, Central Otago. The mineralised structures strike northeast and dip steeply (60•) to the northwest. The zone of mineralisation is intense and occurs as a swarm of veins within a well defined area under 1 km2. Mineralised structures contain 1 cm to 1.8 m thick quartz veins which are traceable as an intricate network of structures for several meters along strike. In the near surface the mineralised structures are hosted within a thick zone of kaolinitized greenschist which developed beneath a regional unconformity surface and an overlying suite of auriferous terrestrial sediments. The thick zone of alteration forms a low northeast trending ridge and is heavily stained by secondary iron and manganese oxides. The source of the iron oxides may be due to the breakdown of iron bearing sulphide minerals within the mineralised structures or the oxidation of associated hydrothermal ankerite. Alternatively the breakdown of chlorite within the westerly dipping greenschist layer could also provide a source for the iron oxides. Quartz veins contain abundant breccias with variably altered clasts of quartzofeldspathic schist. The veins contain sparsely distributed scheelite mineralisation although no sulphide minerals can be observed in hand specimen due to the intense alteration within the host greenschist layer. Hydrothermal alteration of the host greenschist layer adjacent to veins cannot be differentiated from alteration developed beneath the regional unconformity surface due to the pervasive nature of this alteration. The normal faults and associated fractures of the Garibaldi vein swarm developed during middle to late Cretaceous extension whicih accompanied the uplift and exhumation of the Otago Schist belt. The vein swarm at Garibaldi may share affinities with the Manuherikia Fault Zone; a major northeast striking fault zone on the east side of the Manuherikia Valley, Central Otago. Detrital gold grains collected from both the Miocene and Quaternary paleoplacers at Garibaldi Diggings have secondary gold structures preserved on their surface. There is a consistency in morphology and surface textures displayed by detrital gold grains collected from the Garibaldi and Dell Creek placer deposit in the Lower Nevis Valley, Central Otago. The Garibaldi and Dell Creek placer deposits represent two separate parts of the Central Otago alluvial gold system. Department The department where the student is studying primarily. Geology Named locality Named locality describing the field area location. Garibaldi goldfield Thesis description Number of pages, maps, CDs, etc. 79 pages : illustrations, maps, 2 folded maps and 4 sheets in pocket ; 30 cm. + 1 CD-ROM (4 3/4 in.) 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 2012Stewart Creator An entity primarily responsible for making the resource Stewart, James Alistair Date A point or period of time associated with an event in the lifecycle of the resource 2012 Title A name given to the resource Characteristics of gold bearing quartz veins at the historic Garibaldi goldfield, Central Otago, New Zealand Subject The topic of the resource Map structural geology central Otago alluvial gold Garibaldi goldfield gold