1 10 1 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