https://theses.otagogeology.org.nz/files/original/078bc9f23e6cb11708c6d9c817928a68.pdf 74660ae6c3d5a49c5c1019ff62332498 Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource Geology theses OU Geology thesis Thesis or dissertation completed by University of Otago Geology students Location WKT (WGS84) The location stored in WKT (WGS84) format POLYGON ((168.695383064295214 -44.076183822893192,168.682754829705431 -44.175747156909011,168.516629375248129 -44.325706666010838,168.394390677442203 -44.418331331094649,168.391846944000122 -44.443665283999948,168.391641991000029 -44.445802278999963,168.391094758000122 -44.451548977999941,168.383070005000036 -44.535557703999984,168.382384017000078 -44.542727503999963,168.375527746000103 -44.614295081999963,168.369322453000137 -44.678916898999937,168.341084639000115 -44.677791523999971,168.31832879500007 -44.676882088999939,168.305748789000091 -44.676374385999964,168.219500712000013 -44.672869976999934,168.205134337000118 -44.672281321999947,168.192562717000129 -44.671761318999984,168.144562825000122 -44.669772776999928,168.118461907000096 -44.668681669999948,168.044872859000066 -44.66557522799998,168.041641110000114 -44.665435917999972,168.042795005644592 -44.649493611320636,167.976096383347141 -44.646559110303535,168.022543535145218 -44.243449710642395,168.028035652257358 -44.179677295880992,168.246533809614533 -44.189297931019411,168.326929887161242 -44.158310369548545,168.351135560000102 -44.134107501999949,168.392503818000051 -44.0926862699999,168.393093243000067 -44.092095550999929,168.416748730000137 -44.068375623999934,168.545702912381643 -44.073521735834134,168.548043826945189 -44.072610792668229,168.695383064295214 -44.076183822893192)) Author last name Last name of the Author Sinton Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? PhD Advisers Who supervised/advised this student Coombs, D.S. Abstract The Abstract for this thesis The Red Mountain area includes a portion of the Dun Mountain Ophiolite Belt, a linear feature which is exposed for at least 170 km in the southern part of South Island New Zealand. Along most of its strike, the Dun Mountain belt occurs as a series of melanges and tectonic slices with complex structural relationships between mafic and ultramafic lithologies. In contrast, the Red Mountain area comprises a relatively coherent ophiolite sequence in fault contact with surrounding metasedimentary and metavolcanic units. Structurally the area is dominated by the influence of three major fault systems which are subparallel in this region. The Livingstone Fault System comprises the Livingstone and Peanut Faults; the former separates Red Mountain Ultramafites from Haast Schist and the latter separates the Livingstone Subgroup from Red Mountain Ultramafites. Several fairly recent faults are correlated with the Hollyford Fault System. The main Alpine Fault Zone does not occur within the main map area, but some of the faults in the area may be related to this system. The lowest part of the ophiolitic sequence is made up of harzburgitic peridotite with foliated metamorphic tectonite texture. Compositional layering defined by variation in pyroxane/olivine ratio is locally well-developed. Ultramafic dikes and veins are common throughout the peridotite mass; dunite dikes commonly have chromite concentrated along the central zones of the dikes. Mineral compositions are strikingly constant for individual lithologies throughout the ultramafic body and conventional cryptic variation was not observed, even across well-layered iv sequences. Olivine in harzburgite ranges from Fo 90.2-91.2 and up to Fo 92.8 in harzburgitic dunite. Olivine in dunite dikes ranges up to Fo 96. Orthopyroxene in harzburgite is uniform in composition in the range En 90.8-91.6. Harzburgitic dunite orthopyroxenes are more magnesian, at En 91~5-92.2, than those of harzburgite and , as with olivine, orthopyroxene in an orthopyroxenite dike is slightly more magnesian than in harzburgite. Clinopyroxene is even more constant in composition than is orthopyroxene. Mg/(Mg + Fe) ratios in harzburgite and harzburgitic dunites are not significantly different in the range 93.4-94.6. Interstitial clinopyroxene in the orthopyroxenite dike is more magnesian, as is accessory diopside in olivine chromitite. Compositions of chrome spinel are more variable than those of the other phases in the peridotite. Cationic Cr/(Cr + Al + Fe 3+) varies from 0.82 to 0.27. Al 2o3 varies antipathetically with Cr 2o3 but sympathetically with Mg/(Mg + Fe 2+ -2Ti) of spinel in harzburgites and harzburgitic dunites. Al 2o 3 is highest in spinels which coexist with the most aluminous pyroxenes and the evidence suggests that the Al 2o3 content of pyroxenes and the MgAl 2 o 4 content of spinels vary as a function of the bulk alumina of the host rocks. There is no obvious correlation of Mg/Fe with Al/Cr of spinels in dunite dikes; this may reflect a range of equilibration conditions for the dunite dikes. Olivine grains are completely homogeneous but pyroxene and spinel have narrow compositional rims. Both ortho- and clinopyroxene rims are consistently lower in Al 2 o 3 and Cr 2 o 3 relative to cores. Lower alumina rims of clinopyroxene also have higher Mg/(Mg + Fe) than associated cores. Orthopyroxene rims are relatively depleted in Ca/(Ca + Mg + Fe). The pyroxene rims can be V explained by decreased solubilities of Ca-Tschermak and opx components in clinopyroxene and mainly CaTs component in orthopyroxene in response to falling temperature. There are two types of compositional rims on spinal. Earlier rims are enriched in Al 2o3 relative to cores and probably also formed in response to a decrease in temperature. Later rims, rich in magnetite and chromite components, locally obliterate the earlier rims and can be related to low temperature hydrothermal alteration. Fe-Mg and Al 2 0 3 partitioning between silicates and spinal indicate that mineral cores equilibrated at slightly higher temperatures than the mineral rims. Application of the geothermometers of Wood and Banno (1973) and of Jackson (1969) indicate temperatures- of the main equilibration (cores) were in the range 1000- 1050 OURArchive handle The handle from the Otago University Research Archive (OURArchive) <a href="http://hdl.handle.net/10523/3491">http://hdl.handle.net/10523/3491</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. Red Mt (Fiordland) Thesis description Number of pages, maps, CDs, etc. 300 leaves : illus. (part col.) ; 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 1975Sinton Creator An entity primarily responsible for making the resource Sinton, John Maynard. Date A point or period of time associated with an event in the lifecycle of the resource 1975 Title A name given to the resource Structure, petrology and metamorphism of the Red mountain ophiolite complex, New Zealand. Subject The topic of the resource Map Mineralogy Igneous petrology Metamorphic geology harzburgitic peridotite Humboldt Group Livingstone Subgroup peridotite Red Mountain Ophiolite