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dc.contributor.advisorCoombs, Douglas S.
dc.contributor.authorBosel, Craig A.
dc.date.available2017-11-17T01:28:15Z
dc.date.copyright1981
dc.identifier.citationBosel, C. A. (1981). The geology of Bluff Hill, Southland, New Zealand. (Thesis, Bachelor of Science with Honours). University of Otago. Retrieved from http://hdl.handle.net/10523/7751en
dc.identifier.urihttp://hdl.handle.net/10523/7751
dc.descriptionDigital copy stored under Section 55 of the NZ Copyright act.en_NZ
dc.description.abstractThe mineralogy and structure of two gabbronorite intrusions forming Bluff Hill, is described. They intrude volcanogenic metasediments of the Greenhills Group and together comprise a segment of Brook Street terrane (Coombs et al., 1976), the inferred products of a Permian island arc environment. The Bluff Hill Gabbronorite is of arc-tholeiitic affinity and appears to represent the middle zones of a small south-west dipping pluton, the upper levels now removed by erosion. Mineralogical differences and a fractionation trend revealed by microprobe analysis of co-existing pyroxenes provide information on the structure and orientation of the pluton. The original magma was rather hydrous, as evidenced by the abundance of hornblende and the low temperatures (850° ± 100° C) obtained from co-existing pyroxene geothermometry. A convection current origin is put forward to explain several strongly flow-banded, thin xenolithbearing zones within the main mass. A segment of upper level Ocean Beach Gabbronorite, also of tholeiitic affinity,is described from Bluff Hill's western coast, which appears to post-date the Bluff Hill Gabbronorite. Later intrusives include several thick basaltic andesite (?) dykes, innumerable thin hornblende microgabbro veins and dykes, occasional hornblende pegmatite veins and diorite dykes. A Tertiary strandline deposit, the Foveaux Formation (new formation) is described. Its rich brachiopod and warm-water benthic foraminifera fauna would suggest a Waitakian to Otaian age. The cement consists largely of the zeolites thomsonite, gonnardite, and chabaz:Lte together with minor well-crystallized smectite and gibbsite.en_NZ
dc.language.isoenen_NZ
dc.publisherUniversity of Otago
dc.publisherUniversity of Otago
dc.titleThe geology of Bluff Hill, Southland, New Zealand.en_NZ
dc.typeThesis
dc.date.updated2017-11-17T01:27:47Z
thesis.degree.disciplineGeologyen_NZ
thesis.degree.nameBachelor of Science with Honoursen_NZ
thesis.degree.grantorUniversity of Otago
thesis.degree.levelHonours
otago.interloanyesen_NZ
otago.openaccessAbstract Onlyen_NZ
dc.rights.statementDigital copy stored under Section 55 of the NZ Copyright Act.
dc.rights.statementDigital copy stored under Section 55 of the NZ Copyright Act.
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