Arrow Geology.
Year:
Project type:
Abstract:
Greenschists and micaceous greyschists of the Aspiring lithologic association in the Soho Creek/Arrow River area are mapped.
Two syn-metamorphic phases of deformation are recognised in the study area. The "initial" phase, Di, resulted in transposition of lithologic layering, formation of a pervasive foliation, S1, and metamorphic segregation laminae. The second, "dominant" phase, DD, resulted in mesoscopic and macroscopic folding of S1. Where Dominant Phase strain is high, a pervasive SD crenulation cleavage forms, and LD lineations are rotated by inferred high ductile shear strain. The high shear strain may be related to the westward thrusting of the Wanaka lithologic association over the Aspiring lithologic association.
Post-metamorphic flexural deformation resulted in the formation of a widespread microcrenulation, and scattered kink folding.
Faulting has occurred in the southern part of the study area, associated with hydrothermal activity which deposited quartz and calcite in open fissures.
Trace element geochemistry indicates an oceanic origin for metabasites in the study area. Most samples have tholeiitic, MORB character, while some have alkalic, within plate characteristics.
Cr-rich tremolite greenschists,may be a product of metasomatic alteration of serpentinites.
Two syn-metamorphic phases of deformation are recognised in the study area. The "initial" phase, Di, resulted in transposition of lithologic layering, formation of a pervasive foliation, S1, and metamorphic segregation laminae. The second, "dominant" phase, DD, resulted in mesoscopic and macroscopic folding of S1. Where Dominant Phase strain is high, a pervasive SD crenulation cleavage forms, and LD lineations are rotated by inferred high ductile shear strain. The high shear strain may be related to the westward thrusting of the Wanaka lithologic association over the Aspiring lithologic association.
Post-metamorphic flexural deformation resulted in the formation of a widespread microcrenulation, and scattered kink folding.
Faulting has occurred in the southern part of the study area, associated with hydrothermal activity which deposited quartz and calcite in open fissures.
Trace element geochemistry indicates an oceanic origin for metabasites in the study area. Most samples have tholeiitic, MORB character, while some have alkalic, within plate characteristics.
Cr-rich tremolite greenschists,may be a product of metasomatic alteration of serpentinites.
Named Localities:
Thesis description:
vii. 36 p. ill. Photos. Map (folded in pocket). 30 cm.
Department:
OU geology Identifier:
1987Ellery
OURArchive handle:
OURArchive access level:
Location (WKT, WGS84):
POLYGON ((168.900408295000034 -44.913655552999955,168.90027098500002 -44.915434782999967,168.890214950000086 -44.923332396999967,168.863697467000065 -44.922348715999931,168.857305445000065 -44.915673243999947,168.858342391000065 -44.903397092999967,168.858723615000031 -44.898905332999959,168.87424606400009 -44.889304015999983,168.891839924000124 -44.889798520999932,168.901190403000101 -44.903483283999947,168.900408295000034 -44.913655552999955))
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Collection
Citation
Ellery, SG, “Arrow Geology.,” Otago Geology Theses, accessed February 7, 2025, https://theses.otagogeology.org.nz/items/show/211.