Geology of the Lake Ohau ski-basin, South Canterbury, New Zealand.

Author:

Hicks, Murray Darryl.

Year:

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Abstract:

The basement metasediments outcropping in the lake Ohau Ski-Basin and its adjacent valleys are regionally included within the Torlesse (Greywacke) Zone of the Alpine Assemblage. The general geology of the area is described, although an emphasis is placed on sedimentological description and interpretation.
A geological map and cross-section, and several measured stratigraphic sections which span the area from East to West, are presented.
The individual beds of the sedimentary pile are assigned to one of seven facies; each type of the first six facies reflects one or more of the depositional processes included within the spectrum of gravity induced subaqueous mass-transport phenomena, and includes the products of synsedimentary slumping, debris, inertia or turbidity flows; while the seventh facies includes finer sediments attributable to the hemipelagic rain on an ocean floor. Associations of these facies suggest that sedimentation occurred in various depositional environments on a submarine fan system. Suites of facies associations reflect the meandering, progradation, or recession of the main axes of sediment dispersal over the fan complex.
Paleocurrent and paleoslope indicators support this model and suggest that the fan sloped up eastwards to a continental foreland.
Chemical analyses and detrital modes of the sand lithologies require this continental source area to be typically acid-plutonic.
The steeply dipping basement strata are shattered by numerous faults of variable significance, 'while the steeply plunging anticlinal structure which encompasses most of the area is fractured by a N-S fault along its axial plane, and is inferred to be a drag consequence of right-lateral movement along the Ohau Fault; this latter fault is probably of regional significance.
The ยท sedimentary pile has undergone law grade regional metamorphism, and a central N-S isograd separates the rocks of the prehnite-pumpellyite facies in the east from those of the pumpellyite-actinolite facies to the west. The effects of retrogressive metamorphism are apparent from abundant veining.

Named Localities:

Thesis description:

169 p. : illus. (part. col.), maps (3 in pocket) ; 30 cm.

Department:

OU geology Identifier:

1975Hicks

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Location (WKT, WGS84):

POLYGON ((169.803594890000113 -44.225788889999933,169.826090929000088 -44.226251593999962,169.824518099000102 -44.253044059999979,169.802095701000098 -44.252426663999984,169.749140418000025 -44.250950823999972,169.750696976000086 -44.229391171999964,169.774375911000106 -44.209205613999984,169.795843405000028 -44.209755543999961,169.794943217000082 -44.225609741999961,169.803594890000113 -44.225788889999933))

Files

http://download.otagogeology.org.nz/temp/Abstracts/1975Hicks.pdf

Collection

Citation

Hicks, Murray Darryl., “Geology of the Lake Ohau ski-basin, South Canterbury, New Zealand.,” Otago Geology Theses, accessed February 8, 2025, https://theses.otagogeology.org.nz/items/show/84.

Output Formats