Geology of the Southern Skippers Range, N.W. Otago.
Year:
Project type:
Advisers:
Abstract:
A sequence of Permian metavolcanic and metasedimentary rocks of the Alabaster Group, with associated intrusives, have been mapped in the southern Skippers Range. Layered rocks arc generally steeply dipping, and most contacts are fault bounded.
The Eglinton Sub Group - a largely shallow water or sub-aerial sequence - consists mainly of porphyritic metabasic lavas, volcanic breccias and metabasic (and meta-andesitic) dykes of the Mantle Volcanics. Greenstone, tuffaceous breccia and finely bedded, locally hornfelsed, sediments of the Hidden Flats Greenstone are intruded by quartz diorite and granodiorite of the Mackay Intrusives. The Camp Conglomerate, a probable river channel deposit, overlies a small part of' the Mackay Intrusives in the south-western part of the present area. Most of the Mantle Volcanics hove been metamorphosed to prehnite-pumpellyite facies - some may be verging on the pumpellyite-actinolite facies.
To the west, and separated from the Eglinton Sub Group by the Wilmot Fault, is the Skippers Sub Group - here formally upgraded from formational status.
The Skippers Sub Group comprises the Slabby Peak Schist - a metasedimentary sequence of semi-schist with local amphibolitic inclusions; the Lone Stag Layered Complex - a largely deformed originally layered basic and ultrabasic intrusion; and the Hokuri Dykes- a meta-ankaramitic and meta-andesitic,complex dyke swarm. These rocks have been metamorphosed to greenschist facies, and some may be transitional to albite-epidote amphibolite facies.
The Darran·Complex crops out in the far north-west of the area,in fault contact with the Skippers Sub Group. Albite-epidote hornfels rafts are common in these rocks.
Alkali analyses are reported and their significance discussed.
The Mantle Volcanics are envisaged as part of R Permian arc along the western margin or the New Zealand Geosyncline. The arc supplied sedimentary debris to a basin where the parent sediments or the Slabby Peak Schist occur. This basin may possibly be compared with an extensional interarc basin similar to those developed in present day island arcs. Intrusion of the Lone Stag Layered Complex and the extensive swarm of Hokuri Dykes may be genetically related to the orig1n of the proposed extensional basin.
The Eglinton Sub Group - a largely shallow water or sub-aerial sequence - consists mainly of porphyritic metabasic lavas, volcanic breccias and metabasic (and meta-andesitic) dykes of the Mantle Volcanics. Greenstone, tuffaceous breccia and finely bedded, locally hornfelsed, sediments of the Hidden Flats Greenstone are intruded by quartz diorite and granodiorite of the Mackay Intrusives. The Camp Conglomerate, a probable river channel deposit, overlies a small part of' the Mackay Intrusives in the south-western part of the present area. Most of the Mantle Volcanics hove been metamorphosed to prehnite-pumpellyite facies - some may be verging on the pumpellyite-actinolite facies.
To the west, and separated from the Eglinton Sub Group by the Wilmot Fault, is the Skippers Sub Group - here formally upgraded from formational status.
The Skippers Sub Group comprises the Slabby Peak Schist - a metasedimentary sequence of semi-schist with local amphibolitic inclusions; the Lone Stag Layered Complex - a largely deformed originally layered basic and ultrabasic intrusion; and the Hokuri Dykes- a meta-ankaramitic and meta-andesitic,complex dyke swarm. These rocks have been metamorphosed to greenschist facies, and some may be transitional to albite-epidote amphibolite facies.
The Darran·Complex crops out in the far north-west of the area,in fault contact with the Skippers Sub Group. Albite-epidote hornfels rafts are common in these rocks.
Alkali analyses are reported and their significance discussed.
The Mantle Volcanics are envisaged as part of R Permian arc along the western margin or the New Zealand Geosyncline. The arc supplied sedimentary debris to a basin where the parent sediments or the Slabby Peak Schist occur. This basin may possibly be compared with an extensional interarc basin similar to those developed in present day island arcs. Intrusion of the Lone Stag Layered Complex and the extensive swarm of Hokuri Dykes may be genetically related to the orig1n of the proposed extensional basin.
Named Localities:
Thesis description:
100 Leaves : illus, photos, diagms, map (folded in pocket); 27 cm.
Department:
OU geology Identifier:
1971Nauman
OURArchive handle:
OURArchive access level:
Location (WKT, WGS84):
POLYGON ((168.027566626415876 -44.451874879108956,168.022912483185223 -44.444049821895504,168.134844702115259 -44.377429258361822,168.218511937986307 -44.467193213073777,168.16143131753941 -44.561962173317518,168.058608899096896 -44.556596423622764,168.027566626415876 -44.451874879108956))
Files
Collection
Citation
Nauman, CR, “Geology of the Southern Skippers Range, N.W. Otago.,” Otago Geology Theses, accessed October 5, 2024, https://theses.otagogeology.org.nz/items/show/54.