Ovenshine, A. T. and Andrews, P. B. (1975): Petrography and age of quartz-muscovite-chlorite semischist, Site 281, South Tasman Rise

Leg/Site/Hole:
DSDP 29
DSDP 29 281
Identifier:
1976-016993
georefid

10.2973/dsdp.proc.29.140.1975
doi

Creator:
Ovenshine, A. T.
U. S. Geol. Surv., Menlo Park, Calif., United States
author

Andrews, P. B.
author

Identification:
Petrography and age of quartz-muscovite-chlorite semischist, Site 281, South Tasman Rise
1975
Initial Reports of the Deep Sea Drilling Project
Texas A & M University, Ocean Drilling Program, College Station, TX, United States
29
Lyttleton, N. Z. to Wellington, N. Z.; March-April 1973
1117-1121
Drilling at Site 281 on the South Tasman Rise recovered fragments of carbonaceous quartz-muscovite-chlorite semischist. The schist was developed by very low-grade regional metamorphism (greenschist facies) of a sedimentary rock that was poorly sorted and quartz rich. An average of two whole-rock potassium-argon ages of the semischist is 306 + or - 10 m.y. Analysis of the drilling record strongly suggests that semischist bedrock was reached at 159.5 m and was penetrated to a depth of 169.0 m. The results establish the continental nature of the crust underlying the South Tasman Rise. The semischist at Site 281 may correlate with the Cambrian-Precambrian Robertson Bay Group of Northern Victoria Land, Antarctica. A reconstruction of the Australo-Antarctic part of Gondwanaland that places the South Tasman Rise near Victoria Land leads to significant overlap in the Ross Sea area. Following the suggestion of Hayes and Ringis (1973), this overlap can be eliminated by restoring approximately 400 km of left lateral movement between east and west Antarctica.
English
Coverage:Geographic coordinates:
North:-30.0000
West:145.0000East: 174.3000
South:-51.0000

Igneous and metamorphic petrology; absolute age; chlorite; chlorite group; dates; Deep Sea Drilling Project; DSDP Site 281; framework silicates; K/Ar; Leg 29; low-grade; marine geology; metamorphic rocks; metamorphism; mica group; movement; muscovite; Pacific Ocean; Paleozoic; petrography; petrology; plate tectonics; quartz; reconstruction; schists; sheet silicates; silica minerals; silicates; South Pacific; South Tasman Rise; Southwest Pacific; southwest; Tasman Sea; upper Paleozoic; West Pacific; whole rock;

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