Document Type

Article

Publication Title

Geological Magazine

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Publication Date

1-1-1998

First Page

63

Last Page

69

Issue Number

1

Volume Number

135

Abstract/ Summary

Two Proterozoic terranes with different metamorphic histories are distinguished from geological mapping in southwestern Wedel Jarlsberg Land: a northern greenschist facies terrane and a southern amphibolite facies terrane which has been overprinted by greenschist facies metamorphism. To better characterize the tectonothermal history of these terranes we have obtained new Ar-40/Ar-39 mineral dates from this area. A muscovite separate from the northern terrane yielded a Caledonian plateau age of 432 +/- 7 Ma. The southern terrane yielded significantly older Ar-40/Ar-39 ages with three muscovite plateau dates of 584 +/- 14 Ma, 575 +/- 15 Ma, and 459 +/- 9 Ma, a 484 +/- 5 Ma biotite plateau date, and a 616 +/- 17 Ma hornblende plateau date. The oldest thermochronological dates are over 300 Ma younger than the age of amphibolite facies metamorphism and therefore probably do not represent uplift-related cooling. Instead, the Vendian dates correlate well with a regionally widespread magmatic and metamorphic/thermal resetting event recognized within Caledonian complexes of northwestern Spitsbergen and Nordaustlandet. The apparent Ordovician dates are interpreted to represent partial resetting, suggesting that late Caledonian greenschist facies overprinting of the southern terrane was of variable intensity.

Citation/Publisher Attribution

Manecki, M, Holm, DK, Czerny, J, and Lux, D, 1998, Thermochronological Evidence for Late Proterozoic (Vendian) Cooling in Southwest Wedel Jarlsberg Land, Spitsbergen: Geological Magazine, v. 135, p. 63-69. Available on publisher's site at: http://geolmag.geoscienceworld.org/content/135/1/63.short

Publisher Statement

© Copyright 1998 by Cambridge University Press

DOI

10.1017/S0016756897008297

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publisher's version of the published document

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