Universität zu Köln

Fassmer, K., Martinet, I, Miladinova, I, Sprung, P., Froitzheim, N., Fonseca, R. O. C., Muenker, C., Janak, M. and Kullerud, K. (2020). Lu-Hf geochronology of ultra-high-pressure eclogites from the Tromso-Nappe, Scandinavian Caledonides: evidence for rapid subduction and exhumation. Int. J. Earth Sci., 109 (5). S. 1727 - 1743. NEW YORK: SPRINGER. ISSN 1437-3262

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Abstract

Geochronology of ultra-high-pressure metamorphic rocks is able to constrain the timing and rates of subduction-zone processes. Lu-Hf garnet dating has the potential to yield information about the timing of the prograde evolution of subducting rocks under increasing pressure. In combination with other methods, it thus allows constraining the complete P-T-t path with high precision. Ultra-high-pressure eclogites from the Tromso Nappe, the structurally highest tectonic unit of the Scandinavian Caledonides in northern Norway, were dated using Lu-Hf geochronology on garnet. A sample from Tromsdalstind yielded an age of 448.3 +/- 3.6 Ma, interpreted as dating prograde garnet growth due to preserved zoning in the major-element and Lu contents of garnet grains. A sample from the diamond-bearing locality Tonsvika yielded an identical age of 449.4 +/- 3.3 Ma. Garnet from this sample shows a weak zoning in Ca content and near-homogeneous Lu content. These ages are identical within error among each other and with published U-Pb ages of peak-eclogite-facies zircon and rutile/titanite from exhumation-related leucosome veins. Consequently, the entire subduction-exhumation cycle leading to the ultra-high-pressure eclogites lasted only very few millions of years during the Late Ordovician.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Fassmer, K. UNSPECIFIED UNSPECIFIED UNSPECIFIED Martinet, I UNSPECIFIED UNSPECIFIED UNSPECIFIED Miladinova, I UNSPECIFIED UNSPECIFIED UNSPECIFIED Sprung, P. UNSPECIFIED UNSPECIFIED UNSPECIFIED Froitzheim, N. UNSPECIFIED UNSPECIFIED UNSPECIFIED Fonseca, R. O. C. UNSPECIFIED UNSPECIFIED UNSPECIFIED Muenker, C. UNSPECIFIED UNSPECIFIED UNSPECIFIED Janak, M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Kullerud, K. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-335733
DOI:	10.1007/s00531-020-01866-0
Journal or Publication Title:	Int. J. Earth Sci.
Volume:	109
Number:	5
Page Range:	S. 1727 - 1743
Date:	2020
Publisher:	SPRINGER
Place of Publication:	NEW YORK
ISSN:	1437-3262
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language WESTERN GNEISS REGION; UHP METAMORPHISM; UPPERMOST ALLOCHTHON; BEARING ECLOGITE; HP METAMORPHISM; COMPLEX; ROCKS; EXAMPLE; PROGRADE; KYANITE Multiple languages Geosciences, Multidisciplinary Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/33573