Universität zu Köln

Szilas, Kristoffer ORCID: 0000-0002-5541-306X, Hoffmann, J. Elis ORCID: 0000-0001-6670-1393, Hansmeier, Christina, Hollis, Julie A., Muenker, Carsten, Viehmann, Sebastian ORCID: 0000-0001-6138-5862 and Kasper, Haino U. (2015). Sm-Nd and Lu-Hf isotope and trace-element systematics of Mesoarchaean amphibolites, inner Ameralik fjord, southern West Greenland. Mineral. Mag., 79 (4). S. 857 - 877. TWICKENHAM: MINERALOGICAL SOC. ISSN 1471-8022

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Abstract

Fragmented supracrustal rocks are typical components of Archaean high-grade gneiss terranes, such as those in the North Atlantic Craton. Here we present the first major, trace element and Nd-Hf isotope data for amphibolites collected in the yet poorly studied southern inner Ameralik fjord region of southern West Greenland. In addition, new U-Pb zircon ages were obtained from the surrounding TTG gneisses. Based on their trace-element patterns, two different groups of amphibolites can be distinguished. Following screening for post-magmatic alteration and outlying epsilon values, a reduced sample set defines a Sm-147/Nd-143 regression age of 3038 Ma +/- 310 Ma (MSWD = 9.2) and a Lu-176/Hf-176 regression age of 2867 +/- 160 Ma (MSWD = 5.5). Initial epsilon Nd-2970Ma values of the least-altered amphibolites range from 0.0 to +5.7 and initial epsilon Hf-2970Ma range from +0.7 to +10.4, indicating significant isotopic heterogeneity of their mantle sources with involvement of depleted domains as well as crustal sources. Surprisingly, the amphibolites which are apparently most evolved and incompatible element-rich have the most depleted Hf-isotope compositions. This apparent paradox may be explained by the sampling of a local mantle source region with ancient previous melt depletion, which was re-enriched by a fluid component during subduction zone volcanism or alternatively by preferential melting of an ancient pyroxenite component in the mantle source of the enriched rocks.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Szilas, Kristoffer UNSPECIFIED orcid.org/0000-0002-5541-306X UNSPECIFIED Hoffmann, J. Elis UNSPECIFIED orcid.org/0000-0001-6670-1393 UNSPECIFIED Hansmeier, Christina UNSPECIFIED UNSPECIFIED UNSPECIFIED Hollis, Julie A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Muenker, Carsten UNSPECIFIED UNSPECIFIED UNSPECIFIED Viehmann, Sebastian UNSPECIFIED orcid.org/0000-0001-6138-5862 UNSPECIFIED Kasper, Haino U. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-396813
DOI:	10.1180/minmag.2015.079.4.02
Journal or Publication Title:	Mineral. Mag.
Volume:	79
Number:	4
Page Range:	S. 857 - 877
Date:	2015
Publisher:	MINERALOGICAL SOC
Place of Publication:	TWICKENHAM
ISSN:	1471-8022
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language IVISAARTOQ GREENSTONE-BELT; SUBDUCTION ZONE PROCESSES; TARTOQ GROUP; CONTINENTAL GROWTH; NUUK REGION; GEOCHEMICAL EVIDENCE; ANORTHOSITE COMPLEX; SUPRACRUSTAL BELTS; OCEANIC-CRUST; ORIGIN Multiple languages Mineralogy Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/39681