sedimentary geochemistry; isotopic geochemistry; Nd and Pb isotopes; North Atlantic Ocean; sedimentary supplies; paleoceanography; deep circulation
Abstract :
[en] Pb isotopes have been measured in the clay-size fraction of Late Glacial and Holocene deep-sea sediments recovered from two Labrador Sea piston cores that have been previously analyzed for Nd isotopes. The newly acquired Pb isotopic data allow us to better constrain the different source areas that supplied clay-size material during the last deglaciation, until 8.6 kyr (calendar ages). Nd-Pb data can be modeled mainly as a mixture between a Precambrian crust and Lower Palcozoic material originating from the denudation of the pan-African orogen. The old material originates mainly from the Archean, Lower Proterozoic, or both terranes of Greenland (and also probably corresponding terranes of Labrador), although minor input of other Precambrian material is recorded in some detrital carbonate-rich deglacial samples from Orphan Knoll. The Phanerozoic crustal end member consists of sediment material mainly originating from northwestern Europe. This source area is found to be the only significant source of young crustal material in early Holocene sediments from the Greenland Rise. No significant input from the mid-Atlantic volcanism is apparent. This study puts further constraints on the deep circulation pattern during the last deglaciation. It is concluded that at that time, European Phanerozoic material was carried from the Norwegian Sea through the Wyville Thompson Ridge into the Iceland Basin by the North East Atlantic Deep Water. No evidence for an overflow is found either south of the Iceland (Iceland-Scotland Ridge) or through the Denmark Strait. Copyright (C) 2002 Elsevier Science Inc.
Research center :
GEOTOP, UQAM, Canada
Disciplines :
Earth sciences & physical geography
Author, co-author :
Fagel, Nathalie ; Université de Liège - ULiège > Département de géologie > Géochim. sédiment. - Sédiment. mar. & continent. du quatern.
Innocent, Christophe
Gariepy, Clément
Hillaire-Marcel, Claude ; Université de Liège - ULiège > Géochim. sédiment. - Sédiment. mar. & continent. du quatern.
Language :
English
Title :
Sources of Labrador Sea sediments since the last glacial maximum inferred from Nd-Pb isotopes
Publication date :
July 2002
Journal title :
Geochimica et Cosmochimica Acta
ISSN :
0016-7037
eISSN :
1872-9533
Publisher :
Pergamon-Elsevier Science Ltd, Oxford, United Kingdom
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