Sr, Nd, and Pb isotopes and trace element geochemistry of basalts from the Southeast Greenland margin

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doi: 10.2973/odp.proc.sr.163.122.1999
Author(s): Saunders, Andrew D.; Kempton, Pamela D.; Fitton, J. Godfrey; Larsen, Lotte Melchior
Author Affiliation(s): Primary:
University of Leicester, Department of Geology, Leicester, United Kingdom
Other:
Oregon State University, United States
Ocean Drilling Program, United States
Utsunomiya University, Japan
Université de Rennes I, France
RWTH Aachen, Federal Republic of Germany
Institut Méditerranéen de Technologie, France
University of Oregon, United States
Woods Hole Oceanographic Institution, United States
University of Edinburgh, United Kingdom
Université de Bretagne Occidentale, France
Washington State University, United States
Duke University, United States
Ohio State University, United States
Geological Survey of Denmark and Greenland, Denmark
University of California at Davis, United States
University of Tokyo, Japan
University of Queensland, Australia
Institut für Petrographie und Geochemie, Federal Republic of Germany
University of Oslo, Norway
University of Leicester, United Kingdom
University of Michigan, United States
NERC Isotope Geoscience Laboratories, United Kingdom
Danish Lithosphere Centre, Denmark
Volume Title: Proceedings of the Ocean Drilling Program; scientific results, Southeast Greenland margin; covering Leg 163 of the cruises of the drilling vessel JOIDES Resolution, Reykjavik, Iceland, to Halifax, Nova Scotia, sites 988-990, 3 September-7 October 1995
Volume Author(s): Larsen, Hans-Christian; Duncan, Robert A.; Allan, James F.; Aita, Yoshiaki; Arndt, Nicholas T.; Bücker, Christian J.; Cambray, Hervé; Cashman, Katharine V.; Cerney, Brian P.; Clift, Peter D.; Fitton, J. Godfrey; Le Gall, Bernard; Hooper, Peter R.; Hurst, Stephen D.; Krissek, Lawrence A.; Kudless, Kristen E.; Larsen, Lotte Melchior; Lesher, Charles E.; Nakasa, Yukari; Niu, Yaoling; Philipp, Harald; Planke, Sverre; Rehacek, Jakub; Saunders, Andrew D.; Teagle, Damon A. H.; Tegner, Christian; Scroggs, John
Source: Proceedings of the Ocean Drilling Program; scientific results, Southeast Greenland margin; covering Leg 163 of the cruises of the drilling vessel JOIDES Resolution, Reykjavik, Iceland, to Halifax, Nova Scotia, sites 988-990, 3 September-7 October 1995, Hans-Christian Larsen, Robert A. Duncan, James F. Allan, Yoshiaki Aita, Nicholas T. Arndt, Christian J. Bücker, Hervé Cambray, Katharine V. Cashman, Brian P. Cerney, Peter D. Clift, J. Godfrey Fitton, Bernard Le Gall, Peter R. Hooper, Stephen D. Hurst, Lawrence A. Krissek, Kristen E. Kudless, Lotte Melchior Larsen, Charles E. Lesher, Yukari Nakasa, Yaoling Niu, Harald Philipp, Sverre Planke, Jakub Rehacek, Andrew D. Saunders, Damon A. H. Teagle, Christian Tegner and John Scroggs. Proceedings of the Ocean Drilling Program, Scientific Results, Vol.163, p.77-93. Publisher: Texas A & M University, Ocean Drilling Program, College Station, TX, United States. ISSN: 0884-5891
Note: In English. 60 refs.CD-ROM format, ISSN 1096-2514; WWW format, ISSN 1096-7451; all chapters are also available on the included CD-ROM in PDF format and on the Web in PDF or HTML; illus., incl. sects., 3 tables, geol. sketch map
Summary: Voluminous, subaerial magmatism resulted in the formation of extensive seaward-dipping reflector sequences (SDRS) along the Paleogene Southeast Greenland rifted margin. Drilling during Leg 163 recovered basalts from the SDRS at 66°N (Site 988) and 63°N (Sites 989 and 990). The basalt from Site 988 is light rare-earth-element (REE) enriched (Lan/Ybn = 3.4), with εNd(t = 60) = 5.3, 87Sr/86Sr = 0.7034, and 206Pb/204Pb = 17.98. It is similar to tholeiites recovered from the Irminger Basin during Leg 49 and to light-REE-enriched tholeiites from Iceland. Drilling at Site 989, the innermost of the sites on the 63°N transect, was proposed to extend recovery of the earliest part of the SDRS initiated during Leg 152. These basalts are, however, younger than those from Site 917 and are compositionally similar to basalts from the more seaward Sites 990 and 915. Many of the basalts from Sites 989 and 990 show evidence of contamination by continental crust (e.g., εNd(t = 60)) extends down to -3.7, 206Pb/204Pb extends down to 15.1). We suggest that the contaminant is a mixture of Archean granulite and amphibolite and that the most contaminated basalts have assimilated ∼5% of crust. Uncontaminated basalts are isotopically similar to basalts from Site 918, on the main body of the SDRS, and are light-REE depleted. Consistent with previous models of the development of this margin, we show that at the time of formation of the basalts from Sites 989 and 990 (1) melting was at relatively shallow levels in a fully fledged rift zone; (2) fragments of continental crust were present in the lithosphere above the zones of melt generation; and (3) the sublithospheric mantle was dominated by a depleted Icelandic plume component.
Year of Publication: 1999
Research Program: ODP Ocean Drilling Program
Key Words: 02 Geochemistry; 05 Petrology, Igneous and Metamorphic; Alkaline earth metals; Arctic region; Atlantic Ocean; Basalts; Cenozoic; Concentration; Continental margin; East Greenland; Geochemistry; Greenland; Igneous rocks; Isotope ratios; Isotopes; Lead; Leg 163; Metals; Nd-144/Nd-143; Neodymium; North Atlantic; ODP Site 988; ODP Site 989; ODP Site 990; Ocean Drilling Program; Paleogene; Pb-206/Pb-204; Radioactive isotopes; Rare earths; South Greenland; Sr-87/Sr-86; Stable isotopes; Strontium; Tertiary; Tholeiitic basalt; Trace elements; Volcanic rocks
Coordinates: N632822 N632822 W0394648 W0394648
N654215 N654215 W0345216 W0345216
Record ID: 2000063787
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