Low-pressure melting studies of basalt and basaltic andesite from the Southeast Greenland continental margin and the origin of dacites at Site 917

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doi: 10.2973/odp.proc.sr.163.114.1999
Author(s): Thy, P.; Lesher, Charles E.; Mayfield, J. D.
Author Affiliation(s): Primary:
University of California at Davis, Department of Geology, Davis, CA, United States
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
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.95-112. Publisher: Texas A & M University, Ocean Drilling Program, College Station, TX, United States. ISSN: 0884-5891
Note: In English. 71 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. 7 tables
Summary: A series of 1-atm. melting experiments on basaltic flows collected from Holes 918D and 989B in the oceanic succession of the East Greenland continental margin can be used to define possible phase equilibria and liquid lines of descent. A sample from Site 918 (Section 152-918D-108R-2) shows the melting order low-Ca pyroxene (1153°C), augite (1182°C), olivine (1192°C), and plagioclase (1192°C). A sample from Site 989 (Section 163-989B-10R-7) melts in the order of low-Ca pyroxene (1113°C), augite (1167°C), plagioclase (1177°C), and olivine (1184°C). In particular, the relatively early appearance of low-Ca pyroxene distinguishes the melting relations for the oceanic succession from those observed for the basaltic continental succession at Site 917. A basaltic andesite flow from the Middle Series at Site 917 (Section 152-917A-27R-4) shows the melting order of low-Ca pyroxene (1142°C), plagioclase (1173°C), and olivine (1173°C). This melting order is difficult to reconcile with the observed large compositional variations in SiO2 and FeO for the Middle Series, which imply early magnetite fractionation. Major element considerations and rare-earth element modeling of the dacites of the Middle Series suggest that they formed by low extent of melting (<20%) of continental hydrated gabbroic or mafic amphibolite at pressures <8 kbar. These crustally derived melts represent possible contaminants of basaltic magmas of the Lower and Middle Series at Site 917.
Year of Publication: 1999
Research Program: ODP Ocean Drilling Program
Key Words: 02 Geochemistry; 05 Petrology, Igneous and Metamorphic; Andesites; Arctic region; Atlantic Ocean; Basalts; Cenozoic; Continental margin; Dacites; East Greenland; Genesis; Geochemistry; Greenland; Igneous rocks; Leg 152; Low pressure; Lower Tertiary; Magmatism; Major elements; Melting; Metals; Mineral composition; North Atlantic; ODP Site 917; ODP Site 918; Ocean Drilling Program; Ocean floors; Phase equilibria; Pressure; Rare earths; South Greenland; Tertiary; Volcanic rocks
Coordinates: N630534 N630534 W0383820 W0383820
N632930 N632930 W0394939 W0394939
Record ID: 2000063788
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