Thy, P. et al. (1999): Low-pressure melting studies of basalt and basaltic andesite from the Southeast Greenland continental margin and the origin of dacites at Site 917
Leg/Site/Hole:
Related Expeditions:
ODP 152
Identifier:
ID:
2000-063788
Type:
georefid
ID:
10.2973/odp.proc.sr.163.114.1999
Type:
doi
Creator:
Name:
Thy, P.
Affiliation:
University of California at Davis, Department of Geology, Davis, CA, United States
Role:
author
Name:
Lesher, Charles E.
Affiliation:
Oregon State University, United States
Role:
author
Name:
Mayfield, J. D.
Affiliation:
Ocean Drilling Program, United States
Role:
author
Identification:
Title:
Low-pressure melting studies of basalt and basaltic andesite from the Southeast Greenland continental margin and the origin of dacites at Site 917
Year:
1999
Source:
In: Larsen, Hans-Christian, Duncan, Robert A., Allan, James F., Aita, Yoshiaki, Arndt, Nicholas T., Buecker, Christian J., Cambray, Herve, 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 (editor), 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
Publisher:
Texas A & M University, Ocean Drilling Program, College Station, TX, United States
Volume:
163
Issue:
Pages:
95-112
Abstract:
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 degrees C), augite (1182 degrees C), olivine (1192 degrees C), and plagioclase (1192 degrees C). A sample from Site 989 (Section 163-989B-10R-7) melts in the order of low-Ca pyroxene (1113 degrees C), augite (1167 degrees C), plagioclase (1177 degrees C), and olivine (1184 degrees 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 degrees C), plagioclase (1173 degrees C), and olivine (1173 degrees C). This melting order is difficult to reconcile with the observed large compositional variations in SiO (sub 2) 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.
Language:
English
Genre:
Serial
Rights:
URL:
Coverage: Geographic coordinates: North:63.2930 West:-39.4939 East:
-38.3820 South:63.0534
Keywords: Geochemistry of rocks, soils, and sediments; Igneous and metamorphic petrology; 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; Ocean Drilling Program; ocean floors; ODP Site 917; ODP Site 918; phase equilibria; pressure; rare earths; South Greenland; Tertiary; volcanic rocks;
.