Geochemistry and minerals at DSDP Leg 81 Holes ...
The Leg 81 basalts, drilled either from the margins ("dipping reflectors" sequence: Holes 552, 553A, and 554A) or from the "continental" side (Hole 555) of the Rockall Plateau microcontinent, are strongly light rare-earth element (LREE) depleted oceanic tholeiites. The basalts fr...
| Main Authors: | , , , , |
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| Format: | Article in Journal/Newspaper |
| Language: | English |
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PANGAEA
1984
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| Subjects: | |
| Online Access: | https://dx.doi.org/10.1594/pangaea.807088 https://doi.pangaea.de/10.1594/PANGAEA.807088 |
| Summary: | The Leg 81 basalts, drilled either from the margins ("dipping reflectors" sequence: Holes 552, 553A, and 554A) or from the "continental" side (Hole 555) of the Rockall Plateau microcontinent, are strongly light rare-earth element (LREE) depleted oceanic tholeiites. The basalts from the four holes are almost similar. Most of their primary characteristics have been preserved, although they have suffered alteration by seawater. From the petrological and mineralogical points of view, they resemble deep-ocean-floor basalts but show some peculiarities (occurrence of pigeonite and ilmenite as normal components of the groundmass differentiation sequences toward ferrobasalts). Their geochemical characteristics are dominated by their extreme depletion in the most hygromagmaphile elements (Th, Ta, La, and Nb), the concentrations of which are sometimes lower than the corresponding chondritic values. Leg 81 basalts are thus clearly different from continental tholeiites (flood basalts): Possible equivalents in the Thulean ... : Supplement to: Joron, Jean Louis; Bougault, Henri; Maury, R C; Bohn, Marcel; Desprairies, Alain (1984): Strongly depleted tholeiites from the Rockall Plateau Margin, North Atlantic: geochemistry and mineralogy. In: Roberts, DG; Schnittker, D; et al. (eds.), Initial Reports of the Deep Sea Drilling Project, Washington (U.S. Govt. Printing Office), 81, 783-794 ... |
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