(Table 1) Major and trace element composition of basalts from ODP Leg 163 sites and Hole 152-917A

• Main Authors: Larsen, Lotte M, Fitton, J Godfrey, Saunders, Andrew D
• Format: Dataset
• Language: English
• Published: PANGAEA 1999
• Subjects: 152-917A; 163-989A; 163-989B; 163-990A; Aluminium oxide; Atomic absorption spectrometry (AAS); Barium; Calcium oxide; Cerium; Chromium; Cobalt; Copper; DEPTH; sediment/rock; DRILL; Drilling/drill rig; DSDP/ODP/IODP sample designation; Elements; total; Elevation of event; Event label; Gallium; Greenland Sea; Iron oxide; Fe2O3; FeO; Joides Resolution; Lanthanum; Latitude of event; Lead; Leg152; Leg163; Lithologic unit/sequence; Longitude of event; Magnesium number; Magnesium oxide; Manganese oxide; Neodymium; Nickel; Niobium; Ocean Drilling Program; ODP; Phosphorus pentoxide; Piece; Potassium oxide; Rubidium; Sample code/label; Scandium; Silicon dioxide; Greenland; North Atlantic
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.804646; https://doi.org/10.1594/PANGAEA.804646

During Leg 163, in the Southeast Greenland margin, drilling penetrated a thick succession of volcanic rocks that erupted during breakup of the North Atlantic in the early Tertiary. Samples recovered during Leg 163 supplement the samples recovered during Leg 152 from the transect across the volcanic margin at 63°N. During Leg 163, drilling at Site 989 was intended to recover the oldest part of the continental prebreakup series, and drilling at Site 990 was intended to penetrate the transition zone from synbreakup, compositionally variable volcanic products, to postbreakup volcanics with a limited compositional range and a depleted chemical character similar to mid-ocean-ridge basalts (oceanic character). All the lava flows recovered from Sites 989 and 990, however, have an oceanic chemical character with low contents of incompatible elements and high contents of Sc. A dikelet from Site 990 and a previously drilled dike from Site 917 are likewise oceanic. We consider that the two drilled lava flows from Site 989 were emplaced after breakup despite their setting on the innermost part of the continental margin. The succession at Site 990 consists of 13 units of lava flow that show a slight compositional development upsection with Mg# decreasing from ~62 to ~49. This variation is within the limits known from the slightly younger oceanic succession drilled earlier at Site 918, in which the variation is thought to reflect fractionation in magma chambers in the oceanic crust. The reestablishment of magma chambers after the breakup must have been achieved during the interval that the short, undrilled lava succession between uppermost Site 917 and lowermost Site 990 was deposited. All the lava flows from Sites 989 and 990, except perhaps one (Unit 989-1), are crustally contaminated, as judged from their high Ba/Zr (>0.42) ratios. The two dikes appear to be uncontaminated. The contamination most likely took place in magma chambers in the young oceanic rift, which, at this early stage of spreading, could still have ...