Geochemistry at DSDP Leg 82 Holes ...

• Main Authors: Weaver, Barry L, Tarney, John, Saunders, Andrew D
• Format: Article in Journal/Newspaper
• Language: English
• Published: PANGAEA 1985
• Subjects: Deep Sea Drilling Project DSDP; North Atlantic
• Online Access: https://dx.doi.org/10.1594/pangaea.805593; https://doi.pangaea.de/10.1594/PANGAEA.805593

DSDP Leg 82 drilled nine sites to the southwest of the Azores Islands on the west flank of the Mid-Atlantic Ridge (MAR) in an attempt to determine the temporal and spatial evolution of the Azores "hot-spot" activity. The chemistry of the basalts recovered during Leg 82 is extremely varied: in Holes 558 and 561, both enriched (E-type: CeN/YbN = 1.5 to 2.7; Zr/Nb = 4.5 to 9.6) and depleted (or normal-N-type: CeN/YbN = 0.6 to 0.8; Zr/Nb > 20) mid-ocean ridge basalts (MORB) occur as intercalated lava flows. To the north of the Hayes Fracture Zone, there is little apparent systematic relationship between basalt chemistry and geographic position. However, to the south of the Hayes Fracture Zone, the chemical character of the basalts (N-type MORB) is more uniform. The coexistence of both E-type and N-type MORB in one hole may be explicable in terms of either complex melting/ fractionation processes during basalt genesis or chemically heterogeneous mantle sources. Significant variation in the ratios of strongly ... : Supplement to: Weaver, Barry L; Tarney, John; Saunders, Andrew D (1985): Geochemistry and mineralogy of basalts recovered from the Central North Atlantic. In: Bougault, H; Cande, SC; et al. (eds.), Initial Reports of the Deep Sea Drilling Project, Washington (U.S. Govt. Printing Office), 82, 395-419 ...