Petrochemistry and isotope geochemistry of early Palaeogene basalts forming the dipping reflector sequence SW of Rockall Plateau, NE Atlantic

Author(s): Merriman, R. J.; Taylor, P. N.; Morton, A. C.
Author Affiliation(s): Primary:
Br. Geol. Surv., Keyworth, United Kingdom
Inst. Oceanogr. Sci., United Kingdom
Univ. Oxford, United Kingdom
Volume Title: Early Tertiary volcanism and the opening of the NE Atlantic
Volume Author(s): Morton, A. C., editor; Parson, L. M.
Source: Geological Society Special Publications, Vol.39, p.123-134; Early Tertiary volcanism and the opening of the NE Atlantic, London, United Kingdom, Mar. 18-19, 1987, edited by A. C. Morton and L. M. Parson. Publisher: Geological Society of London, London, United Kingdom. ISSN: 0305-8719. ISBN: 0-632-02171-3 CODEN: GSLSBW
Note: In English. 36 refs.; illus. incl. 2 tables, sketch map
Summary: A transect across the passive margin SW of Rockall Plateau was drilled during DSDP Leg 81. Site 555 was located on continental crust of the Rockall plateau. Sites 552 and 553 were located over the wedge of dipping reflectors, and Site 554 drilled the outer high at the transition from the thick wedge of dipping reflectors to normal oceanic crust. New trace-element and Pb-isotope data are presented which characterize three basalt types: 1) Dipping reflector basalts resemble depleted N-type MORB, strongly depleted in LREE and other incompatible elements; they have been contaminated by U-depleted continental crust, or alternatively derived from depleted subcontinental lithosphere. 2) Outer high basalts are less strongly depleted N-type MORB and show no evidence of crustal contamination. 3) Site 552 basalts postdate the onset of subsidence of SW Rockall margin; they are relatively evolved N-type MORB derived from a source similar to that of the outer high basalts but show evidence of crustal contamination. Genesis of the dipping reflector basalts is best explained by a stretching/rifting model, not the 'subaerial seafloor spreading' model. [Authors' abstract]
Year of Publication: 1988
Research Program: DSDP Deep Sea Drilling Project
IPOD International Phase of Ocean Drilling
Key Words: 02 Geochemistry; 05 Petrology, Igneous and Metamorphic; 18 Geophysics, Solid-Earth; Atlantic Ocean; Basalts; Cenozoic; Crust; DSDP Site 403; DSDP Site 404; DSDP Site 552; DSDP Site 553; DSDP Site 554; DSDP Site 555; Deep Sea Drilling Project; Edoras Basin; Geochemistry; IPOD; Igneous rocks; Isotopes; Lead; Leg 48; Leg 81; Lower Paleogene; Metals; Mid-ocean ridge basalts; North Atlantic; Oceanic crust; Paleogene; Partial melting; Passive margins; Pb-204; Pb-206; Pb-207; Petrology; Radioactive isotopes; Rifting; Rockall Plateau; Sea-floor spreading; Stable isotopes; Tertiary; Volcanic rocks; Volcanism; Volcanology
Coordinates: N561724 N561725 W0233141 W0233142
N560519 N560520 W0232036 W0232037
N560233 N560234 W0231323 W0231324
N563341 N563343 W0204655 W0204656
Record ID: 1989014726
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom