(Table 1) Lead isotopic compositions of basalts from DSDP Hole 81-553

The passive continental margin south-west of Rockall Plateau is characterized by a thick sequence of oceanward-dipping seismic reflectors. During Leg 81 of the Deep Sea Drilling Project, these reflectors were sampled at Site 553 and proved to consist almost exclusively of basalt. Here we present lea...

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Bibliographic Details
Main Authors: Morton, Andrew C, Taylor, Paul N
Format: Dataset
Language:English
Published: PANGAEA 1987
Subjects:
81-553
Deep Sea Drilling Project
DRILL
Drilling/drill rig
DSDP
DSDP/ODP/IODP sample designation
Glomar Challenger
Lead-206/Lead-204 ratio
Lead-207/Lead-204 ratio
Lead-208/Lead-204 ratio
Leg81
North Atlantic/PLATEAU
Sample code/label
Rockall Plateau
North Atlantic
Online Access:https://doi.pangaea.de/10.1594/PANGAEA.770021
https://doi.org/10.1594/PANGAEA.770021
Description
Summary:The passive continental margin south-west of Rockall Plateau is characterized by a thick sequence of oceanward-dipping seismic reflectors. During Leg 81 of the Deep Sea Drilling Project, these reflectors were sampled at Site 553 and proved to consist almost exclusively of basalt. Here we present lead isotope data which indicate that these basalts may have been contaminated by ancient uranium-depleted continental crust, or alternatively, derived from a sub-continental lithospheric mantle source. In either case, the implications are that the basalts of the south-west Rockall Plateau formed by eruption through and onto continental basement, not by 'subaerial seafloor spreading'. This conclusion is in accord with gravity models of the area, which predict stretched continental crust beneath the dipping reflector sequence.

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