Drilling on the Iberian margin has documented extreme extension with little or no decompression melting of the asthenospheric mantle. Observations from geophysical studies on the conjugate Newfoundland margin document significant cross-rift asymmetries in basement depth, amount of tectonic extension, and other deep structures. These observations raise fundamental questions about rifting of non-volcanic margins, including the cause and extent of mantle unroofing, the presence or absence of decompression melting, the origin of deep and crustal asymmetry between conjugates, the age-subsidence and strain partitioning history, and the relation of rift events to development of shallow water unconformities and the stratigraphic record. Leg 210 will study the composition and subsidence history of the stratigraphic sequence above basement and igneous/tectonic basement contact on the Newfoundland margin. The proposed drilling is in a position exactly conjugate to the Iberia abyssal plain drilling transect.
The single reentry site is located in 4559 m water depth. A pilot hole will be cored in soft sediments to ~500 mbsf. A second hole will be cored and logged to 1500 m, following which it will cored as deep as possible in the time remaining with a target of 2200 m in sediment with 100 m of basement penetration. The sedimentary sequence is expected to consist of detrital sediments, principally clays and silty clays, with limestone beds and lenses.Download the Leg 210 JOIDES proposal. The preliminary operations plan outlined in the proposal will be finalized at the precruise meeting (6-9 months before the cruise) and published in the Leg 210 Scientific Prospectus.
Staff Scientist: Adam Klaus
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