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doi:10.2204/iodp.sp.339add.2011

Operations plan/Drilling strategy

The Expedition 339 drilling program targets seven primary site and three alternate sites, all located in either Portuguese or Spanish territorial waters (Tables T1, T2, T3), two of which are on the southwest Portuguese continental margin and the remaining five in the Gulf of Cádiz (Figs. F1, F2). The final operations plan and number of sites to be cored is contingent upon changes to the R/V JOIDES Resolution operations schedule, operational risks, and the outcome of a request for permission to occupy these sites.

The coring strategy will consist of advanced piston coring (APC) in two holes (A and B) at each site to refusal using nonmagnetic core barrels, except at proposed Site SHACK-04 where four APC holes to 150 mbsf are planned. Multiple holes will allow us to build a composite section at each site. If a complete composite record of the APC section cannot be achieved by double coring, a third hole (C) may be spot-cored to complete the splice or fill any desirable gaps. The “drillover” technique will be employed to maximize APC penetration where desirable. For planning purposes, the APC refusal depth for most sites is estimated at 100 mbsf, although we anticipate that this may be exceeded at some of the more mud-rich sites. APC refusal will be followed by extended core barrel coring at each site to ~350 mbsf and then by rotary core barrel coring to total depth (Tables T1, T2).

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