Integrated Ocean Drilling Program (IODP) Site U1309 is located on the central dome of Atlantis Massif, 14-15 km west of the median valley axis of the Mid-Atlantic Ridge (MAR), where the seafloor coincides with what is interpreted to be a gently sloping, corrugated detachment fault surface. Two drill holes at this site (Holes U1309B and U1309D) penetrate a multiply intruded and faulted crustal section, providing core that documents the interplay between magmatism, deformation, and. hydrothermal alteration prior to, during, and subsequent to a period of footwall displacement and denudation associated with detachment faulting. Five shallow-penetration holes (Holes U1309A and U1309E-U1309H) were designed to sample the sedimentary carapace and upper few meters of basement, to test the hypothesis that the upper surface coincides with a detachment fault, and to help constrain the temporal history of denudation. Collected sedimentary deposits may provide constraints on the timing of exposure across the dome based on the age and isotopic character of preserved microfossils. Basement rock sampled in these short holes provides initial information on deformation and alteration within the exposed fault and, perhaps, rock adjacent to the fault zone.