Iodp Expedition 307: Site U1317 Summary Modern Carbonate Mounds: Porcupine Drilling

Site U1317 (proposal Site PORC-3A) is located on the northwest shoulder of the Challenger Mound (51o 22.8 N, 11o 43.1W, in 781 to 815 m water depth). Scientific drilling of the Challenger Mound was the central objective of Expedition 307. Specific objectives of drilling Site U1317 were: • To establish whether the mound base is on a carbonate hardground of microbial origin and whether past geofluid migration events acted as a prime trigger for mound genesis. • To describe stratigraphic, lithologic and diagenetic characteristics for establishing the principal deposional model of deep-water carbonate mounds including timing of key mound-building phases. • To define the relationship, if any, between the mound-developing event and global oceanographic events, which might have formed erosional surfaces displayed on high-resolution seismic profiles • To analyze geochemical and microbiological profiles that define the sequence of microbial communities and geomicrobial reaction throughout the drilled sections.