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Contents 1 Site summary 3 Background and objectives 4 Operations 6 Lithostratigraphy 10 Biostratigraphy 11 Paleomagnetism 14 Geochemistry and microbiology 17 Physical properties 21 Downhole measurements 26 Stratigraphic synthesis 30 References Site summarySite U1453 (proposed Site MBF-4A) is in the center of our seven-site transect of shallow-penetration holes. It is located at 8°0.42′N, 86°47.90′E in a water depth of 3690.5 m. Combined with the other transect sites, Site U1453 will document depocenter migration and quantify overall sediment delivery to 8°N since the Pleistocene.Site U1453 is located ~1 km south and ~5 km east of a prominent surficial channel. The channel exhibits pronounced meandering point bars and internal terraces. Sediment transported by this channel has therefore significantly influenced deposition at this site during the channel's lifetime. A prominent buried point bar is located <1 km west of the site. The overall seismic reflectivity at the drill site is relatively high, indicating coarse material throughout most of the drilled section, except for the lower portion of the drill hole. Distinct and variable local spillover deposits were expected at the site in response to the channel and meander evolution. Toward the base of the hole, lower seismic reflectivity and distinct layering is inferred to reflect hemipelagic or distal levee deposition.In addition to coring, downhole logging was introduced as an important objective of Site U1453 after attempts to log at Sites U1450 and U1451 were unsuccessful. Logging data are essential for determining the inventory of lithofacies and structures in the fan given the limitations in completely recovering unconsolidated coarse material and the importance of measuring in situ physical properties and imaging fine-scale sedimentary structures. Therefore, we decided to log Hole U1453A despite its shallow ~215 m penetration to increase chances that we could acquire this critical in situ log data. This was particularly important for characterizing the in situ properties of thick sandy intervals that half-length advanced piston corer (HLAPC) cores returned as loose and liquefied sand. Principal resultsSite U1453 contributes to the overall seven-site transect drilled during Expedition 354. When integrated with the seismic profile and refined chronostratigraphic data from the remaining part of the transect, this site will document fan construction processes and the depocenter migration time frame. Specifically, Site U1453 provides an almost completely recovered succession of silt-and/or sanddominated sheeted units related to the formation and evolution of a large meandering channel system lacking a distinct levee unit. Intercalation of these sheets with thinner levee units either from the large channel or from nearby smaller channels may help us understand why the channel has been apparently maintained in this position for a relatively long time period. This type of configuration is part of the different processes that influence interlevee deposition. A few th...

Background and objectives 4 Operations 6 Lithostratigraphy 12 Biostratigraphy 13 Paleomagnetism 15 Geochemistry and microbiology 18 Physical properties 22 Downhole measurements 22 Stratigraphic synthesis 26 References Hole U1454A Hole U1454B Latitude: 8°0.4067′N Latitude: 8°0.4083′N Longitude: 85°50.9882′E Longitude: 85°51.0025′E Time on hole (days): 0.4 (9.00 h) Time on hole (days): 1.6 (37.5 h) Seafloor (drill pipe measurement below rig floor, m DRF): 3721.0 Seafloor (drill pipe measurement below rig floor, m DRF): 3721.4 Distance between rig floor and sea level (m): 11.1 Distance between rig floor and sea level (m): 11.1 Water depth (drill pipe measurement from sea level, mbsl): 3709.9 Water depth (drill pipe measurement from sea level, mbsl): 3710.3 Total penetration (drilling depth below seafloor, m DSF): 7.5 Total penetration (drilling depth below seafloor, m DSF): 161.8 Total depth (drill pipe measurement from rig floor, m DRF): 3728.5 Total depth (drill pipe measurement from rig floor, m DRF): 3883.2 Total length of cored section (m): 7.5 Total length of cored section (m): 147.4 Total core recovered (m): 7.54 Total core recovered (m): 129.51 Core recovery (%): 101 Core recovery (%): 88 Drilled interval (m): 0.0 Drilled interval (m): 14.4 Total number of cores: 1 Total number of cores: 29 Hole U1454C Hole U1453D Latitude: 8°0.3868′N Latitude: 8°0.3975′N Longitude: 85°51.0033′E Longitude: 85°5.9927′E Time on hole (days): 0.3 (8 h) Time on hole (days): 0.6 (14.00 h) Seafloor (drill pipe measurement below rig floor, m DRF): 3721.4 Seafloor (drill pipe measurement below rig floor, m DRF): 3721.8 Distance between rig floor and sea level (m): 11.1 Distance between rig floor and sea level (m): 11.1 Water depth (drill pipe measurement from sea level, mbsl): 3710.3 Water depth (drill pipe measurement from sea level, mbsl): 3710.7 Total penetration (drilling depth below seafloor, m DSF): 37.2 Total penetration (drilling depth below seafloor, m DSF): 37.1 Total depth (drill pipe measurement from rig floor, m DRF): 3758.6 Total depth (drill pipe measurement from rig floor, m DRF): 3758.9 Total length of cored section (m): 37.2 Total length of cored section (m): 37.1 Total core recovered (m): 30.16 Total core recovered (m): 24.46 Core recovery (%): 81 Core recovery (%): 66 Drilled interval (m): 0.0 Drilled interval (m): 0.0 Total number of cores: 6 Total number of cores: 5