Methods

Abstract

This chapter documents the primary operational, curatorial, and analytical procedures and methods employed during the offshore and onshore phases of Integrated Ocean Drilling Program (IODP) Expedition 347. This information concerns only shipboard and Onshore Science Party (OSP) methodologies and data as described in the site chapters. Methods for postexpedition research conducted on Expedition 347 samples and data will be described in individual scientific contributions published after the OSP. Detailed drilling and engineering operations are described in "Operations" within each site chapter and "Operational strategy" in the "Expedition 347 summary" chapter (Andrén et al., 2015). The information in this chapter will enable future identification of data and samples for further scientific investigation by interested parties. Site locationsAll Expedition 347 sites (Fig. F1) were positioned using GPS coordinates supplied by the proponents and based on previous site surveys. As a number of holes were proposed at each site for different uses (e.g., paleoenvironment and microbiology), a central hole position was taken from the proponent-supplied coordinates (Hole A), and then additional positions were calculated radiating out from this position at 20 m intervals, with Holes B and C on either side of Hole A, running along the site survey seismic lines, and Holes D and E perpendicular to this orientation, again on either side of Hole A (Fig. F2). The spacing interval of 20 m between holes was chosen to limit drilling disturbance between holes while maintaining a close enough proximity to correlate between them, enabling the formation of a composite recovery and lithologic splice.Selected positions were relayed to the Hydrographic Surveyor from Geocean, and the Greatship Manisha was settled into position using a dynamic positioning (DP) system. To maintain station accurately within the required tolerance of <1 m for shallowwater sites, the DP system ran for 30-40 min at each location to build a reliable DP model, after which permission was granted to commence operations. Geocean supplied two transponder systems that were used during coring operations as backup for the DP system should there be a failure in the differential GPS (DGPS) signal because of satellite angles, particularly in the river estuary Methods 1

Site M0060

“…Core recovery was generally good in Hole M0060A, except for a gap between ~101.5 and 117 mbsf and from ~198 mbsf to the base of the hole, where coring alternated between hammer sampling and open-hole intervals. Although all physical property measurements described in "Physical properties" in the Methods chapter (Andrén et al, 2015) were conducted for Site M0060, whole-round core shipboard P-wave velocity data appear to be highly affected by artifacts, similar to those seen at Site M0059 (Little Belt). Discrete Pwave and thermal conductivity data are too sparsely distributed to exhibit any discernable downcore trends, and noncontact electrical resistivity data show little variability.…”

“…To achieve the main objectives of the OSP paleomagnetic work, magnetic susceptibility measurements and rudimentary analyses of the natural remanent magnetization (NRM) were made on discrete specimens of known volume and mass (see "Paleomagnetism" in the "Methods" chapter [Andrén et al, 2015]). The discrete samples were taken from Hole M0060A, with a gap in sampling between 116 and 101 mbsf in the mid-lower sections of Unit V because of poor core recovery.…”

Site M0063

“…F18). Although all physical property measurements described in "Physical properties" in the "Methods" chapter (Andrén et al, 2015) were conducted at Site M0063, wholeround core shipboard P-wave data appear to be highly affected by artifacts. Thermal conductivity data are too sparsely distributed to exhibit any discernible downcore trend.…”

“…Magnetic susceptibility measurements and simplified analyses of the natural remanent magnetization (NRM) were made on discrete specimens of known volume and mass (see "Paleomagnetism" in the "Methods" chapter [Andrén et al, 2015]). A total of 216 discrete samples were taken from Hole M0063D at intervals of ~50 cm.…”

“…Siliceous microfossil data are only qualitative presence/absence data and should be interpreted cautiously until quantitative data are generated. Abundance of benthic foraminifers based on the abundance classification defined in the "Methods" chapter(Andrén et al, 2015), Site M0063. A running average over five samples is plotted onto a single data point.…”