In creating the meters composite depth (mcd) scale, we attempted to ignore data from intervals that were disturbed or distorted by the drilling process (Table T1). This typically includes the uppermost 5-70 cm of nearly every core, which is commonly more water saturated or soupy relative to the sediment below. Only in the first core at each hole, particularly at the mudline (sediment/water interface), would we expect to see such poorly consolidated sediments. We also avoided other distortions, such as gas voids and deformed sediments. Hole 1098C contained additional data gaps caused by the removal of a 5-cm-long interstitial water (IW) sample from the end of each section prior to the measurement on the multisensor track (MST).
The primary data sets used are those collected during Leg 178 with (1) the MST, from which we use the magnetic susceptibility and density that were measured every 2 cm; (2) the Minolta color scanner, from which we use the color reflectance parameters L*, a*, and b* that were measured every 2 cm; and (3) the long-core cryogenic magnetometer, from which we use the inclination and intensity measured every 5 cm (Barker, Camerlenghi, Acton, et al., 1999). Susceptibility or paleomagnetic data collected within 5 cm of the end of each section are ignored, because the sensors that measure these parameters average over several centimeters of core, and so measurements near the ends of the sections are biased. Additional constraints come from core photos and core descriptions.