Physical properties at Site 1211 were measured on both whole-round sections and discrete samples from split-core sections. Continuous whole-round measurements were made of magnetic susceptibility, GRA bulk density, and compressional P-wave velocity using the MST for all Site 1211 cores. No natural gamma radiation measurements were made with the MST at Site 1211. Discrete measurements of compressional P-wave velocity were made at a routine frequency of at least one measurement per split-core section in Holes 1211A, 1211B, and 1211C. Index properties were measured on discrete samples from split-core sections at a general frequency of one measurement per section in Hole 1211A.
All core sections from Holes 1211A, 1211B, and 1211C were routinely measured on the MST for magnetic susceptibility and GRA bulk density at 3-cm intervals (Figs. F26, F27). MST P-wave velocity was routinely measured at 10-cm intervals on all cores from Holes 1211A, 1211B, and 1211C (Fig. F28). All collected MST data are archived in the Ocean Drilling Program Janus database.
Magnetic susceptibility values (Fig. F26) are generally highest in the uppermost ~52 m of the Site 1211 sedimentary column; this interval equates to Pleistocene-Miocene lithologic Unit I (see "Lithologic Unit I" in "Lithostratigraphy"). Peaks in magnetic susceptibility within lithologic Subunits IA and IB may correlate with distinctive ash layers. In the Pleistocene-Miocene section an excellent correlation is also observed between magnetic susceptibility data and color reflectance measurements, primarily the total reflectance value (L*) and the 550-nm wavelength (see "Lithologic Unit I" in "Lithostratigraphy"). Both magnetic susceptibility and color reflectance data in this interval reveal a pronounced cyclicity, which may be useful in identifying astronomically controlled depositional processes. As already observed at Sites 1209 and 1210, a broad peak in magnetic susceptibility (at ~48-52 mbsf) characterizes the uppermost Oligocene/lower Miocene unconformity (see "Biostratigraphy"). Between ~52 and ~81 mbsf, throughout the Oligocene segment of lithologic Unit II, magnetic susceptibility values are generally at background levels. Magnetic susceptibilities are higher in the Eocene and Paleocene segments of lithologic Unit II, between ~81 and ~131 mbsf. A peak in magnetic susceptibility at ~90 mbsf correlates with a clay-rich interval within lithologic Unit II (see "Lithologic Unit I" in "Lithostratigraphy"). Within the Eocene and Paleocene intervals of lithologic Unit II there is also a general downhole trend to lower magnetic susceptibility values. As observed at Sites 1209 and 1210, large peaks in magnetic susceptibility values delineate the K/T boundary, which occurs at ~133 mbsf in Holes 1211A, 1211B, and 1211C (see "Biostratigraphy"). These magnetic susceptibility increases are associated with an increase in clay content and a decrease in carbonate content in this stratigraphic interval (see "Organic Geochemistry"). In Cretaceous lithologic Unit III, magnetic susceptibility values are generally close to background, with the exception of some excursions that are related to chert horizons, and do not exhibit any consistent downhole variation.
Site 1211 MST GRA bulk density data (Fig. F27) do not exhibit a constant downhole increase, as would be expected if increased sediment compaction and dewatering with greater overburden pressure were the only factors controlling this physical property. However, GRA bulk density data do show some distinct variations that relate to lithologic changes at distinct horizons, for example, the uppermost Oligocene/lower Miocene unconformity and the K/T boundary. MST GRA bulk density values exhibit a general downhole increase between the seafloor and ~32 mbsf, within Pleistocene-Pliocene lithologic Subunit IA, before decreasing to lower values through the Pliocene-Miocene components of lithologic Subunits IA and IB, between ~32 and ~50 mbsf. MST GRA bulk density then increases below ~50 mbsf, with a sharp increase at ~53 mbsf occurring at the uppermost Oligocene/lower Miocene unconformity. Cyclical variation in GRA bulk density values, similar to that evident in magnetic susceptibility and color reflectance data (see "Lithostratigraphy"), is found within Pleistocene-Miocene lithologic Subunits IA and IB. Between ~53 and 67 mbsf, within the top of the Oligocene segment of lithologic Unit II, MST GRA bulk density decreases. A general trend to higher values with increased burial depth is then evident until ~105 mbsf, through parts of the Oligocene and Eocene components of lithologic Unit II. Within the lower part of lithologic Unit II (Eocene-Paleocene) MST GRA bulk density values decrease with increased burial depth, with a distinct minimum at ~133 mbsf occurring at the Cretaceous/Paleocene boundary (i.e., between lithologic Units II and III). Within Cretaceous lithologic Unit III, MST GRA bulk density values decrease between ~133 and ~165 mbsf, with a small increase in values in the sediments recovered in the basal part of Hole 1211B.
Hole 1211A GRA bulk density values are consistently higher than the discrete wet bulk density measurements (see Fig. F27; Table T12). These overestimated GRA bulk density values can be explained by the relatively high carbonate content, porosity, and moisture content of sediments; the calibration procedure for the MST GRA sensor is optimized for mixed-lithology sediments. Consequently, the GRA method overestimates the density in carbonate-rich sediments of all lithologic units. This phenomenon is most pronounced in lithologic Unit III because these sediments have the highest carbonate contents (see "Organic Geochemistry").
MST P-wave velocities are plotted in Figure F28. Despite some obviously "out of range" values, reliable P-wave velocities vary between ~1500 and ~1580 m/s, with the highest velocities generally recorded at greater depths in the sediment column. A linear relationship between increased burial depth and higher MST P-wave velocities is not observed at Site 1211. The absence of such a relationship suggests that sediment compaction and dewatering processes are not the only factors influencing P-wave velocity values. MST P-wave velocities do, however, follow the same downhole trends as the MST GRA bulk density data (Fig. F27). MST P-wave values increase between the seafloor and ~15 mbsf, in the Pleistocene part of lithologic Subunit IA, and then decrease between ~15 and ~48 mbsf, through the Pliocene-Miocene components of lithologic Subunits IA and IB. Between ~48 and ~53 mbsf, in the Miocene part of lithologic Subunit IB, P-wave values increase, with an abrupt change from ~1520 to 1540 m/s occurring at ~53 mbsf and corresponding to the uppermost Oligocene/lower Miocene unconformity. From ~53 to ~67 mbsf, P-wave velocities again decrease with increasing burial depth (within the Oligocene segment of lithologic Unit II), before exhibiting a general trend to peak values (~1570 km/s) at ~95 mbsf in the Eocene part of lithologic Unit II. In the Eocene-Paleocene of lithologic Unit II, between ~95 and ~131 mbsf, a further trend to decreasing P-wave velocities with increased burial depth is observed. At ~131 mbsf an abrupt increase in velocity, from ~1520 to ~1570 km/s, characterizes the Cretaceous/Paleogene boundary and an increase in clay content in this stratigraphic interval. In the upper part of Cretaceous lithologic Unit III, from ~131 to ~155 mbsf, MST P-wave velocities decrease, before increasing in the basal portion of Holes 1211A and 1211B.
The downhole trends recorded by the reliable MST P-wave logger (PWL) values also compare well with the discrete measurements of P-wave velocity (Fig. F28, F29; Table T13). However, MST PWL values are generally lower than discrete values; this difference may be due to the assumption in the calibration of the MST PWL that the core liner is full of sediment and that there is no water between the liner and the sediment.
Discrete measurements of compressional P-wave velocity were made on Site 1211 split-core sections using the modified Hamilton frame (PWS3) velocimeter. Data were collected at a routine sampling frequency of one measurement per section (Table T13; Fig. F29). Velocities vary between ~1520 m/s in the soft surface sediments and ~1570 m/s in the more consolidated sediments at Site 1211. Discrete P-wave measurements show a general increase in velocity, from ~1520 to ~1540 m/s, between the seafloor and ~20 mbsf in Pleistocene-Pliocene lithologic Subunit IA, before decreasing to ~1510 m/s at ~47 mbsf in Pliocene-Miocene lithologic Subunit IB. Both of these trends are clearly evident in the reliable P-wave velocity data obtained with the MST PWL (Fig. F28). Between ~47 and ~55 mbsf, in lithologic Subunit IB and the uppermost part of the Oligocene segment of lithologic Unit II, P-wave velocities increase to ~1550 m/s. Velocities then exhibit a general downhole increase through the Oligocene and Eocene segments of lithologic Unit II, to ~1590 (Hole 1211A) or ~1560 (Holes 1211B and 1211C) m/s at ~105 mbsf. In all three holes cored at Site 1211, discrete P-wave values decrease through the Eocene and Paleocene parts of lithologic Unit II and the majority of Cretaceous lithologic Unit III. Superimposed on this downhole trend is a peak in discrete P-wave values that occurs at ~133 mbsf in Holes 1211B and 1211C and delineates the Cretaceous/Paleogene boundary. At the base of Hole 1211B, P-wave velocities between ~162 and ~170 mbsf are higher than those recorded in the upper part of lithologic Unit III.
An excellent positive correlation (R2 = 0.88) between Hole 1211A P-wave velocity and discrete bulk density (Fig. F30) indicates that these two properties are closely related at Site 1211. The lack of evidence for early diagenetic cementation near the seafloor, as shown by high-percentage porosity in the interval 0-50 mbsf (Fig. F31; Table T12), suggests that increasing P-wave velocity and bulk density with depth in the upper ~25 m of Site 1211 is primarily the result of compaction and pore fluid expulsion. The lack of any constant increase in either of these two physical properties with greater burial depth further suggests that compaction and pore fluid expulsion are not the only factors influencing the more deeply buried sediments at this locality. It is highly probable that primary sediment composition was an additional important factor that influenced postdepositional changes following sediment burial on the Southern High of Shatsky Rise, as also indicated at Sites 1209 and 1210 (see "Summary" in "Physical Properties" in the "Site 1209" chapter and "Index Properties" in "Physical Properties" in the "Site 1210" chapter).
Index properties determined for discrete samples from Hole 1211A are listed in Table T12 and shown in Figures F31 and F32. Index properties reflect progressive sediment compaction and fluid expulsion with depth in the sediment column and also indicate changes in sediment composition as defined by lithologic units and subunits (see "Lithostratigraphy"). Bulk and dry density values increase between the seafloor and ~105 mbsf, through Pleistocene-Miocene lithologic Unit I and the Oligocene and Eocene parts of lithologic Unit II. A large stepped increase in both bulk and dry density is further evident at ~53 mbsf, and this change delineates the unconformable (uppermost Oligocene/lower Miocene) boundary between lithologic Units I and II. Below ~105 mbsf, bulk and dry density exhibit a general trend to lower values through the Eocene-Paleocene segments of lithologic Unit II and Cretaceous lithologic Unit III. By comparison, grain density does not exhibit any clear downhole variation, which might explain the relatively good correlation between GRA bulk density and P-wave velocity (Fig. F30). Water content, porosity, and void ratio exhibit a general downhole decrease between the seafloor and ~105 mbsf, through Pleistocene-Miocene lithologic Unit I and the Oligocene and Eocene segments of lithologic Unit II, the corollary to increasing bulk and dry density (Fig. F32). Below ~105 mbsf, in the Eocene and Paleocene portions of lithologic Unit II and Cretaceous lithologic Unit III, water content, porosity, and void ratio exhibit general trends to higher values with greater burial depth. These trends suggest that overburden on the Cretaceous sediments was not sufficient to cause significant downhole water loss and consequent decrease in porosity.
As observed at Sites 1209 and 1210, physical properties data at Site 1211 show variation with depth below seafloor that is controlled by progressive compaction and fluid expulsion only in the uppermost part of the sedimentary column (i.e., between 0 and 20 mbsf). In addition, as at Sites 1209 and 1210, a simple relationship between lithology and physical properties is less obvious at Site 1211 than at Sites 1207 and 1208. The absence of these simple relationships may in part be due to the more continuous Late Cretaceous-Holocene sedimentation at Site 1211 and, hence, the absence of major unconformities spanning long periods of geologic time. As observed for Sites 1209 and 1210, the unusual downhole trends in physical properties data cannot be explained by the sediment burial history alone. The physical properties data suggest that there has been less compaction and diagenesis in the sediments below ~105 mbsf relative to those sediments in the overlying stratigraphic interval. This variability may be a reflection of varying microfossil composition within the Site 1211 sediments and the so-called "diagenetic potential" of different sediments (see "Physical Properties" in the "Site 1209" chapter).