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Physical properties

Physical property measurements were carried out at Site U1314 following the procedures described in “Physical properties” in the “Site U1312–U1315 methods” chapter. These measurements provide important information about processes related to lithology and stratigraphic correlation. Magnetic susceptibility measurements were made with both the MSCL and the multisensor track (MST) system. Additionally, GRA density and NGR were measured with the MST. Discrete P-wave velocities were measured (P-wave sensor number 3 [PWS3]–measuring perpendicular to the core axis) on each section, and moisture and density measurements were measured on two discrete samples per core, usually at the bottom of the first and sixth sections.

Whole-core magnetic susceptibility measurements

The magnetic susceptibility records derived during coring operations at Site U1314 (Fig. F31) show a highly variable record attributed to lithologic and/or mineralogic changes and show multiple excursions toward high values generally associated with IRD layers. Values of magnetic susceptibility are generally between 100 and 500 (0 and 0.03 SI units). These relatively high values are due to a higher magnetic content of these cores associated with the high fraction of terrigenous material. Values increase somewhat downhole. Below ~230 mbsf there is a distinctive change in the frequency content of the signal in Holes U1314A and U1314B.

GRA density

Sediments from Site U1314 show a general increase in bulk density downcore, consistent with a downcore increase in compaction and decrease in water content (Fig. F32). GRA density values vary between 1.3 and 1.5 g/cm3 and are consistent with discrete bulk density values (Fig. F33). Superimposed on this downhole increase in bulk density are fluctuations that may correspond to pebble layers or large clasts (>2 cm) in the core (see “Lithostratigraphy”).

Density and porosity

Bulk and grain density and porosity values estimated from Hole U1314A are shown in Figure F33. Grain density values are relatively uniform with an average value of ~2.7 g/cm3. Porosity decreases downcore from ~80% to 70%. Bulk density and porosity are inversely correlated consistent with the effects of compaction and decreasing water content.

P-wave velocity

P-wave velocities range between 1460 and 1564 m/s (Fig. F34). In Hole U1314A, velocity records from the MST (P-wave logger) and the split-core measurements (PWS3) are in general agreement except for a section between 90 and 120 mbsf, which is not understood.

Natural gamma radiation

Natural gamma radiation provides a means of evaluating the relative clay content of the sediments. NGR counts range from 15 to 30 cps, (Fig. F35). NGR counts are positively correlated with trends observed in magnetic susceptibility and GRA density data.


Sediments cored at Site U1314 are composed of both terrigenous and biogenic material (see “Lithostratigraphy”). Changes in physical properties generally reflect variations in the relative amounts of these components. NGR counts, P-wave velocity, bulk density, and magnetic susceptibility are positively correlated. Large positive excursions in these properties may be attributed to IRD layers.