![]() ![]() Volumetric analysis will require further study.Īnother proposed use for the camera is for the lithologic characterization of ambient-temperature cores because of slight variations in their thermal emission properties attributable to sediment composition or water content. Small-scale hydrate nodules and disseminated gas hydrate were the primary forms identified, suggesting the camera can detect small quantities. It is quicker, simpler, and more compact than the system of thermistors used during Leg 164 (Paull, Matsumoto, Wallace, et al., 1996). The primary benefits of using IR (in preference to estimating temperature differences by touch) include more precise identification of thermal anomalies and the possible estimation of hydrate volume from processed images. IR imaging was shown to successfully identify thermal anomalies in sediment cores attributed to the location of gas hydrate (cold anomalies) and voids (warm anomalies). Infrared thermal imaging was introduced during this leg for technique development prior to expected critical use during Leg 204. These data tables include GRA density, magnetic susceptibility, natural gamma radiation (NGR), P-wave velocity, MAD, thermal conductivity, Hamilton frame velocity (PWS), resistivity, and paleomagnetism. Tables of physical properties in ASCII are provided on the "Log and Core Data" CD-ROM included with this publication. A summary of each of the physical property measurement procedures for Leg 201 is outlined below more detailed descriptions are provided in Blum (1997). Discrete moisture and density (MAD) parameters, P-wave velocities, and electrical resistivity were subsequently measured on each split-core section. Physical properties measured on the MST and thermal conductivity measurements were normally made on whole-round core sections during the same time interval. All other physical property measurements were conducted after the cores had equilibrated to near ambient room temperature (i.e., 22°-24☌), a settling period of typically 2-4 hr, except for cores sampled for microbiology in the cold room. Selected cores from Sites 1225, 1226, 1230, and 1231 were thermally imaged on the catwalk prior to sectioning. In many cases, we used nonstandard downcore spacings and instrument precision to better physically define known zones of special biochemical or geochemical interest. In addition, physical properties can be used to define geochemical and, hence, population and community boundaries. Physical characterization of the subsurface environment, particularly including density, porosity, and matrix composition, is necessary for specification of the hydrodynamic environment that is expected to strongly affect the microbial community. ![]() A suite of physical property measurements were made to support the main scientific objectives of Leg 201. ![]()
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