|MSTDATA (multisensor track data
As with many other ODP legs, the Leg 169 MST data are essentially unfiltered. The user should be aware of this fact and refer to the core photographs, the VCDs, and the physical properies sections in the volume. Although most of the data accurately represents the core as recovered, this is not necessarily what the user requires. In most circumstances, the user is unlikely to require data that reflect the effects of voids in the core, gas in the sediment fabric, and other forms of drilling disturbance. During Leg 169, many of the recovered sediments contained free gas on board the ship and, hence, no velocity values were collected from these regions.
Before using the data, the user should be aware of the problem of varying degrees of disturbance in different lithologies when using different coring tools. Cores were obtained using advanced hydraulic piston corer (APC), extended core barrel (XCB), and rotary core barrel (RCB) tools, and this should be taken into consideration when filtering the data. For example, many of the silty clay turbidite sequences were cored using the XCB, which produces biscuits of relatively undisturbed sediments surrounded by drilling slurry. Typically the P-wave velocity is markedly lower in the slurry (perhaps by 200 m/s). The gamma density can sometimes be markedly lower and, at other times, not so different. The magnetic susceptibility is little affected in such cases. In summary, the user is encouraged to use this data with care as some form of filtering process is almost certainly needed depending on the use to which the data is put.
The MST data files are ASCII files.
The MSDATA files are named according to hole number and type of data file (i.e, GR = gamma ray, MS = magnetic susceptibility, NG = natural gamma, PW = P-wave, and GRA = GRAPE. The filtered MSTDATA files are provided in addition to the raw shipboard GRAPE, index properties, magnetic susceptibility, P-wave, and natural gamma data files, which are presented on the "Log & Core Data" CD-ROM that accompanies this volume.
STRDATA (structure data tables by site). These are individual ASCII files:
If you have questions specifically about this material please contact the Data Librarian (email@example.com) at the Ocean Drilling Program.
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