Wireline Standard Data Processing

ODP logging contractor: LDEO-BRG

Hole: 1068A

Leg: 173

Location: Iberian Abyssal Plain (NE Atlantic)

Latitude: 40° 40.955' N

Longitude: 11° 36.719' W

Logging date: May, 1997

Bottom felt: 5055 mbrf

Total penetration: 955.8 mbsf

Total core recovered: 180.6 m (73.9 %)

Logging Runs

Logging string 1: DIT/HLDT/APS/HNGS (upper and lower sections)

Wireline heave compensator was used to counter ship heave.

Bottom-hole Assembly

The following bottom-hole assembly depths are as they appear on the logs after differential depth shift (see "Depth shift" section) and depth shift to the sea floor. As such, there might be a discrepancy with the original depths given by the drillers onboard. Possible reasons for depth discrepancies are ship heave, use of wireline heave compensator, and drill string and/or wireline stretch.

DIT/APS/HLDT/HNGS: Bottom-hole assembly at ~124 mbsf (upper section)

DIT/APS/HLDT/HNGS: Bottom-hole assembly at ~625 mbsf (lower section).

Processing

Depth shift: No depth shift was required, as the two passes do not overlap. The original logs have been depth shifted to the sea floor (- 5045 m).

Gamma-ray processing: HNGS data from the DIT/APS/HLDT/HNGS tool string were corrected in real-time during the recording.

High-resolution data: No high resolution data was recorded in Hole 1065A.

Quality Control

During the processing, quality control of the data is mainly performed by cross-correlation of all logging data. Large (>12") and/or irregular borehole affects most recordings, particularly those that require eccentralization (APS, HLDT) and a good contact with the borehole wall. A large positive spike was observed on the density log between 295 and 309 mbsf; because no other log shows a similar trend, the data in this interval is considered invalid.

Data recorded through bottom-hole assembly, such as the gamma ray data above 124 and between 608 and 625 mbsf, should be used qualitatively only because of the attenuation on the incoming signal.

Hole diameter was recorded by the hydraulic caliper on the HLDT tool (CALI).

Additional information about the logs can be found in the "Explanatory Notes" and Site Chapter, ODP IR volume 173. For further questions about the logs, please contact:

Cristina Broglia
Phone: 845-365-8343
Fax: 845-365-3182
E-mail: Cristina Broglia