Data Description

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Jarrard, RD et al. (2000): Average dip directions from intervals of dipmeter log in drill hole CRP-2A. doi:10.1594/PANGAEA.143836,
Supplement to: Jarrard, Richard D; Brink, Jason; Bücker, Christian J; Wonik, Thomas; Wilson, Terry; Paulsen, Timothy S (2000): Bedding dips in CRP-2A, Victoria Land Basin, Antarctica. Terra Antartica, 7(3), 261-270, hdl:10013/epic.28277.d001
Bedding dips in the CRP-2A drillhole were determined in two ways (1) analysis of a dipmeter log, and (2) identification of bed boundaries on digital images of the outer core surface. The two methods document the downhole increase in structural dip, to a maximum of 15° in the lowest 150 m of the hole. Dipmeter data, which are azimuthally oriented, indicate a 75° azimuth for structural tilting, in agreement with seismic reflection profiles. Core and log dips indicate that structural dip increases by 5-7° between 325 and 480 mbsf. Both, however, also exhibit high dip inhomogeneity because of depositional (e.g., cross bedding) and post-depositional (e.g., softsediment deformation) processes. This variability adds ambiguity to the search for angular unconformities within the CRP-2A drillhole. Dip directions of different lithologies are generally similar, as are dip directions for the four kinds of systems tracts. Downdip azimuths of sands and muds are slightly different from those of diamicts, possibly reflecting the divergence between ENE offshore dip and ESE glacial advance.
Latitude: -77.005980 * Longitude: 163.719450
Date/Time Start: 1998-10-16T07:30:00 * Date/Time End: 1998-11-25T14:20:00
Minimum Elevation: -177.9 m * Maximum Elevation: -177.9 m
CRP-2A (14.2 km at 096° true from Cape Roberts) * * Latitude: -77.005980 * Longitude: 163.719450 * Date/Time Start: 1998-10-16T07:30:00 * Date/Time End: 1998-11-25T14:20:00 * Elevation: -177.9 m * Recovery: 624 m * Location: off Cape Roberts, Ross Sea, Antarctica * * Campaign: CRP-2 * * Basis: Sampling/drilling from ice * * Device: Core wireline system (CWS) * * Comment: 921 m at 284° from CRP-1. Sea-ice thickness: 2.0 m (1 Oct) to 2.2 m (23 Nov). Sea riser embedded to 13.03 mbsf. Lateral ice movement: 9.87 m to east from 17 Oct to 23 Nov. HQ core to 199.31 mbsf. NQ core to 624.15 mbsf. 13.03 to 45.97 mbsf, 11.29 m (34%) partially following CRP-2. 45.07 to 624.15 mbsf, 548.67 m (95%) new hole. Deepest core-lithology: hard sandy siltstone. Deepest core-age: earliest Oligocene (ca. 33 Ma on diatoms, nannofossils and dinoflagellates)
#NameShort NameUnitPrincipal InvestigatorMethodComment
1Depth, top/min *Depth topmJarrard, Richard D *
2Depth, bottom/max *Depth botmJarrard, Richard D *
3Sample code/label *Sample code/labelJarrard, Richard D *Interval ID
4Azimuth *AzimdegJarrard, Richard D *Compass *Downdip azimuth
5Bed dip *DipdegJarrard, Richard D *Compass *
6Obliquity/tilt *OBLdegJarrard, Richard D *Compass *Eastward tilt
7Number *NoJarrard, Richard D *Number of points
8Confidence *ConfJarrard, Richard D *Student_s t *95% confidence limits
238 data points

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