Downhole Measurements in the AND-1B Borehole, ANDRILL McMurdo Ice Shelf Project, Antarctica
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چکیده
A comprehensive set of downhole measurements was collected in the AND-1B drillhole as part of the on-ice scientifi c programme defi ned for the McMurdo Ice Shelf (MIS) Project. Geophysical logs were recorded over two operation phases and consisted of calliper, temperature, fl uid conductivity, induction resistivity, magnetic susceptibility, natural gamma activity, acoustic televiewer, borehole deviation, and dipmeter. In addition, two standard vertical seismic profi les (VSP) and one walk-away VSP were obtained. Radioactive logs (porosity and density) were not run because of unstable borehole conditions. Although the total depth of the hole is 1285 metres below seafl oor (mbsf), the depth range for in situ measurements was limited by the length of the wireline (1018 mbsf) and by the nullifi cation of some geophysical logs due to the presence of steel casing. A depth correction was derived to account for systematic discrepancies in depth between downhole measurements and cores; consequently, log responses can be directly compared to core properties. The resulting data are amenable to studies of cyclicity and climate, heat fl ux and fl uid fl ow, and structure and stress. When integrated with physical properties and fractures measured on the core, this information should play a signifi cant role in addressing many of the scientifi c objectives of the
منابع مشابه
Comprehensive downhole and core physical-property measurements at the AND-1B Drillsite, ANDRILL McMurdo Ice Shelf Project
As part of the ANDRILL McMurdo Ice Shelf (MIS) Project two comprehensive sets of geophysical data were collected on ice at the AND-1B drillsite. Whole-core physical properties were determined with high vertical resolution to a depth of 1285 mbsf. A multi-sensor-core-logger was used to determine bulk density, sonic velocity, magnetic susceptibility and electrical resistivity. After drilling, a s...
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Talarico, F. and ANDRILL-MIS Science Team, "Clast provenance and variability in MIS (AND-1B) core and their implications for the paleoclimatic evolution recorded in the Windless Bight-southern McMurdo Sound area (Antarctica)" (2007). ANDRILL Research and Publications. Paper 2. Summary Granule-to cobble-grade clasts in the uppermost 575 m of the MIS drill-core (AND-1B) highlight significant down...
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تاریخ انتشار 2013