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Ehrmann, Werner (2001): Clay and smectite content in sediment core CRP-3. PANGAEA, https://doi.org/10.1594/PANGAEA.57868, Supplement to: Ehrmann, W (2001): Variation in smectite content and crystallinity in sediments from CRP-3, Victoria Land Basin, Antarctica. Terra Antartica, 8(4), 533-542, hdl:10013/epic.28283.d001

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Abstract:
The Cenozoic sediments of the CRP-3 drill core from the continental shelf of McMurdo Sound in Ross Sea, Pacific sector of the Southern Ocean, have been investigated for their clay mineral assemblages, especially for the smectite abundances, concentrations and crystallinities. The assemblages of CRP-3 are very different from those of the CRP-1 and CRP-2/2A drill cores. Thus, an almost monomineralic assemblage characterizes the sequence below 330 mbsf. This assemblage is made of well-crystallized smectite with probably authigenic origin between 800 mbsf and 625 mbsf. From 625 mbsf to 330 mbsf the assemblage consists of moderately crystallized smectite that, at least in part, seems to be of detrital origin and thus indicates weathering under a relatively warm and wet climate. In the interval 330-145 mbsf, smectite concentrations fluctuate between 50% and 100% and probably document alternating phases of chemical weathering under a warm and wet climate and physical weathering under a relatively cool and dry climate. Above 145 mbsf the smectite decreases dramatically to concentrations of about 20% and becomes poorly crystalline. In contrast, illite and chlorite become more abundant. Such an assemblage is typical for early Oligocene and younger sediments in McMurdo Sound and reflects physical weathering conditions under a cool climate on a glaciated Antarctic continent. Correlations of the changes in the clay mineral spectrum of CRP-3 with other cores from McMurdo Sound and from other parts of the Southern Ocean has to remain speculative at this stage, because of the poor age control.
Project(s):
Coverage:
Latitude: -77.006000 * Longitude: 163.719000
Date/Time Start: 1999-10-09T00:00:00 * Date/Time End: 1999-11-19T00:00:00
Minimum DEPTH, sediment/rock: 8.97 m * Maximum DEPTH, sediment/rock: 788.94 m
Event(s):
CRP-3 * Latitude: -77.006000 * Longitude: 163.719000 * Date/Time Start: 1999-10-09T00:00:00 * Date/Time End: 1999-11-19T00:00:00 * Elevation: -295.0 m * Penetration: 939 m * Recovery: 936 m * Location: Ross Sea * Campaign: CRP-3 * Basis: Sampling/drilling from ice * Device: Core wireline system (CWS) * Comment: 11.76 km at 76° true from Cape Roberts, 2.04 km at 225° true from CRP-2. Fast ice thickness: 2.0 to 2.2 m. Sea rise embedded to 9.55 mbsf. Lateral ice movement from spudding 5.0 m to 82° true. HQ core to 345.85 mbsf. NQ core to 939.42 mbsf. Core recovery 97%. Phase 1 logging to 345 mbsf, Phase 2 logging to 773 mbsf, Phase 3 logging to 918 mbsf. Deepest Cenozoic lithology and depth: sandstone breccia from 822.87 to 823.11 mbsf. Age of oldest Cenozoic strata: earliest Oligocene or latest Eocene. Deepest core lithology and depth: light red-brown quartz-cemented quartz sandstone to 939.42 mbsf. Age of bedrock: (mid?) Devonian.
Parameter(s):
#NameShort NameUnitPrincipal InvestigatorMethodComment
1DEPTH, sediment/rockDepthmGeocode
2Size fraction < 0.002 mm, > 9 phi, clay<2 µm, >9 phi%Ehrmann, WernerGrain size, sieving/settling tube
3Smectite/standard ratioSmec/stdEhrmann, WernerX-ray diffraction TEXTUR, clay fraction
4SmectiteSme%Ehrmann, WernerX-ray diffraction TEXTUR, clay fraction
5Smectite, integral widthSmec IWd2ThetaEhrmann, WernerX-ray diffraction TEXTUR, clay fraction
Size:
380 data points

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