Passchier, Sandra; Wilson, Terry; Paulsen, Timothy S (1998): Characterisation of breccias in sediment core CRP-1 (Table 1) [dataset]. PANGAEA, https://doi.org/10.1594/PANGAEA.438923, Supplement to: Passchier, S et al. (1998): Origin of breccias in the CRP-1 core. Terra Antartica, 5(3), 401-409, hdl:10013/epic.28315.d001
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Abstract:
CoreScan images were examined to determine the origin of breccias in the CRP-1 core. Breccias occur throughout the core. but are dominant deformation features in the upper 85 m. Breccia textures, boundaries and texture arrangements suggest that in situ fracturing and horizontal planar shearing are important deformation mechanisms in the upper part of the Miocene section. Forceful injections of silt and clay into fractures point to dewatering of overpressurised sediment. Breccias located below 55 metres below the sea floor (mbsf) occur associated with soft-sediment deformation, which is absent in younger intervals of the core. Deformation styles interpreted from the breccia textures, their downcore distribution, and the relations of breccias with sequence boundaries and lithologies, such as diamictites and graded beds, suggest brecciation occurred as a result of subglacial shearing and mass-movement processes. These mechanisms were also proposed for breccias and soft sediment deformation features observed in other McMurdo Sound cores. Subglacial shearing was a possible cause for the development of two thick brecciated intervals at ~44 and at ~79 mbsf, whereas slope failure and redeposition was probably the cause of brecciation below ~85 mbsf.
Project(s):
Cape Roberts Project (CRP)
Coverage:
Latitude: -77.007580 * Longitude: 163.755080
Date/Time Start: 1997-10-17T01:30:00 * Date/Time End: 1997-10-24T02:00:00
Minimum DEPTH, sediment/rock: 41.070 m * Maximum DEPTH, sediment/rock: 147.395 m
Event(s):
CRP-1 (16 km ENE Cape Roberts) * Latitude: -77.007580 * Longitude: 163.755080 * Date/Time Start: 1997-10-17T01:30:00 * Date/Time End: 1997-10-24T02:00:00 * Elevation: -153.5 m * Penetration: 132.06 m * Recovery: 113.32 m * Location: off Cape Roberts, Ross Sea, Antarctica * Campaign: CRP-1 * Basis: Sampling/drilling ice * Method/Device: Core wireline system (CWS) * Comment: sea ice thickness: 1.60 m, recovery 86 %. Age and lithology of oldest strata: 22-24 Ma; mudstone with scattered pebbles.
Parameter(s):
| # | Name | Short Name | Unit | Principal Investigator | Method/Device | Comment |
|---|---|---|---|---|---|---|
| 1 | DEPTH, sediment/rock | Depth sed | m | Geocode | ||
| 2 | Depth, top/min | Depth top | m | Passchier, Sandra | ||
| 3 | Depth, bottom/max | Depth bot | m | Passchier, Sandra | ||
| 4 | Lithology/composition/facies | Lithology | Passchier, Sandra | Visual description | ||
| 5 | Texture | Texture | Passchier, Sandra | Visual description | ||
| 6 | Boundary description | Bound descr | Passchier, Sandra | Visual description | ||
| 7 | Deformation structure, type | Deformation | Passchier, Sandra | Visual description | ||
| 8 | Description | Description | Passchier, Sandra | Visual description | sediment-filled cracks | |
| 9 | Description | Description | Passchier, Sandra | Visual description | associated with breccia | |
| 10 | Interpretation | Interpretation | Passchier, Sandra | Visual description |
License:
Creative Commons Attribution 3.0 Unported (CC-BY-3.0)
Size:
81 data points
Data
| 1 Depth sed [m] | 2 Depth top [m] | 3 Depth bot [m] | 4 Lithology | 5 Texture | 6 Bound descr | 7 Deformation | 8 Description (sediment-filled cracks) | 9 Description (associated with breccia) | 10 Interpretation |
|---|---|---|---|---|---|---|---|---|---|
| 41.070 | 40.35 | 41.79 | diamicton | chaotic/crackle | gradational/sharp | diamicton | subglacial shear? | ||
| 47.165 | 44.10 | 50.23 | fine sandstone | crackle/ chaotic | sharp/gradational | fractures | abundant | diamictite | subglacial shear |
| 57.200 | 55.95 | 58.45 | coarse siltstone | chaotic/rubble | gradational | soft sediment deformation | present | interstratified diamicitite | slope failure |
| 69.250 | 67.60 | 70.90 | silty sandstone | rubble/chaotic | sharp/radational | soft sediment deformation fractures microfaults | diamictite | subglacial shear? | |
| 82.535 | 79.55 | 85.52 | silty fine sandstone | rubble/chaotic | sharp/ gradational | soft sediment deformation | abundant | diamictite w/microfabric | subglacial shear |
| 92.480 | 92.44 | 92.52 | mudstone | chaotic | gradational/sharp | graded beds | slope failure | ||
| 110.420 | 110.38 | 110.46 | clayey siltstone | matrix-supported | gradational | soft sediment deformation microfaults | present | laminated sediments | slope failure |
| 116.350 | 116.22 | 116.48 | sandy siltstone | chaotic | gradational/sharp | soft sediment deformation | interstratified diamicitite | slope failure | |
| 118.745 | 118.19 | 119.30 | silty v. fine sandstone | rubble/matrix-sup. | gradational | soft sediment deformation | laminated sediments | slope failure | |
| 147.395 | 147.32 | 147.47 | fine sandstone | matrix-supported | sharp | bioturbation | slope failure |