| 3295 |
50.0 - 54.0 |
Mud with highly rhythmic, but faint submm- to mm-scale laminae defined by colour rather than obvious grainsize variations. Moderate opal (around 10 percent), TOC content (around 0.25 percent), and high water content (around 40-50 percent). Clasts absent. Moderate diatom abundance (0.5 * 10^9 valves/g). |
Rhythmic laminae suggest influence of traction currents reworking hemipelagic suspension settling sediments or turbidites . Rhythmites can also interpreted as meltwater plumes, but thin nature of facies, and lack of obvious size sorting argues against this interpretation, as plumites are often associated with large volume of subglacial meltwater release and high sedimentation rates (Cowan et al., 1999; McKay et al., 2009). Increased opal and TOC consistent with sub ice shelf setting (Hemer and Harris, 2003). The lack of outsized clasts is indicative of depostion beneath an ice shelf lacking basal debris (Domack et al., 1999, Hemer and Harris, 2003; Mckay et al., 2009) |
plantonic foraminifera (N. Pachyderma) |
8726.0 ± 105.0 |
| 3296 |
50.0 - 54.0 |
Mud with highly rhythmic, but faint submm- to mm-scale laminae and common gravel-sized clasts. Moderate opal (around 10 percent), TOC content (around 0.25 percent), and high water content (around 45 percent). Clasts include: quartz, feldspars, granite,basalt, dolerite,metamorphic lithologies (foliated/mylontic granitoids, metasediments, marble). Benthic and planktonic forams present. Common diatoms (0.74 * 10^9 valves/g). |
Common diatom content and gravel clasts alongside the planktonic/benthic foraminifera suggests a short duration period of pelagic sedimentation in open water with iceberg rafting over the core site. Rhythmic laminae suggest traction currents reworking hemipelagic suspension settling sediments or turbidites (see facies Ml). We interpret that the input of terrigenous material has allowed this short-lived interval to be preserved in the stratigraphy, where as higher in the stratigraphic succession (e.g. Facies Mb), sediment starvation (due to a lack of terrigenous sediment supply) combined with bioturbation does not allow for the preservation of such events. |
benthic foraminifera |
8892.0 ± 155.0 |
