The Neogene stratigraphy of the glaciated European margin from Lofoten to Porcupine

[ Preface ] [ Introduction ] [ Unified Stratigraphy ] [ Pre-Neogene Framework ] [ Miocene to Lower Pliocene ] [ Lower Pliocene To Holocene ] [ High-Resolution Stratigraphy ] [ Key Geoseismic Sections ]

[ WP1 ] [ Figure 24 ] [ WP2 ] [ Figure 25 ] [ WP3 ] [ Figure 26 ]

WP3 - ROCKALL-PORCUPINE

No unified high-resolution stratigraphy exists for the Rockall–Porcupine region at the present time. A number of Pleistocene seismic-stratigraphic units have been identified on the Hebridean margin (Stoker et al. 1993; 1994), but their regional extent remains unknown. In an attempt to provide a preliminary overview for this region this section presents a stratigraphic summary of 27 short cores and one borehole (BGS88/7,7A), focusing on the last 500ka (Fig. 26). The cores are located on the map opposite and represent a range of depositional settings. Age models for these cores are based on various parameters, including planktonic and benthic d18O records, AMS14C age control (down to a maximum 14C age of 43,600 BP), and CaCO3 records, Ca data (XRF logging) or sediment (colour) lightness, all of which trace glacial-interglacial fluctuations of biogenic carbonate, and/or of defined biostratigraphic age points. Identification of the Vedde Ash layer and correlation of sediment properties with the GISP2 ice core provided additional age constraints. The data source, water depth (WD) and length of each core are tabulated in Fig. 26.

The range charts shown in Fig. 26a, Fig 26b and Fig. 26c provide an overview of all the cores for the interval between 0–500ka (marine isotope stages, MIS, 1–13), highlighting those cores that have AMS14C age control and suspected hiati. Ages of isotope stage boundaries are based on Martinson et al. (1987). The charts represent correlations arranged along transects 1–3, which incorporate slope and basin floor environments. Transect 1 is from the SW Rockall Trough, and includes the Feni Ridge sediment drift. Transect 2 extends from the southern Rockall Trough to the Porcupine Basin. It ranges from the transition to Porcupine Abyssal Plain to the upper slope of the Porcupine Basin. Transect 3 incorporates the central and NE Rockall Trough and Hebridean margin, and includes the basin floor, the Barra Fan and the upper Hebrides Slope.

From this database, two additional range charts have been constructed, each allowing sequential higher degrees of accuracy. The interval 0–80,000ka (including MIS 5a) provides more detail on part of the last glacial cycle, particularly for sediment cores with detailed AMS14C age control (Fig. 26d). The interval 0–16,000 14C years shows precise basal ages within Termination I (Fig. 26e). The latter is based on a 14C rather than on a calendar year scale, because the non-linear and telescopic relationship between the 14C and calendar age scales and the occurrence of 14C plateaus during Termination I result in considerable uncertainties for conversion of 14C years into calendar years. Definition and ages of deglacial events follow Björck et al. (1996).

The compilation of these charts is intended as an aid to any future high-resolution stratigraphic interpretation in this region. However, whilst regional correlation between cores from different settings is clearly demonstrated by the charts, they also highlight the potential problems faced in establishing a seismic-stratigraphic framework. Although BGS borehole 88/7, 7A can be correlated temporally with deeper-water sites, such as V28-76 and V28-78, the latter represent condensed sections (<10m thick) with respect to the shelf-margin setting of the BGS borehole (69m thick for the equivalent section). 


TOP

References

Björck, S., Kromer, B., Johnsen, S., Bennike, O., Hammarlund, D., Lemdahl, G., Possnert, G., Rasmussen, T.L., Wohlfarth, B., Hammer, C.U. & Spurk, M. 1996. Synchronized terrestrial/atmospheric deglacial records around the North Atlantic. Science, 274, 1155-1160.

Martinson, D.G., Pisias, N.G., Hays, J.D., Imbrie, J., Moore, T.C., Shackleton, N.J., 1987. Age dating and the orbital theory of ice ages: Development of a high-resolution 0 to 300,000 year chronostratigraphy. Quaternary Research, 27, 1-29.

Stoker, M.S., Hitchen, K. & Graham, C.G. 1993. United Kingdom offshore regional report: the geology of the Hebrides and West Shetland shelves, and adjacent deep-water areas. (London: HMSO for the British Geological Survey).

Stoker, M.S., Leslie, A.B., Scott, W.D., Briden, J.C., Hine, N.M., Harland, R., Wilkinson, I.P., Evans, D. & Ardus, D.A. 1994. A record of Late Cenozoic stratigraphy, sedimentation and climate change from the Hebrides slope, NE Atlantic Ocean. Journal of the Geological Society, London, 151, 235-249.

Source of data for range charts

  1. Bard, E., M., Arnold, P., Maurice, J., Duprat, J., Moyes, J.-Cl., & Duplessy. 1987. Retreat velocity of the North Atlantic polar front during the last deglaciation determined by 14C accelerator mass spectrometry. Nature, 328, 791-794.

  2. Bond, G.C., Heinrich, H., Broecker, W., Labeyrie, L., McManus, J., Andrews, J., Huon, S., Jantschik, R., Clasen, S., Simet, C., Tedesco, K., Klas, M., Bonani, G. & Ivy, S. 1992. Evidence for massive discharges of icebergs into the North Atlantic ocean during the last glacial. Nature, 360, 245-249.

  3. Bond, G.C., Broecker, W., Johnsen, S., McManus, J., Labeyrie, L., Jouzel, J. & Bonani, G. 1993. Correlations between climate records from North Atlantic sediments and Greenland ice. Nature, 365, 143-147.

  4. Bond, G.C. & R. Lotti. 1995. Iceberg discharges into the North Atlantic on millennial timescales during the last glaciation. Science 267, 1005-1010.

  5. Bond, G.C., Showers, W., Cheseby, M., Lotti, R., Almasi, P., deMenocal, P., Priore, P., Cullen, H., Hajdas, I. & Bonani, G. 1997. A pervasive millennial-scale cycle in North Atlantic Holocene and glacial climates. Science, 278, 1257-1266.

  6. Bond, G.C., Showers, W., Elliot, M., Evans, M., Lotti, R., Hajdas, I., Bonani, G. & Johnsen, S. 1999. The North Atlantic's 1-2 kyr Climate Rhythm: Relation to Heinrich Events, Dansgaard/Oeschger Cycles and the Little Ice Age. Geophysical Monograph, 112, 35-58.

  7. Broecker, W.S., Andree, M., Wolfli, W., Oeschger, H., Bonani, G., Kennett, J. & Peteet, D. 1988. The chronology of the last deglaciation: applications to the cause of the Younger Dryas event. Paleoceanography, 3, 1-19.

  8. Cortijo, E., Duplessy, J.C., Labeyrie, L., Leclaire, H., Duprat, J. & van Weering, T.C.E. 1997. Changes in sea surface hydrology associated with Heinrich event 4 in the North Atlantic Ocean between 40° and 60°N. Earth & Planetary Science Letters, 146, 29-45.

  9. Duplessy, J.C., Moyes, J. & Pujol, C. 1980. Deep water formation in the North Atlantic Ocean during the last ice age. Nature, 286, 479-482.

  10. Duplessy, J.C., Arnold, M., Maurice, P., Bard, E., Duprat, J. & Moyes, J. 1986. Direct dating of the oxygen-isotope record of the last deglaciation by 14C accelerator mass spectrometry. Nature, 320, 350-352.

  11. Duplessy, J.-Cl., Labeyrie, L., Arnold, M., Paterne, M., Duprat, J. & van Weering, T.C.E. 1992. Changes in surface salinity of the North Atlantic Ocean during the last deglaciation. Nature, 358, 485-487.

  12. Duplessy, J. C. (pers. comm.).

  13. Duplessy, J. C. & Labeyrie, L. (pers. comm.).


TOP

  1. Flood, R.D., Hollister, C.D. & Lonsdale, P. 1979. Disruption of the Feni Sediment Drift by debris flows from Rockall Bank. Marine Geology, 32, 311-334.

  2. Hall, I.R. & McCave, I.N. 1998. Late Glacial to Recent accumulation fluxes of sediments at the shelf edge and slope of NW Europe, 48-50°N. In: Stoker, M.S., Evans, D. & Cramp, A. (eds), Geological Processes on Continental Margins: Sedimentation, Mass-Wasting and Stability. Geological Society, London, Special Publications, 129, 339-350.

  3. Howe, J.A., Harland, R., Hine, N.M. & Austin, W.E.N. 1998. Late Quaternary stratigraphy and palaeoceanographic change in the northern Rockall Trough, North Atlantic Ocean. In: Stoker, M.S., Evans, D. & Cramp, A. (eds), Geological Processes on Continental Margins: Sedimentation, Mass-Wasting and Stability. Geological Society, London, Special Publications, 129, 269-286.

  4. Jansen, E., & Veum, T. 1990. Evidence for two-step deglaciation and its impact on North Atlantic deep water circulation. Nature, 343, 612-616.

  5. Knutz, P., Austin, W.E.N. & Jones, E.J.W. 2001. Millennial-scale depositional cycles related to British Ice Sheet variability and North Atlantic paleocirculation since 45 kyr B.P., Barra Fan, U.K. margin. Paleoceanography, 16, 53-64.

  6. Kroon, D., Austin, W.E.N., Chapman, M.R. & Ganssen, G.M. 1997. Deglacial surface circulation changes in the northeastern Atlantic: Temperature and salinity records off NW Scotland on a century scale. Paleoceanography, 12, 755-763.

  7. Kroon, D., Shimmield, G., Austin, W.E.N., Derrick, S., Knutz, P. & Shimmield, T. 2000. Century- to millennial-scale sedimentological-geochemical records of glacial-Holocene sediment variations from the Barra Fan (NE Atlantic). Journal of the Geological Society, London, 157, 643-653.

  8. Lagerklint, I.M. & Wright, J.D. 1999. Late glacial warming prior to Heinrich event 1: The influence of ice rafting and large ice sheets on the time of initial warming. Geology, 27, 1009-1102.

  9. McIntyre, A., Ruddiman, W.F. & Jantzen, R. 1972. Southward penetration of the North Atlantic Polar Front: faunal and floral evidence of large-scale surface water mass movements over the last 225,000 years. Deep-Sea Research, 19, 61-77.

  10. McManus, J.F., Bond, G.C., Broecker, W.S., Johnsen, S., Labeyrie, L. & Higgins, S. 1994. High-resolution records from the North Atlantic during the last interglacial. Nature, 371, 326-329.

  11. NIOZ unpublished data.

  12. Richter, T.O., Lassen, S., van Weering, T.C.E. & de Haas, H. 2001. Magnetic susceptibility patterns and provenance of ice-rafted material at Feni Drift, Rockall Trough: implications for the history of the British-Irish ice sheet. Marine Geology, 173, 37-54.

  13. Richter, T.O., Lassen, S., van Weering, T.C.E. & de Stigter, H.C. 2001. High-resolution multiproxy investigations of Late Glacial and Holocene surface and bottom water variability, Feni Drift, NE Atlantic Ocean. EURESCO Conference on Abrupt Climate Change Dynamics: Achieving Climate Predictability Using Paleoclimate Data. Castelvecchio Pascoli, Italy, 10-15 November 2001 (Poster Presentation).

  14. Stoker, M.S., Leslie, A.B., Scott, W.D., Briden, J.C., Hine, N.M., Harland, R., Wilkinson, I.P., Evans, D. & Ardus, D.A. 1994. A record of Late Cenozoic stratigraphy, sedimentation and climate change from the Hebrides slope, NE Atlantic Ocean. Journal of the Geological Society, London, 151, 235-249.

  15. Turon, J.L, (pers. comm.).

  16. Van Rooij, D. (pers. comm.). Renard Centre for Marine Geology, Belgium.

  17. Vidal, L., Labeyrie, L., Cortijo, E., Arnold, M., Duplessy, J.C., Michel, E., Becqué, S. & van Weering, T.C.E . 1997. Evidence for changes in the North Atlantic Deep Water linked to meltwater surges during the Heinrich events. Earth & Planetary Science Letters, 146, 13-27.

  18. http://www.ngdc.noaa.gov

  19. http://www.ldeo.columbia.edu

  20. http://images.pclab.ifg.uni-kiel.de/frameDB.html


TOP

[ WP1 ] [ Figure 24 ] [ WP2 ] [ Figure 25 ] [ WP3 ] [ Figure 26 ]

[ Preface ] [ Introduction ] [ Unified Stratigraphy ] [ Pre-Neogene Framework ] [ Miocene to Lower Pliocene ] [ Lower Pliocene To Holocene ] [ High-Resolution Stratigraphy ] [ Key Geoseismic Sections ]

This page was Last updated 11 September 2002