Wave-form sheeted contourite drift on the Barra Fan, NW UK continental margin

Paul C. Knutz, E. John W. Jones, John E. Howe, Tjeerd J.C. Van Weering, Dorrik A.V. Stow

Publikation: Bidrag til bog/rapport/konferenceproceedingsBogkapitelForskningpeer review

17 Citationer (Scopus)

Abstrakt

The lithology of a 30 m long piston core (MD95-2006) and high-resolution, seismic profiles from the lower Barra Fan, Rockall Trough, reveal a sheeted drift form with internal sediment waves deposited over the last glacial-interglacial cycle. Deposition of these mainly fine-grained deposits was controlled by a combination of downslope and alongslope transport mechanisms that interacted with the positive topography created by debrite lobes on the lower fan. The core penetrates a small field of sediment waves (wavelength approx. 1 km, height 3-6 m), which onlap a debrite lobe dated to the last glacial maximum. The sedimentary sequence shows: (1) silty-muddy contourites deposited during the mid-Devensian (Marine Isotope Stage 3), (2) glacimarine hemipelagites and sandy turbidites deposited between 26 and 18 C14 ka BP, followed by a short phase of erosion and redeposition by bottom currents, and (3) glacimarine hemipelagites and silty-muddy contourites representing the glacial to Holocene transition. On the distal fan edge, a drift sequence with upslope-migrating sediment waves (wavelengths approx. 3 km, height 15-30 m) onlaps the tongue of a previous slide event (pre-Devensian?). These bedforms were probably generated by decelerating, low-density glacigenic turbidity currents, but pirated by contour-following bottom currents on the distal part of the drift.

OriginalsprogEngelsk
TitelDeep-water contourite systems: Modern drifts and ancient series, seismic and sedimentary characteristics
RedaktørerD.A.V. Stow, C.J. Pudsey, J.A. Howe, J.-C. Faugères, A.R. Viana
ForlagGeological Society of London
Sider85-97
Antal sider13
ISBN (Trykt)1-86239-092-4
DOI
StatusUdgivet - 2002
Udgivet eksterntJa

Publikationsserier

NavnGeological Society Memoir
ForlagGeological Society of London
Vol/bind22
ISSN (Trykt)0435-4052

Programområde

  • Programområde 5: Natur og klima

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