Particle-Laden Flow pp 331-343 | Cite as

# Influence of Coriolis forces on turbidity currents and sediment deposition

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## Abstract

Using laboratory analogue experiments I show how the Earth’s rotation can influence the deposition patterns of large-scale turbidity currents. While it has been previously recognized that the EarthÕs rotation can influence the trajectories of turbidity currents (Middleton 1993; Huppert 1998; Kneller & Buckee, 2000) the experiments discussed in this paper represent the first systematic laboratory study of the Coriolis forces acting upon turbidity currents. The scale at which Coriolis forces become important is best expressed using the Rossby number, defined as *Ro = U/fL*, where *U* is a depth averaged velocity, *L* the length scale and the Coriolis frequency, *f*, is defined by *f* = 2Ω sin θ, where Ω is the Earth’s rotation rate and θ is the latitude. Coriolis forces will dominate a current when *Ro* < 1 (Nof 1996). For example a large turbidity current with a velocity of *U* = 10m s^{−1} at a latitude of 45° North where *f* = 1 × 10^{− 4} *s* ^{−1}, has *Ro* < 1 for length scales greater than 100 km.

In this paper I discuss two effects of the Coriolis forces upon large-scale turbidity currents. The first series of experiments document how an increase in the Coriolis parameter resulted in a decrease in the rate of turbulent entrainment of overlying sea-water into a density current. The second set of experiments look at the maximum radius of deposition of a turbidity current on a flat plane, and we find that the resulting radius is inversely proportional to the Coriolis parameter. This result implies that there may be a latitudinal dependence upon the radius of turbidite deposition on the flat oceanic abyssal plane. I compare the scaling developed from these idealized laboratory models to field observations of the 300–500 km spatial extent of the turbidites arising during the 1929 Grand Banks earthquake. By making estimates of the velocity we find that this turbidity current had *Ro* ∼ 1, so that Coriolis forces may have limited the spatial extent of the resulting turbidite.

## Keywords

Froude Number Coriolis Force Gravity Current Turbidity Current Coriolis Parameter## Preview

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## References

- [1]Alavian, V. (1986) Behavior of density currents on an incline. J. Hydraulic Eng. 112:27–42CrossRefGoogle Scholar
- [2]Cenedese, C., Whitehead, J.A., Ascarelli, T.A. & Ohiwa, M. (2004) A dense current flowing down a sloping bottom in a rotating fluid. J. Phys. Oceanog. 34:188–203CrossRefGoogle Scholar
- [3]Dallimore, C.J., Imberger J., & Ishikawa, T. (2001) Entrainment and turbulence in saline underflow in Lake Ogawara. J. Hydraul. Eng. 127:937–948CrossRefGoogle Scholar
- [4]Davies, P.A., Wahlin, A.K. & Guo, Y. (2006) Laboratory and analytical model studies of the Faroe Bank Channel deep-water outflow. J. Phys. Ocean. 36:1348–1364CrossRefGoogle Scholar
- [5]Ellison, T.H. & Turner, J.S. (1959) Turbulent entrainment in stratified flows. J. Fluid Mech. 6:423–448CrossRefGoogle Scholar
- [6]Emms, P.W. (1999) On the ignition of geostrophically rotating turbidity currents. Sedimentology 46:1049–1063CrossRefGoogle Scholar
- [7]Etling, D., Gelhardt, F., Schrader, U., Brennecke, F., Kuhn, G., Chabert d’Hieres, G. & Didelle, H. (2000) Experiments with density currents on a sloping bottom in a rotating fluid. Dyn. Atmos. Oceans. 31:139–164Google Scholar
- [8]Griffths, R.A. (1986) Gravity currents in rotating systems. Ann. Rev. Fluid Mech. 18:59–89CrossRefGoogle Scholar
- [9]Hallworth, M.A., Huppert, H.E. & Ungarsish, M. (2001) Axisymmetric gravity currents in a rotating system: experimental and numerical investigations. J. Fluid Mech. 447:1–29Google Scholar
- [10]Heezen, B.C. & Ewing, M. (1952) Turbidity currents and submarine slumps, and the 1929 Grand Banks earthquake. Am. J. Sci. 12:849–873CrossRefGoogle Scholar
- [11]Hogg, A.J., Ungarish, M. & Huppert, H.E. (2001) Effects of particle sedimentation and rotation on axisymmetric gravity currents. Phys. Fluids 13:3687–3698CrossRefGoogle Scholar
- [12]Horner-Devine, A.R., Fong, D.A., Monismith, S.G. & Maxworthy, T. (2006) Laboratory experiments simulating a coastal river inflow. J. Fluid Mech. 555:203–232CrossRefGoogle Scholar
- [13]Huppert, H.E. (1998) Quantitative modelling of granular suspension flows. Proc. Royal Soc. 356:2471–2496Google Scholar
- [14]Jacobs, P. & Ivey, G.N. (1998) The influence of rotation on shelf convection. J. Fluid Mech. 369:23–48Google Scholar
- [15]Kneller, B. & Buckee, C. (2000) The structure and fluid mechanics of turbidity currents: a review of some recent studies and their geological implications. Sedimentology 47:62–94CrossRefGoogle Scholar
- [16]Middleton, G.V. (1993) Sediment deposition from turbidity currents. Annu. Rev. Earth Planet. Sci. 21:89–114CrossRefGoogle Scholar
- [17]Nof, D. (1996) Rotational turbidity flows and the 1929 Grand Banks earthquake. Deep Sea Res. 43:1143–1163CrossRefGoogle Scholar
- [18]Parker, G., Fukushima, Y. & Pantin, H.M. (1986) Self-accelerating turbidity currents. J. Fluid Mech. 171:145–181CrossRefGoogle Scholar
- [19]Piper, D.J.W., Shor, A.N., Far’re, J.A., O’Connell, S. & Jacobi, R. (1985) Sediment slides and turbidity currents on the Laurentian Fan; sidescan sonar investigations near the epicentre of the 1929 Grand Banks earthquake. Geology 13:538–541CrossRefGoogle Scholar
- [20]Price, J.F. & Baringer, M.O. (1993) Outflows and deep water production by marginal seas. Prog. Ocean. 33:161–200CrossRefGoogle Scholar
- [21]Princevac, M., Fernando, H.J.H. & Whiteman, C.D. (2005) Turbulent entrainment into natural gravity driven flows. J. Fluid. Mech. 533:259–268CrossRefGoogle Scholar
- [22]Shapiro, G.I. & Zatsepin, A.G. (1997) Gravity current down a steeply inclined slope in a rotating fluid. Ann. Geophysicae 15:366–374CrossRefGoogle Scholar
- [23]Turner, J.S. (1986) Turbulent entrainment—the developement of the entrainment assumption and its application to geophysical flows. J. Fluid. Mech. 173:431–471CrossRefGoogle Scholar
- [24]Ungarish, M. & Huppert, H.E. (1999) Simple models of Coriolisin influenced axisymmetric particle-driven gravity currents. Int. J. Multi. Flow 25:715–737CrossRefGoogle Scholar
- [25]Wells, M.G. & Wettlaufer, J.S. (2005) Two-dimensional density currents in a confined basin. Geophys. Astro. Fluid Dyn. 99:199–218CrossRefGoogle Scholar
- [26]Wells, M.G. & Wettlaufer, J.S. (2006) The long-term circulation driven by density currents in a two-layer stratified basin. J. Fluid. Mech. (accepted)Google Scholar