Formation of Precambrian sediment ripples (reply)

Article metrics


Jerolmack and Mohrig1 suggest that the wave- ripple structure we describe2 from cap carbonates deposited in the aftermath of the Marinoan glaciation was created under storms or hurricanes similar to those experienced today on certain oceanic coasts, citing a documentation of large wave ripples on the seabed off the coast of North Carolina. Side-scan sonar images indicate that such ripples have wavelengths of 0.4–3 m, although the ripple dimensions at sites where samples were obtained for grain-size analysis range from 0.77 to 1.37 m, which is somewhat smaller than the Neoproterozoic examples shown in Table 1 of ref. 2 (1.5–4.5 m). In addition, the side-scan sonar equipment could only be deployed during fair-weather conditions after the passage of several hurricanes, which makes the precise hydraulic conditions responsible for the wave ripples uncertain. Nevertheless, Jerolmack and Mohrig raise an important issue regarding the shear stress (or orbital velocity) required to generate the wave ripples.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.


  1. 1

    Jerolmack, D. J. & Mohrig, D. Nature doi: 10.1038/nature04025 (2005).

  2. 2

    Allen, P. A. & Hoffman, P. F. Nature 433, 123–127 (2005).

  3. 3

    Nielsen, P. J. Geophys. Res. 86, 6467–6472 (1981).

  4. 4

    Allen, J. R. L. Dev. Sedimentol. 30, 444–448 (1984).

  5. 5

    Southard, J. B., Lambie, J. M., Federico, D. C., Pile, H. T. & Wiedman, C. R. J. Sedim. Petrol. 60, 1–17 (1990).

Download references

Author information

Correspondence to Philip Allen.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Allen, P., Hoffman, P. Formation of Precambrian sediment ripples (reply). Nature 436, E1–E2 (2005) doi:10.1038/nature04026

Download citation

Further reading


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.