Geologists look to ancient sand ripples for clues to the environmental
conditions in which they formed.
Wave-sculpted ripples form as waves travel across the surface of a body of
These waves cause water beneath the surface to circle around and
around, generating oscillating flows that pick up sand grains and
set them down in a process that eventually carves out troughs and grooves
throughout the sandbed.
Water flows in a circular manner beneath a wave
Current direction affects the shape of the ripple
The size and spacing of wave ripples generally scale with water depth
and wave conditions, and are widely used to reconstruct coastal
environments of the geologic past. Interpretations based on average ripple
dimensions and assumes constant wave conditions.
But many rippled beds contain striking patterns involving defects—deviations
from straight, evenly spaced ripple crests—that suggest more dynamic flow
Ripple defects resembling hourglasses, zigzags, and tuning forks were
likely shaped in periods of environmental changes—for instance, during
strong storms, or significant changes in tidal flows.
As conditions change the ripple pattern develops defects. For example..
as waves get shorter you get narrower ripples and patterns that
as waves shorten even further—creating faster, shorter waves—produce a
pattern of "secondary crests," in which existing ripples appeared to
form temporary "shadow" ripples on either side, took over
on the other hand generating longer waves produces ripples in zigzag
as ripples transform to even wider spacing.patterns resembling
tuning forks are created
So it would seem ripple defects are the intermediate step as the ripple
pattern transform from one stable pattern to a new stable pattern.
The area is currently under study