Geology Reference
In-Depth Information
Fig. 9.25
Surface structures on the Chongming Eastern Flat of
the Changjiang Delta. Small symmetrical wave ripples on the
marshland (
a
) and on the upper bare flat (
b
). Small combined-
flow ripples on the bare flat (
c
-
f
) including the flatten-crested
ripples (
d
) and undulatory to lingoid current ripples (
e
,
f
).
Interfering ripples with the coast-parallel straight-crested ripples
increasingly modified by orthogonal waves seaward from (
g
) to
(
i
); ballpoint pen is 14 cm long and pointing toward the sea.
Increasing wave reworking on the muddy flat to produce small
separate erosion holes (
j
), broaden and connect the holes, turn
muddy deposited layer into patches (
k
), and develop the embry-
onic dunes (
i
) and well-developed dunes topped by small ripples
on the marsh-frontal zone (
m
) and the middle and lower inter-
tidal flats (
n
,
o
)
