Geology Reference
In-Depth Information
Fig. 10.18
Internal sedimentary structures typical for tidal flat
deposits. (
a
) Bidirectional dune cross-bedding with current
dominance from right to left; (
b
) Bidirectional ripple cross-
bedding with well-developed herringbone structures; (
c
) Partly
bioturbated sand with shell layer at depth and shell lag at the
surface. Note partly excavated shell of the bivalve
Mya arenaria
in live position; (
d
) Horizontally bedded sands above several
convoluted bedsets; (
e
) Multidirectional wave and current ripples
in sand. Note the absence of clear herringbone structures;
(
f
) Partly bioturbated, horizontally bedded sand in lower part of
core, grading into partly bioturbated rippled sand in upper part;
(
g
) Flaser bedding typical for muddy sand facies; (
h
) Lenticular
bedding typical for sandy mud facies; (
i
) Weakly laminated sand
in lower core, followed by well preserved lamination in upper
core, both penetrated by a large worm tube, possibly of
Arenicola
marina
(u-part hidden); (
j
) Rooted salt marsh deposit
