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FIGURE 6
Sand flat. (A) Vertical section of a sand-flat deposit with erosional base overlying sub-
tidal sandstone. Early Cambrian St. Piran Formation, Gog Group, southern Rocky Mountains,
Canada. (B) Flat-topped ripples and relict troughs. Late Carboniferous Stull Shale, Kanwaka For-
mation, Waverly fossil site, Kansas, USA. (C) Cross-section view of deep
Arenicolites
isp. Early to
Middle Cambrian Campanario Formation, Mes
´
n Group, Angosto de Perchel, Quebrada de Huama-
huaca, northwest Argentina. Lens cap
¼
5.5 cm in diameter. (D) Bedding-plane view (top) of
Diplo-
craterion
isp. Early to Middle Cambrian Campanario Formation, Mes´n Group, Quebrada de Moya,
Quebrada de Huamahuaca, northwest Argentina. Coin
¼
1.5 cm in diameter. (E) Cross-section view
of
Syringomorpha
pipe rock. Early to Middle Cambrian Campanario Formation, Mes´n Group,
Angosto del Morro de Chucalezna, Quebrada de Huamahuaca, northwest Argentina. Lens cap
¼
5.5 cm in diameter.
These assemblages commonly reflect short-term colonization windows along
dune reactivation surfaces (
M´ngano et al., 1996; Pollard et al., 1993
). In Cam-
brian examples, the ichnogenus
Syringomorpha
may occur in high densities in
rippled sandstone (
Fig. 6
E;
M´ngano and Buatois, 2004a
). Mud drapes formed
during slack water may contain
Planolites
. In modern examples of sand flats,
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