Tidal Flats and Subtidal Sand Bodies - Trace Fossils as Indicators of Sedimentary Environments - page 518

2.1 Supratidal Marshes and Mangroves
Along modern temperate shorelines, the supratidal area may be vegetated by
salt marshes, the cordgrass Spartina being one of the most widespread plants,
their root traces being typically pervasive in such deposits ( Fig. 2 ; e.g., Basan
and Frey, 1977; Edwards and Frey, 1977; Montague et al., 1981; Pomeroy et al.,
1981 ). Along tropical shorelines, mangroves tend to be common, allowing the
formation of extensive root networks of, for example, Avicennia , Rhizopora ,
and Sonneratia ( Fig. 3 A; Cad ´ e, 1998 ). Animal traces include elements of
the Psilonichnus Ichnofacies, with gastropods and crustaceans (mainly crabs)
forming some of the most important marine elements ( Frey and Pemberton,
1987 ; Fig. 2 ). The beetle Bledius arenarius typically constructs dwelling bur-
rows ( Sch¨fer, 1972 ). Insects are by far

the most important terrestrial

FIGURE 3 Modern mangrove and mud flats. (A) Modern mangrove. Gran Mangle, Dominican
Republic. (B) Crab trackway on a modern mud flat near Estancia Maria Luisa, Tierra del Fuego,
southern Argentina. (C) Grazing trail on a modern mud flat between Cabo Irigoyen and Cabo
San Pablo, Tierra del Fuego, southern Argentina.