Lacustrine Environments - Trace Fossils as Indicators of Sedimentary Environments - page 392

FIGURE 8 Trace fossils in balanced-fill lake-type basins. (A) and (B) Examples of profundal trace
fossils of the Mermia Ichnofacies in the Cretaceous of Montsec, Spain. Photographs courtesy of J. de
Gibert. (A) Undichna britannica in lacustrine shales. (B) The arthropod trackway Hamipes didactylus
on a bedding plane of a sandstone interpreted as an underflowdeposit. (C) Palaeophycus tubularis from
shallow-lacustrine deposits of the Triassic Tanzhuang Formation, Jiyuan-Yima Basin, central China.
(D-F) Examples fromtheTiptonShaleMember (RifeBed) of theEoceneGreenRiver Formation,Wyo-
ming, USA. (D) Medium-sized Arenicolites of the Skolithos Ichnofacies produced in sandy soft sedi-
ments of either the eulittoral zone or backshore deposits of the supralittoral zone. Arrows show the U-
shaped lower portion of the traces. (E) Example of a horizontal, large-sized meniscate-backfilled trace
fossil ( Taenidium ;arrow)ofthe Scoyenia Ichnofacies produced in a soft substrate of the eulittoral zone.
(F) Vertical backfilled burrow of the Scoyenia Ichnofacies ( Taenidium ; arrow) with sharp burrow
boundaries in subaerially exposed high-energy littoral-zone sandstones.
3.3 Underfilled Lake-Type Basins
Underfilled lake-type basins ( Fig. 9 ) are those in which the amount of sediment
and water input is less than the potential accommodation, and they are charac-
terized by evaporitic lithofacies associations (e.g., carbonates, evaporite