Neumeier U. (1998) Tidal dunes and sand waves in deep outer-shelf environments,
Bajocian, southeast Jura, France. Journal Sedimentary Research. v. 68/3, p.
507-514.
Abstract
In most studies, tidal deposits are associated with shallow-water coastal
areas. In contrast, this paper illustrates an ancient deep-water tidal environment
located on the outer part of the Jura shelf. The Bajocian (mid-Jurassic) sediments
are composed of fine-grained marly limestones that include several crinoidal
limestone bars. These bioclastic bars are formed by stacked dunes and sand
waves showing typical sedimentary structures of tidal environments. In order
to interpret the sedimentology of the crinoidal limestones, the hydrodynamic
behavior of crinoidal particles was investigated. Derived from a sedimentological,
petrographical, and paleontological approach of the area, the results indicate
dunes and sand waves formed on the outer shelf at a depth of about 100-150
m under the occasional influence of tidal currents. Interpretation of seismic
reflection data indicates a shelf-edge position located about 15 km to the
SE.
go back / retour