The uppermost beds of the 'Latorp Limestone' consist of strongly bioturbated
greyish-brown mudstone to wackestone with numerous discontinuity surfaces (Figs 2D, 5F).
The overlying Awgu Group (Coniacian--Santonian) consists of the grey-blue Awgu-Ndeaboh Shale and the medium to coarse-grained bioturbated
2) show an upward progression into a highly bioturbated
facies with abundant trace fossils, that lacks turbiditic structures.
Several fining-upward cycles are recognised within the formation and these are composed of conglomerate and cross-bedded sandstone in their basal part and bioturbated
siltstone and claystone / mudstone in their upper part (Ghazi, 2005, 2009).
Here, a 10 m thick section composed of heterolithic facies (conglomerates and fine to medium grained sandstones) was deposited under littoral shallow marine conditions, including several tidal channel deposits represented by glauconitic bioturbated
sandstones that bear the local fossil flora.
Mud that's been churned up, or bioturbated
, would be softer, freed of the stiff microbial mat that covered much of the seafloor.
1989), which occurs within the bioturbated
and oxic zones of sediment seafloor.
North of Saguenay River, most of these sediments are deposited on the floor of the Laurentian Channel, which previous studies have indicated to consist mainly of dark grey, bioturbated
, fine silts (Nota and Loring 1964; St-Onge et al.
A typical cycle consists of bioturbated
fine-grained clayey sandstone, passing upwards to horizontally stratified or cross-bedded medium- to coarse-grained sandstone (Adamovic, 1994).
Nitrogen cycling in lake sediment bioturbated
by Chironomus plumosus larvae, under different degrees of oxygenation.
Elsewhere, the marine sediments are horizontally bedded and highly bioturbated
and commonly contain fossil red algal fragments and barnacles.
The association of megarippled sandstone beds and interbedded laminated and bioturbated
fine-grained sediments indicates this sequence was deposited in a near-shore environment.