Low biotic diversity and pauperate
acritarch assemblage in deposits of the Soru Formation reflect once again an unstable environment at the inital phase of the Liivian sedimentation.
The
acritarch record of Australia indicates that pre- and post-Snowball populations are identical and do not indicate repopulation of marine areas by extremophiles that survived both catastrophic glaciation in hot springs and the brutal greenhouse conditions which followed (Grey et al., 2003).
A mineralized alga and
acritarch dominated microbiota from the Tully Formation (Givetian) of Pennsylvania, USA.
Vendian-Lower Cambrian
acritarch biostratigraphy of the central Caledonian fold belt in Scandinavia and the palaeogeography of the Iapetus-Tornquist seaway.
The Lumsden Dam Formation contains the graptolite Rhabdinopora flabelliformis flabelliformis and an
acritarch assemblage of Tremadocian age (White et al.
Still, the impoverished
acritarch assemblage in this formation (Globosphaeridium cf.
The conodont faunas from this area have been studied intensively and David Gelsthorpe (University of Leicester, UK) is currently engaged in a detailed study of
acritarch diversity changes through the Ireviken Event in NW Gotland.
These strata contain the Lontova
acritarch assemblage and a low-diversity small shelly fauna characteristic of the Platysolenites antiquissimus Zone (e.g.
present the discovery of the messaoudensis-trifidum
acritarch assemblage in the upper Tremadocian-lower Floian, Lower Ordovician of
The outcrops also contain undescribed pre-Agnostus pisiformis
acritarch assemblages that confirm the timing of their deposition to the Cambrian Epoch 3 (Palacios et al.
Early Tremadoc
acritarch microfossils were reported by Doyle (1979) and confirmed by Palacios et al.
The messaoudensis-trifidum
acritarch assemblage is known from upper Tremadocian to lower Floian (Lower Ordovician) strata in many localities on the Gondwanan margin (Servais et al.