specpubgsl
The onset of the early Toarcian flooding of the Pliensbachian carbonate platform of Central Tunisia (North-South Axis) as inferred from trace fossils and geochemistry
The flooding of the Lower Jurassic shelf in the North Gondwana Palaeomargin during early Toarcian occurred on a fragmented and irregular topography affected by differential subsidence. The onset of Toarcian sedimentation, in two adjacent sections was characterised by the deposition of limestones under high-energy conditions. The
Châabet El Attaris section was located in a depressed sub-basin, and recorded restricted environmental conditions owing to water stagnation and an oxygen-depleted sea-bottom. The sedimentation of limestones bearing gutter cast structures is related to gravity flows probably linked to storm activities. These processes favoured the
remobilization of sediment at the sea floor, as well as oxygen input to deep waters, as shown by the record of trace fossils including Zoophycos, Ophiomorpha, Chondrites and Diplocraterion . The Kef El Hassine section is located in the upper part of a tilted, less subsident block, as evidenced by its reduced thickness compared with
Châabet El Attaris section; the absence of dark mudstones implies oxic conditions. The Polymorphum Zone consists of limestones showing evidence of sedimentation under high-energy conditions, along with hardgrounds. The occurrence of Zoophycos (deeptiers) in the upper part of some limestone beds of the Polymorphum Zone is linked to
minor erosive processes.
Matias
Reolid
0000-0003-4211-3946
Mohamed
Soussi
Jesús
Reolid
0000-0003-2329-4163
Wolfgang
Ruebsam
Ilef Belhaj
Taher
Emanuela
Mattioli
Moncef
Saidi
Lorenz
Schwark
0000-0003-0683-0817
10.1144/SP514-2021-10
10.1144/SP514-2021-10
http://doi.org/10.1144/SP514-2021-10
The onset of the early Toarcian flooding of the Pliensbachian carbonate platform of Central Tunisia (North-South Axis) as inferred from trace fossils and geochemistry
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Geology