Trace fossils and ichnofabrics across the Volkhov depositional sequence (Ordovician, Arenigian of St. Petersburg Region, Russia)
Ichnofabric (bioturbation and bioerosion) patterns show a conspicuous symmetry across the Volkhov depositional sequence, which suggests a close relationship between the inchnofabric and the sea-level change. Bioclastic limestones interpreted as calcareous tempestites show evidence of relatively deep bioturbation (ca. 15 cm) of high intensity. Ichnogenera Thalassinoides, Chondrites, Paleophycus, ? Dolopichnus, Trypanites, Gastrochaenolites and Planolites participate for the most part in the overall substrate disturbance. Intensive deep bioturbation and even bioerosion occurs in the studied area even below the recently re-interpreted Early/Middle Ordovician boundary. This observation suggests that diverse strategies and deep bioturbation, as well as other modern features (e.g., complex tiering, re-visiting of filled burrows), first appeared during the Early Ordovician in this region.
SNIP (Scopus, 2015): 0.700
IF (ISI, 2015): 1.326
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