The Silurian nautiloid-bearing strata of the Cellon Section (Carnic Alps, Austria): Color variation related to events

Silurian nautiloid-bearing strata (Llandovery–Přídolí) from the Cellon Section of the Carnic Alps (Austria) are compared using the innovative perspective of the color of the enclosing sediment of these fossiliferous beds with coeval regional occurrences along the North Gondwana Margin (Prague Basin, Sardinia, Morocco). Particular attention was placed on distinguishing and comparing the colors of these levels and their general nautiloid faunal composition in order to identify the prevailing features of their occurrence at precise stratigraphic intervals. Red-brown strata usually reflect time-rich or slowly accumulated deposits from a diverse in-situ fauna while black-gray strata are related to single event beds due to episodic deposition probably influenced by currents. Other single event beds of distinctive pink (Gorstian in age) and purple strata (Ludfordian in age) may prove useful as marker horizons.The overall data set available in relation to these diversely colored nautiloid-bearing horizons at the Cellon Section at precise time slices when compared with global eustatic conditions and biotic events has highlighted that these deposits reflect both local phenomena within the depositional basin and regional depositional episodes. These include apparent mass mortality events and the cephalopod limestone biofacies that may be considered as time-specific facies.

► Comparison of Silurian nautiloid-bearing strata along the North Gondwana Margin
► Red-brown strata reflect time-rich accumulations from a diverse in-situ fauna.
► Black-gray strata reflect episodic deposition probably influenced by currents.
► Distinctive pink and purple event horizons may prove useful as marker horizons.
► Overall these Silurian nautiloid strata may be considered as time-specific facies.