GSSP for Aeronian Stage
Definition:
The base of the Aeronian Stage is defined in the Trefawr Track section, 500m north of Cwm-coed-Aeron Farm, Wales, where it coincides with the base of the Monograptus triangulatus Biozone.
Location:
The GSSP is located in the Trefawr Track section, 500m north of Cwm-coed-Aeron Farm, Wales, UK.
Sedimentology:
The GSSP lies within the gently-dipping blocky mudstones of the Trefawr Formation, which principally yield abundant and diverse shelly faunas, but also contain enough graptolites to allow recognition of several biozones.
Primary Markers:
Graptolites:
The base of the Monograptus triangulatus biozone is represented by the incoming of Monograptus austerus sequens.
Secondary Markers:
Graptolites:
Monograptus austerus vulgaris and Diplograptus elongatus occur in the cyphus Biozone, just below the stage boundary.
Correlation Events:
Graptolite FAD Monograptus austerus sequens
Other Locations around the World:
Holland, C. H. and Bassett, M. G. (eds.). A global standard for the Silurian System. National Museum of Wales, Geological Series 9, Cardiff.
References:
Holland, C. H., 1985. Series and Stages of the Silurian System. Episodes 8/2, p. 101-103.
Cocks, L. R. M., 1989. The Llandovery Series in the Llandovery Area. In: Holland, C. H. and Bassett, M. G. (eds.). A global standard for the Silurian System. National Museum of Wales, Geological Series 9, p. 36 - 50, Cardiff.