15 members spent an excellent day under the very able leadership of Noel Pearson to the two current Carboniferous Stage Stratotype sites in Cumbria. Both have recently been the subject of a great deal of new research by specialist palaeontologists, focussed not only on the macro fauna, but on advances in the field of micro fossils.
The leader gave members an excellent summary of the history of research on these two sites and an update on recent findings. Each stage has a basal boundary defined at a specific point in the marine rock section. Stages are chronostratigraphical (time
units). We are fortunate here in east Cumbria to have these two classic sites a short distance apart. The Asbian basal boundary at Little Asby Scar (NY 699083) and the Brigantian at Janny Wood, south of Kirkby Steven (NY 783038).
The morning was spent walking up the Potts Beck valley to the Little Asby Scar location. A short climb up the Scar brought us to the key exposure – a clean rocky scar section where the Stage junction is currently defined. Yellow markings on the cliff face and the obvious signs of coring either side of the junction mark the spot. The finer points of the palaeontology are not obvious in the field, but the whole site is remarkably fossil rich. Some magnificent specimens of corals and sponges kept members occupied for some time. Some unusual dark bands of material also stretched member’s minds. The geomorphological features of the wider region were discussed from the scarp top, which affords excellent views over the karst terrain, the spectacular meandering Potts Beck and the Howgill Fells to the south. The rather complex recent drainage and glacial history of the area was discussed.
A short drive eastwards for the afternoon session brought us to the River Eden Valley and the type section of the Brigantian in the steeply dipping beds exposed along the river bed. A detailed log of the beds was provided to view the section as the group walked upstream from a notable series of waterfalls in the river below the wood. En route we were introduced to a new term at Catagill Scar – a ‘stratomorph’ – an exposed bedding plane surface which now forms a 45º slab of rock on the west bank of the Eden. Rather heavy rain somewhat shortened deliberations on this site, but the day as a whole was an insight to members on how very detailed palaeontology is enabling these sections to be logged and interpreted.
Leader Noel Pearson at the Little Asby Scar site – walking pole to his left lying horizontally at the base of the Asbian.
Janny Wood site. Carboniferous beds dipping upstream (to right in the view). The Brigantian boundary is at the extreme right of the picture.
