Saturday, 4 November 2017

The final excursion ...south Pembrokeshire


Manorbier Beach- sedimentary features and trace fossil.
Top: large arthropod burrow (Beaconites) shown as a gap in the cross lamination of the Old Red Sandstone.
Bottom: mud cracks shown in the sandstone in green due to reduced iron within the red oxidised iron contained in sandstone. Also seen was paleosol, good examples of cross-lamination formed by the migration of ripples and concretions.

Freshwater East.
Left: clear bedding in the Gray Sandstone Group (underlying the Old Red Sandstone). Layers of alternating bands of a fine grained sandstone with clear parallel lamination and finer grained mudstone that is fractured. Some dark fossiliferous material containing Tentaculites.

Saundersfoot- Folding in coal measures (mudstone and sandstone)
Left: syncline and examples of beds sliding over each other.
Right: Lady's Cave anticline. A good example of an anticline with fracture cleavage and as a result has been more heavily eroded at the hinge , hence creating a cave like structure

Saundersfoot- Part of the Pembrokeshire coal field.
Right: the coal seem with fossiliferous horizons and iron stone nodules either side. We found lots of fossils, mainly roots and plant matter including horsetail cross sections and some small leaf fragments

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