Fluvio-deltaic sequence, Amroth

Pembrokeshire, SW Wales

This outcrop exposes sedimentary rocks of the South Wales Lower Coal Measures Formation (312-313 MA). The sandstones, coals and mudstones that can be seen in these cliffs were deposited in an environment dominated by rivers, swamps and deltas during the Upper Carboniferous

The prominent black horizon in the virtual outcrop is a thin coal seam, formed by the burial and compaction of organic matter deposited in a swamp environment. If you look closely, you may notice cross-beds in the pale orange sandstone layers. These formed during deposition of the sandstone in small channels within the larger delta setting.

 

Note the orthogonal fracture patterns on the exposed bedding surfaces - these are related to the Variscan Orogeny that deformed many of the rocks that outcrop locally Pembrokeshire.    

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Lat: 51°44'01.7"N Long: 4°38'38.1"W