Folding at Broadhaven
Pembrokeshire, SW Wales
One of The Geological Society's 100 Great Geosites. Asymmetric folds in interbedded Carboniferous siltstones, shales and coal horizons are cut here by a number of northward-propagating thrusts. This classic structure has been studied in some detail (e.g. Williams and Chapman,1983) as it provides an excellent outcrop example to examine the interplay between faulting and folding during deformation.
Trevayne
Pembrokeshire, SW Wales
Large-scale harmonic fold within Carboniferous siltstones, shales and coal horizons. Close inspection of the fold core reveals several low offset thrust segments which probably formed to accommodate the relatively tight interlimb angle here. The cross-section below shows the transition in structural style between this location, Monkstone Point and Saundersfoot.
Trevayne
Pembrokeshire, SW Wales
Large-scale harmonic fold within Carboniferous siltstones, shales and coal horizons. Close inspection of the fold core reveals several low offset thrust segments which probably formed to accommodate the relatively tight interlimb angle here. The cross-section below shows the transition in structural style between this location, Monkstone Point and Saundersfoot.
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.
Lat: 51°44'01.7"N Long: 4°38'38.1"W
