The
Neath Disturbance is a geological structure which stretches across south
Wales from
Swansea Bay northeastwards as far as
Hereford in western
England. It consists of a series of both
faults and associated
folds which were active during the mountain-building period known as the
Variscan orogeny. This line of weakness probably featured in the earlier
Caledonian Orogeny and perhaps reflects a more ancient line of weakness in the
basement rocks.