Tectonic and mining induced fault reactivation around Barlaston on the Midlands Microcraton, North Staffordshire, UK

The North Staffordshire Coalfield occupies the northern apex of a triangular area of late Proterozoic continental crust, the Midlands Microcraton. Most faults identified at surface in the late Carboniferous rocks originated either as a result of reactivation of structure during the Variscan orogen in the late Carboniferous, or its collapse in the early Permian. The coalfield has been extensively undermined and many examples of mining-induced fault movement have been recorded in the Barlaston area between 1960-2000, The style of ground deformation observed in the area is described. Most movements have resulted in a series of distinct, extensive, fault scarps and fissures on the ground surface, causing widespread damage to structures, property, underground utilities and land. Several phases of fault movement have occurred, separated by periods of relative stability. Fault scarps may occasionally reach 2 m high, being indicative of multi-seam (3+) mining operations. These are restricted to a few metres in width but reach several hundreds of metros in length. The reasons why so many faults have been reactivated around Barlaston, why the surface expression of the faults are different in Carboniferous and Triassic outcrops, and why some faults appear to have reactivated since the cessation of mining are discussed.