SUMMARY

The construction of the Second Runway at Manchester Airport generated an extensive drilling programme and created many temporary exposures in the Mercia Mudstone Group. One large natural exposure, the RIGS cliff, was buried under the runway. During infill and benching, good access was gained to this cliff and details are presented. The succession of the upper half of the Bollin Mudstone Formation was recorded in great detail from colour photographs of borehole core from the Terminal Two and Second Runway projects, enabling correlation across the site. Beds formerly placed in the zone of Quaternary halite dissolution were unusually well exposed, revealing breccias, folding and low-angle faulting. Within this subsidence zone, a sequence was established in gently collapsed Byley Mudstone Formation overlying partly brecciated remnants of mudstones formerly placed within the Northwich Halite. The Mobberley Fault was newly exposed in the diversion of Sugar Brook at the western end of the Second Runway. Four other faults, all with easterly downthrow, were detected farther east.