Seismically induced soft-sediment microstructures (seismites) from Meikleour, western Strathmore, Scotland

At the distal portion of a large glacial outwash fan in eastern Scotland, a suite of both macro- and microstructures was examined. The macrostructures reveal intense soft-sediment deformation indicative of liquefaction, fluidization and loading processes possibly associated with neotectonic effects of seismic activity along the nearby Highland Boundary Fault. The section at Meikleour has already been examined at the macroscale and an interpretation put forward. In a follow-up study, microstructures were examined using micromorphological techniques to attempt to establish if this technique could be successfully used, and to reconsider the macroscale interpretation. In light of micromorphological analyses, a similar interpretation of neotectonic deformations associated with seismic activity is suggested. Microstructures, never hitherto observed in fine glaciofluvial outwash, were interpreted as those possibly associated with strong seismic tremors, since no evidence existed for subsequent overriding by glacial ice, mass movement or related processes that might otherwise explain such unusual microstructures. This work further establishes the validity and reliability in using micromorphological analyses.