THE STRATIGRAPHY AND DEPOSITIONAL CONTEXT OF A TEMPORARY EXPOSURE IN THE ANSTRUTHER FORMATION (STRATHCLYDE GROUP), ANSTRUTHER WESTER, FIFE

A temporary exposure in the Anstruther Formation (Strathclyde Group: V isean, Asbian) behind the now-demolished Anstruther Wester swimming po ol uncovered 13 m of strata within a cyclical sedimentary succession. A total of 68 m of this succession were logged from an arbitrary 10 m below the base of the Johnny Dow's Pulpit sandstone to 5.2 m above the Billow Ness Marine Band. The measured section includes two complete a nd two incompletely measured cycles representing variations on a primi tive 'Yoredale' pattern, in which the transgressive marine shale-carbo nate shelf facies is largely suppressed in favour of upward-coarsening progradational prodelta and delta front, and aggradational delta plai n facies. Each cycle commenced in a non-marine to marginal marine coas tal environment in which shales, thin dolostones (some oncolitic), and 'musselband' shales and dolostones were deposited (the mussels are no n-marine bivalves). Shales were succeeded by progradational channelize d delta front facies, and aggradational delta plain facies also includ ing channel-fill sandstones, typically with pedogenic tops. Variations in cycle thickness relate partly to fluctuations in the supply of san d-grade sediment, and partly to contemporary subsidence, possibly rela ted to tectonic processes. Comparisons are made with the late Briganti an Lower Limestone Formation at St Monans, which together with the Ans truther Formation forms part of a transgressive megasequence initiated late in the Devonian with continental, alluvial, redbeds.