Evidence for active ice retreat and ice-dammed lake formation during deglaciation in Raitts Burn

The Speyside area of the southern Monadhliath Mountains displays an exceptionally welldeveloped suite of landforms and deposits that formed during the latter stages of Late Devensian glaciation in this part of Scotland (Young, 1978; Hinxman and Anderson, 1915; Merritt et al., this guide). This section of the field guide describes the glacial landforms and sediments present in the valley of Raitts Burn (NH 760 047 – 796 036). The burn flows south-eastwards across the north-western flank of Strathspey to join the valley of the River Spey c. 3 km downstream of Kingussie (Fig. 1). Exposed in the cliff sections cut by the burn is a sequence of rhythmically laminated clays, silts and sands, interbedded with ice-proximal diamictons and matrix-rich gravels (Auton 1998; Phillips and Auton, 2000). Detailed examination of the complex suite of sedimentary and glacitectonic structures developed within these sediments has revealed a complex sequence of depositional and deformational events recording the formation and overriding of an ice-dammed lake (Phillips and Auton, 2000). The glacial landform record in the area clearly indicates that this complex pattern of meltwater ponding and ice advance into the lake occurred in response to active ice retreat during the deglaciation of the Raitts Burn basin.