glacial stratigraphy SE Caithness

glacial erratics   moraines  till

till fabric and its first recognition in Caithness

till fabric

The complex glacial stratigraphy of lower Berriedale, where the deposits of the inland ice and Moray Firth ice are inter-bedded

Glacial stratigraphy

One of the main tools for reconstructing the glacial history of an area is to examine the local stratigraphic record. Tills are firm indicators of the former presence of glacier ice and the their fabrics and erratic content provide information about the direction of former ice movement. Where tills are inter-bedded with other sediments, such as meltwater or periglacial deposits then a sequence of events can be built up.

In Caithness, the possibilities for the development of complex stratigraphy has been greatly reduced by the erosive effects of successive ice masses. The latest glaciers tend to erode the loose sediment deposited by earlier ice masses and meltwater. Nonetheless useful information can be provided even when only two tills are superposed, as shown in the example below from the Dunbeath Water. The lower brown till is derived from southeast Caithness and it was deposited by ice moving from the west. This inland till has been partly eroded by a later ice movement from the Moray Firth which left its marker, a dark-grey shelly till. Locally, as at Reay, the shelly till is overlain by a younger inland till.