Loading Events


Saturday, 27 June 2020
9:00 am - 7:00 pm
Event Category:

Queensferry bridges (Bill Gray)

Leader: Richard Smith

This is our annual joint excursion with the Edinburgh Geological Society. Following the excursion, we will have afternoon tea with our EGS colleagues.

The excursion starts on the promenade to set the scene and view the 3 bridges now spanning the Firth of Forth. Then we examine the accessible exposures along the shore to the east of South Queensferry which include the Lower Carboniferous West Lothian Oil-Shale Formation dipping generally westwards above the older Gullane Formation (both Strathclyde Group). The West Lothian oil-shales comprise cycles of thin marine or freshwater limestones followed by lagoonal oil-shales then mudstones, siltstones and sandstones where deltaic systems fed into a wide lagoon (Lake Cadell) which existed in this area about 335 Ma, open to the north-east but bounded to the south-east by the Southern Uplands. To the east the Gullane Formation, comprising sandstone and mudstone but generally lacking oil-shale, was intruded during Upper Carboniferous times by two prominent sills, the Mons Hill teschenitic sill and the Hound Point quartz-dolerite sill. These rocks were folded and faulted during the subsequent Variscan Orogeny. The surface bedrock has gradually been eroded by the elements, including within the last two million years, the Pleistocene glaciations. Subsequent late glacial and postglacial deposits cover much of the bedrock away from the shoreline.

Leaving Gregory Building at 9:00, returning at 19:00, travelling by coach

£30 deposit. This is set at a level to recover the anticipated costs of the trip. A small financial adjustment may be made on the bus on the day of the trip. There will be an additional charge for the afternoon tea.

The numbers on this joint excursion are limited to 15 from each society. Therefore early booking is advisable if you wish to make sure of a place.