{"id":105855,"date":"2023-10-17T13:34:56","date_gmt":"2023-10-17T13:34:56","guid":{"rendered":"https:\/\/www.bgs.ac.uk\/?p=105855"},"modified":"2024-03-05T10:23:56","modified_gmt":"2024-03-05T10:23:56","slug":"what-lies-beneath-loch-lomond","status":"publish","type":"post","link":"https:\/\/www.bgs.ac.uk\/news\/what-lies-beneath-loch-lomond\/","title":{"rendered":"What lies beneath Loch Lomond?"},"content":{"rendered":"\n
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Loch Lomond is a freshwater lake at the heart of the Loch Lomond and Trossachs National Park in the south-west highlands of Scotland. It is surrounded by beautiful landscapes and vistas influenced by past ice ages.  <\/p>\n\n\n\n

Using seismic data, marine geoscientists at BGS have discovered a new sedimentary unit buried in deposits beneath the loch, giving new insights into its past glacial history.<\/p>\n\n\n\n

Scotland in the last ice age<\/h2>\n\n\n\n

Much of the highlands of Scotland were covered by an extensive mountain ice cap 12 900 to 11 700 years ago, during the last period of cold climate (known as the Younger Dryas or the Loch Lomond Stadial). Decades of onshore research have shown how past ice ages have shaped the landscape of Loch Lomond, including carving of the present-day loch itself and its surroundings through processes such as erosion and deposition. However, this new dataset provides an interpretation of the stratigraphy now buried beneath the loch.<\/p>\n\n\n\n

Mapping the loch bed and subsurface features<\/h2>\n\n\n\n

BGS used multibeam bathymetry surveys to gather detailed information about the features on the loch bed. The data revealed a series of flat-topped and prograding features (or the growth of a river delta further out into the sea over time) and ancient glacial geomorphological features. These features include drumlins, which are oval-shaped hills largely composed of glacial drift that form parallel to the direction of ice flow, and streamlined bedrock, created by glacial restructuring of hard beds that produces a collection of extended rock landforms, interpreted as showing the direction of the palaeo-ice advance.<\/p>\n\n\n\t\t\t

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It\u2019s been incredibly exciting to have had the opportunity to interpret these datasets and present the loch surface and subsurface in a way we\u2019ve never seen before. The seismic mapping and interpretation of the Inchmurrin Formation helps us understand past landscapes and geological events that are now buried under the loch bed. We are keen to undertake further research in and around the area, building on the seismostratigraphical framework that we observe in Loch Lomond.<\/p>\n

Nicola Dakin, BGS marine geoscientist.<\/strong><\/p>\n\t\t\t\t<\/div>\n\t\t\t<\/blockquote>\n\t\t\t\n\n\n

BGS geoscientists used seismic data to map the subsurface of the loch. Seismic data uses sound waves, which travel through buried layers of sediment, forming an acoustic image based on density variations between different sediment types. We interpreted the acoustic signature, linking sedimentary processes and depositional environments to past climatic cycles. This provided a framework to create an updated chronostratigraphy within the loch.<\/p>\n\n\n

\"(A)<\/a>
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(A) Boomer and (B) EdgeTech data enabled a visual comparison of the stratigraphy imaged by different acquisition systems BGS \u00a9 UKRI.<\/p>\n<\/div>\n\t\t\t\t\t

\"Expand<\/a><\/div>\n\t\t\t\t<\/figcaption><\/figure>\n\n\n

What did the survey reveal?<\/h2>\n\n\n\n