'One of a kind' window opened into Scotland's past

Geologists say they have been given a "one-of-a-kind" window into Scotland's past, after getting a chance to analyse core rock from the Great Glen Fault - formed hundreds of millions of years ago.

The British Geological Survey (BGS) said materials unearthed in investigation work for a hydro-storage scheme in Lochaber had allowed a rare look into a distant geological past.

The Great Glen Fault is more than 1,000km (621miles) long and 40km (25miles) deep, stretching from Ireland through Scotland to Norway.

Dr Romesh Palamakumbura, a BGS geologist, said it was "incredible" to have access to the rocks and see something so "spectacular and unique".

SSE Renewables has proposed a pumped hydro storage scheme at Coire Glas on the shores of Loch Lochy, near South Laggan.

The core was drilled in 2023 when the project began and was delivered to BGS premises in Edinburgh at the end of 2024, where geologists have since been analysing it.

Tremors and minor earthquakes are sometimes reported in the area, though rocks associated with the fault zone generally remain mostly hidden to the human eye by the waters of Loch Ness, Loch Oich and Loch Lochy.

Geologists were able to study 10m (32ft) of the rocks in an attempt to better understand how such fault systems work and how fluids emerging from deep within the Earth's crust change the properties of the rock.

Dr Palamakumbura added: "It's such an old fault zone, the fault formed as part of the initial formation of Scotland and that was 400 or so million years ago."

He said there was a "fundamental geology" aspect to their studies as they worked to understand "basic crustal processes".

The core will be stored by the BGS with access given to the scientific community and preserved for future generations.

Other bore holes have been drilled at the site, including to a depth of about 650m (2,100ft).

An SSE Renewables spokesperson said: "SSE Renewables is delighted to support the advance in scientific understanding of the Great Glen Fault and similar structures worldwide, thanks to the core that was recovered during the ground investigation for Coire Glas.

"As well as being of scientific value, the recovered core has been critical for understanding ground conditions and managing ground risk as the project progresses towards a final investment decision."