Seeking a Scottish source: Updating the story of Stonehenge’s Altar Stone

"Current Archaeology issue 415 reported on new scientific analysis suggesting that the origins of the Stonehenge Altar Stone lay hundreds of miles from Salisbury Plain, in the Orcadian Basin of north-east Scotland. The story has already moved on, however, with recently published research narrowing the search further, ruling out Orkney itself as a potential source. Rob Ixer, Richard Bevins, and Nick Pearce bring us up to date." November 2024

"This map shows the distribution of the Old Red Sandstone sedimentary basins of Britain and Ireland, highlighting the location and extent of the Orcadian Basin."

Full article: https://the-past.com/feature/seeking-a-scottish-source-updating-the-story-of-stonehenges-altar-stone/

Or at https://www.academia.edu/125350876/_054_CA417_Altar_stone_geology2_EMSCCH