Post Glacial Rebound

A recent paper by the University of London, Southampton, and Manchester; about the discovery of the quarry that provided the 'bluestones' for Stonehenge at Craig Rhos-y-Felin (Mike Parker-Pearson et al., 2015) caught the eye of the world by archaeologists announcing Stonehenge was initially built in Wales and was then transferred to Salisbury Plain 500 years later.

The ‘Craig Rhos-y-Felin: a Welsh bluestone megalith quarry for Stonehenge’ was a report published in December’s Edition of Antiquity Magazine 2016, it stated that a series of radiocarbon dates were found on the site next to a 4m long monolith (ready for transportation) made of a rock which was microscopically identified as the same bluestone as the rocks that surround the existing Stonehenge site. Moreover, the report’s authors had decided that just two random sample dates (the two closest to their own well-publicised hypothesis on Stonehenge's construction date) would be headlined and advertised to the mass media.

Shallow topography, geoid high and intense volcanism
in the northern Mid Atlantic Ridge are interpreted as
enhanced by the loading on the adjacent continents by ice
caps during upper Cenozoic glaciations. The load of ice
packs on the continental lithospheres of North America and
northern Europe generated radial mantle flow at depth. In
our model, these currents, where flowing from west and
east, faced each other below the northern Atlantic, joining
together and upwelling. Numerical modeling of this process
supports the development of dynamic topography leading to
uplift of the sea-floor and inducing a regional geoid high.
The upper mantle, being pumped from the deep mantle and
rising to a few km shallower than average, may have
contributed to larger asthenospheric melting, and to ridge
centered excess magmatism, as observed in the Northern
Atlantic.