Obsidian travels – in the Old World as much as the New World [North America]. It was traded over long distances as it produced a sharp edge ideal for cutting – and was even used for shaving hairs on the face. See https://phys.org/news/2021-06-underwater-site-team-year-old-stone.html …. this concerns the discovery, beneath the waters of Lake Huron, of obsidian flakes – with an origin in Oregon. The artifacts have been dated around 9000 years ago and we are old water levels, at that time, were much lower. Stone walls and hunting blinds have been found 100 feet below the modern surface – representing sea level at that time. One cannot but note that the 6200BC event occurred just 800 years after the date assigned to the obsidian flakes – and may well explain their location under the water. We also know that nearby Niagara Falls was set in motion, or came back on stream, around 8000 years ago. Previously, water was mainly channelled down the St Lawrence valley out into the ocean but after the 6200BC event it was diverted southwards – and the rocks that comprise the falls were thereafter eroded away, backwards. In Indonesia, Sunda Land was drowned, and parts of the continental shelf around Australia. In NW Europe large areas of the continental shelf were submerged – including the southern North Sea basin, the Solent valley, and land off NW Ireland -and many other places not fully explored. It also marks the opening of the Bosporus – even perhaps a greater movement of Atlantic water into the Mediterranean. None of this has been properly studied as it has been assumed to mark a period of rising levels as a result of warm temperatures. However, the Mid Holocene Warm Period came on the heels of the 6200BC event – not prior to it. This involved an extension of the tree line northwards into the tundra and upwards in mountainous areas. Some scientists have speculated it involved a small tilt at the axis of rotation. That would explain the phenomena quite well – but the idea the poles can move or tilt is anathema to mainstream [purely for idealogical reasons}. The problem for the mainstream theory is that rising sea levels, rapidly, at 8000 years ago, requires a lot of ice melt – from somewhere. This is a problem as the Boreal period preceding the 6200BC event is now considered to have been warm – and not as cool as previously allowed. In other words, how much ice was available to melt?