The subsidence of vast landmasses

There has apparently been a vast subsidence of landmasses in many parts of the globe about 11,500 years ago. The following are extracts from Allan& Delair’s ‘Cataclysm.’

“… a radically different disposition of land and water evidently existed until Phaeton’s visit. Large continental landmasses such as Fennoscandia, Appalachia, Beringia, Tyrrhenia and others in the southern hemisphere, existed in regions presently occupied by oceans now often miles deep. Their combined weight was stupendous and its redistribution through crustal collapses catastrophic.”

“… many of these changes occurred around 11,500 years ago at the onset of the Younger Dryas episode …” (when an ice age allegedly occurred).

Appalachia – “… a continental landmass in the North Atlantic, also known as North Atlantis. Now reposing some two miles (3.2km) below the level of the two adjacent continental shelves. Appalachia connected Europe and North America via Greenland and Iceland.” “These crustal … collapses … occurred synchronously with the break-up and drowning of the greater part of Fennoscandia, a now submerged northern landmass formerly connecting Spitzbergen with northern Eurasia.”

“Leaving the Atlantic for the Indian Ocean, we find in the latter interesting evidence for the geologically recent submergence of another extensive landmass or series of large islands which Wallace called the great Southern Continent.”

The Polynesian Islands “… are not volcanic eruptions of the sea floor … but the remains of a great Pacific continent, which was in early times connected with other continental masses.” (Lemuria?)

As well, “These changes extended even to the northernmost Pacific, when a continent-sized landmass, occupying the whole of the Bering Straits and the ocean floor immediately south of it, floundered … The scale of the subsidence … particularly along the eastern coastline of the Kamchatka peninsula, was spectacular. Science knows this sunken land as Beringia.”

Where were the offsetting uplifts of the crust of Earth?