When the world froze, it's climate system didn't stop. Equatorial ice sublimated at a rapid rate (like equatorial ice on Mars, but faster due to more sun and a denser atmosphere to transport water vapour - There's a 2004 paper by Jim Kasting that I need to read). Anyway, snow fell inland in the cold (high) areas and continental icacaps built-up to a global avarage of ~ 3km - that's like Antarctica, but everywhere!

In response, sea level fell by around 1500m. There are complecities due to ice sheet loading of the continents - isostacy and UNloading of the ocean basins, but in practice, areas near the margins of Continents would experience ~ 600m+ sea level fall.

Paul Hoffman sees this - glacial deposits onm top of deep water sediments, while the adjacent shelf is scraped bare, then, when the glaciation begins to end, shallow water sediments ("Cap Carbonates" on top of the glacial deposits, and these shallow-water deposits climb back up the continental margin as the sea rises.

These cap carbonates are crazy things. They accumulate 50-80m thichkness in what appears to be a few thousand years at any one location, as the sea rises. Looks like they're almost a direct chemical precipitate from the deep seawater that is degassing CO2. (But I bet there were bugs in there, "helping").

What a wierd world...