Posted: Oct 23, 2019 11:22 pm
I want to know where a kilometer or more of sediments came from.
Glaciers move massive amounts of sediments around - a strong up thrust of new mountain building will see huge amounts of material carried into river valleys....this can also occur underwater and then be upthrust.
https://www.britannica.com/science/marine-sediment
Arctic: Geology
…have been long periods of marine sedimentation, and consequently the shields are partly buried. In some areas thick sediments were subsequently folded, thus producing mountains, many of which have since been destroyed by erosion. Two main orogenies (mountain-building periods) have been recognized in the Arctic. In Paleozoic times