These are often marked by uplift and volcanic mountain belts on the continental plate.
Before the accretion of the island arc took place, subduction between a continental plate and presumably an oceanic plate was taking place.
This process is uncommon because the denser oceanic lithosphere usually subducts underneath the less dense continental plate.
These deposits offshore were then pushed into the continental plate as a forearc basin rotating slowly over millions of years.
An oceanic plate ordinarily slides underneath a continental plate; this often creates an orogenic zone with many volcanoes and earthquakes.
For the icehouse climate, tectonic activity also creates mountains, which are produced by one continental plate colliding with another one and continuing forward.
So the trench retreated oceanwards, and the old trench and ocean floor become part of the continental plate.
Orogens or orogenic belts develop while a continental plate is crumpled and is pushed upwards to form mountain ranges, and involve a great range of geological processes collectively called orogenesis.
