At the mouth of the river, or where the river's velocity slows too much to carry the sediments.
Tectonic plate movement is run by convection of mantle currents.
Basalt,It Also Makes Up A Large Component Of Earth & Moon Rocks,Forming From Solidified Lava,& Is Made Up Of The Minerals Pyroxene & Plagioclase Fieldspar,Sometimes With A Bit Of Olvine.
