Occurring at the boundaries of plates of varying density, FTP, name these geologic regions where the oceanic lithosphere descends into the mantle.
Intense friction occurs at these sites, producing scrapings of material called melange that pile up into accretionary complexes.  Other features usually present include forearc and backarc basins, deep ocean trenches, and arcs of volcanic islands.  Occurring at the boundaries of plates of varying density, FTP, name these geologic regions where the oceanic lithosphere descends into the mantle.
Intense friction occurs at these sites, producing scrapings of material called melange that pile up into accretionary complexes.  
subduction zone