3. A minimal volume of 5 ml of a pooled BAL sample is needed for BAL cellular analysis. The optimal volume is 10 to 20 ml. It is acceptable to pool all aliquots of the retrieved BAL ï¬uid for routine analyses (including the ï¬rst retrieved aliquot). 4. BAL cell differential counts with greater than 15% lym-
So when a continent meets a continent, no subduction occurs (instead, the plates collide and thicken). True subduction happens only to oceanic lithosphere. When oceanic lithosphere meets continental lithosphere, the continent always stays on top while the oceanic plate subducts.
Transform boundaries, where plates slide alongside each other. A subduction zone is something that happens only with convergent boundaries. Subduction is where, after colliding, one plate sinks below the other. And a subduction zone is the area where two plates are sandwiched on top of each other, like a tectonic BLT. Features & Location of Subduction Zones. Subduction zones are places of high activity.