On the Outer Planes, one cannot access the Inner, and so cannot call upon the power of true elements. However, spells such as fireball or cone of cold still function. And more surprisingly, one can even seemingly call forth elementals themselves. This conundrum confuses some newly-arrived arcanists, but the answer is in fact fairly simple.
Such spells when cast on the Outer Planes don't call forth true elements, but rather pseudoelements; the same as those that make up the Outer Planes themselves. And those that under normal conditions conjure elementals, on the Outer Planes call forth pseudoelementals. These creatures on the surface appear as traditional elementals. However, they are imbued with the base nature if the plane on which they have been conjured, their sentience brought forth as a portion of their source plane. Depending how far the plane is from the conjurer, the pseudoelemental may be even more eager and loyal than usual, or may twist every command to their own whims, seeking at every moment to go against or even harm they who brought them to existence.