I got an Owl to look at my camera, once... and he was not impressed:

It says they melted basalt, so that's your rock type right there. Average temperature of molten basalt is roughly 1100 degrees C. The volcanism seen in Hawaii is generally basaltic lava flows; you can look on youtube for videos of Hawaiian lava flows entering the ocean to get an idea of what happens when lava meets…

Moar! Moar!

"Great Scott [of the Antarctic!]"

"Great Scott [of the Antarctic]!"