The phrase "a pit of lava" is correct and usable in written English.
It can be used in contexts related to geology, fantasy, or descriptions of dangerous environments.
Example: "The adventurers stood at the edge of a pit of lava, feeling the intense heat radiating from its molten surface."
Alternatives: "a pool of lava" or "a lava pit".
While hanging upside down over a pit of lava.
Remove the floor from underneath their feet and let them fall into a pit of lava.
Sonic then disposes of the lamp in a pit of lava in a previously explored level.
When Sonic, Amy and Tails fall into a pit of lava, they are saved by a giant ring which transports them to a different location.
di Piazza pieces together a nose, mouth, and face from things like the side of a mountain, a cloud of fog, or a pit of lava.
For scenes where Kirk and Kruge battle at a precipice over a pit of lava, the shot combined animated lava, clouds (really cotton daubs on black), lightning, and a matte painting.
As a monument to the volcanic mountains that surround the city, dozens of gigantic cement mini-pyramids ring a pit of solidified lava to create a rock garden in which people can hike or climb the walls.
He and Virgil pass by a pit of boiling lava, where demons are pushing screaming souls back into the flaming goo with pitchforks.
To save others, she voluntarily falls in crucifix formation into a pit of molten lava.
Kids will spend timeless hours constructing elaborate, imaginative courses on which to test themselves: A plank of wood and two buckets become a rope bridge over a pit of hot lava; a swing set becomes jungle vines high above angry headhunters; an overturned folding table is the impenetrable wall of Attila the Hun's fortress.
When the young men reach a distant alternate world, they inadvertently tap into an alternate form of energy, a sort of explosively biomorphic geology that opens a pit of monstrous green lava and engulfs Victor.
