The People of the Crater by Andre Norton

An air force pilot adrift in peacetime is recruited to join an Antarctic expedition. When a strange mist downs his plane he discovers an ancient alien civilization which has prophesized his arrival.
Now he and his faithful pet Ana must descend to the depths of the crater and face the Black Ones in order to rescue the fair Thrala, daughter of the Ancient Ones.
The People of the Crater was first published in volume 1 number 1 of Fantasy Book in 1947.
Total Running Time (TRT): 1 hour, 35 min. Reading by Gregg Margarite.
Andre Alice Norton (1912-2005) was an American writer of science fiction and fantasy with some works of historical fiction and contemporary fiction. She wrote primarily under the pen name Andre Norton, but also under Andrew North and Allen Weston. She was the first woman to be Gandalf Grand Master of Fantasy, first to be SFWA Grand Master, and first inducted by the Science Fiction and Fantasy Hall of Fame. In 2005, the Science Fiction and Fantasy Writers of America, announced the creation of the Andre Norton Award, to be given each year for an outstanding work of fantasy or science fiction for the young adult literature market.