We didn't understand much about the film, but we did work out that some super intelligent extraterrestrial planted monoliths all over the place to monitor the progress of humans on earth. One was buried on the moon and when humans finally made it to the moon and uncovered the monolith, a beam shot out from it to the extraterrestrials' planet to let them know that humans were comming along.
Our momolith is planted on a moon scape formed by extreme gold mining over 130 years ago. We won't promise you that a beam will be released to Jupitor, but you can just make believe and make the appropriate noises.
The cache is a flat plastic click container and there is no need to climb into the erosion areas.