treasure trove

an abundant source the ancient city, having been almost perfectly preserved under volcanic ash for nearly 2,000 years, is proving to be a treasure trove of archaeological information Synonyms argosy, cornucopia, gold mine, mother lode, mine, wellspringRelated Words armory, repository, stockpot, store, storehouse, treasure-house; cache, hoard, stash; bonanza, Golconda, gravy train, honeypotNear Antonyms black hole, sinkhole