"found a treasure" is correct and usable in written English.
You can use it when you want to explain that something of great value or importance was discovered. For example: "While exploring the ancient ruins, the archaeology team found a treasure trove of artifacts."
I too found a treasure today after an hour of sweaty searching.
Where Arbus found a treasure trove of humanity in New York's parks, Ms. Dijkstra's subjects gaze politely into the camera.
Traveling no farther afield than the museum's back yard, Bob Braine found a treasure trove of plant life that represents botanical migration.
I found a treasure trove, an article from Proceedings of the Royal Society, Biology, from 2006 that makes even bigger assumptions: that cat parasite affects human culture.
A recent survey of the museum's Japanese metalwork found a treasure that was hidden in plain sight: a copper bell by Unno Moritoshi, an important metal worker of the late 19th century.
In the computer, the agents found "a treasure trove of fraud and hacking material," including files containing 1,200 credit card numbers and bookmarked Web sites pertaining to theft of identity, the prosecutor, Mr. Etra, said in court.
He found a treasure-trove of five-gallon soda kegs, big enough to hold about 25 bottles of wine each, no longer used by the bottlers, who had turned to bag-in-box containers.
They were supposed to use the clues to find a treasure hidden somewhere in the museum.
Singers, singing actors and enterprising opera directors will find a treasure trove waiting for them.
And it recognises how children can find a treasure and a joy in ordinary things.
Scrolling back through its twitter stream you'll find a treasure trove of tweets along a similar vein.
