1 : a collection of valuable things (such as gold and silver coins or jewels) found in a place where it was hidden, buried, etc.
Divers found a treasure trove of gold and silver in the wreckage of a ship that sank hundreds of years ago.
2 : a source or collection of valuable things — usually + of
The area is a treasure trove of fossils. [=the area has a very large number of fossils]
The book is a treasure trove of useful information.