a wealth of = a large amount of 一般接不可数名词
表示“大量”“众多”“丰富”等,可连用不定冠词,尤其用于a wealth of结构（其后可接可数名词或不可数名词）.
如：
He sent me a book with a wealth of illustrations. 他送给我一本有大量插图的书.
Hidden underground is a wealth of gold, silver, copper, lead and zinc. 地下埋藏了大量的金、银、铜、铅和锌.
