a place that has very large supplies of a mineral or other natural resource

The Pacific Northwest has been the motherlode of the nation's aluminum output for 60 years. 太平洋西北60多年来一直是这个国家铝矿的主产地。

Cairn Energy recently struck the motherlode of oil fields in India. 卡恩能源最近在印度的油田找到了产油层。

something that supplies a very large amount of a thing, quality, etc. that you want

The flight data recorder had documented about 200 pieces of information, a motherlode for crash investigators. 飞行记录仪存贮了200条信息，是飞行事故调查员的主要信息来源。

With this market, vintage clothes shoppers have hit the motherlode. 有了这个市场，买旧款服装的人算是找到了好地方。