英wikiより
If El Dorado.png El Dorado is enabled, if a colonial nation has gold producing provinces, it will accumulate all of the gold in a 'treasure fleet counter' and every once in a while, once the meter fills up,
it will send a treasure fleet, providing the overlord with a large sum of money (and inflation), but only as long as the overlord's home trade port is downstream from the colony's.
If the overlord's home trade port is not located downstream from the colony's, then the colonial nation will keep the gold (and any income gained from it) and simply tariffs on it normally.

エルドラドが必要で植民地国家が金山を持ってなきゃいけなくてさらに宗主国のメイン交易ノードが植民地国家の下流になければならない