个旧锡矿闻名于世,但个旧锡矿床有哪些种类?它们又是怎样形成的?知道的人就不多了。这个问题还得从21000万年前说起,那时,个旧、开远、建水一带是一个海湾,这个海湾呈东北—南西方向延伸,长约150公里,宽约90公里左右。它的西面是用滇占陆,南面是哀牢山占陆,南东面是越北占陆。在这个海湾里沉积了厚度达1500—4200米的碳酸盐类的石灰岩、白云岩为主的沉积物,这在地史学上 Gejiu Tin Mine is famous all over the world, but what are the Gejiu Tin deposits? How are they formed? There are not many people who know it. This issue has to be mentioned from 210 million years ago. At that time, Gejiu, Kaiyuan and Jianshui areas were a bay stretching from northeast to southwest, about 150 kilometers long and about 90 kilometers wide. Its west is occupied by the land of Yunnan, the Ailao Mountains occupy the land to the south, the south east is the land of Vietnam. Sedimentary limestone and dolomite-based sediments of 1500 to 4200 meters in thickness are deposited in this bay, historically