1977 Volume 27 Issue 142 Pages 143-154
The Gran Bretaña Mine is located about 140 kilometers to the east of Lima, Central Peru, and has been developed since 1960 as a high grade zinc mine in the central Andes poly-metalliferous zone. The rock units in the mining field consist of sedimentary formations ranging from Early Jurassic to Early Tertiary in age and intrusive rocks of Miocene or Pliocene age. Azulcocha deposit, a major one of the ore deposits of the Gran Bretaña Mine, consists of two orebodies. The one is zinc orebody consisting of mainly sphalerite with minor pyrite, barite and arsenic minerals, and the another one is manganese orebody. The deposit is situated along the Gran Bretaña reverse fault with E-W trend, and is interpreted to be formed as low temperature replacement deposit in limestone bed of Pucara Group of Jurassic age. Geological factors controlling ore deposits are concluded to be as follows:
1) Azulcocha deposit is situated in the outer zone of the mineral zonation which surrounds Chuquipite granodiorite intrusive. Relationship between mineralization and intrusives of Miocene or Pliocene age is observed in the mining field.
2) A large number of known orebodies in the mining field are located in the favorable limestone beds of Pucará Group and Middle Cercapuquio Formation of Jurassic age.
Stream sediment geochemical survey and I.P. geophysical survey were carried out in the mine area. As a result, it is concluded that both methods are useful.
