Haobugao Sn deposit, Bairin Left Banner, Chifeng (Ulanhad) League, Inner Mongolia Autonomous Region, China

Large-sized Sn skarn deposit, located in the NW limb of the northern part of the Huanggang-Ganzhuermiao anticlinorium. The orebodies occur in the contact zone between the Haobugao granitic intrusive and rocks of the early Permian Dashizhai Formation. The main controlling structures for the deposit and the granitic intrusive are NE-striking fracture zones. There are three episodes of late Yanshannian igneous intrusions: (1) a first stage of porphyroid biotite-amphibole adamellite (Xiaohanshan granite); (2) a second stage of biotite moyite (Wulanba and Wulanchulute granite); and (3) a third stage of granite porphyry (Haobugao granite). Wallrock alteration is dominated by skarn. Locally, silica, beresite, epidote, and chlorite alterations occur.

Ref.:
- http://wrgis.wr.usgs.gov/open-file/of03-220/DATABASE/lode_deposits.txt