Features of micro-fabric and the genetic study of Triassic deep polyhalite in the Guang'an area, central Sichuan Basin

摘要

It is an accepted fact that the main solid phase support for potassium in the Sichuan Basin is polyhalite [K2MgCa2(SO4)4·2H2O] rather than sylvineis (KCl) (Gong DX et al.,2015).The mineral types,occurrence characteristics and metasomatism of the polyhalite bearing ore-bed were identified and the origin of the polyhalite was discussed.The polyhalite samples were obtained from the core of Z12,located in Dalong Village,Guang'an City of central Sichuan.The sampling depths were 2974 m (s-1),3023 m (s-2) and 3106 m (s-3).The microbeam analysis of back-scattering images was carried out using a Shimadzu EPMA-1720 Series electron probe micro-analyzer,supplemented by a quantitative spectrum analysis that determined the mineral types.