GEOLOGY AND UTILIZATION OF YANGXIN FORMATION LIMESTONE IN LONGMENSHAN AREA, SICHUAN PROVINCE

The limestone of Yangxin Formation, Permian, is 240-350 m thick with the strike extension more than 50 km, exposed area over 15 km² and abundant resource reserves. The resources is 51.93 Mt within a 0.6 km² range of the study area. In terms of the main chemical composition content in Yangxin Formation limestone, CaO is 49.87%-55.74%, MgO 0.24%-2.80%, SiO₂ 0.38%-5.80%, SO₃ 0.01%-0.40%, and K₂O+Na₂O 0.02%-0.12%, which all meet the requirements of grade-I material for cement. The saturated compressive strength of 41.6-82.4 MPa, firmness of 1%-3% and crushing index of 8.2%-9.6% all reach the required indexes of building stone. The analysis and evaluation on the geological characteristics and physical-chemical indexes of Yangxin Formation limestone show that it can be widely used in cement, building stone and other fields, and has important economic value and significance.