溧水地区锶矿地质特征及找矿方向

GEOLOGY AND PROSPECTING OF STRONTIUM DEPOSIT IN LISHUI DISTRICT

本文系统地介绍了近年来发现的几个锶(钡)矿点产出地质条件,并对各矿床的地质特征进行了对比研究,提出了东西两个成矿单元的新认识,进一步指出了今后的找矿方向。

The stratigraphic sequence under volcanic cover in Lishui area is composed of the Triassic and Jurassic sandstone.The volcanic cover is composed of the Late Jurassic-Early Cretaceous in- termidiate-acidic crystal fragment tuff.There also developes many faults in the mine.The crystal tuff mostly locates in the upper plate of the fault.There has found 5 strontium deposits in which the Aijingshan deposit is the largest one in the whole country.Alteration and Kata-rocks are distr. ibuted along the faults which is seveal tens meters wide.The main alteration is kaolinization. The ore-bearing rock is crystal tuff of the third member of Longwangshan Formation which consists of 50 per cent feldspar and has been altered to kaolinite,sericite etc.The deposit are stric- tly controlled by two main trending faults and rock types.The mineral composition of ore is sing- le celestine. In various rock types of the mine,the content of strontium in crystal tuff of Lon- gwangshan Formation is highest reaching 910ppm.So,the author considers that the s ontium in the deposit mainly comes from crystal tuff.During the Late Yanshanian stage,the strong volcanic eruption resulted in very thick and wide origin rock:feldspar-rich crystal tuff and andesite.In the end of Longwangshan cycle,the volcanic eruption stopped but the volcanic hydratherm solution continuously acted on the formed rock and resulted in the active transformation of strontium.In the other hand,the fault is the favourable conduit for sulfur-rich hydrothermal solution upward maching which infitrating and diffusing in kata-rocks,so that the wall rock has bee deeply altered to form wide distributed kaolinization.