广西栗木水溪庙矿区隐伏花岗岩地表喷气晕研究

THE SURFACE EXHALATION HALO OF HIDDEN GRANITE IN SHUIXIMIAO AREA OF LIMU DISTRICT,GUANGXI PROVINCE

对广西栗木水溪庙矿区灰岩地层的地球化学剖面研究表明,受隐伏花岗岩侵入的喷气作用影响,F,Li,Rb的质量分数在地表灰岩中显著增高。在隐伏花岗岩岩脊(隆)部位之上,上覆灰岩在地表F,Li,Rb的质量分数达到峰值;在距离隐伏岩脊(隆)较远的位置,则含量明显下降,或没有异常反映。由此揭示,碳酸盐围岩中的喷气晕强度与下伏花岗岩顶面的隐伏深度有关,隐伏深度越小,喷气晕越强。F和Li的向上穿透厚度较大,约达600 m;而铷约为300 m。剖面中W,Sn,Nb,Ta等成矿元素的原生晕并不发育。但F Li喷气晕作为一种外带原生地球化学异常,对预测碳酸盐地层之下的隐伏花岗岩体及其岩脊(隆)有较好的指示效果。

The studies of geochemical section in limestone formation of Shuiximiao area, Limu district show that the contents of F, Li and Rb in surfacial limestone increased significantly due to influence of exhalation of the blind granitic intrusion undeneath. Contents of F, Li and Rb in the limestone directly overlying the blind granite ridge/hump reach the peak value. Where is further away the blind granite ridge/ hump contents of these elements declined sharply or have no reflections of anomaly. This reveals that the intensity of exhalation halo in the overlying carbonate rock is related to the depth of hidden granite＇s top, the shallower, the stronger the exhalation halo is. The exhalation halo of F and Li can penetrate a thick- ness of about 600m upward, and Rb can only penetrate a thickness of about 300m or so. Whereas, the primary halos of ore-forming elements W-Sn-Nb-Ta in the section are not developed very well. Therefore, as external primary geochemical anomalies, the exhalation halos of F and Li have good effect in predicting hidden granite and its ridge/hump underlying the carbonate rocks.