【摘要】 黔北务正道地区铝土矿矿床属古风化壳沉积型,成矿母岩具多源性,但主要来源于下覆的中下志留统韩家店组。本文依据Grant提出的质量平衡方程和图解法,对瓦厂坪矿床在成矿过程中元素迁移的富集、贫化(亏损)规律进行了定量研究。结果表明,主要成矿母岩韩家店组砂、页岩→中间产物铝土质页岩、粘土岩是主要元素Al2O3、TiO2显著富集,而SiO2、Fe2O3、MgO、CaO和K2O明显亏损的过程,也是铝质富集的重要阶段;铝土质页岩→致密块状铝土矿形成时,主要元素Fe2O3、MnO、MgO、CaO、K2O明显富集,Al2O3弱富集,SiO2、Na2O亏损;次生作用使铝土矿石中Al2O3、TiO2、MgO进一步富集;微量元素在铝土矿形成过程中总体表现出惰性元素逐步富集,活泼元素逐渐亏损,反映风化、迁移、再富集成矿的特点。更多还原

【Abstract】 The bauxite deposits in the Wuchuan-Zhengan-Daozhen area of northern Guizhou Province are of the sedimentary paleo-weathered crust type.The host rocks are mainly from the underlying middle and lower Silurian Hanjiadian Formation and other sources.Based on the mass balance equation and graphic methods proposed by Grant,element enrichment and dilution rules of element migration in the ore-forming process in the Wachangping bauxite deposit were quantitatively investigated.The results show that during the conversion of Hanjiadian Fm.sandstone and shale as host rocks to the intermediate product bauxitic shale,which was an important stage of aluminous enrichment,the bauxite was markedly depleted in SiO2,Fe2O3 ,MgO ,CaO and K2O,while the major elements of Al2O3 and TiO2 were significantly enriched.In the conversion process of bauxitic shale to dense and compact bauxites,major elements of Fe2O3,MnO,MgO,CaO,and K2O were markedly enriched,while enrichment of Al2O3 was weak,and SiO2 and Na2O were depleted.The compounds of Al2O3,TiO2,and MgO were enriched furthermore by the effects of secondary action.During the bauxite ore-forming process,inert elements were enriched markedly,while the active elements were reduced gradually.All these reflect the characteristics of weathering,migration and then enrichment and mineralization.更多还原