【摘要】 作为胶结物或交代自生矿物,片钠铝石（分子式为NaAlCO₃（OH）₂）大量发育于海拉尔盆地乌尔逊凹陷下白垩统南屯组、大磨拐河组砂岩中。根据片钠铝石稳定同位素组成,探讨了片钠铝石中碳的来源。片钠铝石的δ¹³C分布连续,其范围为-5.253‰～-1.210‰（PDB）,δ¹⁸O分布范围为-24.896‰～-20.960‰（PDB）,考虑到海拉尔盆地探井中未钻遇碳酸盐地层,片钠铝石属岩浆成因碳酸盐范畴。结合与片钠铝石平衡的CO₂的δ¹³C值,含片钠铝石井和幔源CO₂气井分布相吻合且位于燕山期花岗岩或附近的深大断裂带上,认为海拉尔盆地乌尔逊凹陷岩浆活动-砂岩成岩（片钠铝石形成）-幔源CO₂气成藏不论在物质成分上还是在时空上均具备较好的耦合关系,形成片钠铝石所需的CO₂气为与燕山期岩浆作用有关的幔源CO₂气,深大断裂是深部CO₂气向上运移到浅部砂岩的主要通道,片钠铝石形成时因油气充注而介入少量生物成因碳。更多还原

【Abstract】 Dasonite,NaAlCO₃（OH）₂,is widespread as a cement and replacement in sandstone from Nantun Formation and Damoguaihe Formation of the lower Cretaceous in Wuerxun sag,Hailaer basin.The origin of the carbon in dawsonite is studied by stable isotope composition.Dawsoniteδ¹³C（PDB）values range from-5.253‰to-1.210‰and are remarkably consistent.δ¹⁸O（PDB）values range from-24.896‰to-20.960‰.These values indicate magmatic source for carbon in the dawsonite in the view of the fact that carbonate rock is not available in all exploratory well in Hailaer basin.It can be concluded that the coupling between magma activity,diagenesis of sandstone（including the form of dasonite）and CO₂ gas reservoir is fine either in composition or in space-time according to the calculatedδ¹³C values of CO₂ gas in isotope equilibrium with dawsonite and the coincidence of dawsonite- containing well and CO₂ gas well,lying along deep fracture within or adjacent to granite during Stage of Yanshan.Consequently, CO₂ gas forming dawsonite is derived from mantle related to magmatic process during Stage of Yanshan.And deep fracture is main channel transporting CO₂ gas from the deep to shallow sandstone.A little biologic origin carbon owing to petroleum charging intervened when dawsonite formed.更多还原