宣龙地区中元古代铁岩建造成因探讨

The Discussion on the Genesis of Middle Proterozoic Ironstone Formation Xuanlong Area

“宣龙式”铁岩建造是中元古代早期形成的肾状，鲕状铁岩建造，它属于地球上较早的铁岩建造。铁的物质来源是大陆风化壳上的铁质，以氢氧化铁胶体形式搬运至内陆海中。肾状铁岩（叠层石）在生物和胶体化学共同作用下形成于滩后低能带；

癤uanlong Style” ironstone formation is an Early middle proterozoic reniform ironstone and oolitic ironstone formation which is one of the earliest ironstone discovered on the earth.The iron source derived from the heavily weathered crust is transported into the Xuanlong in land sea in the form of iron hydroxide colloid.The reniform ironstone (stromatolithic) is formed behind the high energy shollow band under the biologic and colloid chemical processes;the oolitic ironstone was formed on the high energy shollow band under the mechanic agitation and colloid chemistry.